USDA Avian Influenza Fact Sheet

Release No. 0458.05
Contact:
USDA Press Office (202) 720-4623

Questions and Answers: Avian Influenza
Last Modified: 10/31/2005 

Q. What is avian influenza? 

A. Avian influenza (AI) is a disease found among poultry. AI viruses can be classified into low pathogenicity and highly pathogenic forms based on the severity of the illness they cause in poultry. Most AI strains are classified as low pathogenicity avian influenza (LPAI) and cause few clinical signs in infected birds. In contrast, high pathogenicity avian influenza (HPAI) causes a severe and extremely contagious illness and death among infected birds. 

Q. How is the disease spread? 

A. AI is primarily spread by direct contact between healthy birds and infected birds, and through indirect contact with contaminated equipment and materials. The virus is excreted through the feces of infected birds and through secretions from the nose, mouth and eyes. 

Contact with infected fecal material is the most common of bird-to-bird transmission. Wild ducks often introduce low pathogencicity into domestic flocks raised on range or in open flight pens through fecal contamination. Within a poultry house, transfer of the HPAI virus between birds can also occur via airborne secretions. The spread of avian influenza between poultry premises almost always follows the movement of contaminated people and equipment. AI also can be found on the outer surfaces of egg shells. Transfer of eggs is a potential means of AI transmission. Airborne transmission of virus from farm to farm is highly unlikely under usual circumstances. 

Q. What symptoms do birds with AI demonstrate? 

A. LPAI symptoms are typically mild. Decreased food consumption, respiratory signs (coughing and sneezing) and a decrease in egg production might demonstrate the presence of the disease. Birds that are affected with HPAI have a greater level of sickness and may exhibit one or more of the following clinical signs: sudden death; lack of energy and appetite; decreased egg production; soft-shelled or misshapen eggs; swelling; purple discoloration; nasal discharge; coughing, sneezing; lack of coordination and diarrhea. 

Q. What should producers do if their birds appear to have signs of AI? 

A. If birds exhibit clinical signs of HPAI or may have been exposed to birds with the disease, producers or bird owners should immediately notify Federal or State animal health officials. 

Q. Is it possible for an LPAI strain to become highly pathogenic? 

A. Some low pathogenic subtypes have the capacity to mutate into more virulent strains. While LPAI is considered lower risk, low pathogenic strains of the virus - the H5 and H7 strains - can mutate to highly pathogenic forms. 

Q. Is AI a reportable disease? 

A. HPAI is considered a reportable disease by the World Organization for Animal Health (OIE). OIE has developed animal health standards that classify all H5 and H7 viruses as reportable diseases. 

Q. Does AI threaten human health? 

A. LPAI poses no known serious threat to human health, however some strains of HPAI viruses can be infectious to people. Since December 2003, a growing number of Asian countries have reported outbreaks of HPAI in chickens and ducks. Humans also have been affected, most of who had direct contact with infected birds. The rapid spread of HPAI in 2004 and 2005 is historically unprecedented and of growing concern for human health as well as for animal health. 

Q. Does HPAI currently exist in the United States? Has it ever occurred in this country? 

A. HPAI does not currently exist in the United States. There have been three outbreaks of the disease in poultry in this country--in 1924, 1983 and 2004. 

A HPAI epidemic occurred in the northeastern United States in 1983-84. A highly virulent H5 virus produced severe clinical disease and high mortality in chickens, turkeys, and guinea fowl in Pennsylvania and Virginia. Approximately 17 million birds had to be destroyed. 

In February 2004, USDA confirmed that an H5N2 strain of avian influenza in a flock of chickens in Texas was consistent with HPAI. There was no evidence of any human health implications of this HPAI virus in Texas. USDA worked with state officials to quickly eradicate the disease. Because of the quick response, the disease was limited to one small flock. 

Q. What is USDA doing to prevent the introduction of HPAI into the United States? 

A: USDA recognizes that HPAI poses a significant threat to animal health and has the potential to threaten human health. Accordingly, USDA's Animal and Plant Health Inspection Service (APHIS) has safeguards in place to protect against the introduction of HPAI into the United States. APHIS maintains trade restrictions on the importation of poultry and poultry products from countries currently affected by HPAI. These restrictions include: 

Prohibiting the importation of live birds and hatching eggs from H5N1 affected countries. 
Requiring imports of poultry products from East and Southeast Asia be processed or cooked in accordance with a USDA permit prior to importation to lower the risk of HPAI contamination to negligible levels. 
Requiring all imported birds be quarantined at a USDA bird-quarantine facility and be tested for the avian influenza virus before entering the country. This requirement now covers returning U.S.-origin pet birds. 
Detection 

USDA also works closely with international organizations like the World Organization for Animal Health (OIE), the United Nations' Food and Agriculture Organization (FAO), and World Health Organization (WHO) to assist HPAI-affected countries and other neighboring Asian-Pacific countries with disease prevention, management, and eradication activities. By helping these countries prepare for, manage, or eradicate HPAI (H5N1) outbreaks, USDA can reduce the risk of the disease spreading from overseas to the United States. 

