Areas with high potential for influenza reassortment identified
Researchers have identified several locations, primarily in Asia, where there is high potential for influenza virus reassortment, according to a report in Emerging Infectious Diseases.
“Laboratory experiments have shown that an influenza virus formed by mixing genes from a human seasonal influenza virus (influenza A H3N2) together with genes from the bird flu virus (influenza A H5N1) has high virulence in mice,” Trevon Fuller, PhD, of the Center for Tropical Research at the University of California, Los Angeles, told Infectious Disease News. “This reassortment is important because H3N2 transmits easily among people and H5N1 has a 60% human mortality rate.”
Fuller and colleagues developed a multivariate regression model to evaluate surveillance data on influenza A H5N1 among poultry and influenza A H3N2 among humans. They applied the models to areas across Egypt and Asia to determine where the two infections overlapped and predict hot spots for virus reassortment.
In Egypt, the areas with high potential for reassortment were located in the Nile valley and delta. In Asia, several locations were identified. In China, the coastal provinces bordering the South China Sea and the East China Sea, as well as central China, were predicted hot spots for reassortment. Other areas in Asia with high reassortment potential included the northern plains of India, the western Korean Peninsula and southwestern Japan.
“Within China, the part of the country that is at high risk for H3N2 and H5N1 reassortment is significantly smaller than the part that is at high risk for H5N1 alone,” Fuller said. “The areas in China and Egypt that we predict will have a high risk of reassortment could be prioritized for increased farm and market surveillance and vaccination of poultry.
Fuller said that this model could be applied to other influenza subtypes, or reassortment among strains of other viruses.
Disclosure: This study was funded by the Fogarty International Center at the NIH.