A pelican at Tata zoo and (below) a painted stork, two feathered species that are susceptible to the new strain of virus
Over a dozen wild bird deaths at the National Zoological Park in New Delhi and Gandhi Zoological Park in Gwalior since mid-October have put Tata zoo on high alert for a new strain of avian influenza.
The sprawling zoo, the only private one in the country, boasts 121 species of birds. The ones at immediate risk of contracting the H5N8 - a lower pathogenic subtype of the Influenza A virus - are aquatic birds like the rosy pelican, bar-headed goose, greylag goose and waterfowl. Blood samples of some of these birds will soon be sent to the Regional Diagnostic Laboratory in Calcutta for tests.
"It is our duty to keep the inmates as well as visitors safe. So, preventive measures are being taken based on guidelines issued by the Central Zoo Authority," said Bipul Chakrabarty, director of Tata zoo.
Apart from facilitating blood tests, the zoo has stopped procuring poultry products that serve as soft meat for carnivorous animals. Zookeepers, especially those handling bird enclosures, have been given strict instructions to wear protective gear such as gloves and masks. The premises are also being cleaned with disinfectants.
The National Institute for High Security Animal Diseases (NIHSAD) has confirmed that the virus subtype H5N8 infection in wild birds is being reported for the first time in the country. The H5N8 was reported from 11 countries in 2015 and four including India this year.
The NISHAD has revealed that the H5N8 virus was found in samples of three of the nine birds - five rosy pelicans, three ducks and a painted stork - that died at Delhi zoo between October 14 and 17.
Only the H5N1, which is highly pathogenic unlike the H5N8, affects humans. So, zoo visitors need not panic as yet. There are several strains of avian flu that have only emerged in birds and do not infect humans.
The NIHSAD and allied organisations have been entrusted with the task to investigate the outbreak thoroughly and determine the source of infection, so that zoo authorities across the country can implement suitable strategy to prevent the ingress of the disease in captive birds. The same is under progress.
Tata zoo vet Manik Palit said though avian influenza had not been reported in the east in recent months, wild water birds could be quick carriers of the H5N8. "We are lucky that Jayanti Sarovar (near the zoo) has not been witnessing migratory birds for the past three years. We are at lower risk, but the possibility of contraction can never be ruled out," he said.
The Influenza A is a family of viruses that causes respiratory diseases. The virus subtypes differ in the kind of proteins they carry on their surfaces.
The 'H' stands for hemagglutinin and 'N' for neuraminidase, two proteins on virus body that allow it to enter and exit host cells. The types are numbered according to when they were discovered, which means H1 was identified first. There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes.