Disease Dilema's (Topic 6) Flashcards
What is an infectious disease?
Diseases caused by organisms — such as bacteria, viruses, fungi or parasites
What is an non-infectious disease?
Diseases that are not caused by pathogens but instead by lifestyle factors, environmental toxins, or gene mutations
What is a communicable disease?
Diseases that are spread from one person to another (transmissible). Can happen directly (i.e in contact with blood/bodily fluids) or indirectly (i.e bites from infected insects transmitting the disease
What is a non communicable disease?
Diseases that are not transmissible directly from one person to another. Can be caused by genes, environmental factors or lifestyle choices. Usually a longer duration
What is a contagious disease?
Infectious diseases that are easily passed from person to person through close proximity or direct physical contact (i.e touching, kissing)
What is a zoonotic disease?
Infectious diseases which are transmitted from animals to humans e.g. Bird Flu, COVID-19 (from bats)
What is an epidemic?
the rapid spread of disease to a large number of people in a given population within a short period of time (i.e Ebola in West Africa
What is an endemic disease?
a disease that exist permanently in a geographical area or population group (i.e Malaria in Ethiopia, sleeping sickness in parts of Africa)
What is a pandemic?
An epidemic that has spread worldwide affecting a large number of people (i.e COVID-19, Spanish Flu in 1918-19)
What is a disease vector?
are small organisms such as mosquitoes or ticks that can carry infectious pathogens from person to person/ animals to person
What is a degenerative disease and an example?
A disease in which the function or structure of organs or tissue break down slowly over time, largely related due to aging (i.e CVD, Alzheimers)
What type of disease is Malaria?
Infectious disease (parasites transmitted by mosquitos), Vector -borne disease (spread by mosquitos) and Non-contagious (not spread through close contact)
What type of disease is HIV/AIDs?
Infectious (virus), Contagious (spread through bodily fluids - blood or semen - i.e sexual activity, breastfeeding, sharing needles)
What type of disease is Tuberculosis?
Infectious (bacteria causes it), highly contagious (spread similar to a cold)
What type of disease is cardio-vascular disease? (CVD)
Non infectious, Non communicable, Non contagious
What type of disease is diabetes?
Non -communicable - caused by lack of insulin produced by pancreas (genetic - Type 1). Other type of diabetes (type-2) is related to lifestyle factors (i.e obesity)
Global distribution of Malaria?
Concentrated in ward humid environments in tropics (i.e Africa, Sth America,S and SE Asia). 3.2 billion at risk. Not found in cooler drier areas (i.e deserts, mountainous areas - central highlands in Ethiopia
Global distribution of HIV/AIDs?
35 million worldwide but highly concentrated in Sub-Saharan Africa & Southern Africa. South Africa/Nigeria has highest totals numbers
Global distribution of Tuberculosis (TB)?
9 million cases worldwide. Linked with poverty, overcrowding (contagious and spread through air). Dominant in LIDCs - highest deaths in Africa (i.e Nigeria). HIV increases risk of catching TB (HIV weakens immune system)
Global distribution of Diabetes?
250 million worldwide. Strongly concentrated in North America and parts of E and S Asia (AC and EDC countries)
Global distribution of cardiovascular disease (CVD)?
17 million deaths. Major cause of deaths in ageing populations - esp AC countries but nearly 80% of deaths occurring in low & middle income countries
What is disease diffusion?
The spread of disease across space from its origin
What is public health?
all organised measures (whether public or private) to prevent disease, promote health, and prolong life among the population as a whole
What is expansion diffusion? Examples?
when a disease spreads from source outwards into new areas, whilst carriers in source area remain infected (i.e Bubonic Plague, TB)
What is contagious diffusion? Examples?
disease spreads from a source through direct contact with carrier, therefore is strongly influenced by distance from carrier (i.e Ebola epidemic in West Africa)
What is hierarchical diffusion? Examples?
