Jan 24, 2008 (CIDRAP News) – Outbreaks of H5N1 avian influenza in 15 countries since December 2007 are a potent reminder that the virus is still a global threat, the United Nations Food and Agriculture Organization (FAO) warned today, as officials in Thailand announced they found the disease in poultry again after a 6-month lapse.
The FAO statement said the heightened outbreak activity calls for close monitoring and strong control efforts. Recently affected countries include Bangladesh, Benin, China, Egypt, Germany, India, Indonesia, Iran, Israel, Myanmar, Poland, Russia, the Ukraine, Turkey, and Vietnam. Most outbreaks have occurred in poultry, including chickens, turkeys, geese, and ducks. However, a few of the outbreaks—those in China, Poland, and the United Kingdom—involved wild birds.
Worrisome spots include Indonesia, Bangladesh, and Egypt, where the virus has become deeply entrenched despite major efforts to control the spread of the virus, said Joseph Domenech, the FAO's chief veterinary officer, in the FAO statement.
"The virus has not become more contagious to humans but has managed to persist in parts of Asia, Africa, and probably Europe. It could still trigger an influenza pandemic," he said.
Despite all of the developments that raise concerns, Domenech said his group has seen some positive trends.
"Globally, much progress has been achieved in keeping the H5N1 virus under control. We are better prepared to deal with the disease than we were 3 years ago," he said in the FAO statement. "Surveillance, early, detection, and immediate response have improved, and many newly infected countries have managed to eliminate the virus from poultry."
H5N1 returns to Thailand
The outbreak in Thailand is not included in the FAO's total, but Thai livestock officials today announced that the H5N1 virus was detected in Nakhon Sawan province in the northern part of the country, about 188 miles north of Bangkok, according to a Bloomberg News report. However, a report that Thai officials filed yesterday with the World Organization for Animal Health (OIE) said the H5 virus has been confirmed and that final test results are pending.
According to the OIE report, the virus struck 4,085 broiler chickens at a commercial farm that is housed above a fish pond. The outbreak began on Jan 18, and the birds were tested as part of the country's routine surveillance program. The remaining 55,585 birds were destroyed, the report said. Thailand's last H5N1 outbreak occurred in June 2007, according to the OIE report.
Country-specific outbreak observations
Domenech discussed aspects of outbreaks in several countries. He said India is struggling to control its worst-ever H5N1 outbreak. Yesterday the Associated Press reported that the virus has now spread to nine of West Bengal state's 19 districts and that the outbreak's reach is within 18 miles of Calcutta, India's third-largest urban area.
Indonesia is one of the hardest hit countries in terms of avian outbreaks and human cases. The FAO said the virus has struck 31 of 33 provinces since 2004. Domenech said new H5N1 virus strains have emerged in Indonesia, which means current poultry vaccines may not fully protect against the disease. He said the Indonesian government and the FAO, along with FAO and OIE reference laboratories, are instituting a virus-monitoring program to further examine the problem.
Avian influenza outbreaks seem to be worsening in Bangladesh, where surveillance and control programs have not prevented the virus from spreading to 21 of 64 districts, the FAO statement said. The FAO said it is strengthening its presence in Bangladesh to support government efforts to control the disease.
Egypt had some early success with vaccination campaigns on commercial poultry farms, but its control efforts may have slacked off, because the disease has now reappeared in industrial poultry farms and has spread more widely throughout the country, the FAO reported.
Outbreak reporting, disinfection, culling, movement control, and biosecurity all need to be improved in Egypt, Domenech said, adding that the FAO is working closely with the government to strengthen disease detection, control, and communication. He also said potential changes in the H5N1 virus strains warrant further investigation.
West African countries Benin, Ghana, Nigeria, and Togo all reported H5N1 outbreaks in 2007, the FAO report said. Domenech said that though the Nigerian government launched intense efforts to control the disease in poultry, virus circulation in the country still threatens neighboring countries. He said the FAO will continue working with the Nigerian government to boost disease control measures.
In Europe, where Germany, Poland, Russia, and the United Kingdom recently reported outbreaks, disease detection and immediate response were very effective, particularly in the European Union countries, Domenech said.
"But we are seeing virus infections in poultry that are not transmitted by wild birds. This raises questions about other ways of virus transmission and potential reservoirs of infection, like in free-ranging ducks," he added.
Jan 24 FAO statement
OIE reports on Thai outbreak