There is no scientific evidence available, so far, proving that migratory birds are responsible for the recent or all previous outbreaks of bird flu in Pakistan or elsewhere in the world, said wildlife experts and virologists.
They added, however, that the assumption could not be fully rejected as no scientific study has ever been carried out on migratory birds, at least those who travel to Pakistan once every year from Siberia and Russia.
It is worth mentioning here that some provincial government officials, after the recent outbreak of bird flu in poultry birds in Pakistan, put the blame on migratory birds saying that they were the only source of spreading avian influenza and its deadly strain H5N1 in local chickens.
Talking to The News, the Natural Resource Management (NRM) Coordinator of WWF Pakistan, Rab Nawaz, contradicted the reports that migratory birds were spreading avian influenza in Pakistan or anywhere else in the world and claimed that scientists around the world had proved that the said theory was wrong.
“When we look at the states where avian influenza cases have been reported, it is found that these countries are located on the trade route and not on the route followed by migratory birds. On the other hand, not a single scientific evidence has been presented yet linking avian influenza with the migratory birds” he said.
According to him, several studies conducted by international agencies like Birdlife International (BLI) and Food and Agriculture Organisation (FAO) of the United States proved that wild birds were not the cause of deadly H5N1 strain of avian influenza in the poultry birds.
“How is it possible that birds seriously sick with H5N1 could travel such a long distance between Siberia to Pakistan and other far-flung countries and reach safely to their destination and even return back to their homelands after infecting only the chickens?” he questioned.
However, he admitted that wild, migratory birds could definitely carry diseases and viruses and infect other birds in regions where they go but said it would be highly unjustified to blame them for the deadly poultry disease without any scientific evidence.
Citing England, he said that millions of migratory birds travel to the country every year but they never report such an “outbreak” of bird flu as they take proper measures to keep their poultry industry protected from such diseases.
“In fact, it has more to do with bio-security than innocent wild birds; they are also misguiding the efforts for overcoming the epidemic. Without looking into the real causes of the outbreak, simply blaming the migratory birds would jeopardise the already endangered species of these birds” he said.
Dr Nusrat Jamil, a microbiologist and virologist at the University of Karachi was of the opinion that migratory birds, especially those which are carnivorous or meat eaters, could be the carriers of “microbial and viral load” including strains that cause avian influenza.
“Carnivorous birds eat dead animals and they don’t live in a controlled environment. There are high chances that these migratory birds are responsible for the outbreak of avian influenza as their arrival in the country and eruption of bird flu often occur simultaneously” she said.
But she admitted that there was no scientific study carried out by any organisation yet that could prove the link between the two and stressed the need for conducting proper research as well as monitoring and surveillance of the migratory birds on the pattern of developed countries.
According to the World Health Organisation (WHO) website, the role of migratory birds in the spread of highly pathogenic avian influenza is not fully understood. Sindh government officials, including Director Poultry Dr Ali Akbar Soomro and provincial coordinator on AI in birds, Dr Aslam Jalali, who were quoted by various local newspapers as claiming that migratory birds are the only cause behind the outbreak of avian influenza, could not be approached despite repeated attempts.