"Pig Fever" is sweeping through the expanding Chinese swine industry, according to swine veterinarians who have traveled there this fall.
University of Nottingham, England, swine veterinarians Steven McOrist and Stan Done observed the outbreak first-hand during a recent visit to China's swine veterinary centers.
China's hog industry is "rapidly consolidating" on a scale similar to that in the U.S., McOrist says. This includes the segmentation of farrowing and finishing, with 500- to 1,000-head sow barns and "routine off-site finishing" popping up around Chinese cities.
Comprising a possible combination of Porcine Reproductive and Respiratory Syndrome (PRRS), Porcine circovirus type 2 (PCV2) and other diseases, this year's "Pig Fever" outbreak has swept through this growing number of Chinese finishing facilities, resulting in more than 1 million culls.
"Clinical signs were predominant in finishers and consisted of lethargy, reduced or loss of appetite, high fever and deaths, with occasional coughing only. Pigs and photos we examined also indicated generalized blue skin discoloration in some affected pigs," McOrist says. "Diagnostic tests we assessed from reliable centers showed active PRRS and PCV2 infections, with common secondary Pasteurella infections. Many of the affected farms were also positive for hog cholera infections."
The presence of other disease pathogens in general could have created conditions favorable for the development of a more severe strain of PRRS, McOrist adds.
"One likely situation is that a more acute and lethal form of PRRS, not unlike the previous SAMS (Swine Abortion and Mortality Syndrome) outbreaks in the U.S.A. has now emerged in China, and this is the published suggestion of the Chinese authorities," he says. "It is also possible that 'normal' PRDC (Porcine Respiratory Disease Complex) and PCVAD outbreaks on affected farms had become complicated by active hog cholera."
Controls have been introduced in an effort to control the outbreak that has claimed more than 1 million swine deaths in the past year. McOrist urges heightened observation and intensive treatment for swine populations where symptoms of porcine respiratory diseases are observed.
"Control was being attempted through increased PRRS vaccinations, but few other noteworthy suggestions were apparent," McOrist observes. "[Swine practitioners and producers] are urged to be vigilant for more lethal PRRS cases."