Saturday, February 12, 2011

Bird flu bouts ring health alarms

Fri, Feb 11th, 2011 8:18 am BdST
Nurul Islam Hasib,
Senior Public Health Correspondent

Dhaka, Feb 11 (—Frequent bird flu outbreaks in the poultry farms in Dhaka and on the outskirts of the capital have stoked fears of a serious health threat to Bangladeshis.

Altogether 12 bird flu attacks in a week in Dhaka district, from where the country's only human avian influenza case was detected in May 2008, have the health experts on the edge.

"The virus (H5N1) can pass on to humans from poultry any time given the present situation. It's a public health concern," says Dr ASM Alamgir, an influenza expert with the World Health Organization's Dhaka office.

He says in areas currently experiencing avian influenza outbreaks in poultry, the practice of marketing live birds may pose a significant risk to the people involved.

"Even people should try to avoid coming into close contact with pigeons and crows unnecessarily, as lab tests found the presence of H5N1 in crows during the mass death in 2008 in Dhaka and Chittagong."

He suggests people consume well-cooked poultry products and maintain bio-security in farms.

Avian flu has so far killed 306 people out of 518 infected in 15 countries and most of these cases have been linked to close contact with infected poultry or their secretions.

Bangladesh can be a hot spot for emerging infectious and costly diseases such as bird flu because of population growth and movement, urbanisation, changes in food production and other factors, researches show.

The 15-month old Bangladeshi boy who survived the deadly flu got the virus when his mother slaughtered a chicken at their home in Dhaka's Kamalapur slum and later cuddled him (boy) with unwashed hands.

The Institute of Epidemiology Disease Control and Research (IEDCR) advises doctors to take history of exposure to sick poultry while seeing patients with serious respiratory illness, who might have contracted the deadly strain of human avian influenza virus.

The virus normally spreads between sick poultry but it can sometimes spread from poultry to humans. It does not spread easily between humans, differing in that respect from the milder H1N1 bird flu virus.

"H5N1 (virus) has the potential to cause severe illness in human with a high fatality rate," Alamgir says, but the strain (clade 2.2) of H5N1 which circulates in Bangladesh is less virulent.

"It causes relatively less infection to humans," he says, adding it can be changed into another class (2.1), which is highly infectious to human.

Livestock experts say maintaining bio-security in poultry farms is the key to stave off the avian influenza that also brings colossal damage to the poultry industry with each strike.

Zahin Hasan, director of Kazi Farms Limited, says all of their workers live inside the farm compound and shower before they go to the chicken sheds.

"But for some farms it will not be enough as all village households have backyard chickens and workers living in their village homes can carry the virus to the farm," he says.

Even at a larger farm with standard bio-security, according to Hasan, there is the risk that dogs, goats or backyard chickens may sneak in through gaps in the boundary fence.

To prevent such unwanted entry, Hasan says, poultry owners are now double-fencing every farm –an outer fencing at the boundary and an inner fence around the poultry sheds to prevent dogs, goats or backyard chickens entering the sheds.

"Around the sheds, we kill the grass with chemicals as it provides hiding places for rats, which can also spread the bird flu virus."

He said bird flu outbreaks are disastrous for the poultry industry in that entrepreneurs do not want to invest fearing heavy losses.

Rafiqul Islam, professor of veterinary of Bangladesh Agricultural University, urged the government's livestock department to heighten its surveillance to find out where the virus hides after winter.

He suggests 'one health' approach. "Livestock department is battling to stop the spread of the disease by culling poultry, but the challenges remain elsewhere.

"Community people should be involved in the process of eliminating bird flu from Bangladesh."

The world's first outbreak of bird flu among humans occurred in Hong Kong in 1997, when it claimed six lives. That outbreak was linked to chickens and classified as H5N1.

Bangladesh has recorded 375 outbreaks in poultry in 49 districts since the first outbreak in March 2007.

Different avian influenza studies show that almost all parts of an infected bird are contaminated with the viruses that thrive in low temperature; only 70 degrees Celsius is enough to kill the virus.

The virus can be found inside and on the surface of eggs and can survive in droppings too for at least 35 days in low temperatures.

It was suspected that the mass deaths of crows in 2008 were because they ate the carcasses of H5N1-infected chicken, thrown away by people in the dustbin or open places.

Experts say people should wear protective gear and practise measures in the outbreak areas to prevent personal contamination while slaughtering chickens and handling dead chickens.

They advise people cough into the crook of elbow and wash hands with soap often to reduce the spread of influenza virus at home or in the community

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