Disease Dilemmas

Question 1

What is a disease?

Answer 1

A disorder of structure or function in a human, animal, or plant, especially one that produces specific symptoms or that affects a specific location and is not simply a direct result of physical injury

Question 2

How can disease be classified?

Answer 2

Infections and non-infectious
Contagious and non-contagious
Communicable and non-communicable
Epidemic, endemic and pandemic

Question 3

How is an infectious disease transmitted and what is its cause and what are some examples?

Answer 3

Spread by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi.
Infected by a microbe, most (but not all) infectious diseases are also contagious
Examples: influenza, pneumonia, malaria, TB, HIV/AIDS, polio, yellow fever, measles, cholera, zika virus, dengue fever and tetanus.

Question 4

What is a non-infectious disease, how is it caused and what are some examples?

Answer 4

Diseases that cannot be spread by pathogenic microorganisms (also non-communicable).
Caused by diet, environment, lifestyle, age, gender and inherited genetics.
Examples: asthma, diabetes, cancer, stroke, cystic fibrosis.

Question 5

What are communicable diseases, how are they transmitted and what are some examples?

Answer 5

They are infectious diseases which spread from host to host. Pathogens are passed from person to person or from animal to person (zoonotic disease). They can be transmitted to humans by animals directly (contact), indirectly (in an area where that animal roams) or by a vector (any agent that carries and transmits and infectious pathogen into another living organism).
Examples:
person-to-person - measles, common cold, ebola, influenza, polio, hepatits, TB, HIV/AIDS
animal-to-human - lyme disease
vectors - mosquitoes, worms for malaria or guinea worm

Question 6

What is a non-communicable disease, how is it caused and what are some examples?

Answer 6

A medical condition or diseas that is my definition non-infectious and non-contagious as it is non-transmissible among people or other hosts.
It is due to a lack of physical activity, smoking or poor diet, exposure to air pooution, genetic defects, age and gender may increase the risk
Examples:
age - dementia, cancer, osteoporosis
lifestyle - lung cancer, skin cancer, type 2 diabetes, cardiovascular diseases
nutrient deficiencies - rickets
environmental - asthma
gene mutations - cancer

Question 7

What is a contagious disease, how is it spread and what are some examples?

Answer 7

A class of infectious diseas easily spread by direct or indirect contact between people (communicable and infectious), you can catch it from someone else through contact.
Examples:
bacterial infections - typhoid, cholera, plague, TB
viral infections - ebola, HIV, influenza, measles, rubella

Question 8

What is a non-contagious disease, and what are some examples?

Answer 8

Not spread from person to person by disease carrying organisms but caused by genetics, diet, lifestyle or environment.
Examples: sickle-cell disease, cystic fibrosis, cardivascular disease, skin cancer.

Question 9

What are the temporal and spatial changes in disease patterns?

Answer 9

Historically, communicable/contagious diseases have been the main cause of death, they remain important in LIDCs.
In ACs, medical technologies including antibiotics and vaccination have largely eliminated the most dangerous communicable diseases. Therefore, communicable diseases are now largely seen as diseases of peverty, while non-communicable diseases are associated with richer societies.
Non-communicable diseases are likely to have casues such as age, lifestyle factors, nutrient deficiencies, environmental toxins, or gene mutations.

Question 10

Where are NCDs increasing?

Answer 10

In emerging and developing countries, they kill 38 million people each year with 3/4 of deaths occur in LIDCs and EDCs. NCDs are now the biggest cause of death worldwide (73%) and while the total number of NCD deaths is highest in poorer countries, in richer countries they are responsible for a higher proportion of each country’s deaths.
Many NDCs are said to be ‘degenerative’ diseases, reflecting the growing worldwide ageing population and increasingly unhealthy lifestyles. While degenerative diseases do reflect ageing populations, lifestyle plays a big role and therefore all age groups are affected. In 2013, 16 million people under 70 died from degenerative diseases (82% of which were in LIDCs and EDCs).

Question 11

What is an endemic disease. and where can it happen?

Answer 11

These exist permanently in a geographical area or in a specific human group. The disease is not necessarily present at a high level of occurence but it can always be found in that population. Malaria is endemic in many parts of Africa, sleeping sickness is confined to rural areas in sub-Saharan Africa and caused by the bite of an infected tsetse fly, Chagas disease in Central and Southern America is caused by tiny parasites transmitted by blood-sucking insects.

Question 12

What is an epidemic, and where can it happen?

Answer 12

A disease outbreak that spreads quickly through the population of a geographical area affecting a large number of people at the same time. The Ebola epidemic in West Africa from late 2013, and a year later nearly 25,000 people had been infected, with 10,500 deaths, mainly in Liberia, Sierra Leone and Guinea.

Question 13

What is a pandemic and where can it happen?

Answer 13

Epidemic disease outbreaks that spread worldwide, when a new virus emerges for which most people do not have pre-existing immunity. H1N1 flu virus in 2009, Covid-19 in 2019, the Black Death in the 14th century and Spanish flue 1918-19

Question 14

What is prevelance?

Answer 14

The proportion of cases in a population at a given time (how widespread the disease is)

Question 15

What is incidence?

Answer 15

The occurance of new cases of a disease within a population (risk of contracting a disease)

Question 16

What is mortality?

Answer 16

The incidence of death, usually death rate per 1000 of a population

Question 17

What is morbidity?

Answer 17

The state of being diseased, an amount per 1000 of a population

Question 18

What is epidemiology?

Answer 18

The branch of medicing concerned with the incidence, distribution and possible control of disease

Question 19

What is a chronic disease?

Answer 19

Lasts 1 year or more and require ongoing medical attention or limit activities of daily living or both and are of long duraion

Question 20

What is the distribution of malaria globally?

Answer 20

Malaria is an infectioius but non-contagious disease, which is endemic is 95 countries, but there can be new epidemic outbreaks. Malaria is concentrated in Africa, Latin America and SE Asia. 3.2 billion people live in affected areas and are at risk, although malaria’s risk is greatest in the tropics - 94% of all cases and deaths in 2019 were in sub-Saharan Africa. In 2019, there were an estimated 229 million cases of malaria worldwide and an estimated number of 409, 000 deaths. However, children under the age of 5 are the nost vulnerable groups affected. The global distribution is influenced by climate factors, especially temperature but also humidity and rainfall. The anopholoes mosquito thrives in warm, humid environments, where there is stagnant water in which to lay its larvae, the parasite cannot complete its lifecycle in the female is the temperature dips below 14-18 degrees or above 40 degrees. Malaria mostly occurs in tropical areas near the equator where transmission is all year round. However, transmission cannot occur at high altitudes, areas of aridity or during a cold season (mountains, deserts). There are more than 400 different species of anapheles mosquito and around 30 are major malaria vectors. Malaria is hard to combat, especially where there are human factors such as poor sanitation, and presence of large high density populations contributing to the risk. The mosquitos are most acitve between dusk and dawn, epidemics can occur when the climate and other conditions favour transmission in areas where people have little or no immunity to marlaria or can occure when people with low immunity move into areas with intense malaria transmission to find work or as refugees. The use of insecticides, and the drainage of breeding areas, mosquito nets and education have lowered the risk. Human immunity (partial) in adults is developed over years of exposure which reduces death rates.

From 2000-2015 the global death toll has been cut in half, from 839, 000 to 438, 000. Africa is the world region that is most affected by malaria, in 2015 9 out of 10 malaria victims were on the African continent. To prevent transmission and control the vectors, use incecticude treated mosquito nets and residual spraying indoors. Sleeping under incecticide treated nets can reduce the contact between mosquitos an dhumans by provideing a physical barrier, and population wide protection can result from the killion of mosquitos on a large scale where there is high access and usage of nets in a community. In 2019, an estimated 46% of all people at risk of malaria in Africa were protected by a treated net compared to 2% in 2000. Indoor residual spraying with inseciticides is another powerful way to rapidly reduce malaria transmission, it involes spraying the inside of houses with insecticides typically once or twice a year. Diagnosis and treatment of malaria reduces disease, prevents deaths and reduces transmission. A rapid test (30mins) is now avaliable. However, drug resistance is a recurring problem and monitoring is needed.

Question 21

What is the global pattern of HIV/AIDS?

Answer 21

Human immunodeficiency virus is a communicable disease, infectious and contagious, it is classed as a pandemic.HIV impairs and destroys the function of immune cells and could lead to AIDS. It reduces natural immunity to other viruses, infections and some types of cancer. Transmission of HIV is by human bodily fluids. According to the WHO, 954, 000 people died from HIV related causes in 2017, 50% higher than malaria. The global distribution is highly uneven, there is significant variation in the prevelance but there is a high proportion of the infected adult population found in sub-Saharan Africa, but there are lower percentages of HIV affected adults in ACs, where research, diagnosis, treatment and education programmes are readily avaliable In 2019, 38 million people were living with HIV. HIV has claimed almost 33 million lives so far - an average of a million a year and 68% of adults and 53% of children living with HIV were receiving ART. In some countries, HIV is the leading cause of death. The annual number of deaths from AIDs is declining although prevelance is increasing.

