A pig disease that affected millions of pigs in 10 provinces in China was caused by a new and highly pathogenic strain of blue ear disease. Initially it was thought that a normal PRRS virus was causing the disease.
The new virus strain spread very quickly, resulting in “unparalleled large-scale outbreaks” and caused high fever (40-42 degrees Celsius), shivering and a reddish rash brought on by congestion in the blood capillaries, the scientists wrote. “To our surprise, many grown pigs also died during this epidemic period, which is unlike the case for typical PRRS virus infection,” the scientists said.
Using genetic analyses, the scientists discovered changes in the molecular structure of the virus which made it unusually aggressive. “Environmental factors such as temperature and relative humidity in the summer and secondary bacterial infections may contribute to the generation of highly virulent PRRS,” they said.
China has stepped up its fight against the virus, which has caused enormous economic losses and contributed to soaring domestic pork prices, even feeding into national inflation levels. It launched a vaccination campaign last week.