Bird Flu May Be More Contagious Than Thought
Easy Human-to-Human Spread Surprises Experts
Findings Controversial continued...
At first, Bosman says, he thought the new test had to be wrong. But positive results on the test correlated with the main human symptom of bird flu: the viral eye infection called conjunctivitis or redeye.
"We are pretty confident that the results really reflect true infection," Bosman says.
Walter Orenstein, MD, says it's hard to know what to make of these findings until it's clear that the test Bosman and colleagues used is truly valid. Orenstein is director of the vaccine policy and development program and associate director of the Vaccine Center at Emory University in Atlanta.
"This report is very intriguing. But it is hard to know what it means at this point. We need to know how valid this test is," Orenstein tells WebMD.
But if the test is valid, Orenstein says, it suggests that the 2003 bird flu outbreak spread far beyond poultry workers and their immediate household contacts.
"It would seem to me with that high a household secondary infection rate -- 59% -- you would think it would have gotten out into the community more," he says. "If it turns out to be a valid finding, it is of concern that there was a lot more spread than previously thought."
Even so, Orenstein notes that there's no reason to think that the far more deadly Asian bird flu is spreading as the bird flu did in the Netherlands.
"If true, this report suggests a lot of transmission to humans of a nonvirulent strain. That's very different from the situation in Asia, where you have very limited transmission to humans of a very virulent strain," he says.
Bosman says it's important to find out for sure whether a different test for the Asian bird flu virus would yield different results.
"We now need to assess whether there are more sensitive tests available to look more closely at the possibility of higher prevalence of other flu viruses," he says.