Swine flu follow-up criticised as inadequate

A Hong Kong University study has highlighted worrying gaps in the follow up to last year’s outbreak of H1N1 swine flu in the light of a fast-spreading outbreak amongst pigs in China.

Researchers with the Laboratory of Emerging Infectious Diseases and Department of Microbiology with Hong Kong University’s Li Ka Shing Faculty of Medicine, sequenced viruses collected over 12 years from the snouts of pigs at the territory's biggest slaughterhouse, which receives pigs from all over China.

In January they found a new strain of H1N1 on a surface protein associated with the pandemic flu. This served as a stark reminder of the risks of another swine strain emerging that could spread among people. Flus easily swap their eight genes and any new combination might be able to spread among pigs and eventually reach another human.

The key concern identified by the study was that, while there is widespread testing of humans to monitor variations in flu strains, there are large gaps when it comes to the genetic testing of pigs.

In contrast to the highly organised and health-conscious pig-farm industries of the U.S and Western Europe, the Latin American and Asian industries engage in very little testing. This of real concern because pigs are susceptible to both bird and human flus.

The Hong Kong study, funded by a grant from the U.S government, identified a number of flus now circulating around the earth that pigs may be susceptible to, including six swine flus, several human seasonal ones and two or more avian flus. Included in the latter is the dreaded H5N1, thought to have killed 60 percent of the 500 people known to have contracted it in the last seven years, although it rarely spreads between people. The other is the relatively benign H9N2, which has caused only mild disease in 12 or so known cases.

Last year’s ‘swine flu’ epidemic was so named because the eight genes that comprised it had been observed in Eurasian and American pigs over the last decade. However, it has never been found in any stored samples with its original source still shrouded in mystery.

It has now managed to insinuate itself into 200 countries with new infections being reported every day, albeit with only mild to moderate symptoms. The study reported that swine flu is now circulating happily amongst pigs in China where it is also mixing certain genes with two or more swine flus.

Australia suffered one of the worst swine-flu outbreaks in the Asia Pacific region last year, with nearly 12,000 confirmed cases of the disease and at least 24 deaths. Globally, the World Health Organisation (WHO) recorded around 95,000 known cases occasioning some 429 deaths.