Avian influenza H7N9 has not been found beyond mainland China but that does not mean it is not capable of spreading. According to the Center for Disease Control and Prevention’s (CDC) Emerging Infectious Diseases Volume 21, whether or not it represents a lack of spread is unclear.
H7N9 is a low pathogenic avian influenza (LPAI) found mainly in chickens and in few cases found in ducks, pigeons and quails. Sources of exposure may change if the virus spreads to backyard poultry and large commercial farms.
Because the virus’ virology and epidemiology differ from the well-researched A(H5N1) virus, it is difficult to say how it may spread and what measures can be taken for control.
There have been two complete waves of H7N9 ending in September 2014. Research from these waves suggest the virus is not widespread in wild birds and person-to-person spread is not likely. The virus also seems to be limited to two to three generations of transmissions. The third wave began in October 2014 and has not ended.
Starting February 2013 to March 2015, there have been 602 human cases of the low pathogenic virus. Most of these human cases have had exposure to live poultry or live-bird markets. Although person-to-person exposure is highly unlikely, the more cases develop, the higher the possibility it becomes.
Human infections may cause severe respiratory diseases along with fever, cough, pneumonia and may lead to respiratory failure. The median age of infected people is 58 while mild cases occur mostly in young children.
Although the virus is unlikely to spread to the surrounding countries of Vietnam, Thailand, Cambodia and Laos, they all have the laboratory capacity to detect and monitor H7N9.
According to the CDC, “governments must be vigilant against new and reemerging disease threat by rapidly responding to suspected outbreaks in animals and humans, educating health care professionals and the public, and working with partners to enhance animal health and public health systems.”
