Chlamydiosis

CHLAMYDIOSIS

Synonyms

  • Psittacosis, Ornithosis, Parrot Fever
  • The word "psittacosis" is used when the disease is carried by any species of bird belonging to the Psittacidae family, whereas "ornithosis" is used when other birds carry the disease.

Type of zoonosis

  • Direct anthropozoonosis

Definition

  • Chlamydiosis is an infectious disease caused by Chlamydophila psittaci and contracted not only from parrots, such as macaws, cockatiels and budgerigars, but also from pigeons, sparrows, ducks, hens, gulls and many other species of bird. In human, it is clinically characterized by fever, headache, chills, myalgia, and upper and lower respiratory infection.

Etiology

  • Chlamydophila psittaci (formerly it was known as Chlamydia psittaci).
  • It is an obligate intracellular pathogen.
  • There are different serovars, such as, C.psittaci serovar A, B, C, D and E (known as Cal-10, MP or MN)

Reservoir and incidence

  • The incidence in canaries and finches is generally lower than in psittacine birds.
  • The main reservoirs for C.psittaci are birds.
  • It also occurs in mice, guinea pig, rabbits, cats, frogs and ruminants.
  • C.psittaci serovar A is endemic among psittacine birds.
  • C.psittaci serovar B is endemic among pigeons
  • C.psittaci serovars C and D are occupational hazards for slaughterhouse workers and for people in contact with birds.
  • C.psittaci serovar E isolates (known as Cal-10, MP or MN) have been obtained from a variety of avian hosts.
  • Ovine strains may infect pregnant women.
  • Bird owners, pet shop employees, zookeepers and veterinarians are at risk of the infection.
  • C.psittaci is one of the infectious agents, as potential biological weapons.

Transmission

  • Inhalation and ingestion are the major routes of transmission, and direct contact with infective materials also causes disease.
  • Dry faeces or nasal discharges are highly infective aerosols.
  • Chlamydophila psittaci may survive for several months in the environment.

Disease in birds and animals

  • Conjunctivitis, difficulty in breathing, watery droppings and green urates, air sacculitis, pericarditis, hepatitis, meningoencephalitis, enteritis, urethritis and arthritis.
  • Gastrointestinal and respiratory infection in birds results in shedding of organisms in droppings and nasal discharges.
  • Persistent infection or latency is feature of chlamydiosis in birds.
  • Stress in clinically healthy birds can lead to clinical manifestations and shedding of the organism.
  • In ewes, it causes endometritis with abortion.

Disease in man

  • Incubation period ranges from 7 to 14 days.
  • Mostly, it is asymptomatic, but clinical disease may occur, includes fever, chills, myalgia, anorexia, headache and nonproductive cough.
  • Pneumonitis, hepatosplenomegaly, meningoencephalitis and endocarditis may be present.
  • During the first week of infection, the symptoms mimic typhoid fever. Symptoms include high fever, arthralgia, diarrhoea, conjunctivitis, epistaxis and leukopenia.
  • Rose spots can appear (Horder's spots).
  • Ovine chlamydial infection is more dangerous in pregnant women, is life-threatening, causing late abortion and neonatal death and disseminated intravascular coagulation in mother.

Diagnosis

  • History and clinical signs.
  • Antigen detection in faecal materials and droppings by ELISA.
  • Cultures from respiratory secretions produces typical inclusions called "Leventhal-Cole-Lillie bodies" (LCL bodies) within macrophages in bronchial alveolar lavage fluid.
  • Paired sera for antibody detection with fourfold increase in antibody titres against C.psittaci.
  • PCR

Treatment

  • Drug of choices are tetracycline or doxycycline or chloramphenicol.
  • Treatment must continue for at least 10–14 days after fever stops. However, it may again develop clinical disease.
  • Chlamydia can develop persistent forms (i.e. atypical reticular bodies). This persistent form can lead to chronic clinical course, such as respiratory and genital diseases.
  • Children aged less than 9 years and pregnant women can take erythromycin as an alternative to tetracycline.

Prevention and control

  • Pet birds should be given chemoprophylaxis with tetracycline or chlortetracycline.
  • Human beings should wear protective clothing, such as face masks, gowns, gloves, etc. to protect themselves from inhalation and ingestion of infective materials.
  • Quarantine is must for wild caught birds and should be given chlortetracycline as chemoprophylaxis during quarantine.
  • Aborting ewes should be isolated and aborted materials should be handled with protective clothing.
  • Proper disposal and disinfection of infected and contaminated materials should be followed.
Last modified: Wednesday, 16 May 2012, 5:39 AM