Avian Influenza: Veterinarians FAQ

November 6, 2006

Contents


Special interest to veterinarians

Q: How can companion birds become infected? Can they spread the virus?

A: Even if H5N1 highly pathogenic avian influenza were to be detected in the United States, indoor birds would be at very low risk of becoming infected. Birds housed outdoors should be protected from contact with wild migratory birds (especially waterfowl and shorebirds), their droppings, and water frequented by waterfowl and shorebirds. If infected, it may be possible for companion birds to spread the virus.

Q: How can owners protect their bird(s) if the highly pathogenic H5N1 avian influenza virus is found in the United States?

A: Biosecurity is the first line of defense against transmission of avian influenza (AI) to birds, including companion birds and commercial and backyard poultry. Bird owners should prevent contact between their birds and wild birds, live bird markets, and any source of water that may have been contaminated by wild birds. Consideration should be given to moving flocks and individual birds housed outdoors to indoor accommodations if exposure to wild birds and their feces is likely.

Access to poultry farms should be restricted to essential workers and vehicles, and all equipment and vehicles that enter and leave the farm should be thoroughly cleaned and disinfected. In addition, equipment, personnel, and vehicles should not be loaned to (or borrowed from) other farms. Birds obtained from live bird markets or via slaughter channels should not be brought back to the farm. View the USDA Web site for additional information on biosecurity.

Protecting waterfowl from infection is problematic, because such birds are the natural hosts of all known AI viruses. The only practical measure to limit exposure to pathogenic strains of AI virus is to exclude wild or feral waterfowl from ponds and sources of water supplying the pond. Waterfowl may need to be brought indoors for short periods during an outbreak of AI.

Q: What are the recommended control measures for free-roaming flocks?

A: Be prepared to confine birds indoors or in sheltered enclosures in the event that H5N1 highly pathogenic avian influenza is identified in your area. Ideally, free-roaming poultry should be completely sheltered so exposure to wild birds and their feces is minimized.

Q: Do owners need to move birds inside when highly pathogenic H5N1 avian influenza virus is detected in the United States?

A: It depends on how likely it is that the birds will be exposed to wild birds and/or their feces if they remain in their current housing system. There is a low risk of transmission to companion birds unless they mingle with wild migratory waterfowl or are exposed via water to their feces. If H5N1 highly pathogenic avian influenza is identified in an area close to an owner's flock, state animal health authorities will likely require that owners move their birds indoors as a preventive measure. Biosecurity practices should be strictly followed.

Q: What can exotic waterfowl breeders/fanciers do to protect their birds?

A: Exotic waterfowl breeders and fanciers should exclude wild and feral waterfowl from their ponds and, if possible, the water source feeding those ponds. If an outbreak of H5N1 highly pathogenic avian influenza occurs in close proximity to kept birds, those waterfowl should be penned indoors or in sheltered enclosures until the danger has passed.

Q: Is there a vaccine available to protect companion animals against highly pathogenic H5N1 avian influenza virus?

A: Currently, there is no USDA-licensed vaccine to protect against H5N1 highly pathogenic avian influenza available for use in companion animals.

Q: What testing is available for highly pathogenic H5N1 avian influenza virus infection, and how reliable is it?

A: Tests available and validated for poultry species include real-time reverse transcriptase polymerase chain reaction (rRT-PCR) and virus isolation (VI). The rRT-PCR is performed by all National Animal Health Laboratory Network (NAHLN) laboratories and other national veterinary laboratories approved by USDA National Veterinary Services Laboratories (NVSL) for this purpose. Many NAHLN laboratories perform VI as well.

Both tests can be applied, with caution, to non-poultry species. The rRT-PCR testing performed by NAHLN laboratories is specific for all influenza A viruses, and then further for all H5 or H7 subtypes. This test would be expected to detect infection in any species that is actively shedding virus. Test results can be available in as little as a half day (12 hours), and USDA has indicated that the results of rapid screening can be expected within 4 to 7 hours after receipt by the NVSL. Testing for AI is very reliable, and researchers are continuing to improve testing methods.