Question 22

What can higher % of HIV infected adults in LIDCs be explained by?

Answer 22

Limited funding and avaliablity of drugs
Insufficient numbers of trainded medical staff especially in rural areas
High birth rates among infected women
High levels of illiteracy
However, progress is being made in some LIDCs (Malawi) due to:
Self testing for HIV where testing may not otherwise be avaliable
Anti-retroviral treatment
Elimination of mother-to-child transmission of HIV

Question 23

What is the global pattern of Tuberculosis?

Answer 23

TB is an infectious and highly contagious communicable disease, it needs many hours of contact with someone to catch it, TB is described as an epidemic. It is a bacterial infection spread by the transmission of mycobacterium tuberculosis from person to person through the air and it typically affects the lungs. Risk factors that affect its distribution include living conditions in poor communities where there is overcrowding and there are high density populations and poorly ventilated houses. Limited access to health services is an adverse factor, especially in areas affected by civil unrest or war. TB is not very common in the UK, with 5, 102 cases in 2017, but the UK has one of the highest rates in Europe, mainly amongst immigrant populations. Incidence of TB is worldwide, although 2/3rds of the total are in 8 countries; India, China, Philippines, Pakistan, Nigeria, Bangladesh and South Africa. 1.4 million people died from TB in 2019, and in 2013 there were nearly 9 million cases worldwide, but TB is curable and preventable. TB is present in all regions, 25% of people have an infections and have a 5-15% lifetime risk of falling ill with it. Those with compromised immune systems, malnutrition, diabetes or smokers have higher risk of falling ill. TB is preventable in 30 countries, and worldwide it is the leading cause of death from a single infectious agent (above HIV/AIDS and malaria). 95% of deaths are in LIDCs and EDCs. Sub-Saharan Africa has the highest death rates by far with a large % amongst HIV/AIDS sufferers. Death rates from TB in 2018 out of 100, 0000: 200 in Lesotho, 169 in Central African Republic, 145 in Mozamique and 126 in Namibia. Outside Africa, TB rates are also high in Asia, particularly Myanmar (46 per 100, 000), Indonesia (37), India (33) and Afghanistan (29). People who are infected with HIV are 18 times more likely to develop TB, there were 0.4 million TB deaths among people with HIV in 2015.

Globally, TB incidence is falling by 2% a year. TB is treatable and curable but drug resistant strains can appear due to inadequate treatment, rapid tests are avaliable. It was hoped that with the invention of the BCG vaccine and medicines it would be possible to wipe out TB in the same way that smallpox has been eradicated. Although this is difficult because of:
initial improvement in TB rates in ACs was related to improvements in housing, nutrition and access to treatment, but theres issues are present in man countries that are less developed.
diagnosis TB is children is difficult (mild symptoms).
several strains of TB bacteria have developed resistance to one or more anti-TB medications, making them harder to treat.
the BCG vaccination is effecive against severe forms of the disease, such as TB meningitus in children, but is not efffective against all forms.
the global epidemic of HIV (begun 1980s) has lead to a corresponding epidemic of TB cases because HIV weakens a persons immune system.
the rapid growth of international travel has helped the infection to spread.

Question 24

What is the global pattern of Diabetes?

Answer 24

Diabetes is a non-communicable disease caused by a defucuency of insulin, a hormone secreted by the pancreas, diabetes can lead to heart, blood vessel, eye, kidney and nerve damage. Diabetes was the 17th leading cause of death in 2016 worldwide. Global deaths linked to diabetes increased from 0.61 million in 1990 to 3.8 million in 2017, more people die from diabetes than from TB, malaria and HIV combined. Type-1 diabetes is the result of the body’s deficieny in insulin production, this can develop at any age but often begins in childhood, it is thought to be genetic and not related to diet or lifestyle. Type-2 diabetes is the result of the body’s ineffective use on indulin, approximately 90% of people with diabetes have type 2. The main risk factors for type-2 diabetes are excess body weight, physical inactivity, age, smoking and poor diet. In 2014, there were 422 million people living with diabetes, the majority living in low and middle income countries. 1.6 million deaths are directly attributed to diabetes each year, adults with diabetes have a 2 to 3 fold increased risk of heart attacks and strokes. The disease is widespread in ACs and EDCs and some LIDCs, but there is significant variation. Prevalence is high in North America and in east and SE Asia, and lower in most of Central Africa, Central America and Nordic countries. We tend to view diabetes as a ‘rich world’ disease but the number of type-2 diabetes cases is rising more rapidly in low and middle income countries, in both children and adults. This is largely due to higher life expectancies, the control of infectious diseases, changes in diet and reduction in physical activity.

The number of people with diabetes rose from 108 million in 1980 to 422 million in 2014 (quadrupled). Global prevelance amongst adults over 18 rose from 4.7% in 1980 to 8.5% in 2014. We tend to view diabetes as a wealth country disease, but poorer countries are now carrying a bigger burden, with the fastest growth rate too. Governements need to make sure healthier choices are avaliable and that can be done through legislation. Tackling obesity through education, establishing good eating habits and encouraging physical activity from an early age is important, urban planning can help, due to urbanisation it is harder to walk or cycle to school 23% of low income countries do not have good access to medication such as insulin which is a life-saving mediaction. Many people (50%) are undiagnosed, but the WHO is improving research and surveillance in order to prevent and manage diabetes. Early diagnosis can be accomplished through relatively cheap testing of blood sugar. People with type-1 diabetes require insulin, type-2 cam be treated with oral medication. In the UK there are thought to be over 4 million people affected by diabetes.

Question 25

What is the global pattern of Cardiovascular Disease?

Answer 25

Includes a range of disorders of the heart and blood vessels including coronary heart disease, stroke, hypertension and angina. These are non-communicable diseases and so cannot be passed from person to person. Globally CVDs account for 17.9 million deaths per year, and more die from CVDs worldwode than from any other cause, of which 80% of CVDs are heart attacks and strokes. Incidence rises steeply with age, CVD is a major cause of mortality and morbidity in ageing populations in high income countries, but there are many premature deaths below 70. Low and middle income countries are disproportionately affected, having 80% of all CVD deaths, mortality rates are particularly high in parts of the Middle East, Eastern Europe, South Asia and Africa when standardised by age. Premature deaths from CVD is linked to lifestyle factors, such as smoking, harmful use of alcohol, unhealthy diet and physical inactivity. Underlying causes include population ageing, poverty and hereditay factors. Low income countries and groups have less capacity to control and prevent CVDs, and in low resource settings, healthcare costs for NCDs drain houshold resources and force millions into poverty, limiting development. Rapid, unplanned urbanisation can have negative socio-economic effects, exposing children to crowded living, air and water pollution, inadequate sanitation and tobacco, alcohol and fast food, there is higher incidence where there is poor access to medical care. Poverty is closely linked with CVD, vulnerable and socially disadvantaged people get sicker and die sooner than those of higher social positions because they are at a greater risk of being exposed to unhealthy dietary practices and limited health services. Governments are encouraged to participate in the WHO’s and US CDC’s Global Heart Initiative, launched in 2016 to reduce death rates through education. As GDP per capita increases, age standardised deaths from CVDs decrease, because ACs have more capactiy to diagnose, treat and prevent CVDs.

Question 26

What is disease diffusion?

Answer 26

Diffusion is the movement of particles or molecules from an area of high concentration to an area of lower concentration. The concept of diffusion applies to science, innovations, migration and settlement, as well as the spread of disease, which is the process by which a disease spreads outwards from its geographical source.

Question 27

How will the incidence of disease be affected?

Answer 27

Affected by distance so that places closer to the source of a disease are most likely to see higher incidence.

Question 28

What is expansion diffusion?

Answer 28

Occurs when a disease spreads from its source outwards into new areas of prevelance, whilst carriers in the source area remain infected possible intensifying in the original area. Has one main node and spreads out from there but can be spread by contagious or non-contagious means. (TB)

Question 29

What is relocation diffusion?

Answer 29

Occurs when a disease leaves its source and moves into a new area. Several nodes are formes and can be spread by contagious and non-contagious means. (cholera in Haiti 2010)

Question 30

Is it common to see a mixture of disease diffusion?

Answer 30

Yes

Question 31

What is hierarchical diffusion?

Answer 31

Involes the spread of disease though an ordered sequence of classes or places, for example from large cities to remote villages. Dictates that bigger/more important places with highest conectivity are likely to be affected first. It is a form of relocation diffusion but based of a hierarchy of places. (2009 H1N1 flu virus)

Question 32

What is contagious diffusion?

Answer 32

Describes the spread of disease through direct or indirect contact with a carrier, it is strongly influenced by distance, so individuals in nearby regions have a much higher probability of contact than those in remote regions. In theory, it could take the form of expansion, relocation or hierarchical diffusion. (Ebola in West Africa 2014)

Question 33

What is the Hagerstrand model?

Answer 33

A model based on the spread of agriculture innovation in central Sweden, can be applied to spatial patterns of disease diffusion. It is probablistic rather than deterministic and as a result it produces slightly different outcomes each time it is run.
There are 4 stages to the diffusion process:
1. The primary stage: strong contrast in disease incidence between the area of outbreak and more remote areas.
2. Diffusion stage: diffusion is centrifugal - new centres of disease outbreak occur at distance from the source and this reduces the spatial contrasts of the primary stage.
3. Condensing stage: the number of new cases is more equal in all locations, irrespective of distance from the source.
4. Saturation stage: diffusion decelerates as the incidence of the disease reaches its peak.

Question 34

What three important concepts are highlighted in the Hagerstrand model?

Answer 34

1. A neighbour effect - probability of contact between a disease carrier and a non-carrier is determined by ther number of people living in each 5x5km grid square and their distance apart. Thus, people living in proximity to carriers have a greater probability of contracting a disease than those further away, this distance-decay function is assumed to be geometric in character.
2. The number of people infected - by an epidemic approximated an ‘S-shaped’ or ‘logistic’ curve over time. After a slow start, the number of infected people accelerates rapidly until eventually levelling out - as most of the susceptible population have been infected.
3. Barriers to disease - progression and diffusion of a disease may be interrupted by physical barriers.

Question 35

What are the physical barriers to diffusion?

Answer 35

1. The most important is often distance
2. High mountain ranges
3. Large maritime areas
4. Extensive areas of aridity
   2,3 and 4 keep people contained, restricting movement, with relatively small amounts of in and out migration, spread of disease in and out of these regions is less likely
5. Climate - tropical conditions?

Question 36

What are the socio-economic barriers to diffusion?

Answer 36

National government and international organisation strategies to tack communicable diseases such as:
Medical health checks at international borders and airports
Quarantine
Mass vaccination programmes
Cancelling public events
Curfews
Wearing face masks in public places
School and workplace closures
International travel controls - closing borders which can have great economic impacts that this is an extreme method
Health education programmes
Public health messages
Provision of automatic soap dispensers, toilet flushes and taps in public places

Question 37

What is the effect of globalisation on disease diffusion?

Answer 37

Increases diffusion due to more connected places although it allows for the sharing of research/education/treatment

Question 38

What is the relationship between water sources and disease prevelance?

Answer 38

Unprotected, stagnant water can often be a breeding ground for vectors of disease pathogens, and many people in LIDCs rely on surface water or water from wells for cleaning and drinking

Question 39

What is the relationship between relief and disease prevelance?

Answer 39

Inherently linked to climate, because as altitude changes so does climate; temperature and rainfall regimes affecct vectoor habitatis, on average temperatures decrease by 0.65C per 100m and relief rainfall can be triggered in upland areas, water is also more likely to collect and stagnate in valleys or lowlands.
In Ethiopia, malaria is concentrated in the humid lowlands but absent in cooler highlands: over 2000m it is too cold for P. falciparum to develop in a mosquito vector.

Question 40

How does climate affect disease prevelance?

Answer 40

Temperature, rainfall and humidity influence habitats of disease vectors.
Temperature often influences the rate of vector development and temperature often determines rate of bacterial or viral replication.
Precipitation creates aquatic habitats which allow both disease and pathogens to flourish and complete their lifecycles, monsoon season is particularly dangerous in LIDCs however too much rainfall can wash away immature vectors

Question 41

What does WHO state about vectors?

Answer 41

They are living organisms that can transmit infectious diseases between humans or from animals to humans, many of these vectors are bloodsucking insects and most transmit pathogens via their blood meals, these are often endemic in th etropic and sub-tropics due to idea physical conditions

Question 42

Which vector borne disease causes the most deaths?

Answer 42

Malaria

Question 43

What three physical factors does malaria depend on?

Answer 43

Precipitation - anapholes mosquitoes lay their eggs in water which hatch into larvae. The abundance of aquatic habitats, ideally unpolluted fresh wates, depends on the collection of water that is not flowing, such as puddles towards the end of, or just after, the rainy season, this allows them to complete their life cycles. There are around 400 types of Anapholes mosquito (30 carry malaria) and each have their own preferred aquatic habitats.

Relative humidity - where average monthly humidity is over 60%, often increased by vegetation growth, the mosquito has a better chance of survival and becomes more active.

Temperature - where average temperatures are between 18C and 40C, the mosquito takes more blood meals and increases the number of eggs laid, increasing the number of vectors. The larvae develop faster at higher temperatures, so the parasite has more time to compete its life cycles inside the mosquito.

Question 44

How do the seasons influence disease outbreaks?

Answer 44

Seasonality of temperature and rainfall regimes influences the prevalence of vector borne infectious diseases. These factors affect the time avaliable for vectors and parasites to complete their life cycles and the avaliability of suitable aquatic habitats.
Malaria outbreaks are closely linked to seasonal changes in rainfall, relatively sudden transmission of P. falciparum occurs where seasonality is most marked, such as in tropical areas that are further from the equator in Africa or following monsoonal rainfall in Asia.
Influenza in temperate latitudes of Europe and North America, epidemics tend to peak in the winter. Transmission is more efficient at lower temperatures and when relative humidity is low, and this occurs most in winter but because the north and south hemispheres have different winters, there are two peaks of flu season each year.
Sleeping sickness in the woodland savanna of west and central Africa, outbreaks occur in the wet season when the tsetse fly vector can live longer, there is a significant regression of both vector and parasite in the dry season.

Question 45

How does climate change provide conditions for emerging infectious diseases?

Answer 45

Emerging infectious diseases (EIDs) are new diseases that have emerged in the last 20 years. Either they have ot occurred in human populations before of they have occurred previously but affected only small numbers in isolated places. Outbreaks and diffusion of these diseases can result from changes in climatic conditions in which vectors survive and develop.
Global warming has had the effect of extending the geographical area in which these vector borne diseases are developing. WNV and Lyme disease are expected to spread northwards within the USA and into Canada within the 21st century. Lyme is spreading because ticks thrive in warmer conditions. High temperatures favour the transmission of WNV, now considered a global disease.
Shorter term climate changes include the impact of El Nino Southern Oscillation on rainfall and temperatures in south America especially. Effects such as higher temperatures, heavier rainfall and greater frequency of tropical cyclones and flooding have been persistent enough in some regions to create conditions from the transmission of malaria, cholera or dengue fever. Droughts can lead to a scarcity of clean drinking water or water for sanitation, leading to diahorreal disease.
Some EIDs have re-emerged in areas where conditions have been made favourable to their transmission

Question 46

What are the conditions for zoonotic infectious diseases to spread from animals to humans?

Answer 46

Zoonotic disease are caused by bacteria, viruse, parasites and fungi. Zoonotic diseases are transmitted to humans from disease reservoirs of non-human speciers through:
direct contact with animals, dog or bat bites
insect vector bites, such as mosquitoes
contaminated food or water

Question 47

What are the conditions for rabier to establish and spread form animals to humans?

Answer 47

Rabies is an infectious viral disease causing about 60, 000 deaths annually worldwide. 95% of these occur in Africa and Asia, children being the frequent victims (50% of cases). India accounts for 60% of rabies deaths in Asia and 35% of deaths globally.
Conditions:
Lack of access to immunisation after a bite; incidence is highest in remote and rural communities where vaccines are not readily available or affordable. However 29 million people worldwide recieve a post bite vaccination, preventing deaths (100% mortality rate is disease develops)
Lack of prevention measures, mainly lack of control of stray dogs, insufficient government legislation on dog licensing/behaviour/dog immunisation; many dogs are community property.
Lack of funding for vaccinating dogs against it (most cost effective strategy)
Lack of community education on dog behaviour, bite prevention and immediate care after a bite.

Question 48

What is a natural hazard?

Answer 48

A natural hazard is when a natural process puts human lives, infastructure or economic interests at risk.

Question 49

How do human activities affect natural hazards?

Answer 49

It is important to recognise that many ‘natural’ hazards have both natural and artificial components because hazards are threats of harm mainly to human systems, human activities play a large role in how severe a hazard is. The more severe the geophysical event, the more vulnerable the population, the greater the hazard. For example, when large numbers of people crowd into floodplains and low-lying areas, they are putting themselves in harm’s way, increasing the severity of potential floods.

Question 50

What is the relationship between hazards and disease?

Answer 50

Complex - we often witness major natural hazards leading to the spread of infections. However, major health epidemics are rare in the aftermath of natural hazards alone, main problems arise if:
Large numbers of the population are displaced, gathering in confined spaces
There is poor sanitation and water contamination, wells being contaminated by sewage
There is disruption to infastructure, roads for aid and immediate healthcare provision
There may be interruption of public health programmes, vaccines leading to loger term problems.
Infectious disease transmission or outbreaks may be seen days, weeks or even months after the onset of the disaster, short and long term effects

Question 51

What is the link between disease and levels of economic development?

