Psittacosis is a disease that affects a wide variety of bird species, and other animals. It has been diagnosed in guinea pigs, mice, cats, sheep, cattle, horses, goats, dogs and man. It is caused by a small bacteria called Chlamydia psittaci that is an obligated intracellular parasite of the host infected. This bacteria uses the hosting cell to get all the nutrients necessary to reproduce. It can not reproduce outside of the hosting cell. It has some viral characteristics, but luckily it is sensitive to certain antibiotics.

Transmission

The bacteria is transmitted by the sick animal by secretions, coughing, sneeze droplets or feces. Susceptible animals can be infected by inhalation or ingestion of this organism. Clamidia psittaci can stay in the environment for many months. Some wild birds carry the organism without showing any sign of the disease. Birds in captivity have a higher incidence of the disease due to poor nutrition, overcrowding and other stresses. Psittacosis can be spread quickly by direct contact with infected birds or through ingestion of contaminated food that has been exposed to infected feces or body secretions.

Diagnosing the disease can be very difficult, Psittacosis can be asymptomatic, affecting the fertility of the bird's eggs or showing a high mortality rate among the nestlings. It also can be acute, the bird becomes very sick and dies in a week after the exposure, leaving the pet owner with very little warning.

The severity of the symptoms depends on the route of infection, age and general health condition of the bird.

Clinical signs

There are no specific signs that are characteristic of Psittacosis. Some birds may show general "sick" symptoms (lack of appetite, weight loss, depression, listlessness, watery green droppings, discharge from eyes or nares, or even sudden death). These symptoms are not exclusive and can be related to diseases other than Psittacosis. Many birds can be healthy carriers of the bacteria. These birds can become sick after some stressful events or breeding birds may pass the organism on to their offspring, which may die in the nest or at weaning. Young birds are more susceptible to a severe debilitating infection than adult birds.

Diagnosis

Positive diagnosis of chlamydiosis in the live bird is sometimes very difficult, depending on the species, length of time since exposure, and general condition of the bird. In addition to having the capability of producing disease on its own, chlamydia undermines the immune system and opens the body to a host of other pathogens; thus, bacterial or viral disorders may be occurring at the same time. Because is far easier to diagnose a bacterial problem, the chlamydiosis may be missed.

Some chlamydiosis screening test are available through outside laboratory services, to help to make a diagnosis. There is no single diagnostic test in the live bird that can absolutely show the presence of chlamydia in all cases. A presumptive diagnosis of psittacosis is based on history, clinical signs, X-rays, blood work or other diagnostic methods. If psittacosis is suspected, treatment should begin at once, even as confirmatory tests are being run.

Treatment

If psittacosis has been diagnosed in one of your birds, your veterinarian may recommend treatment of all exposed and potentially infected birds, or exposed birds may be tested first and treatment limited to those that test positive. To reduce the spread of the disease, it is imperative that the patient be isolated from other birds on the premises.

The success of the treatment depends upon the species, age, presence of secondary infections and immune status of the patient. Medication can be given by direct oral administration, by injection, as medicated pellets, or mixed in soft foods. The treatment period will last a minimum of 45 days. Some other supportive therapy may be necessary. There is no immunity to the disease, and birds are susceptible to reinfection even after a full recovery or previous treatment.

Preventive measures

• Take all new birds to an avian veterinarian immediately after purchase for chlamydiosis screening tests.
• Buy birds from a reputable supplier who screens for the presence of chlamydia.
• Isolate and quarantine all newly acquired birds for a period of at least six weeks.
• Periodically monitor breeding flocks for clamydiosis.

Psittacosis in Humans

The chlamydial organism is capable of being transmitted from birds to humans, but this rarely occurs despite the relative high incidence of infection in birds. The infection in humans is mild, but potentially dangerous for sick ,elderly people or immunosuppressed patients(AIDS). Persistent "flu-like" symptoms such as fever, chills, headache, weakness, fatigue and respiratory signs may be experienced. Because the condition in humans nay be mis-diagnosed, anyone who is exposed to pet birds and who develops a prolonged case of the flu should seek the advice of a physician.