Commentary
H5N1 In South Korean Cat
Recombinomics Commentary 12:50
July 24, 2008
Quarantine authorities are investigating whether a cat died of bird flu in Gimje, North Jeolla Province, where a highly pathogenic strain of the disease broke out in April. If the cat is found to have died of avian influenza, it would be the first mammal to die of the disease in Korea. Dr. Kim Chul-joong, a professor at the College of Veterinary Medicine at Chungnam National University, said Wednesday, “We isolated the highly pathogenic strain of avian flu from the dead cat found along the Mangyeong River in Gimje and have asked the National Veterinary Research and Quarantine Service to confirm the cause of death of the cat.”
The above comments indicate H5N1 is still present in South Korea, regardless of the cause cat death. Clade 2.3.2 is circulating in South Korea. This is a sub-clade of 2.3, which is also called the Fujian strain.
There are four clade/sub-clades that have been isolated from dead patients. Clade 1 was confined to southeast Asia and caused the patients deaths in Vietnam, Thailand, and Cambodia in 2004/005. Clade 2.1 has been isolated from patients in Indonesia since 2005. Clade 2.2 (Qinghai strain) has been isolated from patients in a number of countries west of China since 2006. Clade 2.3 (Fujian strain) has been isolated from patients in China and southeast Asia since 2005.
In addition to fatal infections in patients, these H5N1 sub-clades have also been associated with deaths of many mammalian species including clade 1 deaths of wild and domestic cats, dogs, and palm civets in southeast Asia, clade 2.1 deaths of dogs and cats in Indonesia, clade 2.2 deaths of cats, dogs, foxes, stone martens, jackals in the Europe, the Middle East, Africa, and south Asia. In addition to the animal deaths, H5N1 has been associated with asymptomatic infections in mammals and has been used to infect experimental animals such as ferrets and mice.
The clade 2.3.2 from South Korea infected lab mice and ferrets as well as a soldier/ culler who had bird flu symptoms and was H5 PCR positive. The failure to isolate the H5N1 from the soldier does not indicate he was not infected. Similarly, the official cause of death of the cat has nothing to do with the isolation of H5N1 or its current/continued presence in South Korea.
The presence of clade 2.3.2/2.3.4 H5N1 in the cat raises more questions about surveillance in adjacent countries, including Japan and Russia which have isolated Fujian clade 2.3.2 H5N1 recently, which is over 99.7% identical to the H5N1 reported in South Korea. There have been excessive poultry deaths in Russia, bit the poultry was said to be H5N1 negative.
The presence of H5N1 in South Korea suggests H5N1 is endemic in the area, and surveillance detection failures remain a cause for concern.
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