KARACHI: Research needed to trace outbreak causes
KARACHI, Feb 8: The government has yet to undertake an epidemiological study to find out how avian influenza arrived in the country despite the fact that repeated episodes of bird flu have caused colossal losses to the poultry industry and jeopardized the livelihoods of millions over the past five years.
Speaking on the bird flu crisis, poultry experts, nature conservationists and academicians told Dawn that there was a general consensus that no attempt to control bird flu would be effective without such a study.
They suggested that academics must be involved in the study and a holistic approach be adopted that required greater collaboration between scientists, veterinarians, nature conservationists and health professionals. Besides, they said, the government needed to set up state-of-the-art laboratories in public universities where sophisticated tests on viruses could be conducted.
Unless such a scientific study was carried out it was wrong to blame migratory birds for the outbreak of bird flu. There had been incidents of bird flu outbreaks at those places which did not fall in the migratory birds’ route, said Dr Alamdar Hussain, the Pakistan Veterinary Medical Council Secretary-Registrar.
He said: “It might be correct in the case of Sindh, but the proponents of the migratory birds theory should explain how bird flu struck in Islamabad’s suburbs, Charsada and Mansehra. At the Islamabad zoo, too, bird flu was once declared,” he said, emphasising the significance of an epidemiological study to investigate the causes of the disease outbreak which could serve as foundation for intervention in public health.
The veterinary expert stressed that “we can’t afford any further delay by saying that it can never be transmitted to humans because the mixing vessel for gene mutation (pigs in this case) doesn’t exist here. There is panic in the world and 226 people have already died of the deadly infection. We must adopt a strategy after determining the real causes.”
‘Migratory birds are not the main agent’
While government officials continue to blame migratory birds for the outbreak of bird flu in Karachi and elsewhere in the country, recent global studies exonerate migratory birds of this charge to a great extent, claiming that they are not the main agent of the avian flu spread.
At a recent conference held in Bangkok, the international wildlife coordinator for avian influenza at the UN’s Food and Agriculture Organisation, Scott Newman, said that there was no solid evidence that wild birds were to blame for the apparent spread of the H5N1 virus from Asia to parts of Europe, Africa and the Middle East. Also, there was no proof that wild birds were a reservoir for the H5N1 virus.
“We know that some wild birds have probably moved short distances carrying viruses and then they died, but we have not been able to identify carriage of H5N1 across large scale spatial distances and then resulting in spread to other birds and mortality in poultry flocks,” he said.
According to him, fecal tests on some 350,000 healthy birds worldwide had to date only yielded “a few” positive H5N1 results. Furthermore, in instances and places where wild birds were found with the disease, there were no concurrent outbreaks of the virus in poultry.
These views are also supported by the BirdLife International, a global alliance of partnership of conservation organisations operating in over 100 countries. In its August 2007 statement, the Birdlife International says that recent comprehensive analysis of viral lineages in South-East Asia concludes that poultry movements were responsible for multiple reintroductions of the virus, both within and between countries, and that “transmission within poultry is the major mechanism for sustaining H5N1 endemicity in the region”.
This mechanism for sustaining the virus is well explained on a website, The Avian Influenza, Wildlife and the Environment Web, produced by the Scientific Task on Avian Influenza and Wild Birds, which says that the highly pathogenic avian influenza virus infecting poultry, other domestic animals, wildlife and humans, almost certainly originated from the mutation of a low non-pathogenic virus on poultry farms in East Asia. The virus then spreads rapidly within and between farms, taking advantage of local practices in the feeding, housing, slaughtering and trade of domestic ducks, chickens and geese. “Lack of hygiene, overstocking, and mixing of different domestic animals greatly increases the risk of spreading the infection. Movements of people (for example, farmers, veterinarians, journalists and tourists) and legal and illegal trade in caged birds are factors in the spread,” it notes.
Dr Ghulam Akbar, head of World Wildlife Fund (WWF)-Karachi, argued that if one accepted the migratory bird theory then there should have been incidences of bird flu throughout the Indus Flyway and not just at a couple of farms in Gadap.
“Sick birds can’t travel long distances. And this is the time when they start migrating back to their land. Also, one would like to ask why there was no incidence of the deadly infection at the time of birds’ arrival in Sindh. However, mutation of virus can occur and to prepare oneself for that situation academics must be involved in the research studies,” he said.
Supporting his argument, Jehangir Durrani, an ornithologist at present working with WWF’s Indus for All Programme at Keenjhar Lake, said that he had received no report of dead birds lying along any of the water bodies in Sindh. “We are connected with the global positioning system, but there has been no report of any such incidence so far. In fact, there are many farms set up along the lake which release their waste directly into the lake. The polluted water also explains the gradual decline in the number of visitor birds,” he said.
Thatta, which has also become the centre of broiler production in Sindh, has remained safe from bird flu though many wetlands located here attract a large number of migratory birds every year. “These birds have been coming here for centuries and so far we have no problem. I feel there are other reasons for the outbreak of avian influenza which should be focused upon,” said Dr Tauseef Umar, District Officer (Poultry Development) Thatta.