Avian influenza virus resistant to medication

Mutation of the bird flu virus leads to resistance

Chinese researchers warn of mutations in the H7N9 bird flu virus. Avian flu infections, which are currently rampant in China and have already caused numerous deaths, are at least partially caused by pathogens that are resistant to common antiviral drugs, the scientists from the Shanghai Public Health Clinical Center and the Fudan University of Shanghai report in the renowned specialist magazine " The Lancet ”.

Scientists believe that the poor treatment prospects for H7N9 infections in China are associated with pathogen resistance. As part of their study, the researchers examined 14 patients with H7N9 infection who were treated at the Shanghai Public Health Clinical Center. "We analyzed the viral load in the throat, stool, serum and urine samples that was received from these patients," the researchers write. The viral RNA from the samples was also sequenced to investigate possible mutations, to identify resistance to neuraminidase inhibitors and to check their connection with the course of the disease.

Resistance leads to complete therapy failure The Chinese scientists report that all patients developed severe bird flu symptoms such as pneumonia, seven of them had to be artificially ventilated, in three patients the condition worsened and two of them died. In eleven patients, the antiviral treatment initiated with the active ingredients oseltamivir (brand name Tamiflu) or peramivir resulted in a significant “reduction in viral load in cervical / throat swabs”. For the rest, the medication did not show the desired success. The researchers then found that two of these patients who had also received corticosteroids had an "Arg292Lys mutation in the neuraminidase (NA) gene". Resistance to the antiviral drugs is also associated with the mutation, which ultimately resulted in complete therapy failure and death in those affected.

The resistance of bird flu viruses developed with obvious ease and appears to be extremely questionable, the researchers report. "The development of antiviral resistance in H7N9 viruses, particularly in patients receiving corticosteroid therapy, is worrying, must be closely monitored and taken into account in the planning of the pandemic," the Chinese scientists concluded. (fp)

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