1.a. diseases can be classified and their patterns mapped. influenced by number of factors

infectious disease

caused by organisms such as bacteria, viruses, fungi or parasites that are passed diretly or indirectly from person to person

eg measles

non infectious disease

not caused by pathogens caused by other factors such as lifestyle factors, environmental toxins or gene mutation eg lactose intolerance

communicable disease

carried by microorganisms and transmitted through people, animals, surfaces, food or air, vectors, eg covid 19

non communicable disease

chronic diseases, not spread from person to person. 4 main types= cardiovascular, cancers, respiratory, diabetes. eg heart disease

contagious disease

passed directly from person to person through close proximity or physical contact eg flu

non contagious

usually requires a special mode of transmission between person and host such as vectors or transfer of bodily fluids eg malaria

epidemic

increase, often sudden in the number of cases of a disease above what is normally expected in that population in that area eg ebola outbreak

endemic

disease that exists permanently in a geographical area or human group eg malaria in parts of africa

pandemic

epidemic that has spread over several countries or continents, usually affecting a large number of people

zoonotic

infections animal disease that can cause disease when transmitted to humans

morbidity- illness mortality- death with indicators of morbidity

prevalence- total number of cases in a population at a particular time

incidence- number of new cases in a population during a particular time period

incidence rate= number of new cases/ number of people at risk

disability-adjusted life years (DALYs)- number of years lost because of premature death and disability; indicator of health risk and burden of diseasse

global patterns of morbidity differ depending on the type of disease looking at

UK 2021 causes of DALYs: heart disease, back and neck pain, covid19, alzheimer, pulmonary disease, lung cancers, depressive disorders, stroke, diabetes, falls

infectious or communicable are often more common in poorer countries. non communicable diseases are often more common in wealthier countries. lots of heart disease as disease more likely to kill you in developed/developing countries, in all continents. africa largely HIV/AIDS

physical factors which influence the patterns of disease- relief, climate

socio economic- level of development, funding in healthcare etc

UK diseases

1 to 10 is 9 communication 1 infectious. cancers, diabetes, dementia, heart disease etc

malawi diseases

half infectious, 4 non communicable. HIV/AIDS, TB, heart diseases, malaria, other infectious diseases

how to determine severity of a disease

can be through several factors with key ones being case fatality rate- how many of the infected people die, morbidity- how sick people become eg long vs short term, and treatment availability- is effective treatment or vaccines available and exist

polio

infectious, contagious, communicable, can be endemic, rarely epidemic in current times, no pandemic. most mild/ symptom free. 1/200 result in permanent paralysis. nearly eradicated due to vaccination. transmitted by food and water. less than 100 cases worldwide

ebola

infectius, contagious, communicable, not endemic, can be epidemuc, no pandemic. severe haemorrhagic fever, high 65% fatality rate. not easy to cure. primarly found in central/west africa being transferred via direct contact with bodily fluids. severe outbreaks.

how diseases are spread

crowded living and working conditions, inadequate sanitation, unclean water supplies, inadequate nutrition- too little or too much, low income- no medical help no resources (soap, mosquito nets etc), ling working hours. physically or exhausting work, lack of or inaccessible healthcare, exposure to health risks at work as legalisation is not enforced, inadequate education eg HIV/AIDS sufferers not understanding safe sex

diffuse

dispere or be dispered from a centre- point of origin. infectious diseases dont stay put- tend to move and spread, more quicker as people are moving more, globalisation, time space compression, spread more than used to in time period

frictional effect of distance/ distance decay

incidence of a disease is likely to be affected by distance. places closer together/to the source are more likely to see a higher incidence. areas further away from the source are less likely to be affected and/or will be affected at a later date.

4 types of spatial

1. expansion diffusion- there is 1 place of origin. whatever is spread remains in the place of origin as well as spreading out at the same time. eg spanish flu- 40 mil worldwide within months, covid 19

2. contagious diffusion- spread by direct contact. the influence is strongest at the place of origin. the influence lessens as you get further away from the place of origin. eg cholera outbreak at Broad street london 1852- well was contaminated water

3. hierarchal diffusion- spread throughout a class or group of people. this could be where something spreads around one city and then similar spread occurs in another city. eg HIV/AIDS in USA san francisco then major LA and NY- smaller cities and towns. covid

4. relocation diffusion- whatever is spreading moves to a new place in time. there is a leap from one location to another. eg cholera in haiti 2010, brought in by emergency aid workers from nepal. HIV in southern africa along lorry routes

mixed diffusion

combination of contagius diffusion and hierarchical diffusion. AIDS is a prominent example in modern day society of a mixed diffusion disease, often spreading along the hierarchal, networks and contagious diffusion patterns.

sleeping sickness

bite of an infected fly, parasite multiplies in lymph and blood. unspecific symptoms= headaches, fever, weakness. parasite can cross blood brain barrier, migrate to nervous system= neurological changes= sleep disorders, sensory disturbances

treatment= difficult, parasite resistance to existing drugs= risk. only 4 drugs registered for treatment. without treatment sleeping sickness= death. disease occurs regularly in some regions of sub saharan africa- with population at risk of being 70 mil in 36 countries. 11,000 people currently infected with 3000 new in 2015