Recent media reports from China highlight a new form of avian influenza (or bird flu) that has killed several people over the past few months. While we are still learning more about this strain of bird flu, we do know a lot about avian influenza in general, which may help the public, civic leaders, and bird control professionals take the necessary precautions to limit the spread of H7N9 and other bird flu strains.
What is Avian Influenza?
Avian (or bird) influenza is a disease caused by several related types of viruses. There are dozens of strains of each of these related viruses. Most of these viruses are usually only found in birds, while others, such as the common flu virus, can cause illness in humans and other mammals. While there are more than 100 different types (and even more subtypes) of avian influenza, the one recent news reports are concerned about is referred to as H7N9.
What is H7N9 Bird Flu?
H7N9 avian influenza is a strain of bird flu virus that was first reported to cause human infections in China at the end of March 2013. As of the end of April 2013, it has caused 126 cases of human infection in China, including 24 deaths. In humans, the virus causes respiratory infections that can lead to death from pneumonia, acute respiratory distress syndrome, or multiorgan failure. So far H7N9 cases have not spread beyond China, and appear to be limited to people that have had close contact with live infected ducks and chickens at poultry markets.
How does H7N9 Bird Flu Spread?
Bird flu viruses can potentially circulate between wild birds, poultry, and humans. H7N9 was first found in wild birds in the Republic of Korea and Mongolia during avian flu surveillance activities in 2008. During this current outbreak, H7N9 has only been found in chickens, ducks, quail, and captive-bred pigeons at live poultry markets in China. There is evidence that chickens may harbor the disease without showing symptoms, making it difficult to track in poultry markets. No wild birds have tested positive for this strain so far. Transmission to humans is still being studied, but appears to take place primarily from close contact with live infected poultry. There is currently no evidence of direct human-to-human transmission. Officials are still looking for evidence of how the virus may spread between pigeons, other wild birds, and poultry.
How can we protect ourselves from H7N9 and other strains of Avian Influenza?
Most Americans face very limited threats from bird flu viruses at this time, since they do not come into regular and direct contact with infected birds. Other cultures, especially those that support live poultry markets and small-scale poultry production, may face greater risks. Hunters and wildlife professionals, including pest management professionals, should follow the bird handling guidelines outlined by the National Wildlife Health Center. While the risk of infection is usually small, people should avoid contact with live birds or their bird droppings, and they should wash hands with soap and water (or alcohol-based products) thoroughly after any such contact, especially before rubbing their eyes, eating, drinking, or smoking.
Can bird control help stop the spread of H7N9?
While it is too early to know exactly how the H7N9 bird flu is being spread, since it was found in pigeons at a poultry market in Shanghai, it does highlight the importance of bird control in poultry operations and markets. In general, wild birds including feral pigeons should be excluded from areas where they can come into contact with poultry, in order to limit bird flu virus transmission. The United Nations Food and Agriculture Organization (FAO) recommends screening, fencing, or netting be used to keep wild birds away from poultry and other animals. Backyard and commercial poultry growers should follow the bio-security guidelines published by the University of Georgia CAES. While avian influenza should not be over-hyped, bird borne diseases such as avian influenza do pose a risk that should be carefully considered and managed when dealing with wild birds, poultry operations, and other situations where people may come in contact with wild birds and their droppings.