Answer 51

Advanced countries usually have non-communicable disease prevalence vs developing countries having infectious or communicable disease prevalence

Question 52

What does the WHO state about the link between disease and development?

Answer 52

As life expectanvy increases, the major causes of death and disability in general shift from communicable, maternal and perinatal causes to chronic, non-communicable ones

Question 53

What are the temporal changes within the UK with disease and development?

Answer 53

The main causes of death in the 19th century were infectious diseases, vaccination became more effective with public health policies, clean water and improved nutrition, sanitation and housing have led to significant decline in deaths from these diseases, these now cause a very low percentage of all deaths in the 21st century. The main causes of death in the UK today are non-communicable diseases, for men the main cause is coronary heart disease, and for women between 35-49 it is breast cancer, above 80 it is dementia.

Question 54

What is the epidemiological transition?

Answer 54

A characteristic shift in the disease pattern of a population as mortality falls during the demographic transition: acute, infectious diseases are reduced, while choronic, degenerative diseases increase in prominence, causing a gradual shift in the age paterrn or mortality from younger to older ages

Question 55

Who made the epidemiological transition model and what does it show?

Answer 55

Abdel Omran, it illustrates the relationship between development and changing patterns of population age distribution, mortality, fertility, life expectancy, causes of death. Changes are driven by improvements in health care, standards of living and the quality of the environment. According to Omran, societies underfo change in three epidemological phases

Question 56

What is the demographic transition model?

Answer 56

A change in the population dynamics of a county as it moves from high fertility and mortality rates to low fertility and mortality rates. This is linked to the epidemiological transition model.

Question 57

What is the 1st phase of the epidemiological transition model?

Answer 57

The age of pestilence and famine - lease developed countries (Sub-Saharan Africa)
Pre-industrial societies
Mortality is high and fluctuates from year to year
life expectancy is low and variable, averaging around 30 years
Poor sanitation, comtaminated drinking water and low standards of living make people more vulnerable to infectious diseases which dominate mortality
Population growth is slow and intermittent
Today, most countries have passed though this phase

Question 58

What is the 2nd phase?

Answer 58

The age of receding pandemics - developing countries (India)
In industrial societies (LIDCs and EDCs today)
Advances in medical technology, diet, hygiene, and living standards mean epidemics causing large-scale mortality to become rarer
Life expectancy rises above 50 years, death rates start to fall
Population growth is sustained
There is a shift in the main cause of death from infectious diseases to chronic degenerative diseases

Question 59

What is the 3rd phase?

Answer 59

The age of chronic diseases - developed countries (USA, UK, Japan)
Many emerging economies (EDCs) such as Mexico, Brazil and China are now entering this phase
Further improvements in medical technology, hygiene and living standards mean that mortality related to infectious diseases is rare
Life expectancy rises further to above 70 years
Reduced fertility rates mean population growth starts to slow
Degenerative diseases become the main cause of mortality, man-made diseases associated with environmental change (cancer) become more common

Question 60

What is the 4th phase?

Answer 60

Some observers suggest a fourth stage - the onset of delayed degenerative diseases
Medical advances delay the onset of degenrative diseases
The so-called cardivascualr revolution of the past 40 years has raised average life expectancy in ACs from the early seventies to the mid eighties
However, a lack of physical activity and unhealth eating have resulted in the rise of obesity and diabetes as increasingly problematic health factors

Question 61

What are the risks of using Omran’s model to understand health risks over time?

Answer 61

The model is a generalisation
Countries will not all follow the same pattern at the same time
Some countreis are passing through the model at an accelerated rate

Question 62

What is the link between disease and levels of development in LIDCs?

Answer 62

Communicable diseases (diseases of poverty) cause a higher proportion of death and morbidity than non-communiable diseases.
These diseases are classified into 3 groups; animal borne, water borne and food borne. Water borne diseases are now mostly eliminated in ACs but remain endemic in many LIDCs. Their prevalence is due to a number of factors, although most are related in some way to poverty

Question 63

How does poverty affect the prevalence of communicable diseases?

Answer 63

Poverty and disease are tied closely together, with each factor aiding the other
Many diseases that primarily affect the poor serve to also deepen poverty and worsen conditions
Poverty also significantly reduces people’s capabilities making it more difficult to avoid poverty related diseases
Poor hygiene, ignorance in health-related education, non-avaliability of safe drinking water, inadequte nutrition and indoor pollution are faactors exacerbated by poverty

Question 64

How does government/policy affect the prevalence of communicable diseases?

Answer 64

The type and structure of governments and their policies affects the health of the impoverished more than other population groups
Every component of government - from finance, education, housing, employment, transportation and health polity - affects population health and health equity
Impoverished people depend on healthcare and other social services to be provided in the social safety net, therefore avaliability greatly determines health outcomes

Question 65

How do poor health services affect the prevalence of communicable diseases?

Answer 65

Impoverished people’s health outcomes are especially determined by whether they live in a metropolitan area or rural area, according to the WHO
An estimated 30% of the world population lacks regular accuess to existing drugs, rising to over 50% in the poorest parts of Africa and Asia
The implications are profound, over 10 million children die unecessarily each year, almost all in low-income or poor areas of middle income countries

Question 66

How do living conditions affect the prevalence of communicable diseases?

Answer 66

In theory, cities should be better placed than rural districts to cope with infectious disease. However, all too often low-inome countries are poorly resourced and have weak health systems
The threat of infctious disease is increased in LIDCs by the appalling conditions in which millions of people live. Slum housing and overcrowding are closely linked to TB and respiratory illness
Rapid urbanisation reduces the number vaccinated as it is hard to keep track; the risk of urban epidemics rises

Question 67

How does inadequate nutrition affect the prevalence of communicable diseases?

Answer 67

Inadequate food intake gives rise to undernutrition and malnutrition
Undernutrition results from too little food and malnutrition is the result of an unbalanced diet, in particular shortages of protein and essential vitamins
Depletion of macronutrients and micronutriens promotes viral replication - this contributes to greater risk of diseases spreading, and can even aid HIV transmission from mother-to-child
Further, anaemia, a decrease in the number of red blood cells due to lack of iron in the diet, increases viral shedding in the birth canal, which also increases risk of mother-to-child transmission

Question 68

How does inadequate sanitation affect the prevalence of communicable diseases?

Answer 68

Contaminated water and inadequate sanitation are related to diseases of poverty such as cholera, parasitic disease and schistosomiasis
Standpipes and sanitation are provided in many developing areas, but death rates are not significantly reduced. To effectively decrease the morbidity and mortality, populations require access to water from home instead from outside. Therefore, in addition to the installation of standpipes, water supplies and sanitation should be provided within houses

Question 69

How do environmental conditions affect the prevalence of communicable diseases?

Answer 69

High temeperatures and abundant rainfall create the conditions for a wide range of infectious diseases - malaria, dengue fever, sleeping sickness, filariasis, yellow fever, ebola
Polluted water from wells and surface streams provides a disease resovoir for cholera, typhoid and bilharzia
Meanwhile, poo drainage provides breeding sites for disease vectors such as mosquitoes and water snails that transmit diseases like malaria and bilharzia

Question 70

How does climate change affect the prevalence of communicable diseases?

Answer 70

Climate change - increases inteperature, rainfall and humidity - has stimulated transmission of vector-borne diseases and extended their geographic range
Warmer and wetter conditions have favoured the growth and spread of mosquitoes carryign tropical and sub-tropical diseases, such as WNV, malaria, and dengue fever

Question 71

What are spirals (positive feedback)?

Answer 71

The riddle of health and economic development - it can spiral in two directions
Upwards - as economic development supports better healthcare, this in turn leads to higher productivity and further economic growth
Downwards - as poor health slows economic development, either there is less money from healthcare or money is diverted that should be spent on sustaining economic development

Question 72

What are the reasons for the higher proportion of deaths from non-communicable diseases (diseases of affluences) in Acs?

Answer 72

Successful reduction or elimination of communicable diseases: this is partly the result of government wealth and affluence of households, enabbling investments in medical advances
High standards of living including proper sanitation, clean water supplies and good nutrition
Education and awareness of potential medical conditions

The result is that health populations have longer life expectancies, but prolonged life expectancy inevitably increases the proportion of deaths and illnesses connected to degenerative diseases and old age.

Question 73

What is the prevalence of non-communicable diseases in ACs linked to ?

Answer 73

Behavioural risk factors such as tobacco use, physical inactivity, harmful use of alcohol and unhealth diet
In addition, air pollution and overnutrition contribute to these conditions
Heightened risks are increasingly apparent in younger age groups

Question 74

Why are non-communicable diseases in EDCs and LIDCs are an increasing problem?

Answer 74

Gloablly there is a growing proportion of non-communicable diseases in low and middle income countries, where mortality from NCDs occurs increasingly at younger ages.
Overnutrition, once confined to the developed world is becoming a significant health problem in the developing world

Question 75

What is obesity? What causes it?

Answer 75

When a person has a BMI of over 30, it can lead to a range of further diseases/complications, including heart disease, type 2 diabetes, stroke and cancer (overweight is a BMI greater than 25).
Sedentary lifestyle (TV, video games), sedentary jobs (service sector, sitting in offices, using computors), increasing car usage, diets containing large amounts of sugar and calories (processed, fast food), food marketing (deals on unhealthy food products), lack of government inclination to tackle food industry giants, poor euducation about diet and consequences of obesity, rural-urban migration (change in lifestyle, higher likelihood of working in offices rather than primary sector), environment has an important influence on decisions people make about their lifestyle - 'obesogenic environments' places, especially uraban areas that encourage unhealthy eating or inactivity.
Worldwide obesity has tripled since 1975, 30 years ago 15% of the world's population was overweight now 39% are overweight and 13% obese, over 2 billion adults in the world are overweight, over 378 children and adolescents aged up to 19 are overweight or obese, average calorie intake was 1996 per person 30 years ago now it isi 2234.

Question 76

What is type 2 diabetes? What causes it?

Answer 76

A chronic condition where blood sugar levels become too high because the hormone insulin isn’t being produced in large enough quantities to breakdown glucose ingested, diabetes is a major cause of blindness, kidney failure, heart attacks, stroke, limb amputation.
Type 2 diabetes is linked with lifestyle, particularly weight and is more common in older age groups, it is a disease of affluent countries. Raised blood-sugar levels so diet is also a large factor. Food marketing, diets containing large amounts of sugar and calories, processed and fast foods are especially bad. Poor education about diet and lack of understanding about the disease, lack of exercise and tabacco use can also be linked to onset. Lack of diagnosis and treatment, the consequences of diabetes can be avoided or delayed with diet, physical activity, medication and regular screening and treatment for complications.
3.9 million people in the UK have diabetes. 90% of these have type 2. Diabetes is the fourth biggest cause of NCD deaths globally (1.6 million deaths per year) and the seventh leading cause overall. 422 million people worldwide (8.5% of global population) have diabetes, the majority living in low and middle-income countries, where prevalence has increased faster than in ACs. The number of people with diabetes rose from 108 millio in 1980 to 422 million in 2014.

Question 77

What is cardiovascular disease? How is it caused?

Answer 77

Conditions involving narrowed or blocked blood vessels, which can lead to chest pain, heart attack or stroke.
Build up of fatty material in arteries, diet and lack of exercise therefore a cause of CVD. High cholesterol clogs up arteries, high levels of cholesterol in the blood are caused by poor diet (lots of saturated fats), harmful amounts of alcohol, smoking and lack of exercise. High blood pressure (hypertension) damages artery walls making it easier for fatty material to buildup, high blood pressure is caused by ageing, smoking, harmfu amounts of alcohol, poor diet, lack of exercise and a lack of sleep. Smoking is harmful to the arteries because of the chemicals in nicotine. CVD can lead to heart attacks if an artery which supplies bood to the heart is blocked, CVD can lead to a stroke if an artery which supplies blood to the brain is blocked. Lack of early diagnosis and treatment (lifestyle interventions and drug treatment).
CVDs are the number 1 cause of death globally. CVDs account for the largest number of global NCD deaths per year, in 2016 17.9 million followed by cancer (9.6 million) and respiratory diseases (4.2 million). At least 3/4 of the world’s deaths from CVDs occur in EDCs and LIDCs. CVD accounts for approx 26% of the UKs deaths every year.

Question 78

What is cancer? How is it caused?

Answer 78

Cancer is a condition where cells in a specific part of the bbody grow and reproduce uncontrollably, the cancerous cells can invade and destroy surrounding healthy tissue including organs.
Causes vary according to the type of cancer, but around 1/3 of deaths from cancer are due to the leading 5 behavioural and dietary risks, high body mass index, low fruit and veg intake, lack of physical activity, tobacco use and alcohol use. Tobacco use is the most important risk factor and is responsible for 22% of deaths. Cancer causing infections, such as hepatitis and human papilloma virus (HPV) are responsible for up to 25% of cancer casus in low and middle income countries. Late stage presentation and inaccessible diagnosis and treatment are common. In 2017, only 26% of low-income countries reported having pathology services generally avaliable in the public sector. More than 90% of high-income countries reported treatment services are avaliable compared to less than 30% of low-income countries.
Cancers are the second biggest NCD cause of death globally (9.6 million deaths per year). 1 in 6 deaths from cancer. 70% of deaths in LIDCs and EDCs. Over 350, 000 people were diagnosed with cancer in the UK in 2017. 50% of all cancer cases in the UK each year are diagnosed in people aged 70 and over. 4 in 10 cancer ases in the UK each year are linked to lifestyle factors. Smoking the largest single preventable cuase of cancer each year in the UK.

Question 79

What is a communicable disease?

Answer 79

Any infectious disease which spreads from host to host

Question 80

What is mitigation?

Answer 80

The effort to reduce loss of life and property by lessening the potential impact of disasters, taking action now - before the next disaster - to reduce human and financial consequences later

Question 81

What is response?

Answer 81

A reaction to something after it has happened

Question 82

What is malaria?

Answer 82

A life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. In 2015, 91 countreis and areas had ongoing malaria transmission. Malaria is preventable and curable, and its subject to mitigation and response efforts that are dramatically reducing the malaria burden in some places. Between 2010 and 2015, malaria incidence (the rate of new cases) among populations at risk fell globally by 21%. In that same period, malaria mortality rates among populations at risk fell by 29% globally among all age groups, and by 35% among children under 5. Sub-Saharan Africa carries a disproportionately high share of the global malaria burden, in 2015, the region was home to 90% of malaria cases and 92% of malaria deaths. Whilst malaria deaths are on the decline globally, Africa still takes the burden of the disease

Question 83

What are the causes of malaria?

Answer 83

Plasmodium parasites in the hosts of Anopheles mosquitoes and humans. The mosquitoes act as vectors and transmit the disease to humans by biting. Tropical and sub-tropical climate allows mosquitoes to develop, whilst precipitation leads to stagnant water which allows the mosquitoes to flourish.
Mountain ranges - main barrier - (relief associated with drop in temps), deserts (too dry) and areas where the heat is too intense and actually inhibits mosquito breeding (climate change) are the barriers to diffusion of malaria>

Question 84

How is malaria transmitted?

Answer 84

Anapholes mosquitoes lay their eggs in water, these hatch into larvae which then emerge as adult mosquitoes, the female mosquitoes seek a blood meal to nurture their eggs. Each species of mosquito have their own preferred aquatic habitat. Transmission is more intense in places where the mosquito lifespan is longer (parasite can complete development within mosquito) and where it prefers to bite humans rather than other animals. The long lifespan and strong human-biting habit of the African vector species is the main reason why nearly 90% of the world’s malaria cases are in Africa. Transmission also depends on climatic conditions that may affect the number and survival of mosquitoes, such as rainfall patters, temperature and humidity. In many places, tranmission is seasonal, whith the peak during and just after the rainy season. Malaria epidemics can occur when climate and other conditions suddenly favour transmission in areas where people have little to no immunity, or migration of low immunity people to high transmission areas. Partial immunity is developed over years of exposure, and while it never provides complete protection, it reduces risk that the infection will cause severe disease, for this reason most malaria deaths in Africa occur in young children, whereas in area with less transmission and low immunity, everyone is at risk.

Question 85

Mitigation and response strategies to deal with malaria

Answer 85

Vector control - insecticide-treated mosquito nets, indoor residual spraying, antimalarial drugs to prevent infection
Early diagnosis and treatment after infection (usually through artemisinin-based combination therapy)
Surveillance
Problems: resistance to insecticides
resistance to anti-malarial drugs

Question 86

How does increasing global mobility impact on the diffusion of disease?

Answer 86

Increased global mobility diminishes the importance of:
physical barriers
‘friction of distance’ of disease
expansion diffustion (instead relocation and hierarchal diffusion predominate)

Increased global mobility will lead to:
increased rate of disease spread
more extensive spatial patterns of disease spread

Globalisation: increased travel and trade at a global scale, this leads to a growth of global networks and flows based around:
increased size and number of airports and aircraft to handle increased intensity of global air travel
increased car ownership - impacts more on local and regional scales
increased number of railways
development of high-speed trains and cross-border railways
greater shipping intensity due to continerisation and increased scale of international scale
-these make disease diffusion more likely

Question 87

How might increasing global mobility impact on the ability to respond to disease?

