More than 9 million chickens killed to control Dutch avian influenza

Apr 4, 2003 (CIDRAP News) – More than 9 million chickens have been killed and another 2 million are likely to meet the same fate in the battle to contain the month-old epidemic of highly pathogenic avian influenza (HPAI) in the Netherlands, according to reports from there.

Dutch Agriculture Minister Cees Veerman this week ordered the destruction of almost all remaining chickens in the Gelders Valley, a number estimated at more than 2 million, according to a report on ProMed-mail, the Internet-based reporting system of the International Society for Infectious Diseases.

Recent reports from Reuters and other sources have said that more than 9 million of the Netherlands' total of about 100 million chickens have already been destroyed because of the epidemic. The epidemic, which surfaced at the end of February, has been mostly confined to the Gelderland province. However, a Reuters report today said that two new suspected cases of the disease have been found outside Gelderland, prompting quarantines.

The Dutch Agriculture Ministry announced Apr 2 that 153 poultry farms were "definitely infected" with HPAI and another 43 farms were "seriously suspected" of infection, according to the ProMed-mail report. The report also said that an influenza virus has been detected in dead wild ducks and crows in the Netherlands, and tests were under way to determine if it is the same as the outbreak virus.

The Dutch outbreak also has spread to the human population to a limited degree. European health authorities report that 247 people who were exposed to infected poultry have had conjunctivitis or influenza-like illness, but the number of cases has fallen since mid-March, possibly in response to control measures.

An article in the Mar 27 issue of Eurosurveillance Weekly says that several workers who had been exposed to infected poultry contracted conjunctivitis on Mar 11, and some tested positive for influenza A(H7N7), the HPAI virus. By Mar 26, an enhanced surveillance effort had identified 247 people who had been exposed to infected poultry and had conjunctivitis, influenza-like illness, or other symptoms.

Of the 247 patients, 65 (26%) tested positive for influenza A(H7N7), 5 had influenza A(H3), 137 had no virus, and 40 were still awaiting results, the report said. "No double infections with influenza A/H7N7 and A/H1 or A/H3 viruses have been found. Coinfection with both human and avian influenza virus could potentially lead to a reassortment of both viruses and result in a new pandemic," the report stated.

The number of reported conjunctivitis cases and the proportion of cases featuring H7N7 virus declined after Mar 13, possibly because of control measures adopted around that time, according to the article. The control measures included use of protective glasses, masks, and treatment with oseltamivir, an antiviral drug.

See also:

ProMed-mail report (Apr 2)

Eurosurveillance Weekly report

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