Cat bird flu risks 'overlooked'

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Cats who eat infected chickens can contract the deadly H5N1 virus

It is vital to restrict the spread of bird flu in cats in order to

protect human health, scientists warn.

Writing in Nature, scientists from Erasmus Medical Centre, Rotterdam,

say the risk is being overlooked.

 

They say cats can contract the virus by eating infected chicken or

through close contact with other cats - both new ways of mammals

becoming infected.

 

However, animal health experts said there was a " limited risk " to

humans from infected mammals with H5N1 flu.

 

 

Transmission between species

The first report of domestic cats dying of the H5N1 virus emerged in

Thailand in 2004 when 14 out of 15 cats in a household near Bangkok

fell ill and died.

 

One had eaten a chicken carcass on a farm where there was an outbreak

of the virus.

 

We do not want to exaggerate the risk, but if it is there then

health officials must take the necessary steps

 

Professor Albert Osterhaus, Erasmus

 

Post-mortem examinations on three of the cats confirmed the presence

of H5N1.

 

Since then, there have been deaths among cats in Indonesia, Thailand

and Iraq, where H5N1 appears to be prevalent among poultry.

 

And the disease is common among cats in Indonesia.

 

A dead cat was also found in Germany in March after the H5N1 virus

was found in wild birds.

 

There have been reports of big cats dying from the deadly H5N1 virus -

including 147 tigers who died in a Thai zoo after eating infected

chicken.

 

Dogs at risk

 

The Erasmus researchers say there is too little data to establish

what the minimum dose needed to infect cats is or whether cats can

excrete the virus even if they are uninfected.

 

It is also not known whether they can transmit the virus back to

poultry or even on to humans.

 

Cats seem to be an evolutionary blind alley

 

Professor Peter Openshaw, Imperial College

 

The scientists warn that other carnivorous animals including dogs,

foxes and seals are also vulnerable to infection.

 

Professor Albert Osterhaus, the lead author of the Nature report,

told the BBC News website: " This is a concern where the H5N1 virus is

endemic among poultry.

 

" We do not want to exaggerate the risk but if it is there then health

officials must take the necessary steps. "

 

He said these included keeping domestic cats inside, ensuring dogs

were kept on the lead and quarantining any animals that showed signs

of ill health.

 

" It's not easy for a person to be infected by a cat but where a child

is in close contact with a sick animal or it has diarrhoea or is

licking someone, it is a possibility. "

 

But he stressed: " In areas where the virus is not endemic, these

measures are not necessary. "

 

Precautions

 

Professor Peter Openshaw, head of respiratory infections at London's

Imperial College, said: " At the moment, cats seem to be an

evolutionary blind alley.

 

" They mainly get a gut or lung infection and haven't been shown to be

able to transmit to man.

 

" However, cats might form a bridge to man since they often live in

close domestic contact - in the same way that nursing a sick pet bird

has been shown to do. "

 

A spokesman for the Animal Health Service, part of the Food and

Agriculture Organization (FAO) of the UN, said there were certain

parts of the world where H5N1 was present where any bird-eating

animal posed a " limited risk " to humans.

 

Precautionary measures for pet animals were needed in such places, he

said.

 

He said the FAO, along with the World Health Organisation and the

World Organisation for Animal Health, planned to carry out research

to look at cat infections and the role cats l could play in the

development of avian flu.