Mon, Jan 26, 2015 - Page 3 News List

INTERVIEW: Veterinary expert critical of avian flu steps

Three new highly pathogenic strains of avian influenza were discovered in Taiwan this month. Lai Shiow-suey, an honorary professor of veterinary medicine at National Taiwan University, tells Jennifer Huang, a staff reporter for the ‘Liberty Times’ (the sister newspaper of the ‘Taipei Times’), that the government and poultry industry have been negligent in their efforts to combat the flu epidemic

By Jennifer Huang  /  Staff reporter

National Taiwan University honorary professor of veterinary medicine Lai Shiow-suey gestures during an interview in Taipei on Jan. 15 with the Liberty Times about the avian influenza epidemic in Taiwan.

Photo: Liao Chen-huei, Taipei Times

Liberty Times: What are the possible sources of the new strains of avian influenza?

Lai Shiow-suey (賴秀穗): The H5N8 subtype had never before been seen domestically. According to the Council of Agriculture, the “H5” hemagglutinin genome sequence of the local H5N8 strain is more than 90 percent similar to the one seen in South Korea, and the South Korean subtype shares the same origin with the ones found in Japan and China. It can be assumed that H5N8 was transmitted from South Korea or China by migratory birds.

H5N8 was found in China in 2013 and in South Korea’s duck farms in early 2014, causing massive death in layer ducks. Sporadic deaths of chicken infected with H5N8 were reported in Japan in April last year, and the subtype has also been found in the UK, Germany, the Netherlands and Italy since November last year.

The World Organization for Animal Health [OIE] subsequently issued a warning by the end of 2014, saying that H5N8 is a highly pathogenic strain that poses a major threat to various birds and even humans.

What worries me is that H5N8 must have existed in Taiwan for more than three months, and its contact with local viruses must have engendered another series of genetic reassortments.

The new strains of H5N2 and H5N3 that are affecting Taiwan have not been seen in neighboring nations, so it is unlikely that the new strains have their origins outside Taiwan.

The “H5” hemagglutinin component of the new strains of H5N2 and H5N3 is almost the same as that of the H5N8 seen in South Korea, which suggests the new strains could result from the mutation prompted by the local viruses’ contact with H5N8 transmitted from abroad.

The new strains of H5N2 and H5N3 have evolved into a highly pathogenic version of their low-pathogenic subtypes due to the introduction of the highly pathogenic H5N8.

LT: Ducks and geese farmers claimed that they had not thought that waterfowl could contract bird flu. Do the new strains have a different way of transmission? Were the measures adopted by the government ineffective?

Lai: Virus-carrying migratory birds usually stay somewhere close to water, so the virus is usually transmitted to the waterfowl first. Yet geese and ducks generally have higher tolerance to virus compared to chickens, so the infection might not necessarily cause massive deaths in geese and ducks.

However, the virus could take a heavy toll in chickens before being transmitted to mammals such as pigs and humans.

The recent subtype has caused a high mortality among waterfowl, with the death rate of geese at about 90 percent. It is obvious that Taiwan is dealing with a highly pathogenic subtype that overshadows anything the nation has ever seen.

However, the outbreaks of H5N8 in neighboring nations clearly indicated that the recent subtype could infect both waterfowl and landfowl. Duck farms in South Korea have seen serious flu epidemics since January last year, and by the end of last year the OIE warned that all kinds of birds are susceptible to H5N8.

H5N3 has infected chickens and ostriches in Germany and France, and a low-pathogenic strain of H5N3 was found in duck farms in Hualien County as early as 2013.

The fact that those new strains of avian influenza could transmit themselves to both waterfowl and landfowl should have alarmed the government and encouraged it to promptly enforce all the necessary measures at every poultry farms.

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