In China , large - scale outbreaks of severe diarrhea <*> have occurred in pigs since late 2010 .
caused by viruses
In China , large - scale outbreaks of severe diarrhea caused by viruses have occurred in pigs since late 2010 .
In China , large - scale outbreaks of severe diarrhea caused by viruses have occurred in pigs since late 2010 .