A deadly strain of avian influenza is starting to emerge in Asia, alarming international public health officials who say there is no vaccine for the disease. Their fear is compounded by the discovery reported this week in the journal Science that cats can become ill with the flu. Cats could provide another souce of viral illness, making it much harder to contain a human influenza outbreak. International public health officials are bracing for what they fear may be a global influenza pandemic which they say could lead to widespread illness and death, and for which there is, as yet, no vaccine. The problem is an aggressive A strain of the avian flu virus, which originates in Asia in birds and is passed to humans through live poultry usually bought at market for consumption. Pigs can also harbor the virus and pass it to humans. Virologist Thijs Kuiken of Erasmus Medical Center in Rotterdam, Netherlands says researchers have now discovered another source of the avian flu virus: cats. "It's another potentional host, yes," he said. Scientists had long suspected cats could harbor the avian flu but they hadn't been able to prove it, informs VOANews. According to CBS News, house cats can catch bird flu, become sickened by it, and spread it to each other, Dutch researchers say. The findings may mean the H5N1 bird flu virus that killed at least 26 people in Vietnam and Thailand in 2003 and 2004 has acquired the ability to spread between mammals. Health officials fear human and bird flu forms of the virus could mix in mammals, mutating into a type that could spread more easily between people, creating the conditions for an influenza pandemic. In an experiment, virologist Thijs Kuiken of the Erasmus Medical Center in Rotterdam and his colleagues infected kittens between four and six months old with H5N1 virus. Virus from a fatal human case was inoculated into the windpipe of the cats. They found six cats developed an infection and transmitted it to two others housed with the sick animals. Symptoms included fever, lethargy, difficulty breathing and in one case, death. For the first time, a type of bird influenza has been shown to infect and sicken house cats, which has some experts worried that there may one day be a strain of severe flu that can pass easily from human to human and create a pandemic. The flu strain in question is the 2003-2004 outbreak in Asia of the H5N1 virus, which caused massive poultry slaughters in eight Asian countries and also led to at least 34 human infections, at least 23 of which were fatal. During the outbreak, there were also anecdotal reports of fatal infections in cats. The news is startling to some because domestic cats had been thought to be largely resistant to actually getting ill from influenza A viruses such as this one, even though they could be infected. But others said the findings don't point to impending calamity. "We're still a long way off from saying cats are vitally important in this chain," said Dr. Susan McLellan, a tropical medicine and infectious diseases expert at Tulane University School of Medicine and School of Public Health. This report also has nothing whatsoever to do with the average North American house cat, McLellan emphasized -- only cats that spend a lot of time on farms in Asia with infected birds. McLellan was not involved in the study, which is reported in the Sept. 3 online issue of Science. The researchers tested whether domestic cats would become sick if the H5N1 virus was introduced into the airways or by feeding infected chickens to the cats. The six cats in the study all developed severe lung disease and transmitted the disease to two additional cats that were living nearby, publishes HealthDayNews.
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