Dogs catch flu directly from birds, study finds (Reuters)

WASHINGTON (Reuters) - Dogs can catch influenza directlyfrom birds, Korean researchers said on Wednesday, saying theirfinding shows pets could play a role in future pandemics.

Several pet dogs became ill and died from what turned outto be purely avian strains of seasonal flu virus, theresearchers reported in the journal Emerging InfectiousDiseases.

"Our data provide evidence that dogs may play a role ininterspecies transmission and spread of influenza virus,"Daesub Song of Green Cross Veterinary Products Company Ltd inYong-in, South Korea and colleagues reported.

The dogs had H3N2 influenza -- a strain similar to one ofthe flu strains now circulating among humans. But geneticanalysis showed the dogs were infected with viruses directlyfrom birds, Song´s team said.

Doctors know animals pass flu viruses to one another. Manyexperts believe most, if not all, influenza viruses originateamong birds.

The H5N1 avian influenza virus, which is sweeping throughflocks in Asia, Africa and parts of Europe, has occasionallypassed to humans, infecting 376 people and killing 238 of them.It has also occasionally infected dogs, cats, clouded leopards,civets and dozens of bird species, from swans to coots.

The fear is that it will somehow change or combine into aform that is easily passed from one human to another, sparkinga pandemic that would have the potential to kill hundreds ofmillions of people globally.

H3N2 is found in birds and is also a very common human flustrain. But the varieties that infect birds and people lookdifferent on the genetic level.

Song´s team investigated outbreaks among dogs.

"From May through September 2007, cases of severerespiratory disease occurred in animals at three veterinaryclinics located 10 to 30 km (6 to 18 miles) apart in KyunggiProvince and one kennel located in Jeolla Province (southernSouth Korea)," they wrote.

A miniature schnauzer recovered, but a cocker spaniel, twoKorean Jindo dogs and a Yorkshire terrier died.

Another 13 dogs in a shelter were affected, and there isevidence some dogs infected others.

DNA analysis showed the viruses from the dogs closelyresembled those from Chinese chickens or ducks in Hong Kong,Japan and China.

"Transmission of avian influenza A virus to a new mammalianspecies is of great concern because it potentially allows thevirus to adapt to a new mammalian host, cross new speciesbarriers and acquire pandemic potential," they wrote.

They believe the dogs were infected via food.

"We posit that this transmission results from feeding dogsuntreated minced meats of ducks or chickens," they wrote.

"In South Korea, untreated duck and chicken meats,including internal organs and heads, have been widely used tofeed dogs for fattening in local canine farms or kennels."

It is possible some of the dogs were infected viarespiratory secretions in live bird markets, and passed thevirus to others, they added.

"Live-bird markets are thought to constitute a missing linkin the epidemiology of avian influenza viruses because theybring together numerous hosts, such as chickens, ducks,turkeys, geese and doves, in a high-density setting, whichrepresents an ideal environment for virus interspeciestransmission," they wrote.

(Reporting by Maggie Fox, editing by Will Dunham and ToddEastham)