—but it takes very little viable organism to result in a massive loss of life in a barn: any introduction on footwear, on clothing or on a vehicle that brings it onto the property improperly.
Then there are other diseases where it is a considerable load and you have to be exposed; you have to bring a large load of the organism and expose it quite closely to the animal for it to transmit.
You can just look at COVID, right, and the initial strains of COVID we had. We know now. We were worried about paper and all the rest of it, and it turned out that it actually had to take a fair bit of exposure to be able to transmit. Now, with the new strains, we find that it doesn't take very much, and that even not wearing a mask outside and being in close proximity to people can result in a transmission. It's strain-dependent, even with viruses. Certainly, fungi are different from viruses, which are different from bacteria.
The question can be answered in many different ways, but the possibility is there for it to transmit very easily, depending on the disease.