Sunday, June 16, 2013

H7N9 in China appear resistant to Tamiflu

hat-tip Flutrackers
Xinhua Guangzhou on June 16 (Reporter Xiao Sisi) H7N9 avian influenza virus in Chinese patients who appeared resistant to Tamiflu information for some time due to the scientific community attention, experts believe that the drug-resistant worthy of attention, but not tight.
Shanghai Medical College, Fudan University, Key Laboratory of Medical Molecular Virology, Shanghai Public Health Clinical Center Adjunct Professor YUAN Zheng-hong researchers led by emerging infectious diseases research team found that: individual human infection with H7N9 avian influenza Tamiflu antiviral therapy in patients 19 days is still in its throat swab samples detected H7N9 virus nucleic acid, suggesting that the virus has emerged mutations and drug trends. The end of May, the results have been published in leading international online medical journal "Lancet", causing great concern world counterparts.
"Tamiflu" is the expert had recommended for the treatment of human infection with H7N9 avian influenza drug of choice.
Experts, Duffy's mechanism of action is inhibition of virus replication. South China Agricultural University Vice-Chancellor, Ministry of Agriculture Key Laboratory of Animal Disease Prevention and Control Director Liao Ming introduction of avian influenza virus hemagglutinin of influenza virus HA is to help the host protein adsorption, NA neuraminidase is to help the virus in the host body proliferate substances. The existing "Tamiflu" and other drugs for neuraminidase inhibitors. "48 hours is a high incidence of viral replication, early use of drugs can effectively prevent viral replication experiments show that the human body strains isolated for 'Tamiflu' sensitive."
For information on the emergence of resistance Duffy, State Key Laboratory of Respiratory Diseases, Professor Chen Ling believes that this "concern, but no need to stress."
"Against influenza viruses have 'three tricks', in addition to Tamiflu, as well as zanamivir, Napa zanamivir two drugs effective for the treatment of H7N9 virus. Theoretically, the influenza virus is unlikely to have the same time for all three drugs resistant in other words, resistance to Tamiflu, while the other two are not resistant. "he said.
He explained that the virus if administered during the breeding process, the virus under pressure, will try to escape, the occurrence of natural variability, drug resistance, but for the virus, the mutation is also a "last resort."
"Usually a virus can survive for long, the result is a stable trait of variation is unavoidable circumstances change, which is also characteristic of the virus - changes to its own growth and less favorable if the medication is not standardized, such as the concentration is not enough, time is not standardized, the virus will have enough time to escape, mutate, but removed the drugs after a period of time, resistance is likely to disappear. "he said.
At present, China has begun to enter the summer, experts say bird flu basically over. But experts also warn that this winter epidemic unpredictable, H7N9 avian influenza virus may come back. "Using a non-high-risk time period, can be prepared in advance."
Chen Ling believes that "even while the three drug resistance, there are other ways to combat H7N9 avian influenza, such as in patients who extracted serum antibodies injected into the patient, but this approach can not last long, because the ex vivo generated antibody declined over a few months in addition, there are a number of ways, for example in the horse's body into the inactivated H7N9 influenza virus, antiviral extract serum, and then after purification treatment, can also be used person Another way is to pay close attention to production of H7N9 avian influenza vaccine research and development. Based on past experience, the time is enough. "
Developed anti-H7N9 avian influenza virus drugs are also on the agenda. "Retreat one step, if the next resistance is universal, or three drugs simultaneously use it to produce drug, there is a need to develop new drugs. Such drugs are not only neuraminidase inhibitors, but monoclonal antibodies and polyclonal antibodies (antibodies were identified viruses several different places), these can encourage the development of new drugs. "Chen Ling said.
Liao Ming believes that the next need to strengthen the monitoring of avian species and humans infected with avian influenza epidemic monitoring. 

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