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Zoonosis
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A zoonosis is a disease or infection that passes naturally from vertebrate animals, the ones with a backbone, to people. The germ that causes it is called a pathogen, and what defines a zoonosis is that it reaches us from an animal.
That crossing has a name: spillover, and it means getting past the biological barrier that separates one species from another. The pathogen spills over like a river overflowing its banks onto someone else's land. It can arrive through direct contact with the animal, or through food, water or the environment. Humans are usually accidental hosts: the pathogen ends up in our bodies by chance.
After that crossing, not all zoonoses follow the same path. Some, like HIV, started as zoonoses and later mutated into strains that circulate only among humans. Others, like salmonellosis, can come back again and again as outbreaks.
In brief
A zoonosis is a disease or infection that is naturally transmitted from vertebrate animals to humans.
The pathogen crosses the biological barrier between species, a step called spillover, and reaches people through direct contact or through food, water or the environment; humans are usually accidental hosts.
The pathogen spills over like a river overflowing its banks onto someone else's land.
Some, like HIV, start as zoonoses and later mutate into human-only strains; others, like salmonellosis, can cause recurring outbreaks.
Sources (2)
- World Health OrganizationZoonoses, WHO fact sheetPublished
- National Center for Biotechnology Information, StatPearls PublishingZoonotic-Related Diseases, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated