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Bird flu moves into wild animals and pigs

Recent stories indicate that the bird flu has been hopping between species, and is now infecting wild animals.
Bird flu moves into wild animals and pigs

Recent stories indicate that the bird flu has been hopping between species, and is now infecting wild animals. The flu, which has spread rapidly, more than likely moves in flocks of wild migrating birds (chickens as we know do not migrate, and the disease spread with great speed over the Asian continent in just a few months).

Bird flu pounces on cat species
From The Times, AFP
February 21, 2004

THE deadly H5N1 strain of bird flu has been detected in two tigers and a domestic cat in Thailand in the first confirmed cases of the disease in the cat family.

"We found the same virus that has been found in chickens," said Therapol Sirinaruemitr, from Bangkok's Kasetsart University, which tested the animals.

The connection between the spread of avian flu and the wide dispersal of birds and their wide ranging migration patterns are an indication that massive kills of chickens is unlikely to prove to be an effective strategy to contain avian bird flu in poultry.

Wild Flocks Could Spread Bird Flu For Years
Updated: Thursday, Feb. 19, 2004 - 10:39 AM

Beijing (dpa) - The apparent role of migratory birds in spreading bird flu is likely to make the disease impossible to eliminate for many years, a World Health Organization expert said on Thursday.

"We know that avian influenza will be around while there are migratory wild birds," WHO animal disease expert Jeffrey Gilbert told Deutsche Presse-Agentur dpa.

Wild Birds Should Not Be Killed to Fight Bird Flu
Wednesday February 18, 10:02 am ET
Strict Controls and Surveillance Needed to Keep Wild Birds Away From Poultry

WASHINGTON and ROME, Feb. 18 /PRNewswire/ -- Eliminating wild birds is not an appropriate measure to control the spread of the avian influenza virus, the UN Food and Agriculture Organization (FAO) said today.

Killing wild birds will not help to prevent future bird flu outbreaks, FAO said.

Prevention needs to be based on a control and surveillance system to ensure that any contact between wild birds and poultry is avoided or at least monitored.

Asian birds are also known to migrate to the North American continent, and there are also numerous interlocking migration routes that would allow the flu to reach both the European and African continents.

Bird-flu fears stir flurry of precautions in U.S.

By Diedtra Henderson
Denver Post Science Writer
NEW YORK CITY - If a killer avian flu now sweeping Asia hits stateside, the best poultry producers could hope for is to limit infections to birds in a single state. That's the thinking behind killing all 89,000 chickens at two farms last week to contain a milder bird flu in Delaware.

The alternate nightmare, though: The Asian H5N1 virus and a human flu virus simultaneously pounce on a human, swapping genetic parts and creating a hybrid flu. When a similar bird-human flu struck nearly a century ago, about 20 million people died.

That fear has international experts scrambling to keep the killer strain of bird flu confined to Asia. Their strategies are dramatic - closing Asian live-bird markets that aid the virus' leap from wild to domestic birds, locking down Asian poultry farms, and imposing quarantines at U.S. hospitals for suspected bird-flu patients with a history of recent travel to affected countries.

Bird disease experts are training their binoculars on potential suspects, like bar-tailed godwits, for testing. The five to six days of nonstop flight made by the shorebirds has long fascinated researchers. Now they're of interest because they sidle next to potentially infected birds during an East Asia pit stop. And, while at Alaska breeding grounds, they mingle with domestic birds that later migrate across the nation.

"If it is proven, then you've got some major concerns because you get birds going to China, China Sea and Japan," he said.

Pigs are an important carrier species, since pigs can be infected with both human and avain flu, and also come into contact with both species. Not surprisingly pigs have been found to be carriers of the disease, and this makes for the possibility of genetic mixing between the human and avian strains of the flu. Flu viruses are known to be prolific mutators, changing their gene code as much as every couple of weeks, and it is now known that viruses and even higher organisms possess a natural ability to trade genetic material, so the discovery of avian flu in pigs provides just one more point of contact for genetic mixing between human and avian strains of the virus.