Serologic (blood serum) testing has not been validated for species other than poultry. For suspected cases, necropsy is best performed at a NAHLN facility. Veterinarians should contact the laboratory before submitting birds for necropsy. View a directory of NAHLN laboratories.

Q: If infection with highly pathogenic H5N1 avian influenza virus is suspected, what diagnostic samples should be obtained, how should they be shipped, and where should they be shipped?

A: The oropharyngeal, cloacal, or nasal mucosa of ill animals should be sampled, using polyester or nylon-tipped swabs with plastic shafts. Do not use swabs containing calcium alginate or those with wooden shafts. Samples should be sent to laboratories that are members of the National Animal Health Laboratory Network (NAHLN), and should be packaged and shipped following regulations for transport of diagnostic, potentially infectious material. Birds that have died after showing signs consistent with highly pathogenic avian influenza (HPAI) should be shipped directly to the NAHLN laboratory for necropsy and testing. Contact the NAHLN laboratory for specific, up-to-date information on the appropriate collection and submission of samples and carcasses. View the final rule regarding select agent handling requirements. View related guidance on the CDC Web site.

Appropriate precautions (e.g., use of personal protective equipment) should be taken when obtaining samples from birds. Necropsies of birds that are suspected to have died from infection with H5N1 HPAI should be performed by laboratories that have appropriate biosecurity. Clinicians should take care to minimize exposure risks to themselves and their staff. Related guidance is available here: View related guidance on the U.S. Department of Labor Web site.

Q: Does testing for highly pathogenic H5N1 avian influenza virus infection require euthanasia?

A: Depending on the species of bird and situation, a necropsy may be warranted to determine whether a bird or flock of birds is infected with H5N1 highly pathogenic avian influenza. Such a decision is best made following consultation with the USDA-APHIS Area Veterinarian-in-Charge, State Veterinarian, and state public health veterinarian.

In the absence of formal protocols developed and recommended by such regulatory agencies, if an animal is suspected to be infected with avian influenza, it may be appropriate to submit samples to at least one of the diagnostic laboratories in the National Animal Health Laboratory Network (NAHLN) for preliminary diagnosis before recommending euthanasia, particularly for companion animals. View a directory of NAHLN laboratories.

Q: If results of a test are positive, what will be done to the affected companion animal? Will it have to be euthanatized? What about other pets in the household, including companion birds?

A: Unfortunately, risks associated with transmission of avian influenza (AI) from companion animals to other animals and people have not been well documented, and making specific recommendations for management of affected animals is difficult. In general, pets should be quarantined and the premises disinfected if H5N1 highly pathogenic avian influenza (HPAI) is suspected. In the absence of other recommendations, treatment of affected companion animals is symptomatic.

Based on information currently available, the risk of H5N1 HPAI virus transmission from an infected cat or dog to a person or another animal appears to be very low, and euthanasia is unlikely to be necessary. Standard isolation procedures should be followed. Veterinarians and staff treating a dog or cat with a confirmed or suspected infection should maintain the dog or cat in an isolated cage in the clinic, and minimize direct contact. When handling is necessary, gloves, a mask, and protective eyewear should be worn. Surfaces and equipment, including food and water dishes and litter boxes, should be thoroughly disinfected. Disposable materials should be treated as biohazardous waste. View additional guidance on the U.S. Department of Labor Web site.

Pets exhibiting clinical signs consistent with infection that remain at home should be confined in a separate room away from people and other animals. Owners should minimize direct contact with the animal, wear disposable gloves when handling it, and avoid being scratched or bitten. Confirmation of infection should be sought as soon as possible.

Final decisions are likely to be made by public health authorities and may be highly situation-dependent. To date, formal recommendations regarding euthanasia of companion animals affected by H5N1 HPAI virus have not been made.

