ASK THE VET (Avian influenza)

This article first appeared in SQUAWK, the newsletter of the Big Apple Bird Association and is reprinted with permission.

The "flu" (influenza) season is rapidly approaching and so it seems appropriate to talk about avian influenza. The influenza viruses may be divided into three large groups. Only on group, "A," can infect people, other mammals and birds. The influenza virus undergoes constant mutation or changes, which is why a large number of people, mammals and birds are always susceptible to infection.

Avian influenza can be found world wide. Migratory birds, especially ducks and geese, are believed to be important reservoirs for the virus, and are able to shed it in their respiratory secretions, ocular secretions and droppings. Infected wild birds are able to transmit the virus to domestic birds such as chickens and turkeys. Asymptomatic carrier birds may also transmit the virus. Birds can spread the virus to humans and other mammals, and humans are believed to be able to infect their pet birds.

Clinical signs, if present, may include depression, anorexia (loss of appetite), dyspnea (labored breathing), swelling of the head, ocular discharge and diarrhea. Some infected birds may be asymptomatic and recover, while others may die suddenly, without showing signs of illness. Very pathogenic strains may cause bleeding problems.

The influenza virus is transmitted by direct contact with respiratory secretions and feces. Ponds containing infective feces are important sources of infection for susceptible birds. Although a pet bird could spread the virus to a human, the more important consideration is that a human, sick with the flu, can infect his or her pet bird. If a person has the flu, he should try to maintain minimal contact with his bird while ill and practice good hygiene. Birds showing signs of illness should be separated from other birds, examined by a veterinarian and treated symptomatically. Chlamydia and mycoplasma, as well as several other viruses, may cause signs similar to Avian Influenza. A definite diagnosis requires isolation and identification of the virus.

Although vaccines have been developed for influenza A in domestic fowl, there are of limited value because the virus is undergoing constant change.

An important way of preventing exposure to the virus is preventing contact of domestic birds with wild birds and migratory birds that may be carrying the virus.