Immunology & Public Health Infectious Diseases & Epidemiology Immunology & Public Health

Pathogens Anything that can cause a disease Can include: Viruses – e.g. measles Bacteria – e.g. cholera Fungi – e.g. athlete’s foot Protozoa – e.g. malaria Multicellular Parasites – e.g. hookworm

Disease transmission Infectious Disease – capable of being transmitted from one person to another Transmitted by: - direct physical contact - inhaled air - indirect physical contact - body fluids - faecal-oral route/water borne - vectors (e.g. mosquitos)

Control of transmission Quarantine: - isolation of infected individual Antisepsis: - inhibition/destruction of disease causing micro-organisms - e.g. sterilising surfaces Individual responsibility: - good hygiene - sexual health - appropriate food handling Community responsibility: - quality water supply - safe food webs (e.g. food inspection, pasteurisation) - appropriate waste disposal - control of vectors (e.g. using insecticides)

epidemiology The study of disease characteristics, such as: - location of outbreak - patterns and speed of spread - geographical distribution Disease spread patterns: Sporadic Endemic Epidemic Pandemic These studies allow for appropriate control measures E.g. treatment, vaccinations

HIV statistics

Immunisation & Vaccination Immunisation: – developing immunity to a disease-causing organism Naturally acquired active immunity: - surviving an infection, and forming immunity against it Artificially acquired active immunity: - exposure to a weakened or altered form of a pathogen/toxin - acts as an antigen - initiates immune response E.g. by injection, nasal spray - often combined with an adjuvant - a chemical which promotes the antigen’s activity - enhances immune response

Vaccination programme

Vaccine clinical trials Initially trials are carried out on animals Then 3 clinical phases on humans - to prove they are safe and efficacious Phase III: Placebo-controlled: - control group are given a placebo Double Blind trial: - subjects don’t know if they are receiving active treatment or placebo - nor do the doctors - eliminates bias Randomisation: - subject details entered onto computer - people put into groups randomly Experimental error: - computer ensures this is minimised - age, gender etc mixed as much as possible - aided by as large a sample as possible - results can then be put to statistical analysis