Summary Epidemiology of Infectious Diseases

Infectious Disease Epidemiology: Major Differences • A case can also be an exposure • Subclinical infections influence epidemiology • Contact patterns play major role • Immunity • There is sometimes a need for urgency (www) Epidemiology • Deals with one population • Risk  case • Identifies causes Infectious disease epidemiology  Two or more populations  A case is a risk factor  The cause often known (www) What is infectious disease epidemiology? Two or more populations Humans Infectious agents Helminths, bacteria, fungi, protozoa, viruses, prions Vectors Mosquito (protozoa-malaria), snails (helminths-schistosomiasis) Blackfly (microfilaria-onchocerciasis) – bacteria? Animals Dogs and sheep/goats – Echinococcus Mice and ticks – Borrelia What is infectious disease epidemiology? (www) A case is a risk factor … Infection in one person can be transmitted to others (www) What is infectious disease epidemiology? The cause often known  An infectious agent is a necessary cause What is infectious disease epidemiology used for?  Identification of causes of new, emerging infections, e.g. HIV, vCJD, SARS  Surveillence of infectious disease  Identification of source of outbreaks  Studies of routes of transmission and natural history of infections  Identification of new interventions (www) What is infectious disease epidemiology? Concepts Specific to Infectious Disease Epidemiology