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Chlamydiosis In Birds

Introduction:

Chlamydophila psittaci causes many important diseases in humans (zoonosis) and in animals It is generally described as Chlamydiosis or Psittacosis in parrots and Ornothosis in all other animals including man.

C. psittaci has a wide spectrum of hosts, ranging from most psittaciform birds, non-psittaciform birds and mammals including humans, horses, pigs, cattle, sheep, cats, dogs, lagomorphs and rodents. The bacteria is known to infect more than 370 avian species in which it causes varying morbidity and mortality. Of all the birds that can be infected, the strains from parrots, ducks and turkeys cause the most severe disease in humans. Avian infections are often asymptomatic, although outbreaks may occur in turkeys, chickens and ducks.

Chlamydiosis is a notifyable disease in South Africa.

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Chlamydial Family:

The family Chlamydiaceae constitutes a group of obligate intracellular bacteria that are ubiquitous world-wide and infect both humans and animals. The family possesses two genera namely the genus Chlamydia with the species C. muridarum, C. suis and C. trachomatis and the genus Chlamydophila with the species C. abortus, C. caviae, C. felis, C. pecorum, C. pneumoniae and C. psittaci.

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Natural Hosts:

Most bird species can get the disease, but it is found more commonly in parrots and waterfowl. The disease is often asymptomatic (without any clinical signs) in birds. Cockatiels are very often carriers. Apparently more than 50% of cockatiels in pet shops are affected. Most human infections originate from parrots and pigeons.

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Transmission Of Chalamydiosis:

The disease is highly contagious. Elementary bodies (infective parts of the organism) are present in the feathers, the feather dust, dried faeces and aerosols of affected birds and are dispersed by air circulation. Infectious elementary bodies can survive in the environment for several weeks. Elementary bodies is inhaled and are taken into respiratory cells by phagocytosis (cell swallowing) where they later start to multiply and cause disease. The disease may occur whenever there is close and continued contact with infected birds. Birds can also transmit the disease via eggs (vertical transmission) meaning that chicks can be born with it.

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Mechanism Of Chlamydiosis:

Disease is caused by a toxin that is produced by the Chlamydial organisms.

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Symptoms Of Chlamydiosis:

In general acutely affected symptomatic birds present with the so-called sick bird syndrome, i.e. ruffled feathers, low body temperature and can be collapsed. Respiratory signs include conjunctivitis (inflammation of the membranes of the eyes), dyspnoea (difficult breathing) and sinusitis (inflammation of the sinuses). Birds will also present with yellow to green urates (greenish faeces), dehydration and will usually die within one to two weeks. In poultry, the disease varies from one producing high morbidity and mortality to one that is asymptomatic.

In chronic cases the disease will present with the same signs as above plus central nervous system signs like tremors, convulsions and opistotonus (rhythmic eye movement). Pigeons, finches and small parakeets may develop keratoconjunctivitis with no other clinical signs.

In man the clinical signs range from a flu-like syndrome to a severe systemic disease with pneumonia and encephalitis. More specific signs include fever, headache, chills which may progress to atypical pneumonia, meningitis, liver and renal disease if untreated. Chlamydiodis can be fatal!

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Diagnosis Of Chlamydiosis:

The diagnosis of chlamydiosis is based on the results of a polymerase chain reaction test (PCR). The test identify certain genetic components of the organism. A 5 day pooled faecal sample can be submitted or a choana/cloacal swab can be tested. The diagnosis is usually done by a trained veterinarian in conjunction with a specialized bacteriologist.

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Treatment Of Chlamydiosis:

The treatment of all species are based on the antibiotics tetracyclines and fluoroquinolones. Treatment is usually for more than 45 days.

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High Risk Group:

Young birds exposed to high doses of the virulent strain are at risk for acute disease. Most birds in contact with affected, especially wild birds.

Immunocompromised humans, like sick people, young and old and people infected with HIV. Bird farmers, bird breeder, veterinarians and abattoir workers and farm workers working with affected birds.

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Prophylaxis / Prevention, Risk Reduction & Control Of Chlamydiosis:

Disease in humans can be controlled by controlling the disease in birds:

Adequate import / export control
Quarantine period of at least 45 days
Pellets treated with tetracycline based antibiotics
Knowledge of the carrier status of birds (i.e. regular tests)
Correct aviary and bird management
Public awareness
Adequate preventative measures such as face masks at bird necropsies or when in close contact with known affected birds.

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"If you think I should add more information to this section or think that something is incorrect, contact me and let me know. I would love to hear your ideas or methods you might use that is different than ours."

Last updated 9 February 2009 by Renier Delport

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"Always remember only to buy healthy animals from reputable pet shops and breeders. Make sure to buy animals that are captive bred in your own country and that it is not illegally imported or caught from the wild."