Psittacosis, also known as parrot fever or ornithosis, is a zoonotic infectious disease caused by the bacterium Chlamydia psittaci. Birds are the main reservoir, and human infection usually follows inhalation of aerosolised dried droppings or respiratory secretions from infected birds. Although many human infections are mild, psittacosis can cause pneumonia and occasionally severe complications including endocarditis, hepatitis, and neurologic disease.
Transmission and reservoirs
C. psittaci commonly infects birds, including psittacine birds such as parrots, parakeets, cockatiels, and budgerigars, but human infection has also been linked to pigeons, turkeys, chickens, ducks, and other birds. Many infected birds have no obvious clinical signs but may shed organisms in feces and respiratory secretions for prolonged periods.
Humans are infected mainly by inhaling dust contaminated with dried droppings or respiratory secretions from infected birds. Diagnostic methods include serology, polymerase chain reaction, and other specialized laboratory testing.
Treatment
Tetracyclines, especially doxycycline, are generally considered first-line therapy for psittacosis in adults. Prevention focuses on reducing exposure to infected birds and contaminated dust. Recommended measures include washing hands after handling birds or items in cages, wetting surfaces before cleaning, avoiding dry sweeping or vacuuming of contaminated material, and using gloves and appropriate masks when handling infected birds or cleaning their cages.
History
Psittacosis was first documented in the 1870s, with major outbreaks occurring in the early 20th century. A significant outbreak in 1929–1930, linked to imported parrots, led to increased scientific interest and research into the disease. The causative agent, Chlamydia psittaci, was identified in the 1930s, paving the way for improved diagnostic techniques and treatment options.
Since then, regulations on the pet trade and public health interventions have contributed to reducing the spread of psittacosis, though sporadic outbreaks continue to occur.
In birds
thumb|An immature [[little blue heron with psittacosis]]
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.
Signs
C. psittaci in birds is often systemic and infections can be inapparent, severe, acute, or chronic with intermittent shedding. Signs in birds include "inflamed eyes, difficulty in breathing, watery droppings, and green urates."
Diagnosis
Initial diagnosis may be by symptoms, but is usually confirmed by an antigen and antibody test. A polymerase chain reaction-based test is also available. Although any of these tests can confirm psittacosis, false negatives are possible, so a combination of clinical and laboratory tests is recommended before giving the bird a clean bill of health. and is typically either inhaled or ingested. Reported case counts decreased between 1988 and 2010 and have remained low overall since then, although periodic outbreaks still occur. Systematic review evidence suggests that poultry, especially turkeys, chickens, and ducks, are important sources of zoonotic transmission in addition to parrots and other pet birds.
Notable casualties
In 1930, during the 1929–1930 psittacosis pandemic, Lena Rose Pepperdine died of parrot fever. She was the first wife of George Pepperdine, the founder of Pepperdine University.
References
- The initial content for this article was adapted from sources available at https://www.cdc.gov.
External links
- Psittacosis on Birds n Ways
- Ornithosis in Pigeons - Pigeonpedia