Answer 87

Easier to access/record health data from remote areas which can help to target interventions in areas at greatest risk or deliver mitigation strategies in a more effective manner.
Easier to raise awareness.
Easier to transport medical supplies/equiptment/staff and clean water around the world (even to remote areas).
Refridgerated containers and aircraft storage means medicines/vaccines can travel further than ever before.
Global collarboration helps us to work together to contain and repond more effectively.
Need to implement politically ‘difficult’ reponses (travel restrictions, quarentines).
Disease is less contained and faster spreading than ever, therefore it is becoming more difficult to contain within more localised boundaries.
Response has to keep up with faster rate and greater spatial extent of disease diffusion.

Question 88

A disease outbreak: H1N1 2009

Answer 88

Rate of spread:
influenza spreads easily through coughing and sneezing and is highly infectious
Method of spreading:
diffused through relocation and hierarchal from country to country, but on a local scale expansion and contagious diffusion
Patterns of outbreak distribution:
The outbreak started in Veracurz, Mexico, the virus was similar to the Spanish flu pandemic in 1918, it quickly spread to other parts of Mexico and North America. Most of Africa and parts of Asia had no cases confirming hierarchal diffusion. The disease followed hierarchal diffusion because North America, Australia and the UK had a high incidence of cases - they are developed, globalised countries with more transport links allowing for relocation diffusion, on a smaller scale contagious and expansion diffusion will have occurred.

Question 89

What is a multilateral agency?

Answer 89

An agency with funding that comes from multiple governments or an institution representing a group of countries

Question 90

What is a bilateral agency?

Answer 90

Governemental agencies in a single country which provides aid to developing countries (USAID)

Question 91

What is an NGO?

Answer 91

A non-profit organisation that operates independently of any government, typically one whose purpose is to address a social or political issue

Question 92

Examples of multilateral agencies (all belong to the UN)

Answer 92

World Health Organisation (WHO) - the directing and coordinating authority on international health within the UN system
World Bank
United Nations Children’s Fund (UNISEF)
United Nations Development Programme (UNDP)

Question 93

Examples of bilateral (government agencies)

Answer 93

United States Agency for International Development (USAID)
United States Public Health Service (USPHS)
Centre for Disease Control and Prevention (CDC)

Question 94

Examples of NGOs

Answer 94

Red Crescent Movement
International Red Cross
Medecins Sans Frontieres

Question 95

What does the WHO do?

Answer 95

Gathers health data - from 194 member states and publishes them annually in the World Health Statistics, which is avaliable to each country to provide an insight to health risks, mortality from communicable diseases and non-communicable diseases, government spending on healthcare.
Provides leadership and identifies priority areas in matters critical to health - takes a leading role for epidemics and outbreaks of new diseases and develops gobla strategies to combat diseases such as malaria, HIV and tuberculosis.
Researches health problems - research groups dedicated to influenza, tropical diseases, mental health and vaccines, these are often in partnership with other international agencies.
Monitors the international health situation
Supports UN member states to devise health strategies - an important part such as during the 2015 Nepal earthquake, delivered mobile medical units as emergency health services.
Provides technical support during health crises
Sets targets - to improve prevention, diagnosis, treatment and care, promoting research into new drugs and insecticides is also as important as predicting the spread of disease.

Question 96

What are the impacts on disease mitigation and response by remoteness/distance?

Answer 96

Increased distance means disease is less likely to spread via contagious or expansion diffusion, if a place is remote and therefore not well connected, it is less likely to be infected by relocation or hierarchal diffusion therefore mitigation strategies may be less necessary in the first place. Equally, if the origin of the disease is in a remote region, it is less likely to spread outwards and can usually be contained more easily.
However, there will be delayed arrival of medical assistance and emergency aid. Isolation can lead to a lack of immunity, meaning that when a disease does reach a remote region the effects can be more severe. Health data from remote areas is less well recorded and harder to access, this means that targeting interventions in areas at greatest risk or deliver mitigation strategies in effective manners are not tailored exactly to a region. Awareness is likely to be reduced due to the diminished effect of global connections. Education initiatives are less likely to reach remote communities.

Question 97

What are the impacts on disease mitigation and response by relief

Answer 97

Can isolate communities and restrict population movements, meaning diseases are less likely to spread to areas with extreme relief, therefore mitigation strategies may not be necessary. Some diseases are not a risk at high altitudes.
However, there will be delayed arrival of medical assistance and emergency aid. Isolation can lead to a lack of immunity, meaning that when a disease does reach a remote region the effects can be more severe. Health data from remote areas is less well recorded and harder to access, this means that targeting interventions in areas at greatest risk or deliver mitigation strategies in effective manners are not tailored exactly to a region. Awareness is likely to be reduced due to the diminished effect of global connections. Education initiatives are less likely to reach remote communities.

Question 98

What are the impacts on disease mitigation and response by water?

Answer 98

Can isolate communities and restrict population movements, meaning diseases are less likely to spread to areas with extreme relief, therefore mitigation strategies may not be necessary. Some diseases are not a risk at high altitudes.
However, there will be delayed arrival of medical assistance and emergency aid. Isolation can lead to a lack of immunity, meaning that when a disease does reach a remote region the effects can be more severe. Health data from remote areas is less well recorded and harder to access, this means that targeting interventions in areas at greatest risk or deliver mitigation strategies in effective manners are not tailored exactly to a region. Awareness is likely to be reduced due to the diminished effect of global connections. Education initiatives are less likely to reach remote communities.

Question 99

What are the impacts on disease mitigation and response by natural hazards?

Answer 99

Aid workers may already be in the area to deal with the aftermath of a natural hazard (Haiti, earthquake and cholera outbreak). Hazard response teams can lead to improved disease awareness for the future and also can lead to infastructure improvements which may help to combat diseases in the first place.
However, natural hazards can have isolating effects on communities (cutting off road access, damaging power lines - communication, gas pipes, sewage and water pipes), as well as hampering relief efforts, all of these things can lead to heightened risk of diseases (particularly water-borne diseases) spreading in the aftermath of a hazard event. Also, financial resources aimed at dealing with hazards can mean resources are diverted away from disease mitigation.

Question 100

What does isolation do to susceptibility to disease?

Answer 100

Until the mid-twentieth century the vast rainforest of the Amazon Basin isolated hundreds of indigenous Indian tribes from the outside world, for many this isolation was a disater. With little or no immunity to common ‘western’ diseases (influenza, measles, chickenpox) early contact with cattle ranchers, oil explorers and loggers often proved fatal. In Peru, half of the Nahua tribe, contacted for the first time in teh early 1980s, was wiped out by disease following an exploration on their land. A similar tragedy happed to the neighbouring Murunahua traibe, contacted for the first time in the mid 1990s by illegal mahogany loggers

Question 101

What does isolation mean for outbreaks of water-borne diseases?

Answer 101

Outbreaks of water-borne diseases resulting from poor hygiene and contamination of water supplies, often accompanies natural disaters such as floods and earthquakes. In remote and isolated regions that are particularly difficult to acces, disease can quickly get out of hand and assume epidemic proportions. After the 2005 Pakistan earthquake and 2015 Nepal earthquake, medical teams and emergency aid struggled to reach the remote regions. In Nepal, many isolated villages were cut off by landslides, meaning epidemics took hold before medical help could arriver.

Question 102

What is the link between remoteness and the risk of disease?

Answer 102

Remoteness can protect the wider population from disease risks. The Ebola virus first appeared in equatorial Africa in the 1970s, the communities affected were so isolated in the Congo rainforest that the disease was contained. In 1996, hunters in a remote part of Gabon fell ill with Ebola after they ate a dead chimpanzee infected with the virus. Of the 31 cases, 23 people died from the disease, including some of the hunters’ family members. Ebola did not spread beyond the tribe itself. In 2014, Ebola struck a less remote region of Africa and the number of infectioins and deaths were considerably higher. In 2018, there was another Ebola outbreaks, this time in DRC, this spread rapidly killing well over 500 people.

Question 103

Where does medicine from nature orginate from?

Answer 103

Many modern medicines originate from natural compounds found in wild plants. Long ago, the Greek physician, Hippocrates, recorded more than 300 medicinal plants and herbs, which were classified accoring to physiological action. Before the advent of scientific medicine, the healing qualities of many plants were so well known that their common name reflected this (woundwort, bladderwort, lungwort and liverwort). Now, scientists have been able to identify the active constituents in tehse plants and sythesise tham in the lab. The first naturally derived medicine isolated from a plant was morphine. They are used as analgesics to reduce pain. Other alkaloids (quinine) were extracted from wild plants, and towards the end to the century, glycosides were discovered.

Question 104

What is the source of salicin, what are its growing conditions and what can it be used for?

Answer 104

Bark of white willow and other willow species. Widespread on riverbanks, floodplains and wetland throughout the temperate zone. Thrives on a range of soils, from light sands to heavy clay with a soil pH from 5.5 to 8.0. Acts like aspirin, used for pain relief, gout, osteoarthritis.

