Bird flu viruses can resist fever, increase threat to humans: Study

Bird flu viruses can replicate at temperatures higher than a typical fever one of the bodys ways of stopping viruses in their tracks increasing the threat to humans according to new researchHuman flu viruses which cause seasonal flu are known as influenza A virusesFever protects against severe infection from humanorigin flu viruses with just a 2 degrees C increase in body temperature enough to turn a lethal infection into a mild diseaseResearchers from the universities of Cambridge and Glasgow UK showed that while raising body temperature to fever levels is effective at stopping humanorigin flu viruses from replicating it is unlikely to stop avian or bird flu virusesUnlike human flu viruses avian influenza viruses tend to thrive in the lower respiratory tract In fact in their natural hosts which include ducks and seagulls the virus often infects the gut where temperatures can be as high as 40 to 42 degrees CThankfully humans dont tend to get infected by bird flu viruses very frequently but we still see dozens of human cases a year Bird flu fatality rates in humans have traditionally been worryingly high such as in historic H5N1 infections that caused more than 40 per cent mortalityrdquo said Professor Sam Wilson from the Cambridge Institute of Therapeutic Immunology and Infectious Disease at the University of CambridgeUnderstanding what makes bird flu viruses cause serious illness in humans is crucial for surveillance and pandemic preparedness efforts This is especially important because of the pandemic threat posed by avian H5N1 viruses Wilson addedThe study published in the journal Science used in vivo models mice infected with influenza viruses to help explain how fever protects us and why it may not be enough to protect us against avian influenzaThe team simulated in mice what happens during a fever in response to influenza infections To carry out the research they used a laboratoryadapted influenza virus of human origin known as PR8 which does not pose a risk to humansAlthough mice do not typically develop fever in response to influenza A viruses the researchers were able to mimic its effect on the virus by raising the ambient temperature where the mice were housed elevating the body temperature of the miceThe research also revealed that the PB1 gene of the virus important in the replication of the virus genome inside infected cells plays a key role in setting the temperaturesensitivityViruses carrying an avianlike PB1 gene were able to withstand the high temperatures associated with fever and caused severe illness in the miceThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever