Mutation of Bird Flu virus into a new strain is possible warn Japanese scientists

Main Category: Bird Flu / Avian Flu
Also Included In: Flu / Cold / SARS
Article Date: 18 Apr 2004 - 0:00 PDT

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Japanese scientists warn that the mutation of the Bird Flu virus into a new strain is possible. Despite a series of declarations by prefectural governments in Japan that bird flu has been contained, health experts stressed that precautionary measures should not be relaxed and efforts should be made to boost cooperation among related ministries.

Experts pointed out that the virus could mutate into a new strain of virus.

After Yamaguchi and Oita prefectures (in Japan) stated that the virus had been eradicated, Kyoto prefectural government followed suit early Tuesday.

In Osaka and Hyogo prefectures, from which shipments of chickens and eggs have been restricted under the Domestic Animal Infectious Diseases Control Law, the spread of bird flu is believed to have slowed.

The Agriculture, Forestry and Fisheries Ministry agreed, saying: "The virus is vulnerable to high temperature and humidity. It's highly likely that the number of outbreaks will decrease."

However, considering research on patterns of the spread of viruses in the past, such a conclusion seems to have been reached too hastily.

In Japan, the spread of human influenza viruses peaks in winter and drops in early spring.

However, Masato Tashiro, the head of the third department of virus research at the National Institute of Infectious Diseases (NIID), said, "This general principle can't be applied to bird flu."

For example, fatalities from bird flu occurred in Thailand and Vietnam, tropical humid countries with high temperatures, and the virus spread throughout the region despite the climate, which differs greatly from that of Japan.

But the difference in sanitary conditions between Southeast Asia and Japan make it difficult to compare the situations.

Some experts deny a relationship exists between the spread of the virus and the seasons. "Bird flu does not react to seasonal fluctuations," said Nobuhiko Okabe, head of the NIID's Infectious Diseases Surveillance Center.

In Kyoto Prefecture, it was confirmed that the virus had spread to crows in the first of such reports worldwide. Infected crows continued to be found even after chickens had been buried, and the route of infection remains unknown.

Toshihiro Ito, a professor at Tottori University's agricultural department who has researched the subject, said the virus was likely to have been transmitted from crow to crow. "There seems to be a chain of infections among crows," Ito said.

Therefore, it is possible that the virus could evade eradication for some time, according to Ito. "I can't deny the possibility that another outbreak could occur," he said.

Other researchers believe that the virus could have been spread by humans, remaining on surfaces or objects and being transferred by touch. The National Institute of Animal Health, which is under the jurisdiction of the Agriculture, Forestry and Fisheries Ministry, compared and analyzed the genetic makeup of viruses detected in Asian countries, but has yet to identify a route of infection.

Some experts believe the virus was brought into the country by migratory birds. Based on this hypothesis, the Environment Ministry conducted a survey on such birds, but suspended the project at the end of March.

"Research of this nature is meaningless unless it's conducted on a wider scale over a period of time," Ito said.

Shigeru Omi, chief of the West Pacific region bureau of the World Health Organization, believes the virus already has taken hold in East Asia.

A WHO official said the announcements stating that bird flu had been eradicated "seemed to have been issued in the consideration of interested parties, such as the domestic poultry industry."

"The possibility of another outbreak in this region remains," he added.

Japan, therefore, should continue its vigil and maintain preventative measures and research.

The president and executives at a poultry farm in Kyoto delayed reporting the outbreak to the authorities and subsequently may have caused the spread of the virus to other areas. As a consequence, the president of the poultry farm was arrested.

The outbreak of SARS last year was exacerbated by the failure of Chinese authorities to publicize the disease in its initial stage, teaching the world a hard lesson.

Early discovery and containment are effective in restricting the spread of an infectious disease, even though this practice was not carried out in the Kyoto case. Authorities must keep this in mind when responding to such situations in the future.

Discussions on the topic have tended to focus on compensation to poultry farmers and ensuring that chicken meat was not contaminated.

However, attention to bird flu should not wane as it could evolve into a new strain of influenza through mutation, as was seen in the case of Spanish influenza in the 20th century.

Therefore, the Agriculture, Forestry and Fisheries, the Health, Labor and Welfare, the Environment and other ministries and agencies must combine efforts to tackle the problem on a national level.

From:
http://www.yomiuri.co.jp/newse/20040417wo34.htm