Colorization of this transmission electron micrograph shows H5N1
viruses in gold.
The worst outbreak of highly pathogenic H5N1 avian influenza ever to hit India, the world's second most populous country, refocused international attention on the virus early this year.
The United Nations Food and Agriculture Organization stated that recent H5N1 outbreaks in 15 countries demonstrate that the zoonotic disease remains a global threat and requires close monitoring and strong control efforts.
New H5N1 outbreaks occurred between December 2007 and late January 2008 in Bangladesh, Benin, China, Egypt, Germany, India, Indonesia, Iran, Israel, Myanmar, Poland, Russia, Ukraine, Turkey, and Vietnam. Most of the outbreaks occurred in domestic poultry—including chickens, turkeys, geese, and ducks—except for a few cases involving wild birds in China, Poland, and the United Kingdom.
"Globally, much progress has been achieved in keeping the H5N1 avian influenza virus under control. We are better prepared today to deal with the disease than we were three years ago," said Dr. Joseph Domenech, chief veterinary officer for the FAO. "Surveillance, early detection, and immediate response have improved, and many newly infected countries have managed to eliminate the virus from poultry.
"But the H5N1 avian influenza crisis is far from over and remains particularly worrying in Indonesia, Bangladesh, and Egypt—where the virus has become deeply entrenched despite major control efforts."
According to the FAO, countries should continue to keep a close eye on the evolving situation.
"The virus has not become more contagious to humans but has managed to persist in parts of Asia, Africa, and probably Europe," Dr. Domenech said. "It could still trigger a human influenza pandemic."
As of late January, India was struggling to control the H5N1 outbreak in the state of West Bengal—but the country had not reported any cases of human infection.
In Indonesia, almost all of the 33 provinces have experienced an H5N1 outbreak since 2004. The country recently reported its 100th fatal human infection.
"We have observed that new H5N1 avian influenza virus strains have recently emerged in Indonesia, with the possible effect that vaccines currently in use may not be fully protecting poultry against the disease," Dr. Domenech said. "This requires more investigations and the development of better poultry vaccines."
Many districts of Bangladesh have experienced H5N1 outbreaks. The situation seems to be worsening, according to the FAO, and Bangladesh borders West Bengal. According to the U.S. Central Intelligence Agency, Bangladesh protested India's previous attempts to fence off high-traffic sections of the porous border.
Egypt has stepped up its fight against the virus, Dr. Domenech said, but recent outbreaks indicate a need for stronger control efforts.
As of Feb. 5, the World Health Organization had recorded 359 cases of human infection with H5N1 avian influenza—including 226 fatalities. The WHO just launched the Influenza Virus Tracking System, an online database to track H5N1 viruses that countries have shared via the Global Influenza Surveillance Network and the selection of viruses for vaccine development. The interim version is at www.who.int/fluvirus_tracker.