Bird flu continues to hover as a spectre over much of Asia as more nations report that the H5N1 virus has been found within their fowl and fears rise that it could mutate into a form that leads to human-to-human transmission and kills far more than the 200 people around the world who have died from the infectious disease since 2003.
India has become the latest nation to be affected by an outbreak of bird flu, as the virus was recently detected in 13 of 19 districts in the eastern state of West Bengal. More than 3 million birds have been culled since mid-January and experts have attributed the outbreak to such factors as smuggling of poultry from bird flu affected Bangladesh and inadequate culling initiatives. But while individuals have been isolated because of suspicious symptoms, no human case of bird flu has been reported.
The virus has been detected in 47 of 64 districts in Bangladesh, where about 1.25 million birds have been slaughtered since March 2007, at a projected US$650 million cost to the economy. As in India, no human case has been reported, although on Mar. 6, 2008, the owner of an infected poultry farm and his family were quarantined.
“West Bengal state of India and Bangladesh has similarities in terms of environment, which is why it appears that there may be some common environmental factors that worked behind the spread of the H5N1 virus in both the countries,” says Swapan Jana, secretary of the Society for Social Pharmacology, an Indian nongovernmental organization. Factors that may play a role in possible human infection could include the fact that “both the countries are densely populated, a large number of common masses lack health consciousness in both the countries and many people, particularly in rural areas, keep poultry in their houses.”
Indonesia continues to be the worst hit by the disease, with 11 people having already died this year, raising the nation's total number of deaths caused by bird flu to 105. “Poor hygiene, close contact between human beings and poultry, lack of proper medical care include some of the factors, which may contribute behind the human deaths due to bird flu in Indonesia,” Jana says.
In Thailand, where 17 deaths from bird flu have been reported since 2004, no human case has been detected in 2008, but H5N1 was recently detected at a poultry farm.
In Myanmar, 1 case of human infection was reported in December 2007, while China reports that 3 humans have died from bird flu thus far this year and that a father caught bird flu from his son in December 2007. Vietnam's death toll is 4, but 10 provinces have detected the virus this year and over 30 000 fowl have been culled. Poultry have also been infected in Laos, Pakistan and Nepal.
The ongoing risk to humans remains large, WHO spokesperson Gregory Hartl stated in an email interview. “As long as the H5N1 virus remains so widely entrenched in animals, there is always the possibility that the virus may mutate into a form which is easily transmissible among humans.” — Sanjit Bagchi MBBS, Kolkata, India
Figure. Health officials put ducks into sacks at a farm in Muan, about 390 km south of Seoul on Apr. l8, 2008. South Korea confirmed a new outbreak of bird flu at a duck farm in Jeongeup and said it was investigating 2 other possible cases days after reporting an outbreak at a nearby chicken farm. Image by: Reuters/No New