Authorities announced on January 31st that several Massachusetts swans tested positive for low-path avian influenza, or bird flu. There is no threat to human health.
Twelve dead swans were found in Mill Pond of Westboro, Massachusetts in December, launching a joint investigation by the Massachusetts Department of Energy and Environmental Affairs and the United States Department of Agriculture’s Wildlife Services. Of the 12 swans, four tested positive for low path bird flu. The remaining eight birds tested negative for bird flu, and the cause of death is unknown.
Low pathogenic avian influenza, often called North American bird flu or LPAI, is a relatively mild disease. It is common in wild birds and rarely fatal. According to a spokesman for the Division of Fisheries and Wildlife in Massachusetts, this type of bird flu is “fairly common in water fowl here… but I have to stress there is no human risk.”
LPAI has been reported in wild birds across the United States for many years, though historical reporting cannot be considered comprehensive, as there were no requirements to report or track LPAI before 2006. Currently, suspected LPAI cases in the US are tracked by the United States Department of Agriculture (USDA) and reported to the World Organization for Animal Health (OIE).
Contrast LPAI with highly pathogenic avian influenza, or HPAI, that is increasingly found in Asia. HPAI is very infectious and often fatal to domestic poultry such as chickens or turkeys. HPAI can infect humans and is also often lethal. Generally, humans catch this form of bird flu through direct contact with an infected animal. Most recently, HPAI has been responsible for two deaths in 2012 in Vietnam’s Mekong Delta.
For more information about high pathogenic versus low pathogenic avian influenza, please refer to the Disease Daily’s Q&A.