Scientists have conducted research to determine the risk of transmission for people who are exposed to birds infected with highly pathogenic avian influenza (HPAI) A H5 within the U.S.
This newly emerged HPAI A H5 set of viruses triggered outbreaks throughout flocks of birds within the U.S.
The viruses are genetically different compared to HPAI H5 viruses, some of which can trigger illness in humans. These outbreaks typically occur in Africa and Asia.
To determine the transmission risk from animals to humans, scientists studied the HPAI H5 virus transmission throughout the U.S. They compared three groups of people. The first study involved the quantity of people who had self-confirmed exposure to birds with the infection. The second included people with acute respiratory infections (ARI) who had positively tested for bird flu using serologic testing or real-time reverse transcription PCR from December 2014 to March 2015. The third group involved people who had ARIs throughout a post-exposure period that lasted 10 days.
Researchers found that throughout 60 outbreaks in 13 states, 164 people had exposure to birds infected with the virus. Five of these people had ARI just 10 days after their exposure. None of these people tested for H5 influenza virus infection. This suggests that there is not a significantly high risk of HPAI H5 virus transmission from animals to humans.
