# 457
The idea that there is some hidden reservoir of the H5N1 virus, other than birds, has been long suspected. We've heard, of course, of cats being infected, and occasionally dogs and other small mammals, but the feeling has been we've been missing . . something.
Among flu many flu watchers, rodents have been a favorite suspect. They are ubiquitous on many farms, can get in and out of bio-secure areas with ease, and could possibly explain the small percentage of human cases without a direct link with infected poultry.
In recent months, the South Koreans, during their culling operations, have resorted to basically eliminating everything that moves in the culling zone, which has further raised suspicions.
Today we get this, from asahi.com. Rodents, they say, are suspected. Not proven. But another very interesting facet to this story.
Rodents suspected in spread of avian flu
02/16/2007
THE ASAHI SHIMBUN
Scientists suspect rats spread the recent outbreaks of avian flu at four farms in Miyazaki and Okayama prefectures after the H5N1 virus strain was brought over by migratory birds from China.
The experts agree that the migratory birds triggered the infections at the four poultry farms over the past month. But they said at a meeting Wednesday that the way the disease spread indicates that other factors were involved.
Inspectors found that nets and coverings were in place to prevent large migratory birds from coming into contact with the poultry.
In addition, dead chickens at three of the farms were found in areas farthest from the entrance of the coops, so the wild birds were not likely the direct source of the infection.
"It's possible that small rodents, such as rats, carried the virus into the chicken coops," said Toshihiro Ito, a professor of veterinary microbiology at Tottori University who chairs the team of specialists.
He said the rats were likely infected by the wild birds from China.
The task force, appointed by the Ministry of Agriculture, Forestry and Fisheries, said the H5N1 strain at the four farms was identical to the one that killed thousands of wild birds at Qinghai Lake in western China starting in 2005.
The strain was also similar to one found in duck droppings in South Korea in January.
"It is possible the virus was brought to western Japan by a route that went through China and the Korean Peninsula," Koichi Otsuki, a professor of veterinary microbiology at Kyoto Sangyo University, said.
According to specialists, migratory birds follow three main routes in winter. One route passes over Hokkaido, another crosses the Sea of Japan and the third goes through the Korean Peninsula.
Ducks are believed the likely carriers of avian flu because most ducks are not affected by the disease.
However, the avian flu virus multiplies in the intestines of ducks and is released in their droppings.
An Environment Ministry study confirmed that wild ducks were within a 10-kilometer radius of the infected farms in Japan.
Nets and other measures at the farms in Japan should have been enough to keep out large wild birds, like ducks, but rats and small birds could still enter the coops.
If the specialists confirm that rats were indeed the carriers of avian flu, it would be very difficult to avoid similar outbreaks.
