India should look into the genes of its people to see why various strains of avian influenza virus were not affecting them, an American virologist said on Tuesday.

"When analysing the genomics of Indians, we may find some special characteristics resisting the disease. But that aspect cannot be interpreted as Indians are not being susceptible to bird flu viruses because these viruses are constantly mating and 'reassorting' to create newer strains", said Robert G. Webster, a World Health Organization (WHO) expert and professor at the Department of Infectious Diseases, St. Jude Children's Research Hospital in Memphis, US, at the Rajiv Gandhi Centre for Biotechnology in Thiruvananthapuram.

He added that several types of avian flu viruses were not creating concerns in India as they were in Eurasian countries and North America.

Webster also cautioned that other than H1N1, highly pathogenic sub-types like H5N1 and H7N9 can spread across the borders, since in neighbouring China, new viruses and avian flu were constantly evolving.

Wild birds were crossing the Himalayas to spread flu in India, he said.

Webster added that vaccination for poultry in China was not providing immunity and now the country was eliminating poultry markets in Hong Kong and Shanghai, which was a good solution.

"Some of these viruses may attain the capability for a human-to-human infection which can be lethal," the virologist explained.

He argued for a universal human vaccination against avian flu as epidemics of the disease might occur at any time.

"Instead of manufacturing huge quantities of vaccine, countries should maintain a seed stock of viruses to manufacture vaccines as and when necessary depending on the nature of flu", he stated.

"Human surveillance in India is satisfactory, according to WHO standards. But it has to be strengthened to include intermediary hosts like pigs and ducks and to avoid pork and white meat at the time of incidence of the disease," he noted.

"In Asian countries, there is always a tussle between the health and agriculture departments when a ban on poultry markets is advocated."