Zoonotic diseases: From animals to people

Zoonotic emerging infectious diseases are transmitted from a host animal, or reservoir species, to humans, sometimes by way of an intermediate host known as a vector. Diseases that can be spread from person to person (e.g., through respiratory droplets, like COVID-19) have the potential to become pandemics.

Host/ Reservoir Vector/ Intermediate HostHuman InfectionPrimary Drivers
Vector-borne zoonotic pathogens
Ex: West Nile virus, Lyme disease

Vector-borne pathogens with zoonotic origin; now restricted to people
Ex: malaria, dengue fever


Direct transmission pathogens from animal host; no secondary transmission
Ex: hantavirus pulmonary syndrome, rabies
Pathogens with reservoirs of both wild and domestic species
Ex: avian influenza

Respiratory droplets

Ex: Hendra, Nipah

Ex. Ebola, Marburg

Bodily fluids


Respiratory droplets


Primary Drivers

Land-use change

Climate change

Agricultural intensification

Permanent live animal markets, wildlife farming, and wildlife trade

Wild animal hunting, butchering, and consumption

Explore More

World Wildlife magazine provides an inspiring, in-depth look at the connections between animals, people and our planet. Published quarterly by WWF, the magazine helps make you a part of our efforts to solve some of the most pressing issues facing the natural world.

View all issues