disease spreads from a source through an ordered sequence of places - i.e large well connected places to smaller more isolated places (i.e H1N1 - swine flu - spread from major U.S cities out to smaller towns after arriving from Mexico)
Main concepts of Hägerstrand’s diffusion model? What type of diffusion was it applied to? (4)
1) Applied to contagious disease diffusion
2) People living closer to carriers are more likely to catch disease; ‘the neighbourhood effect’
3) Physical barriers may interrupt progress of disease diffusion
4) No. of people infected reflects an ‘S’ curve shape; slow start, accelerates rapidly and then levels out when more pop. are infected
What is relocation diffusion? Examples?
when a disease spreads from source outwards into new areas that are spatially separate from source - leaving the source area (i.e cholera being taken from Nepal to Haiti by U.N aid workers)
How do global patterns of temperature & precipitation
1) Vector-borne diseases (i.e. malaria, dengue fever) need warm/humid condition AND stagnant water to exist. High prevalence in Tropics (but altitude can alter pattens as high alt = colder)
How do global patterns of relief impact pattern of disease? (2)
1) Relief can be a barrier to disease - i.e increase in altitude = lower temperatures = certain vectors can’t survive (i.e. mosquitoes in Central Highlands in Ethiopia
2) Low relief = easier to flood = drinking water & sewage mix = spread of cholera & diarrhoeal diseases increase
How do global patterns of temperature impact pattern of disease? (3)
1) Warm conditions = perfect environment for vector-borne diseases to multiply (i.e vector-diseases high prevalence in tropics)
2)Cold conditions can enable common cold virus to spread more efficiently - 5°c or lower is optimum
3) Cold conditions can act as barrier for vectors - Mosquitoes get lethargic below 10
How do physical factors impact vector diseases? (2)
1) Lots of surface water (closely linked with high rainfall) = more potential breeding sites for vectors like mosquitoes = higher prevalence
2) Mountainous terrain = high altitude = cooler = vectors can breed/survive
How do seasonal differences impact pattern of disease? (2)
1) Monsoon seasons/Rainy seasons = rapid increase in vector-borne diseases (increase in stagnant water after heavy rains)
2) Less common colds in Summer as temperatures too high for virus to spread effectively
How will climate change impact pattern of disease for West Nile Virus? How is it spread?
WNV spread by mosquitoes. USA example - found in warm states like Texas in USA but as temperatures increase due to climate change it could migrate north into higher latitudes (i.e S Canada) as temp increase there
How will climate change impact pattern of disease for vector-diseases like Malaria?
1) Changes to weather patterns could lead to heavier rainfall/longer rainy seasons in some tropical countries = more stagnant water for vectors to breed in
How will climate change impact pattern of disease for water-borne like Cholera or Diarrhoea?
1) Changes to weather patterns could lead to heavier rainfall & more flooding in some LIDCs = higher chance of low-lying areas flooding and sanitation/drinking water becoming mixed = increase in water-borne outbreaks
How will climate change impact pattern of disease for Lymes Disease? How is it spread?
Lyme Disease spread by ticks. Ticks like warm conditions. Could spread into northern latitudes as temp increase (i.e Canada) but disappearing from areas in Souther States (i.e. Texas) where the temperatures will become too hot.
How will climate change impact pattern of disease for Sleeping Sickness? How is it spread?
Spread by tsetse fly. Found in Sub-Saharan Africa in areas where temp is 20-26°c. Climate change will mean disease will spread into Southern Africa BUT disappear from East Africa (temps too hot and so fly dies)
Name 3 diseases that are zoonotic
Sleeping Sickness, Malaria, Dengue Fever, H1N1 (Swine Flu), COVID-19
Name 2 factors that involve barriers and movement that can increase the probability of catching a zoonotic disease? (2)
1) No physical barriers to restrict the movement of wild animals
2) Ineffective controls on the movement of infected domestic animals in a country (i.e No ‘Pet Passports’, No screening at borders of animals)
Name factors that relate to urbanisation or animal healthcare that can increase the probability of catching a zoonotic disease? (4)
1)Urbanisation creates suitable habitats for animals that area carriers for zoonotic diseases (i.e foxes, racoons & skunks)
2) Urban areas with poor sanitation mean animal faeces and human drinking water can mix
3)Limited vaccination of pets and domestic livestock = diseases spread easily
4) Limited control of animals in urban areas (i.e feral dogs in LIDCs)
What is the relationship between human contact and zoonotic diseases
Prolonged contact (i.e cattle farming, poultry farms) increases the chances of catching zoonotic disease
What does epidemiological transition model show the relationship between?
Development and changes to structure of population in terms of mortality, life expectancy and causes of death
What is stage 1 in epidemiological transition model called?
Age of pestilence and famine
What societies are in stage 1 of epidemiological transition model? State of mortality & life exp?
Pre-industrial societies (i.e in modern world only remote tribes in Amazonia would be in this stage). Epidemics common & mortality = high (fluctuates) Life exp = low (30 yrs)
Which type of disease dominates cause of deaths in Stage 1 of epidemiological transition model?
Infectious diseases kill most people (i.e Bubonic Plaque in 1340s in UK)
What is stage 2 in epidemiological transition model called?
Age of receding pandemics
What societies are in stage 2 of epidemiological transition model? State of mortality & life exp?
LIDCs mainly (i.e DRC). Large epidemic rare & mortality dropped due to medical/sanitation improvements. Life exp = improved slightly (50 yrs).
Which change in cause of deaths has occurred by Stage 2 of epidemiological transition model?
Infectious declining but chronic and degenerative diseases growing (i.e DRC - top cause of death is Malaria but Heart disease/Stroke now in top 10)
What is stage 3 in epidemiological transition model called?
Degenerative and Man-made disease stage
What societies are in stage 3 of epidemiological transition model? State of mortality & life exp?
EDCs mainly (i.e China & Brazil). Even further medical/sanitation improvements = low mortality. & infectious diseases rare. Life exp = 70 yrs
Which change in cause of deaths has occurred by Stage 3 of epidemiological transition model?
Infectious disease is rare as cause of death. Chronic & Degenerative diseases dominate. Man-made diseases more common - i.e cancer from pollution (i.e India - air pollution = lung cancer but heart disease in top 3)
What is stage 4 of epidemiological transition model and how is it different to previous stages?
Delayed degenerative diseases. Medical advances have halted degenerative diseases (i.e degenerative CVD, Alzheimers) & improved awareness about exercise (i.e ‘cardiovascular revolution’). Life exp = 75-80s
Cause of deaths in stage 4 of epidemiological transition mode
Chronic & Degenerative diseases dominate. Obesity & diabetes are increasingly important as causes of death
What are causes of high prevalence of communicable diseases in LIDCs? (4)
1) Lack of government resources to manage healthcare services.
2) Poverty = poor household sanitation = water-borne diseases
3) Less regulation = more environmental pollution = cancers (air pollution) & water-borne (i.e poor sanitation).
4). Poorest countries in tropics = high temps/rainfall = perfect conditions for vector borne diseases
What are causes of high prevalence of non-communicable diseases in ACs? (3)
1) More sedentary lifestyle (i.e high car ownership due to disp. Income) = increased obesity.
2) Poor diet (overconsumption) and diets with high fat/salt content (i.e fast foods/ ready meals)
3) Often service based economies = less physical activity
Who are W.H.O? How many member states? Who do they work with?
1) World Health Organisation are part of the U.N and are ‘global guardian of health’
2) 194 member states.
3) Work with member states & other U.N agencies (i.e. UNICEF, World Bank) plus NGOS (i.e. International Red Cross)
What does the W.H.O does to combat disease on international level? (6 different things)
1) Collects data on diseases & causes of death
2) Provide leadership during health crisis and offer advise to member states
3). Offer technical assistance during health crisis/emergencies.
4) Help member states with health strategies
5) Research health problems (i.e. the effects of COVID/malaria vaccine with pharma companies).
6) Sets global standards - i.e Safe Air Pollution levels
Specific A01 examples of what W.H.O does to combat disease on international level? (5 different things)
1) Collects data (World Health Statistics = every year on causes of death).
