1. Effect of disease
Chapter 39

2. Disease on a population
Disease – impairment of normal body function
Caused by – pathogens, poor diet, stress
Disease acts a limiting factor – has a regulatory effect
Not as serious an effect as before (‘Black Death’)
HIV potentially as damaging

3. HIV statistics

4. Use of vaccines Immunisation
– increasing a persons resistance to a disease
Vaccination
– deliberate introduction of an altered pathogen to help immunity
Smallpox:
Completely eradicated, because…
Spread through direct human contact only (no other hosts)
Immunity from vaccination is long term
Virus has only 1 antigen, easy to make a vaccine
Most diseases change too quickly for vaccination
- still have a regulatory effect

5. Control of childhood diseases
Developed countries:
most diseases controlled by vaccinations etc.
e.g. measles, whooping cough, diptheria, tetanus, polio, TB
Governments have minimum targets (95%) & immunisation schedules
Developing countries:
Despite initiatives (e.g. EPI) many millions die of the same diseases
Lack of info, money etc prevent children being immunised properly

6. Hygiene, sanitation & living conditions
Developed countries:
Social & economic factors help reduce disease mortality
E.g. hygiene, waste disposal, nutrition
Epidemics prevented by –
advance warnings
increased vaccine availability
general good health
Developing countries:
Lack of clean water, sewage disposal etc.
Contaminated water = 80% of diseases (e.g. diarrhoea)
- clean water, sanitation etc are badly needed