Germans Move to Prevent Bird Flu
June 12, 2005
An outbreak of Severe Acute Respiratory Syndrome, or SARS, a few years back killed 800 people world-wide and hit several Asian economies hard. The global community saw itself facing a highly contagious virus and moved fast to close off infectious regions, quarantining entire cities and blocking off major transport routes. The SARS scare sent a wake-up call to the international health community and drove home the necessity of global cooperation in preventing such epidemics.
Scientists are now worried about a strain of bird flu, known as H5N1, which has already killed several dozen people in Asia and has the potential to mutate into this century's first pandemic, rivaling the 1918 Spanish flu which killed millions. The avian flu virus is currently transmitted by domestic birds. It hits mostly in regions where poultry and human beings live in closely confined spaces.
Although at the moment H5N1 cannot be easily transmitted from human to human, scientists say it is only a matter of time until this happens. They also worry that migratory birds could carry the virus around the planet and thus spread the epidemic. Last month, more than 1,000 migratory geese were found dead from the strain of avian flu in China, an early warning sign of the virus' ability to spread, said German virologist Robert Webster.
"At the end of the breeding season, bareheaded geese migrate to India and across the Himalayas," he said. "Chances are that the H5N1 from Asia will increase, and that is not good news, because the north and south migration routes all overlap."
Slow transmission around the globe
Webster, who is advising all countries to check their wild bird populations for the virus, said it may not reach Europe this year, but given time the virus will slowly transmit across the breeding ranges of various birds.
"It is not encouraging," he said.
Anja Globig, who works for the Federal Research Institute for Animal Health on the island of Riems, heeded the warning and called on volunteers and hunters to take probes from the droppings of wild birds. After collecting more than 2,500 probes of ducks, geese, swans, sea gulls, storks and birds of prey, she injected the material into live chicken eggs. In 21 cases, the virus appeared.
"Among the ducks, which are regarded to be carriers of the influenza, 7.7 percent turned out to be positive," she said. "In one location in Germany, on the island of Föhr, we found 14 percent of the wild birds to be carriers of the virus, which is a lot."
Wild geese the "culprits"?
However, she also warned that the viruses detected were not related to the Asian avian flu virus, the H5N1. But there were viruses among those detected which have the potential to mutate and can trigger diseases in chickens, as a 2003 outbreak of avian plague in the Netherlands showed.
There, chickens were infected with a virus called H7N7, most likely transmitted by wild geese. In the tight confines of the chicken stalls, the virus was able to adapt and spread. Some 30 million birds needed to be slaughtered, almost 100 people were infected, and a veterinarian treating the chickens died.
In order to prevent a repeat of the epidemic, Globig said free range chickens need to be put under special observation.
Mandatory testing
"The most important thing is not to feed the animals out in the open, which attracts wild birds," she said. Apart from that, poultry should be checked twice a year for the sub-types of avian flu.
In the German state of Lower Saxony, such regular tests are already mandatory. If one of the virus strains is detected, the birds must be slaughtered before the virus can mutate and pose a threat to human and animal health. Alternatively, animal breeders could adopt a widespread vaccination of poultry, a practice still not readily available on the market.
Virologists like Robert Webster have stressed the importance of investing more research in developing effective vaccines.
"There is great emphasis in putting energy into vaccine strategies for humans," he said. "I would argue that the first emphasis should be stopping the H5N1 virus at the source: domestic ducks and chickens."