Team studies disease outbreak among pigs in China

A group of scientists traveled to China in December to investigate an ongoing outbreak of high-fever disease in swine that has killed millions of pigs since 2006.

The team members were Dr. Butch Baker, senior clinician at Iowa State University College of Veterinary Medicine; Dr. Eric Neumann, previously with the National Pork Board and now a senior lecturer at the Massey University veterinary institute in New Zealand; Ying Fang, PhD, a veterinary microbiologist at South Dakota State University, who is originally from China; Dick Hesse, PhD, director of diagnostic virology at Kansas State University College of Veterinary Medicine; and Johnny Callahan, senior scientist specializing in development of viral assays at Tetracore Inc., one of the trip's sponsors.

Dr. Neumann recounted the visit for the board of the American Association of Swine Veterinarians, also a trip sponsor, during the AASV annual meeting in March. Team members spent two weeks visiting farms to observe the clinical signs of the high-fever disease in pigs, collecting samples to test for viral agents, and consulting with Chinese scientists. Real-time assays identified the presence of porcine reproductive and respiratory syndrome virus, classical swine fever virus, and porcine circovirus type 2b. Tests did not find African swine fever virus or PCV2a.

According to a brief summary from the National Pork Board, another trip sponsor, the most common combination of agents in pigs with the disease was the PRRS and PCV2b viruses—and the second most common was the CSF and PCV2b viruses.

A letter in the November/December 2007 issue of the Journal of Swine Health and Production, from two English veterinarians who also traveled to China recently, suggested that co-infection with an American strain of PRRS virus and a virulent CSF virus is a possible cause of the high-fever disease. The letter adds that Chinese scientists have focused on the theory that the problem is a highly pathogenic PRRS virus strain.

The National Pork Board noted, in its summary of the December investigative trip by U.S. scientists, that swine diseases in China may pose biosecurity risks for the global pork industry. The team seeks to publish its findings in the near future.