Q: What are the risks to humans and other animals while awaiting test results, and what precautions should be taken?

A: Risks to humans and other animals exposed to infected animals vary considerably by species and situation; in general, closer, more prolonged contact equates to increased risk.

While awaiting test results, animals suspected to be infected should be quarantined, and family members, pets, and other animals that may have been exposed should be monitored for signs of illness. Animal owners and veterinary staff should be made aware of risks to themselves and other individuals with whom the animal may have come in contact.

The advice of local, state, and federal public health authorities should be sought in the management of suspected cases, and these officials must be notified of confirmed cases. View contact information for the USDA-APHIS Veterinary Services Area Office in your state. View a listing of public health veterinarians by state.

Q: If highly pathogenic H5N1 avian influenza virus infection is suspected in a companion animal, when should I report it, and to whom?

A: If any type of poultry is suspected to be infected (backyard flocks, live bird markets, show chickens), the State Department of Agriculture or the USDA (1-866-536-7593) should be notified immediately, per the Code of Federal Regulations (9CFR161.3). If the affected animal is a companion animal (e.g., cat, dog, pet bird), depending on your state regulations, either the State Veterinarian or the state public health veterinarian should be notified. View contact information for the USDA-APHIS Veterinary Services Area Office in your state.

Q: Can/Should I treat highly pathogenic H5N1 avian influenza virus infection in my patients?

A: If an animal is observed to have clinical signs and a history of exposure to the H5N1 highly pathogenic avian influenza (HPAI) virus, treatment should not be initiated without first notifying appropriate federal and state authorities. If a poultry farm is affected, the premises and bird(s) should be immediately quarantined, and exposure to birds should be limited, until regulatory officials can respond or direct the veterinarian regarding an appropriate course of action. Currently, infected poultry are destroyed when H5N1 HPAI infection is confirmed. If the virus is identified in poultry, the remaining live birds in the flock or on the premises will likely need to be euthanatized because of the high risk of spread to other birds and flocks. Amidst concerns about preserving the effectiveness of human antiviral medications, on March 22, 2006, the FDA published a final rule prohibiting the extralabel use of adamantine and neuraminidase inhibitor classes of antiviral drugs in chickens, turkeys, and ducks.

Because other diseases may cause similar clinical signs, treatment of affected cats or dogs should begin pending confirmation of infection. Specific antiviral agents are not available for cats or dogs infected with H5N1 HPAI, and drugs used to treat humans with influenza (e.g., neuraminidase inhibitors) have not been adequately explored in these species. Recommended treatment is, therefore, supportive. How cats and dogs naturally infected with H5N1 HPAI will respond to treatment is not known. The extent of risk to veterinarians and clinic personnel posed by animals that receive medical care and survive is also not known. View guidance on the U.S. Department of Labor Web site and the veterinary infection control guidelines issued by the National Association of State Public Health Veterinarians.

Q: How can I differentiate highly pathogenic H5N1 avian influenza virus infection from kennel cough or canine influenza?

A: A dog in the United States is very unlikely to become infected with H5N1 highly pathogenic avian influenza (HPAI) virus, since the virus has not yet been detected in North America. Because there is very little information about H5N1 HPAI infection in dogs, it is also not possible to describe with certainty what clinical signs a dog might have if it becomes infected.

Given this lack of information, professional experience suggests the course of disease would likely be similar to that described for experimental infections of cats with the avian influenza virus. If/when H5N1 HPAI virus is detected in the United States, it should be considered on the list of differential diagnoses for a dog exhibiting respiratory signs. Lacking a more complete description of typical clinical signs, differentiation from kennel cough or canine influenza would be difficult without laboratory confirmation.

Q: How can I differentiate highly pathogenic H5N1 avian influenza virus infection from feline upper respiratory tract infection?