Question 105

What is the source of caffeine, its growing conditions and what it is used for?

Answer 105

Tea, coffee, coca and other plants. Trpoical and sub-tropical conditions with temperatures averaging 20-27C with abundant rainfall (1000-2000mm/yr). Soils which are well drained, with good orgainic content and nitrogen. Stimulant for central nervous system, heart, muscles, migraine, epidural, anaesthesia.

Question 106

What is the source of quinine, its growing conditions and medical usage?

Answer 106

Dried bark of cinchonas evergreen tree. Average temperatures above 20C, humid conditions with annual rainfall in excess of 2000mm over at least 8 months. No frost, well drained, fertile soils with abundant organic matter and good moistrue holding capacity. Malaria, kills the parasites in red blood cells.

Question 107

What is the source of colchincine, the growing conditions and medical usage?

Answer 107

Autumn crocus. Moist, temperate climate conditions. Deep, well drained soils with slightly acidic pH (c6.5) and good mositure retention. Cancer and gout.

Question 108

What is the source of nicotine, growing conditions and medical usage?

Answer 108

Tobacco plant. Optimal mean daily temperatures 20-30C. Rainfall 600-800mm, with 20-30mm every two weeks in the growing season and frost free conditions, Light to medicu textured soils with good drainage. The main active ingredient in new drugs to treat wounds, Alzheimer’s, depression.

Question 109

What is the source of morphine, growing conditions and medical usage?

Answer 109

Dried latex from seed pods of several species of opium poppy. Warm, humid conditions. Clear sunny days with temperatures 30-38C. Susceptible to frost and wet weather. Deep, clay loam, well drained soils rich in humus. Soil pH 6-7.5. Pain reliever.

Question 110

What is the source of artemisinin, growing conditions and medical usage?

Answer 110

Artemesia annua plant leaves. Temperate climape, optimal temperatures 13-29C, frost tolerant. At least 600-650mm rainfall. Soils light to medium textured, well drained and fertile with a soil pH between 6-8. Anti-malaria agent.

Question 111

What is the source of digitalis, growing conditions and medical usage?

Answer 111

Temperate climatic conditions, tolerates high rainfall, cool summers and acidic soils. Dropsy, heart failure.

Question 112

What is the Rosy Periwinkle? Growing conditions? Traditional uses? Medicinal value? Global trade? Biopiracy?

Answer 112

The rosy periwinkle is a small evergreen shrub which is native to Madagascar, although it is now common in many tropican and sub-tropical regions. The plant requires a warm tropical climate without frost and where soils are well drained but mositure retaining and slightly acidic. The rosy periwinkle’s use in traditional medicines is long established, from the treatment of wasp stings in India, to diabetes in China and the Philipines, it is also a popular ornamental garden plant. However, the plant came to the attention of scientists in the late 1960’s when analysis revealed it contained 70 alkaloids, several of which have significant medicinal value. Vincristine is successfully used in chemotherapy in childhood leukaemia and has helped increase survival rates from 10% in 1970 to 90% in 2012. Vinblastine has also proved highly effective in treating Hodgekin’s lymphoma. Currently scientists have been unable to synthesise these alkaloids and production of the drugs relies on commercial cultivation of the rosy periwinkle, mainly in India, central Asia and Madagascar. Global sales of vincristine and vinblastine are worth hundreds of millions of dollars annually to Eli Lilly, the US pharmaceutical giant that developed them. However, few of the profits are channelled back to Madagascar and its indigenous rainforest people, this is an exploitation of biological resources. It deprives LIDCs like Madagascar of valuable international trade, potential exports and value added. Biopiracy inders economic growth and progress in tackling poverty and inequality.

Question 113

What is biopiracy?

Answer 113

The exploitation of biological resources, this is unsustainable because it deprives LIDCs of valuable international trade and potential exports. It hinders economic growth and progress in tackling poverty.

Question 114

What are the conservation issues with supply and demand of medicines from nature?

Answer 114

Medicinal plants are mainly sourced from wild populations; only a small number of medicincal species, like the rosy periwinkle are cultivated. Medicinal plants supply the raw material for pharmaceutical medicines, though the majority of drugs are made from synthesised products. In contrast, most products used in traditional medicine are harvested from wild plants - 80% of the developing world (5billion) rely on traditional medicines so demand is high. As a consequence, the most sought after species collected and delivered to market are under enormous pressure. Market demand has led to an increased pressure on the natural resources that lend to the production of some of these plants. The most serious proximate threats when extracting medicinal plants generally are habitat loss, habitat degradation, and over harvesting. Additional reasons for decline of wild medicinal plants are the preference of Traditional Chinese Medicine for wild plants rather than cultivates, and the preference for roots rather than leaves, flowers and seeds, this is less sustainable.

Question 115

Survival of wild medicinal plant species?

Answer 115

Increasingly, the sourcing of wild medicinal plants for traditional Chinese medicine is unsustainable, it reduced plant populations and their genetic diversity, endangering their survival. Slow growing plants, and those occupying highly specialised niches - associated with climate, relief or soil properties, are particularly vulnerable. At least 4000 species are threatened and 14 acutely endangered.

Question 116

What are the miracle cures most at risk?

Answer 116

Yew tree - cancer drug paclitaxel is derived from the bark, but it takes six trees to create a single does so growers are struggling to keep up.
Hoodia - plant has sparked interest for its ability to suppress appetite, but vast quantities have alreagu been ‘ripped from the wild’ as the search for the miracle weight drug continues.
Magnolia - has been used in traditional Chinese medicine for 5, 000 years as it is believed to help fight cancer, dementia and heart disease. Half the world’s species threatened, mostly due to deforestation.
Autumn crocus - Romans and Greeks used it as poison, but now one of the most effective treatments for gout.

Question 117

What are the issues with conservation and why are they problems?

Answer 117

Its not just collecting that threates medicinal plants, habitat destruction, in particular deforestation in the tropics, is of even greater concern. Tropical rainforests are extraordinarily biodiverse, containing 70% of terrestrial plant species, and yet no more than 1% have been screened for potential medical use. Thus, on medical grounds alone, there are powerful reasons to conserve the rainforest and protect its genetic diverstiy. Deforestation rates averaging 325km/day, may species have become extinct before scientists have a chance to investigate or even discover them. In the past, pharmaceutical companies exploited rainforest ecosystems, targeting medicinal plants for cultivation and synthesising chemical compounds, however, benefints for the local people have been negligible. To many, this is seen as a type of theft also known as biopiracy.

Question 118

How to protect habitats and natural ecosystems?

Answer 118

One response is to use the medicinal plants as a means of conserving not only habitats, but entire ecosystems.
In the 1980’s scientists identifies and extracted prostialin, a powerful new drug for treating HIV, found in the bark of the Samoan mamala tree in teh Samoan rainforest. Parts of the revenues from sales of the drug are returned to Samoa as compensation for protecting the rainforest and to assist economic development in forest communities. The National Cancer Institute in the USA and the Swedish International Development Authority also provides funds for economic development and forest protection in Samoa. Thus, the local people benefit directly from forest conservation, a sustainable supply of valuable medicinal plants is assured, and ecosystems flourish an dprovid a range of free ecological services at both local and global scales. As a result, Samoa’s national park was established to encourage local healers to use medicinal plants in a sustainable way, in order to pass their knowledge on to the next generation.

Question 119

What are some global campaigns on disease eradication?

Answer 119

Global campaigns to eradicate major human diseases have had limited success. A notable exception was the worldwide eradication of Smallpox in 1979. Currently WHO and other agencies are working to eradicate Poliomyelitis (polio), Malaria and Dracunculiasis (guinea worm)

Question 120

What is Polio?

Answer 120

A highly infectious viral disease, which mainly affects young children, the virus is transmitted person-to-person and is spread mainly through the faecal-oral route or, less frequently, by a common vehicle (contaiminated water/food) and multiplies in the intestine, from where it can invade the nervous system and can cause paralysis. Initial symptoms include fever, fatigue, headache, vomiting, stiffness in the neck, and pain in the limbs. 1 in 200 infections leads to irreversible paralysis (usually in the legs). Among those paralysed, 5-10% die when their breathing muscles become immobilised, while there is no cure for polio it can be prevented by vaccination. Prior to the development of a vaccine in 1952, polio killed or paralysed 600, 000 people a year.

Question 121

Actions taken against Polio?

