Question: How do viruses spread in animals?

Martin Johnsson answered on 13 Mar 2020:

It depends on the virus, and it’s the same ways as viruses spread in humans (we’re animals, after all 🙂 ).
An animal that is infected will produce virus particles. It depends on what part of the body the virus infects where those particles end up: they may be in the animal’s poo, or in small drops of water in the air the animal breeds out, and so on.
The way the virus spreads is that new animals come into contact with those virus particles, for example by eating them or breathing them in. Again, it depends on the virus what the route of infection is, because different viruses are able to infect different parts of the body.
Farm animals often live very close together in large groups, so infection might spread easily. Therefore, farmers are very careful about hygiene when entering their farms, bringing in equipment and moving animals around. Maybe you’ve been to a farm visit and been asked to put on protective clothing, and make sure you’ve not been in contact with other farm animals for a certain period of time. That is as a precaution against spreading infections, like viruses.