2). Provide leadership (during COVID-19)
3). Offer technical assist during health crisis (social distancing, hand washing)
4). Help states with strategies (helped Ethiopia tackle malaria with 5 year plan).
5) Research health problems (i.e. the side effects of COVID)
6) Global standards (PM levels for air pollution)
What is H1N1? Where did it start? What were estimated number of deaths?
1) Swine flu.
2)April 2009 in Mexico.
3). WHO average deaths = 284,500 but estimates between 151k-575K
What type of disease is H1N1 and how it is spread amongst humans? (2)
1) Zoonotic & infectious disease.
2) Spread amongst humans via coughing and sneezing like regular influenza
Where was H1N1 most prominent? How did W.H.O respond? When did pandemic subside? (3)
1) Mexico, North America & U.K/Australia.
2) Declared public health emergency in April 2009 & declared it pandemic in June 2009.
3) Declining numbers by May 2010 (WHO = pandemic over, Aug 2010)
How can physical barriers positively mitigate the spread of disease? (2)
1) Certain physical barriers (i.e a huge rainforest, desert, mountains, ocean) can isolate communities from contact with diseased population & the barrier stops communicable diseases reaching them.
2) Remoteness can also protect main population if disease originates in isolated areas
Examples (A01) of where physical barriers has stopped spread of disease (3)
1) Remote Amazonian tribes (i.e Nahua) were protected from communicable diseases due to unpeneterable forest for 1000s of years (until recent contact with miners/loggers in 1980s).
2) Island communities in Pacific had no COVID cases due to large distance of ocean between them.
3). Ebola originated in remote TRF in Africa in 1980s = its remoteness reduced its spread for many years
How can physical barriers cause problems for the spread of disease?
1) Barriers like mountains/seas means it can be hard to reach remote communities if a disease outbreak occurs = harder to get assistance too
Example of where physical barriers made it harder to combat a disease (2)
1). Nepal EQ in 2015 - Gorkha region the mountains mean it is 2 days walk to healthcare. Landslides cut off the mountain tracks & so medical teams could not combat the cholera cases that broke out in mountain communities.
2). Polio still present in Pakistan mountains as it is difficult to get vaccinators to these areas
How many people living with HIV now and when was it considered height of pandemic?
35 million now. Height of pandemic - 1980s
Highest concentration of infections & deaths for HIV
70% infection = Sub-Saharan Africa & highest deaths in Southern Africa
How did the U.N set HIV/Aids as prioirty disease to be solved? Has there been success? (3)
- It was a Millenium Development Goal (6a) and is a Sustainable Development Goal (3.3 - Fight Communicable disease). They currently encourage “90,90,90” strategy - 90% aware of status, 90% taking ART, 90% virally supressed.
- SUCCESS: HIV deaths have declined and so have new infections since 2000s.
- However - still pandemic levels as over 38 millon people living with it.
Which organisations work with the UN to tackle the aids pandemic?
National governments, NGOs (Oxfam), Other arms of U.N (Unicef/WHO) & private organisations (Bill & Melinda Gates Foundation & The Global Fund - finance part of HIV)
What are three main areas for combatting the HIV pandemic?
Prevention, Diagnosis & Treatment
What is prevention in HIV mitigation context? (3)
1) Involves educating the public on how HIV is spread (i.e. through blood & semen, educating through TV adverts/posters).
2) Promoting human rights and equality for those at most at risk of HIV (i.e. reduce discrimination & stigma so those at risk access health programmes)
3) Male Circumcision - this reduces transmission of HIV
A01 examples of prevention strategies used in HIV pandemic?
1) Education campaigns - ‘Worlds Aid Day’ every year by U.N (1st Dec).
2) ‘What’s Your Risk’ TV advert in South Africa and also TV adverts in the UK during the 1980s ‘Iceberg’ advert.
- Male Circumcision promotion posters produced by South African govt.
