May 24, 2007 (CIDRAP News) – Veterinary officials in Wales confirmed a low pathogenic H7N2 avian influenza outbreak today at a farm near the northern town of Denbighshire, a day after Nigeria reported its first H5N1 avian flu outbreak since late January.

The outbreak in Wales involves Rhode Island Red chickens that the farmers bought 2 weeks ago, the British Broadcasting Corporation (BBC) reported today. The birds began dying the day after they arrived at the farm, and by May 17, 10 of 15 had died.

The British Department of Environment, Food and Rural Affairs (DEFRA) in a statement said the remaining 30 birds on the farm were being culled today, and authorities have placed a 1-km restriction zone around the farm. The source of the outbreak is under investigation, and farm workers and others who may have had contact with the birds were being tested, DEFRA said.

The BBC report said two adults who were on the farm have symptoms of influenza and are receiving precautionary treatment.

Some countries, including the United States, destroy birds infected with any H5 or H7 influenza virus, because mild strains of these subtypes can mutate into highly pathogenic forms.

Christianne Glossop, chief veterinary officer for Wales, told the BBC that authorities don"e;t believe the disease is spreading rapidly. "While we are taking this very seriously, this is a low pathogenic avian flu," she added.

In February, England experienced its first H5N1 avian flu outbreak at a turkey farm in Suffolk, which led to the culling of about 152,000 birds. In April 2006 a low-pathogenic form of H7N3 avian influenza struck three English farms, leading to the culling of 50,000 poultry.

A handful of H7N2 outbreaks in poultry were reported in the United States in 2004, involving farms in Delaware, Maryland, and New Jersey.

Though H7N2 is not considered a human health threat, one of the few known human cases of avian flu in the United States involved an H7N2 virus. In November 2003 a Caribbean immigrant from Yonkers, N.Y., was hospitalized with influenza, which the Centers for Disease Control and Prevention (CDC) later identified as H7N2. Health authorities were puzzled by the case because the man had had no known contact with birds.

Nigeria reports new outbreak
Meanwhile, health officials in Nigeria confirmed an H5N1 outbreak in birds in Namaturu village in the country"e;s northern state of Zamfara, Agence France Presse (AFP) reported yesterday. Aminu Abdulrazak, a state health minister, said 200 birds were culled and the area was disinfected to curb the spread of the disease.

Nigeria"e;s last outbreak occurred in late January, according to a report from the United Nations Food and Agriculture Organization (FAO). The disease is now considered endemic in the country.

In February, Nigeria reported its first human H5N1 case, in a 22-year-old woman who fell ill and died after helping butcher an infected chicken. Nigeria has had no confirmed human cases or deaths since then.

Experts support poultry vaccination
In a report following an international poultry vaccination conference in Verona, Italy, the FAO said disease reporting and control policies have improved, but stressed the importance of poultry vaccination for stamping out the H5N1 virus, particularly in countries where the disease is endemic. The agency said poultry vaccination should be used along with other control measure such as culling flocks and controlling the movement of birds.

Poultry vaccination for H5N1 has sometimes been controversial. Experts contend that if poor quality vaccines are used, vaccinated birds can become infected without being visibly sick, which can lead to further spread of the virus.

The hallmarks of a successful vaccination program include use of a high-quality vaccine that meets OIE standards, rapid and safe delivery of the vaccine, systematic monitoring of vaccinated flocks, control of poultry movement, and adequate financial resources, the FAO report said.

"Any vaccination policy should include an exit strategy so that countries do not rely on costly long-term vaccination campaigns," the FAO said.

In Nigeria, commercial poultry farmers are vaccinating their birds despite a government ban, the United Nations Integrated Regional Information Networks (IRIN) reported today. Mohammad Saidu, head of Nigeria"e;s World Bank-funded avian flu control program, warned that improper vaccination practices can contribute to the spread of H5N1, the IRIN report said. He added that Nigerian avian flu experts are concerned about reports that poultry farmers are buying vaccines from local markets that offer poorly regulated imported vaccines or products that are fake.

In a February report on the status of H5N1 in Nigeria, the FAO recommended that the country add vaccination to its avian flu control strategies. However, Saidu, in the IRIN report, said more research is needed. "The outcome of our studies in the country will help us make an informed decision," he said.

WHO confirms human case in Indonesia
In other developments, the World Health Organization today recognized a fatal human case of H5N1 avian flu that was reported by the Indonesian government yesterday. The illness struck a 5-year-old girl from the Wonogiri district of Central Java. She became ill May 8, was hospitalized May 15, and died 2 days later, the WHO said. Initial investigations indicate she had been exposed to dead poultry.

The case increased Indonesia"e;s H5N1 toll to 97 cases with 77 deaths and raised the global total to 307 cases with 186 deaths, according to the WHO.