Disease Information for Psittacosis/ornithosis: Definition

  • In medicine (pulmonology), psittacosis -- also known as parrot disease, parrot fever, and ornithosis -- is a zoonotic infectious disease caused by a bacterium called Chlamydophila psittaci (formerly Chlamydia psittaci) and contracted not only from parrots, such as macaws, cockatiels and budgerigars, but also from pigeons, sparrows, ducks, hens, sea gulls and many other species of bird; The incidence of infection in canaries and finches is believed to be lower than in psittacine birds; Symptoms: In humans, after incubation period of 5-14 days, the symptoms of the disease range from inapparent illness to systemic illness with severe pneumonia; It presents chiefly as an atypical pneumonia; In the first week of psittacosis the symtoms mimic typhoid fever: prostrating high fevers, arthralgias, diarrhea, conjunctivitis, epistaxis and leukopenia; Rose spots can appear and these are called Horder"s spots; Splenomegaly is frequent toward the end of first week; Diagnosis can be suspected in case of respiratory infection associated with splenomegaly and/or epistaxis; Headache can be so severe that suggests meningitis and some nuchal rigidity is not unusual; Towards the end of first week stupor or even coma can result in severe cases; The second week is more akin of acute bacteraemic pneumococcal pneumonia with continuous high fevers, cough and dyspnoea; X rays show patchy infiltrates or a diffuse whiteout of lung fields; Bloodwork shows leukopenia, thrombocytopenia and moderately elevated liver enzymes; Differential diagnosis must be made with typhus, typhoid and atypical pneumonia by Mycoplasma, Legionella or Q fever; Exposure history is paramout to diagnosis; Complications in the form of endocarditis, hepatitis, myocarditis, arthritis, keratoconjunctivitis, and neurologic complications (encephalitis) may occasionally occur; Severe pneumonia requiring intensive-care support may also occur; Fatal cases have been reported (less than 1% of cases); Diagnosis involves microbiological cultures from respiratory secretions of patients or serologically with a fourfold or greater increase in antibody titers against C; psittaci in blood samples combined with the probable course of the disease; Typical inclusions called Leventhal -Colle-Lillie bodies can be seen within macrophages in BAL fluid; Culture of Chlamydia psittaci is hazardous and should only be carried out in biosafety laboratories; Epidemiology

    Since 1996, fewer than 50 confirmed cases were reported in the United States each year; Many more cases may occur that are not correctly diagnosed or reported; Bird owners, pet shop employees, and veterinarians are at risk of the infection; Some outbreaks of psittacosis in poultry processing plants have been reported; Treatment : The infection is treated with antibiotics; Tetracyclines and chloramphenicol are the drugs of choice for treating patients with psittacosis; Most persons respond to oral therapy (100 mg of doxycycline administered twice a day , 500 mg of tetracycline hydrochloride administered four times a day) or 500 mg of chloramphenicol palmitate orally every 6 hours; For initial treatment of severely ill patients, doxycycline hyclate may be administered intravenously at a dosage of 4.4 mg/kg (2 mg/lb) body weight per day divided into two infusions per day (up to 100 mg per dose); 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; Although its in vivo efficacy has not been determined, erythromycin probably is the best alternative agent for persons for whom tetracycline is contraindicated (e.g., children aged less than 9 years and pregnant women).

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