The genetic make-up of some indigenous people in Alaska and Australia might make them more susceptible to the H7N9 avian flu virus currently found in China.
“The findings suggested that there may be ethnic differences in the ability to mount an immune response to the H7N9 virus,” says Katherine Kedzierska, of the microbiology and immunology department at the University of Melbourne and the study’s lead author. “Due to genetic differences in a protein complex involved in cell-mediated immune responses, people may vary in their ability to mount this kind of immune response against the H7N9 influenza virus that emerged unexpectedly in February 2013.”
The new influenza virus originated in birds and caused an outbreak in China in March 2013 and infected more than 140 people. The flu strain resulted in a very high mortality rate of 30 percent due to severe pneumonia and acute respiratory distress syndrome.
Professor Peter Doherty, lead author of the study, says the findings shed light on what had happened during the catastrophic 1918-1919 influenza pandemic during which high adult mortalities—up to 100 percent—were reported in some isolated Alaskan villages.
“There are some populations that are at high risk from influenza disease,” Doherty says.
“Similarly, as many as 10 to 20 percent of Indigenous Australians died of influenza in 1919, compared to less than 1 percent mortality rate in non-Indigenous Australians. Hospitalization and morbidity rates were also higher for Indigenous Australians,” he says.
“This was also the case during the recent 2009 H1N1 pandemic influenza, with 16 percent of hospitalized Australians being Indigenous.”
“The genetic susceptibility of Indigenous Australian and Alaskans would have resulted from isolation of indigenous populations from the viruses like influenza. The indigenous populations were not subjected to evolutionary pressures caused by the viruses over the centuries.” explains Kedzierska.
The study appears in the Journal Proceedings of the National Academy of Sciences.
Source: University of Melbourne