The disease was also detected among the wild cats in Asia. But he assured that the humans need not worry because as of now there have been no documented cases of a cat transmitting the virus to people.
Maria Cheng of the World Health Organization in Geneva said that tigers and snow leopards in a zoo in Thailand became infected after being fed chicken carcasses.
She also said that further studies about the transmission patter of the virus by the cats should be studied in detail.
Cases were reported of three house cats being infected near Bangkok. Officials said that one cat had eaten a dead chicken on a farm where there was a bird flu outbreak, and the virus apparently spread to the others.
World Health Organization (WHO) said that tests on three civets that died in captivity in Vietnam also tested positive for the bird flu virus. The source of the infection in these animals was unknown. It also calculated the official number of bird flu cases to be 173 and the number of deaths as 93.
Statistics show that about twenty-one people in Turkey tested positive for H5N1 and four children died of the disease.
Health officials are concerned H5N1 could mutate into a form that is transmitted easily among humans, which could lead to a pandemic.
After the virus was detected in the wild cats scientists are particularly concerned about bird flu infecting pigs. The fear is that the two viruses the one infecting the bird and the other which infects the humans would swap genetic material and create a new virus that could set off a human flu pandemic.
Several other European nations were affected with the flu but the worst outbreak was in Russia, where it devastated a poultry farm in the southern region of Krasnodar.
Gov. Alexander Tkachev said that more than 100,000 chickens at a farm in the village of Lavliniskaya have been culled to prevent the spread of the disease.
A total or a partial ban was laid on French poultry products after H5N1 was confirmed in commercial birds by forty-three countries.
Authorities in Sweden and Hungary also said they were conducting further tests to confirm whether wild birds that had tested positive for a form of bird flu were infected with the H5N1 strain.
Slovenia, as well as the southern German state of Bavaria, both registered new cases of H5N1 in wild fowl.
Bernard Vallat, director of the Paris-based World Organization for Animal Health said that everybody should be very careful and that there is an increased risk of bird flu.