MONDAY, Jan. 24, 2005 (HealthDayNews) -- In what may be the first documented case that the dangerous avian flu can be transmitted between humans, a new study concludes an 11-year-old girl in Thailand likely transmitted avian flu to her mother and aunt last summer.
These would be the first documented cases of person-to-person transmission of the H5N1 avian flu, which has wreaked havoc across Asia in the past year, according to an article in the Jan. 27 issue of the New England Journal of Medicine. The article was released early to coincide with the University of Michigan Bioterrorism Preparedness Initiative conference.
With this new evidence, an editorial and perspective article in the same issue of the journal call for preventive measures that would avoid a worldwide pandemic of the disease.
The avian flu in Asia has been particularly bad, with more than 120 million poultry dying or destroyed between January and March 2004, stated an editorial in the journal. According to the World Health Organization (WHO), 52 people in Thailand and Vietnam have been infected and 39 have died over the past year.
In Vietnam, two more people died from bird flu last Saturday, the Associated Press reported, bringing the total to nine dead in just three weeks. WHO officials are investigating whether there was human-to-human transmission in the case of two Vietnamese brothers who tested positive for the virus, the AP reported. WHO was also quoted as saying that isolated instances of transmissions among humans does not necessarily raise the specter of a pandemic.
Experts have long worried that this particular avian virus will mutate enough to spread easily among humans, triggering just such a pandemic.
"The concern is that the H5N1 avian strain can change, eventually emerging as a virus that can easily spread from human to human," said Dr. Mark Beilke, an associate professor of medicine at Tulane University Health Sciences Center in New Orleans. "Right now, human-to-human transmission has been limited to this report."
There may have been cases of human-to-human transmission last year in Vietnam but they couldn't be documented, added Dr. Arnold S. Monto, author of an accompanying perspective article and a professor of epidemiology at the University of Michigan School of Public Health in Ann Arbor. There have also been cases of human-to-human transmission which didn't result in actual disease. "We know it can happen," Monto said.
This particular strain of the virus, H5N1, emerged in 1997 and has gone through changes, making it more virulent.
Here's how the report described the incident:
The girl lived with her aunt in a province of Thailand and slept and played in an area under the elevated house where the family's chickens often wandered. The flock of free-ranging chickens had been sick, with the last ones dying on the last two days of August 2004. The girl's aunt buried the last five chickens on August 29 or 30, using plastic bags to protect her hands.
The girl fell ill on Sept. 2 and was admitted to a local hospital on Sept. 7. She was transferred to the provincial hospital the next day, but died three hours after admission.
The girl's mother traveled four hours from Bangkok on Sept. 7, stopping at the girl's house only for 10 minutes before heading for the hospital. Both mother and aunt provided unprotected nursing care for the girl.
The mother developed symptoms three days after her daughter died, and it appeared unlikely that her 10-minute stop at the house would be enough to allow bird-to-human transmission. She later died. The aunt fell ill on Sept. 16, 17 days after her last exposure to the chickens. The accepted incubation period is two to 10 days.
The message from this latest report is that people need to be ready, Monto said. "We would suppose that the virus would not be as efficient in transmitting early on. This is a hypothesis, but there's a lot of evidence that this might be the case," he said. "This would give us an opportunity to try to snuff it out at its source." To that end, Monto said, there needs to be a global stockpile of antivirals (some countries are already doing this), as well as a plan for distribution to areas where an outbreak occurs.
A vaccine is also needed. "When it comes to avian flu, everybody is like a child," Monto said, referring to the fact that humans have no immunity to the virus. "Maybe we should be using a vaccine for H5N1 in people even though it wouldn't be exactly like the virus that might come along. At least this would prime us so that we'd have a better response."
Although such a pandemic might never occur, Monto said, "the message is that we need to be ready."
More information
The World Health Organization has more on avian flu.