Answer 121

The successful eradication of smallpox in 1980 spurred the creation of the Global Polio Eadication Initiative in 1988 supported by national governments, WHO, Rotary International, the US Centres for Disease Control and Prevention, UNICEF, and later joined by key partners including the Bill and Melina Gates Foundation and Gavi, the Vaccine Alliance. Overall, since GPEI was launched, the number of cases has falled by over 99%, from an estimated 350, 000 cases then, to 33 reported cases in 2018. Of the three strains of wild poliovirus, wild poliovirus type 2 was eradicated in 1999 and no case of wild poliovirus type 3 has been found since the last reported case in Nigeria in November 2012. In 1994, the Americas were certified polio free, followed by the Western Pacific Region in 2000 and the European Region in June 2002. On March 2014, the South-East Asia Region was certified polio fee, meaning that transmission of wild poliovirus has been interrupted in this bloc of 11 countries stretching from Indonesia to Inda. This achievement marks a significant leap forward in global eradication, with 80% of the world’s population now living in certified polio free regions. However, as long as a single child remains infected, children all over the world are at risk of contracting polio. Failure to eradicate polio from these last remaining strongholds could resuly in as many as 300, 000 new cases every year, withing 10 years, all over the world.

Question 122

By 2011, Polio had not yet been eradicated completely from its endemic countries of Afghanistan, Pakistan and Nigeria, why?

Answer 122

War, poverty, religious beliefs, remoteness/isolation, insurgencies, environmental conditions, sanitation/living conditions. Rainy season helps the spread which hinders eradication.

Question 123

What are some barriers to change relating to Polio?

Answer 123

Within Afghanistan, Pakistan and Nigeria, uptake of the vaccination to provide immunity for children remains uneven. Political instability and more than 80 murders of health workers in Pakistan and Nigeria in recent years by military extremists has interrupted vaccination programmes, this is a major setback for the GPEI. In addition, since 2013, new outbreaks of polio have re-emerged in war torn Iraq and Syria, where vaccinations and basic hygiene has broken down. In the past, resistance to vaccination programmes, related to political and cultural factors as well as ignorance, provided unexpected challenges, especially in Pakistan and Nigeria.

Question 124

What are the greatest barriers to global polio eradication?

Answer 124

Poverty/lack of basic health infastructure - which limits vaccine distribution and delivery (especially when multiple doses are needed) - funding management and community perceptions of vaccine safety, insecurity of human resources, mutations of virus.

War - civil ear and internal strife creates a disruption to delivery of vaccine and to sanitation - political pressures and corruption.

Cultural barriers - the sometimes oppositional stance that marginalised communities take against what is percieved as a potentially hostile intervention by outsiders - USA sterilistation of Muslim populations using intentionally contaminated vaccines after Afghanistan invasion and Iraq, suspicion of modern biomedicine, colonialism and the projection of the power of western nations, refusing vaccines as resistance to western expansionism, suspicions that vaccine contained contraceptives, exacerbated by the CIA’s fake hepatits B immunisation to collect blood samples from Osama bin Laden’s Abbottabad compound in order to confirm the genetic identity of the children and his own presence leading to his killing.

Climate - maintaining the potency of live vaccines in extremely hot or rmote areas - the oral poliovaccine must be kept at 2-8C for vaccination to be successful.

Question 125

Polio case study

Answer 125

Caseload: Polio cases have decreased by over 99% since 1988, 350, 000 cases in more than 125 endemic countires to 74 reported cases in 2015. Of the three strains, type 2 was eradicated in 1999, type 3 cases are down to the lowest levels ever, no reported cases since Nigeria in November 2012.
Innovation and research: The Polio Research Committee reviews polio eradication research, identifies knowledge gaps, determines research priorities and funding levels; the overall strategy. The PRC is comprised of global experts from a variety of disciplines, including virology, epidemiology, sociology and public health. The Polio Pipeline annual publication provides ongoing research by the GPEI. Developing affordable inactivated polio vaccine and preparing for stopping routine use of OPV by developing affordable options for IVP use.
Global Polio Eradication Initiative: Renewed international determination to finish polio eradication - WHO adoption of resolution 59.1, outlined procedures for reporting and addressing polio cases, inclusion of polio in the Internation Health Regulations; requirements issue by the kingdom of Saudi Arabia for pilgrims attending Haj to be vaccinated against polio with OPV. Assists countries in carrying out surveillance for polio and large scale vaccination rounds. Refined laboratory procedures allowed the confirmation of poliovirus 50% faster than before. New tools such as monovalent vaccines (mOPV) were developed which significantly reduced transmission of type 1. In 2009 the Global Polio Eradication Initiative now has an amoury of five different vaccines to stop polio transmission. World Polio Day was established by UNICEF partner Rotary International.
Polio Eradication and Endgame Startegic Plan 2013-2018: is the first plan to eradicate all the types of polio disease simultaneously. Launch improved immunisation campaigns. Oral polio vaccines (OPV) will be phased out an inactivated polio vaccines (IVP) will be gradually introduced. Polio-free countries must adress gaps in surveillance to detect suspected polio cases. Accessing the most marginalised and hard-to-reach communities, sharing heath expertise.

Question 126

What are grassroots strategies?

Answer 126

Projects that are planned and controlled by local communities, perhaps with the help of NGOs to help their local area, they are smaller scale and not as expensive.

Question 127

What are top-down schemes?

Answer 127

Usually large scale and very expensive involving governments and/or large external organisations, llocal people who will be affected by the scheme have little say in the process and have little influence in the project.

Question 128

What does the grassroots strategy for Guinea Worm involve?

Answer 128

In Ghana in West Africa, the Guinea Worm eradication strategy has partnered with the Ghana Red Cross Women’s CLubs to reduce transmission. This innovative programme involve teaching women volunteers how the Guinea Worm is transmitted and how transmission can be prevented. The volunteers then visit local villages and educate local communities.

Question 129

What is the life cycle of a Guinea Worm?

Answer 129

Entering the body - a person drinks water containing tiny eater fleas that are infected with guinea larvae.
Multiplying - the fleas are digested, releasing the larvae into abdominal tissues, where they mate.
Growing - female wormd, growing up to 1m long, move through the body mostly to lower limbs.
Leaving the body - about a year later, the worm emerges from the blister it creates, the victim in pain rushes to cool the limb in water.
Infesting the water - on contact with water, the worm releases clouds of larvae.
Infecting the water fleas - water flease consume the worm larvae, whcih resist digestion.

Question 130

What does the responsibility of the women volunteers include?

Answer 130

Monitoring, identifying and reporting all new cases of Guinea worm. Ensuing that those infected did not contaminate water sources. Distributing, checking and replacing water filters that remove water fleas (the vectors) from drinking water. Identifying water sources used by the community and requiring treatment with larvicides

Question 131

Why in the past was work by male volunteers met with limited sucess?

Answer 131

This was because men frequently work outside villages and it is mainly women who are responsible for sourcing water and its use for household consumption. Women were able to appreciate the value of filtering drinking water and avoiding contamination of water sourced by people already infected by the parasite.

Question 132

Has the grassroots strategy for Guinea worm been successful?

Answer 132

Highly successful, and the Guinea worm has been eradicated from Ghana. WHO reported that in 1989 there were more than 179, 000 cases, but by 2010 the country reported its last indigenous case of the disease.

Question 133

Is it probable that Ghana will remain Guinea worm free?

Answer 133

In the 1980s, the parasitic infection was widespread in 20 countries, 16 of which were in Africa, with more than 3.5 million people infected. The annual incidence globally has decreased from 892, 640 in 1989 to 542 cases in 2012. Since 1995, WHO has certified 12 countries in the African risk belt as countries free of Guinea worm transmission. Guinea worm remains endemic in 4 countries; Chad, Ethiopia, Mali and South Sudan. Ethiopia has reported 3 cases and South Sudan 5 although Mali has reported zero human cases since the beginning of 2016. Therefore, it is not likely that Ghana will remain free as long as there are other countries in the area with some cases still which may transfer over borders this is as a result of poor water infastructure and high population movement across the region.

Question 134

Why is Dracunculiasis (Guinea worm) eradicable?

Answer 134

Diagnosis is easy and unambiguous, relying on visual recognistion of the emerging worm. The intermediate host is not airborne but restricted to stagnant water bodies. Control interventions are simple and cost effective. The disease has limited geographical distribution and transmission is seasonal. There is no known animal reservoir.

Question 135

The Guinea worm disease and its transmission

Answer 135

Detecting all cases within 24 hours of worms emergence. Providing new safe drinking water sources. Converting unsafe sources into safe water sources. Constructing copings/installing boreholes with handpumps to reduce water contact. Ensuring regular and systematic filtering of drinking-water collected from shallow unprotected wells. Treating unsafe water sources with temephos to kill the Cyclops. Advocating healthy drinking-eater behaviours in communities through health education.

Question 136

Reporting of Guinea worm

Answer 136

Reporting on a regular basis, evein if there are zero cases. Managing the certification process for global eradication country by country. Consolidating advocacy for eradication of the disease. Maintaining global and national Dracunculiasis databases to monitor the epidemiological situation.

Question 137

Implementing effective case containment of Guinea worm

Answer 137

Wound is cleaned and bandaged regularly until the worm has been completely expelled. A volunteer from among the communitiy trained in basic dracunculiasis surveillance and management. Community members are educated regarding prevention and containment, they are encouraged to filter drinking water regularly.