Psittacosis (Ornithosis) Symptoms, Etiology, Treatment and Prevention

Psittacosis also called Ornithosis (or simply called Parrot disease or Parrot Fever) is an infectious disease of birds (Zoonosis) such as Parrots, Chickens and Pigeons that can be transmitted to humans and it is caused by bacterium called Chlamydia psittaci and transmitted by Psittacine birds such as Parrots and other birds (parakeets and macaws). Humans get infected when they inhale droplets from air. Psittacosis causes symptoms such as severe pneumonia in humans that can last for several weeks. The pneumonia of psittacosis last for weeks and is generally more dangerous than the type caused by Chlamydia pneumoniae. When the infection by Chlamydia psittaci occurs in birds it is called Avian chlamydiosis while in humans it is called Psittacosis.

Ornithosis (Psittacosis) Epidemiology

Psittacosis or Ornithosis affects birds worldwide and can also be observed in poultry. Occurrence of Psittacosis in a human patient shows that there is a source of infection from birds which needs to be eliminated. Psittacosis was first reported in 1879 in Europe. In 1929, there was a major outbreak of Psittacosis in the United States of America.

Psittacosis Pathogenesis

The natural hosts of Chlamydia psittaci are birds and the organism causes infections of the respiratory organs, genital tract, intestinal tract, and the conjunctiva of parrots and other birds with similar systems being affected in Humans too. Psittacosis is spread to humans by inhalation of dust (from bird excrements) containing chlamydia psittaci and infection sometimes occur too through inhalation of infectious aerosols – but this is rare.

Psittacosis Symptoms and Signs

  1. High fever
  2. Headache
  3. Difficulty in breathing (dyspnea)
  4. Severe atypical pneumonia
  5. Joint pains
  6. Diarrhea
  7. Conjunctivitis
  8. Splenomegaly
  9. There could be bleeding from the nose (epistaxis)

Psittacosis should be suspected in patients having respiratory tract infection with associated nose bleeding and enlargement of the spleen (splenomegaly)

Psittacosis Incubation period

The incubation period of Psittacosis is 1 to 3 weeks and it is followed by atypical pneumonia.

Psittacosis Diagnosis

  1. Diagnosis of Psittacosis can be difficult even in the laboratory hence the isolation of the organism (Chlamydia psittaci) occurs by growing it using sputum specimen in special cell cultures in well-equipped laboratories.
  2. Psittacosis can also be diagnosed using the complement binding reaction which helps to identify antibodies against a certain chlamydia antigen that is common to all chlamydiae (this test therefore will show positive to any chlamydial infection and not just to psittacosis). The test is therefore not specific.
  3. The antibody test of choice for Psittacosis is indirect micro-immunofluorescence

Psittacosis Treatment

Psittacosis responds very well to treatment using Tetracyclines such as doxycycline and macrolides such as erythromycin. There may be relapse even after treatment with these drugs.

Psittacosis Prevention

  1. Avoid keeping poultry around residential areas
  2. Use facemask when entering poultry houses
  3. Avoid keeping of parrots and pigeons and other birds as pets
  4. Report any known case of ornithosis affecting poultry

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