Lapses in halting avian flu outbreak

鳥インフルエンザ対策不手際

Chickens at the farm — one of the largest in Kyoto — began dying in large numbers Feb. 20. More than 133,000 died. But the operator firm, Asada Nosan, did not inform health authorities for reasons that suggest willful negligence. The epidemic was confirmed Feb. 28 after officials inspected the site, acting on an anonymous tip that chickens there were dying en masse.

Furthermore, Asada Nosan sold 15,000 live chickens to slaughterhouses at the end of February before testing began, and some of the birds are thought to have spread the virus at one or more of the processing centers. The shipments, made well ahead of schedule, raised questions about the firm's business ethics; it reportedly was trying to "empty the farm of sick chickens" by selling those that were alive.

Avian flu outbreaks — and any viral epidemics, for that matter — require basically the same steps to prevent their spread: early discovery and quick containment. In another words, speed is of the essence. Asada Nosan made a grave mistake by failing to report the outbreak for as long as a week, increasing the risk of infection far and wide.

The case in Yamaguchi, discovered in mid-January, was the first bird flu attack in Japan in 79 years. Since then, chicken farmers across the country presumably have taken a variety of precautionary measures. But Asada Nosan was evidently not among them. Apparently concerned more about profit than safety, it tried to minimize losses by clearing its live inventory.

The firm's reporting failure could constitute a violation of the law governing infectious diseases that affect livestock. The law requires farmers and veterinarians to report immediately any case of bird flu infection, either real or suspected. The Ministry of Agriculture, Forestry and Fisheries is empowered to take disciplinary and other actions, including bringing criminal charges, against offenders.

Asada Nosan says it did not report the deaths because it suspected an outbreak of enteritis — not avian flu. This explanation won't wash. Since few vets in the country have firsthand knowledge of the disease, it is reasonable to suspect an outbreak of bird flu when a large number of chickens start dying. The firm should have reported the outbreak immediately. Then it should have stopped all shipments, perhaps for a week or so, until tests were completed.

The three outbreaks in Japan, including the small case that occurred in Oita Prefecture in mid-February, are thought to have originated from different sources. This raises the disturbing possibility that the deadly virus may be hiding in other parts of the country. Equally disturbing, some routes of infection will likely remain a mystery, as is often the case with investigations of viral infections.

As the avian flu pandemic continues to sweep much of Asia with no end in sight, the big challenge for Japan is to stop the spread in its tracks. Otherwise, the virus could spread to much of the country. Although no one in Japan has been found infected, there is no assurance that bird-to-human transmissions will not occur in the future. In Vietnam, it is reported that two-thirds of the more than 30 people who became infected have died.

For a start, health checks should be conducted on all workers at chicken farms and processing facilities nationwide. In the case of Asada Nosan's Kyoto farm, it is urgent that an estimated 200,000 chickens be disposed of safely, including those that have died. Dead chickens, unless properly treated, could be a source of infection.

There are no reports, in Japan or abroad, of people becoming infected from eating chicken eggs or meat. Experts point out that viruses die at temperatures of higher than 70 C. Which means that consumers should not panic. For all the potential risks posed by avian flu, food safety is not immediately endangered.

The Japan Times Weekly
March. 13, 2004
(C) All rights reserved

      2月20日以来、同養鶏場で鶏13万羽以上が死亡したが、経営会社の浅田農産は関係当局に一切連絡しなかった。匿名の通報があったため、当局が検査して大量感染が確認された。

      検査が始まる前に、浅田農産は生きている1万5000羽の鶏を屠殺場に出荷したため、ウィルスが広範囲で蔓延したと見られる。同社の企業倫理には重大な疑問がある。

      ウィルス性の疫病の蔓延を防止するためには、早期発見と迅速な感染防止が必要だ。浅田農産は、1週間の間、疫病の発生を隠し、感染の危険を増大させた。

      1月に山口県で確認された鳥インフルエンザは、日本で79年ぶりに発生したものだ。全国の養鶏場はいろいろな予防措置を取ったと思われるが、安全よりも利益に眼がくらんだ浅田農産は別だった。同社が問題を関係当局に届けなかったことは家畜の感染症に関する法律の違反行為とされ、農水省は刑事告発をすることができる。

      これまでに、大分県での発生を含め、3件の鳥インフルエンザ感染が確認され、他地域でも感染が隠されている可能性もある。

      鳥から人間に鳥インフルエンザが感染しないという保証はない。ベトナムでは感染者30人以上のうち3分の2が死亡したという。

      まず、養鶏場、屠殺場の労働者に対する健康診断を実施すべきである。浅田農産では、死亡したものも含め20万羽の鶏を安全に処分することが肝要だ。

      鶏肉や卵を食べて鳥インフルエンザに感染した例は国内外で報告されていない。食品の安全は今のところ危険にさらされておらず、ウィルスは70度以上の過熱で死滅するので、消費者はパニックに陥るべきでない。