A study suggests that some North American avian influenza A H7 virus strains have potential to infect humans and spread from human to human.
The study recently published in the Proceedings of the National Academy of Sciences USA was carried out at the Centers for Disease Control and Prevention.
Most cases of avian influenza infection in humans have resulted from contact with infected poultry or contaminated surfaces. However, avian influenza A H7 viruses are fairly common in birds, they rarely infect humans.
Dr. Jessica Belser, the C.D.C. lead author on the project said that it is so important to watch influenza viruses carefully, because they are constantly changing.
Three recent H7N2 strains and two H7N3 strains from North America were tested and found to bind to varying degrees to both avian and human receptors. One H7N2 virus was found to have the greatest binding to the human sugar receptors. This study¡äs findings suggest that these North American avian influenza A H7 viruses are partially adapted to recognize sugar receptors preferred by human influenza viruses.
A different avian influenza virus, H5N1, which began spreading among birds and poultry in Asia in 2003 and has spread to birds in other countries in Europe, the Near East and Africa are also being closely monitored by health officials. Approximately 400 human cases of H5N1 have been reported throughout the world although none have occurred in the United States or even the Northern hemisphere.
Source: Proceedings of the National Academy of Sciences of the USA