China pig disease unlikely to affect people -experts

HONG KONG, May 9 (Reuters) A disease that has wiped out as many as a million pigs in China in the past year is unlikely to spread to humans, leading veterinarians said today.

Chinese officials have blamed the epidemic on Porcine Reproductive and Respiratory Syndrome (PRRS), or blue ear disease, which is caused by a virus in the arterivirus family.

''No, we have no indication whatsoever that that (spread to humans) can happen at all,'' said Albert Osterhaus, a virology expert at the Erasmus University Medical Centre in Rotterdam.

''There are a lot of viral infections that do occur in certain animal species and are restricted to that particular species, and of course you can never say that something could never happen,'' he said.

''But it is highly unlikely especially when the virus has been around in pigs for quite some time already. I don't think it is likely,'' said Osterhaus, a veterinarian by training.

According to a veterinarian at Hong Kong's Agriculture and Fisheries and Conservation Department, PRRS is a very common pig disease, and vaccines are available to prevent it.

PRRS was first recognised in the United States in the mid-1980s. The disease has cost the US swine industry an estimated 600 million dollar each year.

The virus causes still-births, fever, loss of appetite, diarrhoea, redness of the skin and mortality rates of up to 50 percent on some farms.

The ears of affected pigs turn blue, thus giving it the household name ''blue ear disease''.

VIRUS WIDESPREAD The virus accumulates in white blood cells in the lung tissues of pigs. The white blood cells would normally ingest and remove invading bacteria and viruses, but not in the case of the PRRS virus. Instead, the virus multiplies inside white blood cells and eventually kills them.

Although Beijing has not published any figures, Chinese industry officials say the disease has caused a million pig deaths since the first outbreak in southern Jiangxi province in May last year.

The disease, which China has blamed on a strain of the virus, has since spread to many provinces in the south and northeast.

Osterhaus said the spread probably had to do with the way pigs are raised, with the close proximity of farms in China.

''It depends largely on the way animals are being kept and the possibility of contact between different farms. The disease has been spreading quite intensively in the world, so I don't think from that point of view that China is in a particular (unique) situation,'' he told Reuters by telephone.

China's Disease Control Centre at the Ministry of Agriculture is working to find effective vaccines against the current strain of the virus in China, but that might not be easy because the virus mutates quickly, said an official at the centre.

China issued draft rules for pig slaughterhouses to protect people's health and the quality of pork products on Wednesday.

Slaughterhouses must be licensed and approved by local governments and environmental bureaux, and must be located away from drinking water supplies, residential districts and public areas, the Ministry of Commerce said on its Web site.

REUTERS GL PM1742