Hong Kong University reports swine-pandemic flu reassortant

A laboratory at Hong Kong University (HKU) detected a reassortant made up of a swine influenza virus and the pandemic H1N1 virus in a sample obtained from a slaughterhouse pig as part of a surveillance programme.

 

It is the first reported reassortant between the two types of viruses. The virus was detected in a pig that was imported from the Chinese mainland, which has been notified about the finding, Hong Kong's agriculture department said in a statement. It was detected during HKU's regular influenza surveillance.

 

The agriculture department said that the finding does not pose a public health risk or present any food-safety issues.

 

Dr Malik Peiris, a microbiology professor who heads HKU's surveillance programme, said in the statement that the finding is not unexpected, likely occurs worldwide, and was only detected in Hong Kong because of intensive surveillance. He said further tests are under way to further characterise the virus.

 

A spokesman for Hong Kong's Centre for Health Protection, however, said that preliminary findings suggest the reassortant is sensitive to oseltamivir (Tamiflu).

 

So far the new virus has not turned up in surveillance of human flu specimens obtained from Hong Kong residents.

 

Hong Kong's Food and Environment Hygiene Department said it would step up inspection of imported live pigs and is reminding those who work with pigs to observe good hygiene and to wear appropriate masks and protective gear while working. It said about a third of those involved with pig farming and slaughtering have received the pandemic H1N1 vaccine.

 

Rodney B. Baker, DVM, president of the American Association of Swine Veterinarians and senior clinician in Iowa State University's College of Veterinary Medicine in Ames, said that it is not clear from the Hong Kong government statement how HKU researchers determined the reassortant, what gene is involved, or what the identity of the swine virus is.

 

"Reassortment is always a possibility, so finding this virus or similar viruses in Asia is not surprising," he said.

 

So far, analysis of swine and pandemic H1N1 viruses have revealed that genetic components of the pandemic H1N1 virus, which likely originated somewhere in Asia, were not present in swine influenza viruses before the pandemic, Baker said.

 

Baker said China produces 600 million to 800 million pigs each year and that most swine are not kept in biosecure buildings, as they are in the US. He added that all pigs entering Hong Kong come from mainland China, representing a tiny portion of Asia's total pig production. Despite the intensive surveillance in Hong Kong, very little swine surveillance is conducted throughout the rest of Asia.