Are pigs carrying flu superbug?
By Anjana Ahuja
The Avian flu that has claimed 22 lives in the Far East has now been found in pigs. Because the animals are vulnerable to both bird and human flu, scientists fear the virus could mutate inside them into a superstrain like the one that killed up to a fifth of the world's population in 1918.

a United Nations organisation in Vietnam has reported that the virus has been found in pigs in Hanoi, although the news has been played down by the authorities and not yet confirmed by the WHO. The pigs, which showed no symptoms, apparently tested positive for H5N1 in nasal swabs; the WHO says that the presence of the virus in nasal cavities means the pigs may simply be contaminated but not infected (the virus has to defeat the animal's immune system to take hold).

Although the virus does not yet appear to be able to jump from human to human all those infected have caught it by handling poultry its appearance in pigs is bad news. At best, it could mean that we are unlikely to see H5N1 consigned to the history books just yet. At worst, it is a nightmarish plot twist that has the potential to create a flu virus that can spread like wildfire in people. The most famous pandemic the outbreak of Spanish flu in 1918 killed at least 20 million people and more likely double that. At the time, the world population was only around 1.8 billion and mass tourism which has spread diseases around the world at incredible rates did not exist.

Pigs are a crucial part of the story because they can catch both bird flu and human influenza: it is possible that a pig could become a cocktail shaker for the avian and human strains. That creates a chance of the two strains genetically rearranging themselves into one highly pathogenic (disease-causing) hybrid virus. This daughter virus could be the worst of all worlds, combining extraordinary virulence with easy transmissibility. The current strain seems exceptionally nasty: it has killed 70 per cent of those infected, including young, fit individuals. Moreover, flu viruses are known to have poor photocopying machinery: each replication increases the odds that a nasty virus will emerge.

There are a number of factors that seem to be contributing to a potential human disaster. First there is lag time between the discovery of a flu and the development of a vaccine, and while research is underway to study bird flu, given that a human variant would be a mutation, there may yet be still more lag time as the human variant is researched, if and when one emerges. (Given the spread of this flu among the wild animals and especially among the pigs, the probability of such a mutated version of the virus emerging is increased, in particular given how prolific flu viruses are at mutating and swapping genes.) Even after a vaccine is discovered, there remains the problem of manufacturing and distributing the vaccine, and here the virus definately has the upper hand, since the development of flu vaccines is a tedious process, and even worse, requires a large number of chicken eggs (just the sort of thing you wouldn't have as increasing number of chickens are slaughtered to fight the spread of the virus). It is interesting to note this correlation, in that the virus kills off the host required to create vaccines which would then halt its spread (a truly weird example of synchronicity).

The rise of the crowded conditions of the factory farms for animals is also a contributing factor in the development of such a disease. Chickens are typically packed tightly into spaces allowing each chicken only a little over a square foot of space. Heavy use of antibiotics to allow animals to survive in the crowded conditions of the modern animal factory have created the conditions where only the most virulent deadly chicken flu could survive by running the gauntlet of modern day antiobiotics, emerging from that marathon as a kind of superbug (something similar is happening in hospitals where overuse of antibiotics among humans has created the new phenomenon of the lethal superbug that first emerges in hospital settings and then threatens to get loose out in the wild). It was predictable that such a virulent strain of disease would emerge from the factory farm, and here the problem is more severe than that faced by hospitals, where there is at least the chance to disinfect and return the place to something approaching sanitary conditions after the superbug is discovered. This type of sanitation is not possible in a factory farm environment, and in any case, given that this strain of avian flu is already in the wild, carried by migrating birds, infecting wild animals and pigs, it will be with us for a while, until finally it does the inevitable and trades a gene with a human flu virus, becomes air borne, and its human created virulence follows a vector back through the animals populations which were its original hosts to the human population at the top of the pyramid.