- The situation in Indonesia continues to worsen, now with
H5N1 widespread in cats. The news of bird flu in cats (mammals) refocuses
attention on the danger that H5N1 will now easily evolve into a human form.
- The situation has arisen because bird flu, despite all
attempts to contain it, has become widespread in poultry and birds. Cats
allowed to roam outdoors, eat birds and/or poultry and become infected. This
new situation in cats should alert people to the need to keep cats indoors
or away from birds and raw poultry parts in countries where bird flu is
endemic and widespread.
- From ProMed Mail
- Deadly H5N1 May Be Brewing In Cats
- By Debora Mackenzie
- New Scientist (print edition)
- Bird flu hasn't gone away. The discovery, announced last
- the H5N1 bird flu virus is widespread in cats in locations
across Indonesia has refocused attention on the danger that the deadly
virus could be mutating into a form that can infect humans far more easily.
- In the 1st survey of its kind, an Indonesian scientist
has found that in areas where there have been outbreaks of H5N1 in poultry
and humans, one in 5 cats have been infected with the virus and survived.
This suggests that as outbreaks continue to flare across Asia and Africa,
H5N1 will have vastly more opportunities to adapt to mammals than had been
- Chairul Anwar Nidom of Airlangga University in Surabaya,
Indonesia, told journalists last week that he had taken blood samples from
500 stray cats near poultry markets in 4 areas of Java, including the capital,
Jakarta, and one area in Sumatra, all of which have recently had outbreaks
of H5N1 in poultry and people.
- Of these cats, 20 per cent carried antibodies to H5N1.
This does not mean that they were still carrying the virus, only that they
had been infected, probably through eating birds that had H5N1. Many other
cats that were infected are likely to have died from the resulting illness,
so many more than 20 per cent of the original cat populations may have
- This is a much higher rate of infection than has been
found in surveys of apparently healthy birds in Asia. "I am quite
taken aback by the results," says Nidom, who also found the virus
in Indonesian pigs in 2005. He plans further tests of the samples at the
University of Tokyo in February 2007.
- Amin Soebandrio, head of medical sciences at the Indonesian
ministry for research and technology, confirmed the report. He says that
the infection has also been found in dogs and cats on the Indonesian island
of Bali, which has also had outbreaks of H5N1. The new findings follow
reports that unusually large numbers of dead cats have been found near
many outbreaks of H5N1. "Javanese farmers even have a word for the
cat disease," says Albert Osterhaus of Erasmus University in Rotterdam,
the Netherlands. It was Osterhaus's lab which in 2004 found that cats can
catch the H5N1 virus. Like humans, some cats die and some recover. But
unlike humans, infected cats shed large amounts of the virus and pass it
to each other.
- Infected cats may not directly increase the danger of
people catching the virus, as humans seem to catch the current strain only
with difficulty even from birds, which they kill, pluck and eat. The main
worry, says Osterhaus, is that as the virus replicates in cats, it will
further adapt to mammals and acquire the ability to spread more efficiently
to people and from person to person, unleashing a human pandemic.
- Nidom's findings are the 1st to indicate what proportion
of cats can become infected by H5N1. No cats have been tested in Hong Kong
or China. In Bangkok, Thailand all the cats in one household are known
to have died of H5N1 in 2004. Tigers and leopards in Thai zoos also died,
while last year , 2 cats near an outbreak in poultry and people in
Iraq were confirmed to have died of H5N1, as were 3 German cats that ate
wild birds. In Austria, cats were infected but remained healthy (New Scientist,
18 Mar 2006, p 6).
- Though Osterhaus says Nidom's figures must be confirmed,
he says they aren't surprising, and is even encouraged that they aren't
worse. A higher percentage of infected predators than prey makes sense,
as each predator eats many prey animals. "At least that percentage
shows the virus has not completely adapted to cats, yet," Osterhaus
says. If it had, all cats in a stricken area should be infected, as with
ordinary flu in humans.
- Osterhaus emphasizes that the cat infections still pose
a potential threat. "We know the 1918 pandemic was a bird flu virus
that adapted to mammals in some intermediate mammalian host, possibly pigs,"
he says. "Maybe for H5N1, the intermediate host is cats." If
similar percentages of cats are infected at every outbreak location, there
must have been many thousands of cat infections since the virus emerged,
compared to 267 confirmed cases in humans. Every sick cat is a chance for
the virus to adapt, and with renewed outbreaks this year  in birds,
people or both in China, Indonesia, Japan, South Korea, Hong Kong, Viet
Nam, Thailand, Egypt and Nigeria, it is getting plenty of such chances.
- Killing cats won't solve the problem, Osterhaus warns.
Like shooting wild birds, it is unlikely to have much impact and could
send infected animals elsewhere. It would also lead to a population explosion
of disease-carrying rodents, which the cats normally keep in check.
- "Cats must just be kept from eating sick chickens,"
Osterhaus says, though this will be a tall order in open-air markets across
Asia and Africa, which are typically swarming with hungry cats. In Jakarta
this week, officials are slaughtering thousands of banned backyard poultry
then handing them back for their owners to eat. Some of the birds could
well be infected despite appearing healthy. It is hard to imagine the local
cats not getting their share.
- Patricia A. Doyle DVM, PhD
- Bus Admin, Tropical Agricultural Economics
- Univ of West Indies
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