PUNE: A report on Avian influenza surveillance in wild migratory, resident, domestic birds and in poultry in Maharashtra and Manipur during avian migratory season 2006-07 by National Institute of Virology (NIV) and Ela Foundation, Pune states there is no convincing evidence yet showing infected wild birds can carry influenza virus along established, seasonal long-distance migration routes.
This negates the stand taken by World Health Organisation (WHO), which had blamed migratory birds for outbreak of H5N1 virus causing Bird Flu in India. The report titled Avian influenza surveillance in wild migratory, resident, domestic birds and in poultry in Maharashtra and Manipur, India, during avian migratory season 2006-07, has been published in the journal Current Science (Vol. 97, N0. 4, 25 August 2009).
India reported outbreaks of Highly Pathogenic Avian Influenza (HPAI) H5N1 in poultry in the states of Maharashtra, Gujarat and Madhya Pradesh (February-April 2006); Manipur (July 2007); West Bengal (January 2008) and Tripura (April 2008). The role of migratory birds in the transmission of the Highly Pathogenic Avian Influenza (HPAI) H5N1 remains a subject of debate. Avian Influenza (AI) surveillance in wild migratory, wild resident, domestic birds and poultry was undertaken during 2006-07.
“Long-term screening and surveillance of migratory birds for the presence of AI virus is necessary as part of wider range of preparedness to avert the future appearance of the virus in a pandemic form in humans,” the report stated. Since 2003, HPAI H5N1 virus has spread to Europe and Africa and virus from birds in West Siberia, Europe and Africa is similar to that from Qinghai lake, China. Importantly, East and Central Asian Flyways of migratory birds, which include India in their path, overlap extensively in West China (around Qinghai Lake), Mongolia and Central Siberia allowing interchange of diseases between these areas and particularly with India.
“The present study does not report any HPAI H5N1 or any other AI viruses from sampled birds during the study period. Although AIV has been reported earlier in the species/families of birds elsewhere, the screened population in the present study was free from any AI infection,” Associate Professor, Ela Foundation, Satish Pande told Sakaal Times. No convincing evidence has yet shown that infected, asymptomatic wild birds can or do carry influenza virus along established, seasonal long-distance migration routes.
“The hypothesis that migratory birds can transport HPAI H5N1 over long distances rests on the assumption that some infected, virus-shedding wild birds show no or only mild symptoms and migrate long distances unhampered,” he said. A total 1,968 faecal samples comprising 1,369 samples of migratory and resident birds, and 599 samples from poultry and ducks were collected from eight districts of State and two districts of Manipur (July 2007) between Dec-2006 and April-2007. Samples of 10 avian families of wild migratory birds, four families of wild resident birds totalling 36 species, were screened for AIV.