DHAKA, 11 January 2008 (IRIN) - The recent deaths of a number of exotic birds at Bangladesh's national zoo in Dhaka have heightened concerns over a potential bird flu outbreak.

Their deaths, now being studied, follow the culling of some 20,000 chickens at the nearby government-owned Central Poultry Farm at Mirpur on 29 December where the deadly H5N1 virus had already been detected. The farm shares a common boundary wall with the zoo in Dhaka.

Since the virus first appeared in March 2007, the authorities have culled over 322,000 chickens, including some 40,000 backyard fowls, at some 86 poultry farms in 21 out of Bangladesh's 64 districts. Over 3 million eggs have also been destroyed.

Earlier, the Ministry of Fisheries and Livestock had confirmed five more instances of avian influenza in the country - three in Gaibandha and one each in Nilphamari and Dinajpur districts.

About 500 fowls at a poultry farm at Phulhat, in Sadar sub-district, Dinajpur District, reportedly died from bird flu 22-25 December.

The latest case of bird flu was reported from a village in Pabna District in the northwest of the country and some 160km from Dhaka, where the authorities culled 6,000 chickens and destroyed 2,500 eggs in the first week of January.

Culling is generally viewed as a first line of defence for containing potential outbreaks of the virus, followed by the mass vaccination of poultry in high risk areas, the World Health Organization (WHO) believes.

No human infections so far

But while there has yet to be a single reported case of human infection anywhere in the country, health experts remain concerned.

Bangladesh is the most densely populated country in the world, with 975 persons for every square kilometre of land.

This, coupled with particularly hot and humid weather, extreme poverty and a number of traditionally bad health practices, places this river delta nation of over 150 million inhabitants at a higher risk to any contagious disease, including the H5N1 virus.

Dhaka zoo put on alert

Following the death of a rhea and emu bird last week, the zoo authorities have beefed up prevention efforts.

On 10 January, Kazi Fazlul Haq, curator of the zoo, told IRIN bird cages were being disinfected twice daily, as were the entry and exit points of the zoo.

Additionally, antiseptic footbaths were now in place at the zoo's entrance, while a protective bamboo fence had been placed around birdcages to ensure people remained at a safe distance, he said.

The Dhaka National Zoo has some 1,220 birds (69 species), 412 mammals (58 species) and some 50 reptiles (13 species).

Bio-security measures

Bidhan Chandra Saha, a senior veterinarian at the country's department of livestock and research, said bio-security measures were key in protecting birds and poultry from all types of infectious agents - viral, bacterial, fungal or parasitic.

Apart from being highly contagious among poultry, avian influenza viruses are readily transmitted from farm to farm by the movement of live birds, people (especially when shoes and other clothing are contaminated), and contaminated vehicles, equipment, feed, and cages, says the WHO.

Highly pathogenic viruses can survive for long periods in the environment, especially when temperatures are low, the world health body says.

"Bird flu spreads with swabs, nasal discharge and the faeces of infected birds through the air," Profesor Nazrul Islam of the Department of Virology at the Bangabandhu Sheikh Mujib Medical University was quoted by Bangladesh's Daily Star newspaper as saying.

"If people come in contact with infected birds, they risk the chance of being infected with the virus through inhalation. If someone touches an infected bird and eats food with that hand, there is a possibility of getting infected," he said.

But zoo officials believe there is no cause for alarm, with local media reports now suggesting that at least one of the birds may have died from a simple cold instead.

"There is no reason to panic," M Fazlur Rahman, another zoo official, remarked. "We have taken initiatives to make the zoo more hygienic and have disinfected the cages and the water bodies in the zoo."

As part of the precautionary measures, all the branches of the trees adjacent to the bird sheds have also been chopped off to prevent close contact between captive and free birds, he said.

Poultry industry in jeopardy?

Meanwhile, the impact of a potential bird flu outbreak on Bangladesh's vital poultry industry is still being felt.

According the South Asia Enterprise Development Facility, a multi-donor facility managed by the International Finance Corporation of the World Bank Group (with US$810 million in total investment till mid-December 2007), the poultry sector supports five million people directly or indirectly through 150,000 poultry farms, constituting 1.6 percent of Bangladesh's gross domestic product (GDP).

Moreover, this figure only includes commercial farms and does not account for the more than 2 million backyard coops run by rural families, mainly women.

In recent years the poultry industry has been growing at an annual rate of about 20 percent, recording a turnover of US$1.25 to $1.5 billion in 2006. But industry analysts estimate the 2007 figures may well have already fallen below this mark.

Battered by avian flu fears, monsoon floods and a devastating cyclone this past November, the country's booming poultry industry is shrinking.

"The industry is undergoing a silent form of famine," warned MM Khan, a technical adviser and spokesman for the Bangladesh Poultry Industries Association. "I do not see anything good in the coming days."

Bird flu has killed 216 people in 12 countries since 2003, the vast majority in Asia, according to the WHO.

sa/ds/cb

© IRIN. All rights reserved. More humanitarian news and analysis: http://www.IRINnews.org

IRIN news