H5N1 – the highly pathogenic strain of the avian influenza (AI) virus - has now infected and killed poultry in scores of countries across Asia, Middle East, Europe and Africa
Few of the regions affected so far are regarded as ‘hot spots’, where genetic mutation and re-assortment - which would allow easy virus transmission to and between humans – are considered probable. Potential disaster areas also have a high proportion of small farm and domestic poultry flocks and close contact between people and live birds or carcasses right along the production and marketing chain. Authorities have little control over the industry as a whole and poor veterinary infrastructure allows rapid spread of the virus with disease becoming endemic in a short period of time.
There is now a new potential ‘hot spot’ to worry about, following the emergence of H5N1 in Bangladesh. Early indications do not look good for swift management of the disease.
H5N1 struck chickens at the state-run Biman farm complex in Savar, 40km north the capital Dhaka, and it was subsequently reported on a dozen more farms in places around the city, including Gazipur and Narayanganj to the north-east and south-east, respectively. Latest reports indicate at least 12,000 birds have already died and around 38,000 culled.
The government had already banned imports from 50 countries including neighbouring India and Myanmar following outbreaks there, and it has now set up surveillance, restriction and culling zones around the outbreaks. Indications are that the disease has been spreading for some time and there are already difficulties enforcing regulations.
Dr Duangvadee Sungkhobol, WHO representative said, “The government had taken aggressive measures to stop the spread of the disease and WHO has confidence that it [the government] would be able to limit the spread.”
Another UN official expressed concern and told Reuters, “Maybe the outbreak of avian influenza started weeks or months before but the authorities took a long time to confirm it. We are talking to the government and relevant agencies to find out the extent of H5N1 spread in Bangladesh.”
The Bangladesh government announced the outbreak on 22 March following confirmation of virus and sub-type by a testing laboratory in Thailand. Chickens were dying in numbers during February but local laboratories said they had succumbed to Newcastle disease. It took almost a month before government sent the samples to Thailand and the real extent of H5N1 became apparent. The Daily Star in Bangladesh reported that Jirani area where chickens, chicks and eggs were destroyed on 23-24 March (following confirmation of H5N1 at Savar) had been declared an ‘infected area’ for three months under the Bangladesh Animal Disease Law, 2005.
In what looks like a rapidly unfolding disaster, the army was called in to complete a cull at a state run farm at Jirani Bazar, 30km north of Dhaka. According to Reuters, workers protested and refused to carry out the cull saying, “If the birds go, we will starve to death”. Late identification and action and little control over disease spread and development are factors that allowed H5N1 to get out of control so quickly and easily in Indonesia and Nigeria.
According to the Bangladesh Poultry Industries Association, there are 130,000 large and small poultry farms producing 250 million broilers and 6 billion eggs annually. Annual turnover is more than US$750,000 and around 5 million people earn at least part of their living from poultry farming. The Department of Livestock figures records just 52,000 registered farms but another 152,000 non-registered farms with up to 20 poultry each. It goes without saying there is a high level of close contact between poultry and people at backyard and domestic poultry production and market levels in Bangladesh.