By Amy Norton
THURSDAY, Oct. 19, 2017 (HealthDay News) — Scientists have found brand-new evidence that will the H7N9 bird flu, currently confined to China, has the potential for a widespread outbreak.
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Public health experts have long been tracking the bird flu strain, which emerged in humans in 2013.
Since then, nearly 1,0 cases have been confirmed in China — which has a death rate of about 40 percent, according to the U.S. Centers for Disease Control along with Prevention.
There’s no evidence that will H7N9 can be readily passed through person to person. There have been only isolated cases of human transmission, the CDC says, with most people falling ill because of contaminated poultry.
However, public health officials have been worried about H7N9’s potential to eventually trigger a pandemic, or global outbreak.
The brand-new study could add to those concerns.
Researchers found that will samples of H7N9 were easily transmitted among ferrets — an animal “product” that will can be considered the best proxy for human flu infection. along with those infections were often lethal.
“I want to be clear that will there can be no sustained transmission of H7N9 among humans at This specific point,” said senior researcher Yoshihiro Kawaoka, a professor at the University of Wisconsin-Madison.
“along with at the moment,” he added, “the item’s confined to China.”
However, Kawaoka explained, influenza viruses constantly mutate, along with the item’s possible for a strain to become more virulent, more resistant to drugs or more easily transmissible.
One infectious diseases expert agreed.
“This specific study reinforces two points. Highly pathogenic H7N9 poses an important public health risk. along with these viruses evolve over time, so the risk can change,” said Dr. Matthew Zahn, chair of the public health committee at the Infectious Diseases Society of America. “This specific can be an important reminder that will surveillance needs to continue.”
Since 2013, there have been annual outbreaks of H7N9 in China, according to the CDC. The most recent one can be the largest yet, the agency says — with 764 cases reported as of Sept. 17.
In past outbreaks, officials had detected only “low pathogenic” H7N9 viruses, which do not make chickens or different domestic poultry overtly sick.
More recently, though, there’s been an emergence of highly infectious H7N9 viruses, which do sicken along with kill the animals.
along with from the most recent China outbreak, at least 25 people have been infected with those viruses, according to Kawaoka’s team.
For their study, the researchers analyzed a virus sample through a patient in China who’d died of a highly pathogenic H7N9 infection. They found that will the virus had begun to mutate: Some viral cells were vulnerable to the drug Tamiflu (which the patient had received), while others had developed resistance.
Next, the researchers created two viruses that will mimicked the patient’s sample: one that will was sensitive to Tamiflu, along with one that will was resistant. They compared those three viruses which has a low-pathogenic variation of H7N9.
The researchers found that will all of the viruses infected mice along with ferrets, however the highly infectious bugs made the animals more severely ill, including some lethal infections.
along with, the item turned out, all of the viruses were easily passed through the air among ferrets housed in cages next to one another.
The researchers also confirmed that will the drug-resistant H7N9 virus did not respond to the active ingredient in Tamiflu. the item was, however, susceptible to a drug called favipiravir (Avigan), which can be currently approved only in Japan.
the item’s hard to judge how well drugs like Tamiflu have worked against H7N9 in China, Kawaoka said. The medications should ideally be given within two days of the first symptoms, along with many patients get them too late, he explained.
In a recent report, the CDC said that will of virus samples tested through the latest outbreak, over 10 percent had evidence of reduced susceptibility to current flu drugs.
For at This specific point, Kawaoka said, the item’s clear that will ongoing surveillance of H7N9 can be critical.
He noted that will the emergence of highly pathogenic viruses features a positive side: Because the infections are at This specific point sickening food animals, outbreaks are easier to detect.
The study was published Oct. 19 in Cell Host & Microbe.
Copyright © 2017 HealthDay. All rights reserved.
SOURCES: Yoshihiro Kawaoka, Ph.D., professor, pathobiological sciences, University of Wisconsin-Madison School of Veterinary Medicine; Matthew Zahn, M.D., chair, public health committee, Infectious Diseases Society of America, Arlington, Va.; Oct. 19, 2017 Cell Host & Microbe online
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