Ornithosis is an infectious disease that affects many bird species around the world. It can also be transmitted to humans and other mammals. In Germany, ornithosis is a very common disease which is found in pigeons. Ornithosis is particularly frequent from May to July and from October to December. It is only in young birds that the disease causes substantial losses. If adult pigeons are infected, they usually do not show any, or only very slight symptoms.

Causes

It is caused by Chlamydia psittaci, a bacterium found in the droppings of birds. It is a rare disease fewer than 50 cases have been reported in the U.S. in the past 5 years.

Bird owners, pet shop employees, workers in poultry processing plants, and veterinarians are at increased risk for acquiring this infection.

Symptoms

Ornithosis occurs in 2 forms : -

The acute form- it can be recognised in young pigeons from wheezing noises, uni- or bilateral conjunctivitis and muco-aqueous enteritis with diarrhoea.

The chronic form- it is more often found in adult birds, which, however, show few or no signs of the disease. Pigeons that have recovered are a dangerous source of infection for young pigeons and for humans due to their latent shedding of the pathogen.

The symptoms of ornithosis in live birds are highly variable. The birds may be symptomless carriers that occasionally shed Chlamydia. The organism may cause mild respiratory disease, opthalmia or in it's severe form hepatitis, peritonitis and high mortality. Because of the high incidence of the disease in South Africa and the variable nature of the presenting symptoms, it is advisable to routinely screen birds hospitalized in an avian clinic, or birds incorporated into a breeding collection.

Treatment

Treatment must be supervised by an avian veterinarian. Treatment usually takes 30 to 45 days, or longer. Your veterinarian will advise you on the best way to treat your bird. The most common treatments are injectable doxycycline, Oral doxycycline, Doxycycline medicated food or water and fluids and supportive nutrition.

In past years, tetracycline hydrochloride has been administered to patients intravenously (10-15 mg/kg body weight per day divided into four doses per day). Remission of symptoms usually is evident within 48-72 hours. However, relapse can occur, and treatment must continue for at least 10-14 days after fever abates.