At a time when misinformation abounds about avian influenza, more commonly referred to as bird flu, it is important to provide Americans with factual information about the virus. The U.S. Department of Agriculture has dealt with the virus among bird populations for many years and while there is reason for concern, there is also a long history of preparation and prevention efforts.
Birds have a flu season just as humans do and some strains of bird flu are as common in the U.S. and elsewhere as the human flu. Much like the human flu, these common, less transmissible strains of avian influenza can cause illness in birds and are sometimes fatal. These are called low pathogenicity, or “low path,” avian influenza (LPAI). The second type is high pathogenicity, or “high path,” avian influenza (HPAI). Pathogenicity refers to the ability of the virus to produce disease. USDA pays close attention to HPAI, as well as two strains of LPAI that can become more deadly, the H5 and H7 strains.
The bird flu was first detected in the U.S. nearly a century ago. High path strains of the virus, the more dangerous type, have been detected three times in our country in 1924, 1983, and 2004. By 2004, our response capabilities enabled us to confine the disease to a single flock of birds and quickly stamp it out. No serious human illness has been associated with these outbreaks in the U.S.
Yet, there is concern. A high path strain of the disease, H5N1, has been detected in parts of Asia and Europe. People have contracted and died from the disease, most of whom had direct contact with infected birds. Because influenza, by its very nature, has the ability to mutate, there is concern about the potential for this strain of the virus to become more transmissible.
USDA works to protect bird populations, which can help to protect people. USDA attacks the disease at its source overseas by working closely with international organizations to assist affected countries with disease prevention, management, and elimination. USDA also bans the importation of birds and poultry products from AI-affected countries. Additionally, USDA quarantines and tests imported live birds, including pets, to ensure they do not bring AI into the U.S.
Recognizing that the disease could reach the U.S. through other avenues, a four-part surveillance system is in place to monitor bird populations. To encourage poultry producers to report sick birds, we have an outreach campaign called “Biosecurity for the Birds.” It provides steps to reduce bacteria on farms and recognize bird flu symptoms. The commercial poultry industry is very active in prevention and testing, working with us to conduct more than a million random tests per year plus additional testing of sick birds. Another surveillance program specifically targets the live bird markets, where bird flu has been found in the past. The fourth program involves migratory birds. Since 1998, USDA scientists have tested more than 12,000 wild migratory birds in the Alaska flyway. None have tested positive for the more dangerous strains of bird flu.
USDA demonstrated the ability to eradicate even the more dangerous type of bird flu in 2004 when it was quickly detected the virus in the southern U.S., confined it to one flock, and eliminated it without a single human illness. In the event of a larger scale outbreak among birds, USDA maintains a stockpile of bird vaccines that would help to confine an outbreak. Additionally, more than 40,000 certified private veterinarians and 450 specially trained animal-disease experts are ready to respond.
There is currently no evidence that the more dangerous strains of the bird flu are present in the U.S. Nevertheless, be assured that we are enhancing our surveillance efforts and working very closely with the U.S. Department of Health and Human Services, as well state and industry partners, to enhance our emergency response plans.
We've learned a great deal from past experiences with bird flu and we are putting that knowledge to good use. So, if you hear about a detection of bird flu in the U.S., remember that some strains of bird flu, the low path type, are as common as the human form of the flu and pose no known threat to humans. In the event that a high path type would be reintroduced in the U.S., know that USDA stands ready to quickly respond.
Dr. Ron DeHaven is Administrator of USDA's Animal and Plant Health Inspection Service.