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Chlamydiosis/Psittacosis in Birds

Author: Peter Wilson, Avian Vet


It is important for all bird owners to be aware of the disease chlamydiosis or psittacosis and its potential for infecting humans. Chlamydiosis, sometimes referred to as Parrot Fever, is caused by an intracellular parasite called Chlamydophila psittaci.


Transmission – This organism is found in feather dust and dried up faeces and is dispersed by air circulation. Transmission of Chlamydophila is primarily through inhalation of contaminated dust from droppings of feathers. Infection risk is increased by close contact with infected birds that are shedding the organism. A large number of birds carry the organism in their system but will only show signs of the disease when stressed. For this reason, the disease is more common in birds stressed through transport, overcrowding or malnutrition. Some birds are carriers of the disease and will shed the organism to infect other birds but not show signs themselves.


Clinical Signs – Birds suffering from Chlamydiosis exhibit many of the usual sick bird signs e.g. Lack of appetite, weight loss, depression, greenish diarrhoea. However, as Chlamydiosis affects the respiratory system as well as the gastrointestinal system, other signs such as discharge from the nose or eyes, sneezing and respiratory problems also occur in birds infected with the disease. Breeding birds can pass the organism to their young. Young birds are more susceptible to severe infection than adult birds and may die in the nest or soon after weaning.


Diagnosis –Because the symptoms of Chlamydiosis are not specific and can mimic a large range of diseases, examination and tests by an experienced avian veterinarian are essential to diagnose the infection. Once Chlamydiosis has been positively diagnosed, appropriate treatment can be administered.


Treatment – Doxycycline is the preferred treatment for Chlamydiosis. The treatment is for six weeks. The medication can be administered orally, in the drinking water or by weekly injections. It is recommended that all exposed birds in the household or aviary should be treated at the same time to reduce the spread or recurrence of the disease. Cages should be thoroughly cleaned and disinfected. Birds that are severely affected will need intensive care and supportive therapy such as crop feeding with high energy, liquid food supplements, a heat source and sometimes intravenous or sub-cutaneous fluids. A severely affected bird may die despite treatment.


Transmission to Humans – Humans can also contract Chlamydiosis from infected birds. Elderly, pregnant, sick or very young people, immunosuppressed people or those on chemotherapy are in greater danger or becoming infected with the disease. Symptoms in humans include persistent flu-like signs, chest pains, fever, chills, headaches, weakness and fatigue. Any family members who exhibit these signs should seek medical advice. A simple blood test will diagnose the disease in humans and an appropriate course of antibiotics can be administered. Neglect of the symptoms or a delayed diagnosis may result in serious illness.


Preventive Measures – All new birds should be quarantined for a period of 6 weeks. During the quarantine period, they should be examined and screened for Chlamydiosis by your avian veterinarian. At a bird’s yearly health check, it should also be examined for any signs of the disease and tested and treated if appropriate. Chlamydiosis is a serious killer of pet birds. However, if diagnosed early and appropriately treated, it can be overcome.


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