As H7N9 Moves Down South...

(Credit: ChinaFotoPress/Getty Images)

The world's first case of human infection with the H7N9 avian influenza was found in mainland. As of 27 April 2013, a total number of 121 H7N9 avian influenza cases were confirmed, in which 23 people died.

So far the only human deaths were reported with H7 (H7N7) and H5 (H5N1) viruses that are highly pathogenic for poultry, according to the Central Veterinary Institute of Wageningen University in the Netherlands. Infections with H9N2 subtype (low pathogenic for poultry) are also known in humans. This H9N2 virus has certain genes that encode for internal proteins, related to genes of the highly pathogenic H5N1 virus. The highly pathogenic virus H7N9 now found in China does not have features that makes it highly pathogenic for poultry, but does have some genetic characteristics (e.g. mutation in HA that allows for better binding to human receptor, deletion in NA and mutation 627 in polymerase PB2), that also occur in for poultry highly pathogenic viruses which have been detected in human infections with fatal outcome.

Earlier in the month, there were rapid testing for live chickens that were being supplied to Hong Kong. The Secretary of the Food and Health Bureau, Ko Wing-man said that, there have now been more than 26,000 samples being tested but none of the chickens were infected with H7 virus. The serum test will soon be introduced in Hong Kong, but due to technicalities, the exact timing for that is still not confirmed.

As the "5-1" Golden Week is approaching, the increase in people and logistics will also enhance the risk of virus transmission. Ko Wing-man pointed out that there have been new cases of H7N9 human infection in the three neighbouring provinces - Guangdong, Fujian, Hunan and Jiangxi. This confirms the existence of the H7N9 virus in the poultry market of these three provinces. Authorities will shortly be meeting with Guangdong experts to discuss the need to adjust the risk rating. Mr Ko was concerned about the possibility of the epidemic moving to the south. He pointed out that, "Hong Kong should get psychologically prepared, since the H7 virus may appear in both poultry or humans." However, he called on members of the public not to worry too much about the virus, since, at this stage, it is not transmissible amongst people. Even if the first case appears in Hong Kong, it can sufficiently be dealt with through early diagnosis and early isolation.