A: Clinical signs in naturally infected cats have not been extensively described, but signs in experimentally infected cats include fever, listlessness, conjunctivitis, difficulty breathing, and death. These signs are commonly encountered in other respiratory disease syndromes of cats, so laboratory confirmation of H5N1 highly pathogenic avian influenza virus infection is necessary for a definitive diagnosis.

Q: If a bird is suspected or confirmed to have highly pathogenic H5N1 avian influenza virus infection, is the staff that handled the bird at risk?

A: Potentially, depending on the extent of contact. Appropriate personal protective equipment should be worn when examining animals suspected to have H5N1 highly pathogenic avian influenza (HPAI). Local, state, and federal public health authorities should be notified if avian influenza infection is suspected.

The US government has developed policy regarding personal protective equipment that must be worn and additional safeguards that must be adopted by 'first responders' to H5N1 HPAI within poultry flocks. For information on recommended personal protective equipment, visit the U.S. Department of Labor Web site.

Q: If a companion animal is suspected to have highly pathogenic H5N1 avian influenza virus infection, how should the premises be disinfected?

A: The H5N1 highly pathogenic avian influenza (HPAI) virus can be easily inactivated with various EPA-approved disinfectants. The USDA-APHIS Area Veterinarian-in-Charge, the office of the State Veterinarian, and state public health authorities should be contacted for specific instructions on the most appropriate approach to disinfection.

The Environmental Protection Agency (EPA) registers pesticides, including disinfectants, for decontamination and control of pathogens on environmental surfaces of livestock and food-related facilities and equipment. More than 90 disinfectant products are registered and intended for use against influenza A viruses on hard, nonporous surfaces, including poultry houses, farm equipment, veterinary premises, and industrial settings. A list of suitable products is on the EPA Web site. These products are typically used by the poultry industry to disinfect their facilities. Although no products are specifically approved for the H5N1 HPAI virus, the EPA believes that currently registered avian influenza A products will be effective against the H5N1 HPAI strain, when used in accord with label directions and precautions.

Q: How do I safely dispose of dead birds?

A: In the case of wild birds, USDA-APHIS Wildlife Services personnel are available to determine whether the carcasses are appropriate for avian influenza testing (or for another potentially infectious disease). Carcasses should not be disturbed prior to that decision being made. CDC has developed handling guidelines for dead birds.

If a companion bird has died, and if the practitioner suspects H5N1 highly pathogenic avian influenza (HPAI) as the cause, the State Veterinarian or the USDA-APHIS Area Veterinarian-in-Charge should be contacted for advice regarding samples for testing and disposal of the carcass.

If it is determined that it is appropriate to dispose of a dead bird, wear disposable gloves and place the bird in a plastic bag and seal it. The bird can then be disposed of as recommended by the USDA, State Veterinarian, or state public health veterinarian.

Q: Where do I look for additional information and resources?

A: Links to Information about Avian Influenza

American Veterinary Medical Association Influenza Resources
American Association of Avian Pathologists Avian Influenza Position Statement
Association of Avian Veterinarians (AAV)
National Association of State Public Health Veterinarians (NASPHV)
Department of Health and Human Services Information on Pandemic Flu and Avian Influenza
Centers for Disease Control and Prevention (CDC) Avian Influenza (Bird Flu)
Human Infection with Avian Influenza A (H5N1) Virus: Advice for Travelers
USDA Avian Influenza (Bird Flu)
USDA Biosecurity for the Birds
USDA-APHIS Veterinary Services Area Offices (listing by state)
Designated State Veterinarians (listing by state)
Designated State Public Health Veterinarians (listing by state)
USDA-APHIS Wildlife Services (listing by state)
FDA and Pandemic/Avian Influenza
Guidance for Protecting Workers Against Avian Flu
EPA: Registered Antimicrobial Products with Label Claims for Avian (Bird) Flu
US Poultry & Egg Association
World Health Organization (WHO) Avian Influenza Resource
Food and Agriculture Organization (FAO) of the United Nations (Avian Influenza)