This is sort of scary.  I think it could have something to do with water contamination.  There are so many types of bacteria.  There are also so many different types of pesticides used in farming.  I do think it's strange that this happened in a small area, which again, would lead me to think contamination of the ground or water.  I wonder about the reference to the cattle, thinking that might have something to do with it.  Scary stuff!