History of Epidemics

Key definitions

epidemic

an outbreak of a disease that affects a large number of individuals at the same time

endemic

a disease that is always present in an area

pandemic

a global pandemic spreading across continents

Zoonosis

• When viruses move from animals to humans

• Around 60% of human infections are estimated to have an animal origin.

• Around 75% 'jump species' from animals to people.

• More than 330 diseases emerged between 1940 and 2004

Human : Animal interactions

• Intensive Wildlife Farming

• Wildlife Hunting

• Live Animal Markets

• Domesticated Animals 

• Exotic pet trade

How are they transmitted?

• Food-borne infections

• Water-borne infections

• Vector-borne infections

• Proximity or indirect contact with animals

• Direct contact with animals

Other routes of emergence

• appear ‘out of nowhere‘

• reappears after a period of time eg. plague

• Disseminate from an isolated population to naive populations e.g. Zika virus

• Mutation and adaptation e.g. Influenza virus

• Natural disasters e.g. cholera

Causative Agents

Bacteria

• plague

• sphillis

• typus

• typhoid

• cholera

Viruses

• smallpox

• influenza

• polio

• HIV

• ebola