What is diagnosis & treatment in HIV mitigation context? (2)
1) Diagnosis = rapid diagnostic tests to screen blood & saliva samples (esp in AC countries)
2) Treatment = use of anti-retroviral drugs (ARVs) to suppress HIV virus and stop it developing into AIDs
A01 examples of diagnosis & treatment strategies used in HIV pandemic?
The Global Fund has helped provide funding for ARVs (anti-retroviral drugs) to nearly 18 million people globally. The cost of ARVs has reduced from $10k a year to nearly $100 a year per patient but still too expensive for some LIDCs
Barriers to combatting HIV spread? (3)
1) Stigma of having AIDs is still a problem in some countries leads to less people getting tested
2) Stigma leads to discrimination = patients refused treatment or sacked from jobs, deportation in places like Egypt
3) Some LIDCs do not have financial resources to screen or treat patients effectively
What is Salicin used for? Conditions for growth? (2)
1) Pain relief (i.e asprin)
2) Likes waterlogged conditions (near rivers) and can be in variety of soil types (light sands or heavy clay)/ slightly acidic or alkaline soils
What is Caffeine used for? Conditions for growth? (2)
1) Used as stimulant for heart, muscles etc
2) Tropical conditions (27°c), heavy rainfall (1000-2000mm a yr) & well drained soils that are rich in nitrogen
What is Quinine used for? Conditions for growth? (3)
1) Malaria (from dried bark of tree)
2) Warm (above 20°c) and no frost. Lots of rainfall (above 2000mm).
3) Well drained soils that hold organic matter well.
What is Morphine used for? Conditions for growth? (2)
1) Pain relief (i.e after an operation)
2)Very warm conditions (30-38°c), no frosts and well drained soils - prefers clay/loam soils
What is the relationship between medicinal plants & developing world?
Rely on traditional medicines made from medicinal plants. 80% of developing world use traditional medicines (rather than synthetic ones made in labs) and so demand for medicinal plants is very high
Why are some wild medicinal plants under threat? (3)
1) Overharvesting for use in practices such as traditional Chinese medicine (TCM).
2) TCM predominanalty uses roots (rather than leaves) which causes whole plant to be taken.
3) Some plants are slow-growing and aren’t given time to recover.
Relationship between deforestation and medicinal plants?
Loss of undiscovered medicinal plant lost every year due to habitat destruction (only 10% of Amazon TRF plants used by natives have been scanned for medicinal value/. Estimated 1 important drug lost every 2 years due to deforestation)
A01 example of a plant threatened by over-harvesting
Himalayan Yew in Nepal threatened as cutting down tree to get anti-cancer drug Taxol
What drug have they aimed to preserve in Samoa, how do they get it and what is it used to combat?
Prostatin (used for treatment of HIV) extracted from bark of Mamala Tree
Which two organisations worked together in Samoa to preserve medicinal plants? What was the agreement?
1) AIDS Research Alliance (from USA) & Samoan Govt.
2)Alliance allowed to extract drug from trees but 20% of profits from Prostatin would go to Samoan govt in return for not cutting down forest/keeping sustainable supplies of the tree
What is the NGO that has also been part of the package to keep sustainable medicinal plants in Samoa? (2)
1) Seacology.
2) Provided healthcare centres & funded ‘aerial’ walkway to promote tourism and stop need for Samoan’s to cut down forests for timber
Conservation Issues - the facts
- 1970’s - 21,000 medicinal plants listed
- In China, 4941 of 26,092 native species are used for medicinal purposes (18.9%)
1,300 native European species are used for medicinal purposes, 90% of which are harvested from the wild - 25% of drugs in AC’s are derived from wild plant species
- 80% of population in developing world rely on traditional medicines (80%)
What does disease eradication mean?
- Permanent reduction to zero of a disease
Top-down strategies for disease eradication?
- Imposed by international organisations and national governments
- Rely on the availability and sustained use of resources
- Can lead to substantial changes to risk
Not all countries can afford this strategy
What is a patent drug?
- Exclusive right to produce drugs for maximum 20 years from development
