date:May 29, 2014
many veterinarians also believe it is spreading through animal feed.
Harry Snelson, a veterinarian who represents the American Association of Swine Veterinarians, said repeat occurrences tend not to be as severe as the first outbreak, although farms are still losing pigs.
One potential reason for repeat outbreaks is that high levels of the virus, found in fecal material, overwhelm hogs' natural immunity, Snelson said.
It probably doesn't take a whole lot to override the level of immunity tha