Recent months have seen much information in the news about avian influenza, the H5N1 virus, and its impact on people and birds. The important facts to know are:
- “Avian flu” is one of several dozen viruses in the Type A influenza group. They are distinguished from one another by their serotypes, such things as H5N1, H3N2, H7N4, etc. Some of these viruses, such as the H3 series, infect only humans, others preferentially infect horses, or dogs, or even porpoises. Some can infect several species, although they typically have a preference for one type of host, e.g., bird or human.
- The particular concern lies with the serotype called H5N1, a virus for which waterfowl, especially ducks, are natural reservoirs – that is, most birds that carry the virus are not affected by it and can shed virus in large quantities; a few may sicken and die, but most will have clinically inapparent infections.
- The H5N1 virus is particularly lethal for chickens. In areas of the world where free-ranging chickens are allowed to mingle with wild waterfowl, there has been significant direct and indirect mortality in chickens, the latter through culling to limit spread. Millions of chickens have been killed in Southeast Asia in the last three years to control the spread of the disease.
- The virus does not pass readily from bird to human and, to date, not at all between humans. About 112 cases have occurred in humans as a result of direct contact with chicken or duck blood from butchering or consuming uncooked products. Almost half of the humans that have been infected have died, a very high mortality rate.
- In the summer of 2005, evidence began to emerge that the virus was moving out of Southeast Asia, westward into China, Russia, Siberia, and Eastern Europe, most likely from movements of poultry and also migratory water birds. It is expected to move west and south on the wings of migrating water birds during the months of October and November 2005.
- The virus is not vector-borne like West Nile virus. Mosquitoes and other insects are not involved in its transmission.
- Birds other than waterfowl, chickens, and turkeys are rarely infected with influenza. There is one report of a wild peregrine falcon in Beijing in 2004 having died from H5N1. In October 2005, a South American parrot died of the H5N1 avian flu strain in a quarantine facility near London.
- While the possibility exists of a circumpolar migrant water bird such as a crane or pintail duck picking up the virus in Asia and introducing it into North America, the likelihood is very remote at this time. There is little likelihood that it could be introduced by poultry other than by an act of smuggling or terrorism.
How The Raptor Center is responding
Presently, scientists at The Raptor Center and the University of Minnesota College of Veterinary Medicine think that there is only a remote chance that the H5N1 virus will be introduced into North America. In terms of protection of The Raptor Center’s birds, staff, and volunteers, there is little likelihood that TRC’s education birds would become exposed to and contract the virus except under the most bizarre of circumstances. Therefore, The Raptor Center is not taking any special precautions.
It is possible that an infected injured wild bird such as a great horned owl, bald eagle, peregrine falcon, or other bird that may feed on water birds could introduce the virus into The Raptor Center. Before that is likely to occur, however, there would in all likelihood be overt evidence of the virus circulating in the Midwest--in which case, we would review our admission and quarantine procedures for incoming birds. Presently, there is no concern, hence no additional precautions are being taken.
Please forward any questions you have to Dr. Patrick Redig, director of The Raptor Center, at firstname.lastname@example.org.
Find out more
To keep track of the current status of avian influenza, visit these Web sites:
- www.who.dk/ Click on Influenza and Avian Influenza in the left-hand column.
- www.cdc.gov/ Click on the box marked Avian Influenza.
For more information about avian influenza in poultry, visit the University of Minnesota College of Veterinary Medicine's avian influenza Web page.