Disease Flashcards
Learn.
Endemic
A disease which exists permanently in a geographical area or population group. Examples include sleeping sickness, confined to rural areas of in sub-Saharan Africa
Epidemic
An often sudden increase of a disease above what is normally expected in that population. The disease attacks many people at the same time and spreads through a population in a restricted geographical area.
Pandemic
An extensive epidemic- a pandemic is more widespread, affecting many countries or continents.
What parasite is malaria caused by?
The Plasmodium parasite
What are the two common Plasmodium parasites that spread malaria?
Plasmodium Falciparum- mainly found in Africa, the most common parasite
Plasmodium Vivax- Mainly found in Asia and South America
What type of mosquito spreads malaria?
Anopheles Mosquito
How is malaria spread? And how does it effect a person?
The mosquito bites someone who is already effected with malaria, the Mosquito is then infected
Malaria cannot move from person to person.
The parasite enters the bloodstream and travels to the liver.
The parasites grow and multiply in the red blood cells and at regular intervals, the infected blood cell bursts, releasing more parasites into the blood.
In 2015, how many people where at risk of malaria and in how many countries?
3.3 Billion people across 97 countries
Cases of malaria in 2015
214 Million cases of malaria world wide
How is HIV spread?
Bodily fluids of an infected person, i.e. semen, viginal and anal fluids, blood and breast milk.
Most commonly sex with no condom and sharing needles
What is the treatment for HIV?
There is no cure for HIV however, antiretroviral drugs (ARVs) manages it
2015 people living with HIV
36.7 million people were living with HIV/AIDs
How many people died from AIDs related infections
1.1 million
How many women globally are living with HIV
17.8 million 51% of all adults living with HIV
What Bacteria is TB caused from?
Mycobacterium tuberculosis
What Is latent TB and how many people have it?
One-third of the population are said to have latent TB, which means people have been infected by TB but are not yet ill with the disease and cannot transmit the disease.
How likely are people with TB to fall ill with TB
only 10% lifetime risk of falling ill with TB
In 2015 how many people fell ill with TB?
10.4 million people fell ill with TB
What percentage of TB deaths are in developing countries
95% of the TB deaths are in LIDCs
What are the two types of Diabetes and how are they different?
Type 1- Body’s immune system attacks and destroys the cells that produce insulin, It is characterised by deficient insulin production and requires daily administration of insulin. The cause of type 1 diabetes is not know and not preventable.
Type 2- The body doesn’t produce enough insulin, or the body cells don’t react to insulin. Type 2 diabetes comprises the majority of people with diabetes around the world and is largely the result of excess body weight and physical inactivity.
Prevalence of diabetes
422million in 2014.
Deaths caused by diabetes
2012 1.5 million deaths
CVD “risk factors”
high blood pressure, high cholesterol, smoking, inactivity, obesity and diabetes.
How many people died from CVD in 2015
17.7 million representing 31% of all global deaths. Of these deaths, an estimated 7.4% where due to coronary heart disease and 6.7 million were due to stroke
Expansion Diffusion
Disease spreads out from the source in all directions from the point of origin. The disease diffused outwards into new areas in the immediate vicinity. Carriers in some areas remain infected
Example of Expansion Diffusion
TB in East Asia- clustering of some of the 22 high-burden countries which account for 80% of all TB cases
Relocation DIffusion
Disease spreads into new areas, leaving the origin/source of the disease behind. The disease is not contracted I n areas between the source and new area (whilst being carried from one location to another) The disease dies out in its previous location.
Example of relocation diffusion
Cholera in habit originated in Nepal, and was brought over by Emergancy aid workers after the earthquake in 2010
Contagious Diffusion
Disease is spread through direct contact. Individual hosts carrying the disease pass it on to new contacts. Strongly influenced by distance (nearby individuals/regions have much higher probability of contact than remote ones). Contagious spread tends to occur in a centrifugal manner from the source region onwards.
Example of contagious diffusion
Ebola in West Africa in 2014-15
Hierarchical Diffusion
The disease spreads down through a particular system. Disease spreads through an ordered sequence of classes or places, usually from the largest centres to smaller, more isolated centres. Diffusion is also channelled along road, rail and air transport networks which facilitate contact between carriers and susceptible populations.
Example of Hierarchical diffusion
H1N1 (Swine Flu) started in Mexico City, but saw prevalence in other large cities e.g. LA, NYC AND Chicago before being contracted in smaller cities and rural towns in 2009
What are the stages of the Hagerstrand Model
Primary step, Expansion step, condensation step, and then saturation step.
What does that Hagerstrand Model Primary step involve
There is a strong contrast in disease incidence between the area of outbreak and more remote areas
What does the hagerstrand model Expansion Step involve
Diffusion is centrifugal- new centres of disease outbreak occur at distance from the source and this reduced the spatial contrast of the primary stage
What does the Hagerstrand Model Condensing Stage involve
The number of new cases is more equal in all locations, irrespective of distance from the source
What does the Hagerstrand Model Saturation Stage involve
Diffusion decelerates as the incidence of the disease reaches its peak
Name 4 physical barriers to disease diffusion
1-Distance, (the greater the distance away from the source, the lower the incidence of the disease) 2-Isolation/remoteness of a location, as there is relatively little migration in/out of the area 3-Mountain ranges restrict migration and have colder climates meaning some diseases cannot survive. 4-Large bodies of water restrict amounts and rates of migration
Name 4 socio-economic barriers to disease diffusion
Political border check the international spread of disease, e.g. travel ristrictions, immigaration control, addressing and monitoring the health of travellers, and closing borders. Public health education/advice and national campaigns. Mass vaccination programs to protect large populations against disease. Changing social norms E.g. using a condom, tissues and regular hand washing
How does climate effect patterns of disease?
Temperature, rainfall and humidity influence habitats of disease vectors e.g. the Anopheles Mosquito, and the tsetse fly which transmits sleeping sickness are both endemic in tropical climes.
How does relief effect patterns of disease
The influence of altitude on temperature and rainfall regimes affects vector habitats. E.G. in Ethiopia at over 200m it is usually too cold for P. falciparum to develop the mosquito vector
How does water sources effect patterns of disease
Stagnant water affects prevalence of eater-borne diseases, such as Guinea worm disease, also creates a breading ground for mosquitos.
What three factors does malaria depend on
Rainfall, Temperature and Relative Humidity
Why do malaria need rainfall to spread?
Female Anopheles mosquitos lay their eggs in water- these hatch into large. The abundance of aquatic habitats, ideally involuted fresh water, depends on collection of water that is not fooling, such as puddles towards the end of, or just after rainy season.
Why is malaria effected by temperature?
Where arvage temperature is between 18 and 40 the mosquito takes more blood meals and increases the number of eggs laid, increasing the number of vectors. The large develop faster at higher temperatures and so the parasite has more time to complete its life cycle inside the mosquito.
Why is malaria effected by Relative Humidity.
When the average monthly RH is over 60% the mosquito becomes more active and has a better chance of survival