APHIS also recognizes that prevention is only one part of a comprehensive strategy and therefore continues to work closely with its Federal, State, and Tribal partners and industry stakeholders to have effective and coordinated emergency response plans at the ready should an outbreak of HPAI occur in the United States. 

Q. What is USDA doing to monitor the U.S. for AI among birds? 

A: The USDA Animal and Plant Health Inspection Service (APHIS) works with states to monitor and respond to outbreaks of LPAI. APHIS has provided funding and support personnel to states when LPAI has been detected. When HPAI is detected, APHIS personnel are primary responders, due to its infectivity and high mortality rate among poultry. Close attention is also given to two subtypes of LPAI, the H5 and H7 strains, because of the potential for them to mutate into HPAI. The AI strain infecting both birds and humans in Asia is the HPAI H5N1. There is presently no evidence of HPAI H5N1 existing in the U.S. - neither in animals nor humans. 

In addition to international import restrictions, APHIS and State veterinarians are specially trained to diagnose foreign animal diseases regularly conduct field investigations of suspicious disease conditions. This surveillance is assisted by university personnel, State animal health officials, USDA-accredited veterinarians, and members of the industry who report suspicious cases. APHIS and State animal health officials work cooperatively with the poultry industry to conduct surveillance at breeding flocks, slaughter plants, live-bird markets, livestock auctions, and poultry dealers. 

Q. What can poultry producers do to prevent an AI outbreak on their farms? 

A. Poultry producers should strengthen biosecurity practices to prevent the introduction of AI into their flocks. The following are some sound biosecurity practices: 

Keep an "all-in, all-out" philosophy of flock management. 

Avoid skimming flocks-birds left behind are exposed to work crews and equipment that may carry poultry disease viruses. Process each lot of birds separately, and clean and disinfect poultry houses between flocks. 

Protect poultry flocks from coming into contact with wild or migratory birds. Keep poultry away from any source of water that may have been contaminated by wild birds. 

Permit only essential workers and vehicles to enter the farm. 

Provide clean clothing and disinfection facilities for employees. 

Thoroughly clean and disinfect equipment and vehicles (including tires and undercarriage) entering and leaving the farm. 

Do not loan to, or borrow equipment or vehicles from, other farms. 

Change footwear and clothing before working with your own flock after visiting another farm or live-bird market or avoid visiting another bird farm if possible. 

Do not bring birds from slaughter channels, especially those from live-bird markets, back to the farm. 

If AI is detected, farms must be thoroughly cleaned and disinfected. AI is inactivated by heat and drying and it is also very sensitive to most disinfectants and detergents. The area to be disinfected must be clear of organic material, which greatly increases the resistance of avian influenza virus' resistance to disinfection. 

Q. Does proper food handling prevent avian influenza? 

A. The USDA Food Safety and Inspection Service (FSIS) is working to educate the public about safe food handling practices in response to numerous questions from the public about the human risk associated with avian influenza. LPAI, the type commonly found in the U.S., is not transmissible by eating poultry. If HPAI were detected in the U.S., the chance of infected poultry entering the food chain would be extremely low. Nevertheless, proper handling and cooking of poultry provides protection against HPAI, as it does against other viruses and bacteria, including Salmonella and E.coli. USDA continually reminds consumers to practice safe food handling and preparation every day: 

Wash hands before and after handling food; 

Prevent cross-contamination by keeping raw meat, poultry, fish and their juices away from other foods; 

Wash hands, cutting board, knife, and counter tops with hot, soapy water after cutting raw meats; 

Sanitize cutting boards by using a solution of 1 teaspoon chlorine bleach in 1 quart of water and 

Use a food thermometer to ensure food has reached proper temperatures -details available on-line at 
http://www.fsis.usda.gov/ . 

Current science indicates that-- as with all foodborne pathogens-- proper cooking of poultry minimizes the risk of illness from consumption of poultry. Using a food thermometer is the only sure way of knowing if your food has reached a high enough temperature to destroy foodborne pathogens including bacteria and viruses. USDA recommends cooking whole birds to 180 °F as measured in the thigh using a food thermometer. When cooking pieces, the breast should reach 170 °F internally. Drumsticks, thighs and wings should be cooked until they reach an internal temperature of 180 °F. Ground turkey and chicken should be cooked to 165° F. The minimum oven temperature to use when cooking poultry is 325 °F. Remember to wash hands with soap and warm water for 20 seconds before and after handling raw poultry. 

Q. Are poultry products from countries with avian influenza allowed into the United States? 

A. No. Poultry products imported to the U.S. must meet all safety standards applied to foods produced in the U.S. Currently, no poultry from flocks with confirmed cases of high-pathogencity avian influenza or reportable types of low-pathogenicy avian influenza (H5 or H7) are allowed to be exported to the United States. 

Q. How do I get more information about avian influenza? 

go to http://www.usda.gov/birdflu - or Food Safety Information: USDA Meat and Poultry Hotline - 1-888-MPHotline (1-888-674-6854) TTY: 1-800 256-7072