For initial treatment of severely ill patients, doxycycline hyclate may be administered intravenously. Remission of symptoms is usually evident within 48–72 hours. However, relapse can occur, and treatment must continue for at least 10–14 days after fever subsides. Epidemiology
Psittacosis was first reported in Europe in 1879.In 1929, a highly publicized outbreak of psittacosis hit the United States. Although not the first report of psittacosis in the United States, it was the largest up to that time. It led to greater controls on the import of pet parrots. The aftermath of the outbreak and how it was handled led to the establishment of the National Institutes of Health.From 2002 through 2009, 66 human cases of psittacosis were reported to the Centers for Disease Control and Prevention, and most resulted from exposure to infected pet birds, usually cockatiels, parakeets, and macaws. Many more cases may occur that are not correctly diagnosed or reported. Bird owners, pet shop employees, zookeepers, and veterinarians are at risk of the infection. Some outbreaks of psittacosis in poultry-processing plants have been reported. In birds
In birds, Chlamydia psittaci infection is referred to as avian chlamydiosis. Infected birds shed the bacteria through feces and nasal discharges, which can remain infectious for several months. Many strains remain quiescent in birds until activated under stress. Birds are excellent, highly mobile vectors for the distribution of chlamydial infection because they feed on, and have access to, the detritus of infected animals of all sorts.
X-rays show patchy infiltrates or a diffuse whiteout of lung fields.Complications in the form of endocarditis, liver inflammation, inflammation of the hearts muscle, joint inflammation, keratoconjunctivitis (occasionally extranodal marginal zone lymphoma of the lacrimal gland/orbit), and neurologic complications (brain inflammation) may occasionally occur. Severe pneumonia requiring intensive-care support may also occur. Fatal cases have been reported (less than 1% of cases). Transmission route
The Chlamydia psittaci bacterium that causes psittacosis can be transmitted by mouth-to-beak contact, or through the airborne inhalation of feather dust, dried faeces, or the respiratory secretions of infected birds. Person-to-person transmission is possible, but rare. Diagnosis
Blood analysis usually shows a normal white cell count, but marked leukocytosis is occasionally apparent. Liver enzymes are abnormal in half of the patients, with mild elevation of aspartate transaminase. The erythrocyte sedimentation rate and C-reactive protein can be markedly elevated. Differential diagnosis must be made with typhus, typhoid, and atypical pneumonia by Mycoplasma, Legionella, or Q fever. Exposure history is paramount to diagnosis. 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-Cole-Lillie bodies" can be seen within macrophages in BAL (bronchoalveolar lavage) fluid. Culture of C. psittaci is hazardous and should only be carried out in biosafety laboratories. Treatment
The infection is treated with antibiotics; tetracyclines and chloramphenicol are the choice for treating patients. Most people respond to oral therapy doxycycline, tetracycline hydrochloride, or chloramphenicol palmitate.