Possible Human Spread of Bird Flu
Limited Spread Within Family Not Bird Flu Breakout
Feb. 2, 2004 -- The bird flu may have spread from a Vietnamese man to his bride and his sisters, the World Health Organization reports.
If confirmed, it would be the first time one person has caught the virus from another. All other human cases appear to have been caught directly from infected birds. The WHO and Vietnam health authorities are conducting a detailed investigation.
To date, there is no evidence that the bird flu is spreading among humans. Genetic analyses show that none of the bird flu viruses isolated from people have obtained any new genes that might make them more easily spread among humans.
As of Feb. 2, there are 14 confirmed human cases of bird flu -- highly pathogenic avian influenza A (H5N1) -- in Thailand and Vietnam. Dozens of other cases are suspected in the East Asian nations where the virus is wreaking havoc on the poultry industry and local economies. Millions of chickens and ducks have been slaughtered in efforts to halt the wildfire spread of the disease. However, the virus also affects wild birds and may spread from nation to nation as these birds migrate.
Wedding Ends in Grief
The wedding was held in Vietnam on Dec. 30. While making the wedding meal, news reports say, the groom and one of his sisters prepared a duck. On Jan. 7, the groom was hospitalized in Hanoi. He died on Jan. 12 of respiratory illness. His two sisters and his new bride all became ill. Only the bride survived.
The groom was cremated before samples of his virus could be obtained. However, no other members of his family became infected. There's no evidence that he, his wife, or his sisters passed the infection to anybody else. And there's still no evidence that the bird flu is spreading from person to person anywhere in Vietnam or Asia.
For that to happen, experts say, the bird flu would have to transform itself into a human flu. It could do that -- it happened three times in the 20th century. But the transformation calls for a series of low-probability events. A human -- or another mammal, such as a pig -- would have to get infected with bird flu and human flu at the same time. That would let the two viruses swap genes, a process scientists call reassortment.
What keeps public health officials up at night is the nightmare scenario in which a deadly bird virus recombines to create a new virus -- a deadly human virus. Such a virus would spread quickly because few humans would have any immunity. Nobody knows exactly what would happen in this doomsday scenario, but CDC officials estimate that, without a vaccine, such a virus could cause some 200,000 deaths in the U.S. alone.
Just in case, the WHO and CDC are working feverishly on an H5N1 vaccine. The technology exists to make one, but the process is likely to take six months at least. Large-scale production would take longer. The U.S. and other nations also are stockpiling flu drugs. Strategic use of these drugs might slow the spread of a new human flu, but many experts wonder whether there are enough of these drugs to do the trick.