Now this should give you what I call the big pause…Scientists taking the first look at the genetics of the bird flu strain that recently killed 3 men in China say the virus could be harder to track than its better-known cousin H5N1 because it might be able to spread silently among poultry without notice. What?!?!?!?

The scientists announced on April 3 that the H7N9 virus is troubling because it can generate no symptoms in poultry while seriously sickening humans. Dr. Masato Tashiro, a WHO scientist studying the virus’ genetic data, says the virus also appears to have mutated into a form that enables it to more easily infect animals such as pigs, meaning they could serve as hosts that spread the virus more widely among humans.

“We speculate that when this virus is maintained in poultry the disease will not appear, and similar in pigs, if they are infected, so nobody recognizes the infection in animals around them, then the transmission from animal to human may occur,” said Dr. Masato Tashiro, director of the World Health Organization’s influenza research center in Tokyo and one of the specialists who studied the genetic data. “In terms of this phenomenon, it’s more problematic.”

OK, that might be the biggest understatement of the…. century!

This behavior is unlike the virus’s more established relative, the virulent H5N1 strain, which set off warnings when it began ravaging poultry across Asia in 2003. H5N1 has since killed 360 people worldwide, mostly after close contact with infected birds.

It this illness continues to spread throughout China and beyond China, it would be a much more significant problem than the H5N1 virus because with H5N1 you can see evidence of poultry dying.  In this new virus this would be more or less a silent virus in poultry species that will occasionally infect humans.

Scientists closely monitor bird flu viruses, fearing they may change and become easier to spread among humans, possibly sparking a pandemic. There’s no evidence of that happening in China.

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ProMED Digest V2013 #146