Why do migratory birds not pose more of a threat from a virology/contamination perspective?

Question

I understand that millions of birds cross continents each year to migrate. Obviously they don’t get immunised or anything like that. I’m just wondering how they don’t bring foreign bacteria/diseases with them?

My mind goes to Australia which has very strict laws for what you can bring in to the country, however they can’t stop what migrating birds bring in.

Thanks!

In: 9

Answer 1

Humans have very little contact with migratory birds, compared with how much contact we have with domesticated birds like chicken. So the former pose much less concern than the latter.