Apr 25, 2003 (CIDRAP News) – The recent death of a Dutch veterinarian due to an avian influenza virus was an isolated case and did not involve an unusual form of the virus, according to World Health Organization (WHO) and Dutch government officials.

In a statement issued yesterday, the WHO said, "Based on available evidence, WHO concludes that the death is an isolated case, as no efficient human-to-human transmission has been detected."

The current outbreak of highly pathogenic avian influenza (HPAI) in the Netherlands, caused by influenza virus A:H7N7, began in late February. Since then, 83 people have had confirmed H7N7 infections, including conjunctivitis in 79 cases and mild influenza-like illness in 13 cases, the WHO reported. Tracing of the veterinarian"e;s contacts has not revealed any transmission of the severe form of the disease to others.

The 57-year-old veterinarian died Apr 17, 2 days after visiting a poultry farm affected by HPAI. The WHO statement said he died of acute respiratory distress syndrome, and H7N7 was the only respiratory pathogen detected in pathology tests.

The Dutch outbreak has sparked concern that a dangerous new influenza virus could arise if the avian virus crossed into humans already infected with influenza. But Dutch Agriculture Minister Cees Veerman, in an Apr 23 letter to the Dutch Parliament, said, "It is now known that the influenza virus found in the veterinarian is identical to the circulating avian influenza virus. Thus a mutation of the virus has not taken place."

The WHO statement noted that avian influenza viruses have crossed into humans before. In Hong Kong in 1997, the H5N1 strain of avian influenza caused its first outbreak in humans, leading to 18 cases and 6 deaths. In mid-February of this year, the same strain infected two people in Hong Kong, killing one.

WHO officials said people in contact with infected poultry flocks should see a doctor if they experience any symptoms of respiratory disease. WHO is currently assembling an H7N7 test kit, which will be ready in 3 weeks.

Veerman"e;s report said 18.3 million birds on 1001 Dutch poultry farms had been killed as of Apr 21 in the battle to contain the HPAI epidemic. The Dutch poultry industry reportedly had about 100 million birds before the outbreak began. In addition, more than 500,000 birds have been destroyed in neighboring areas of Belgium.