Psittacosis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Psittacosis 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. As a systemic zoonotic infection with protean clinical features, the major risk factor is exposure to birds. Hence, bird owners, veterinarians, those involved with breeding and selling birds, and commercial poultry processors are most at risk. Patients typically present with 1 week of fevers, headache, myalgias, and a nonproductive cough. Although pneumonia is the most common manifestation, all organ systems can be involved. Serology remains the mainstay of diagnosis; however, polymerase chain reaction techniques offer a rapid and specific alternative. Doxycycline is the treatment of choice.
Historical perspective
The word psittacosis is derived from the Greek work 'Psittakos', which means parrot. Psittacosis infects psittacines (parrots, parakeets, cockatoos). 'Ornithosis' is a term used if it infects other types of birds. It is assumed that the origin of psittacosis is in South America, where the rain forests are populated with many species of psittacine birds. Aboriginal tribes were fond of these birds and used their feathers as parts of their ceremonial clothing. Other psittacine birds were kept as pets in aboriginal villages. [1]
Classification
C psittaci may be classified into eight serovars according to variation in the major outer membrane protein (MOMP): serovar A to F, WC and M56.[2]
Pathophysiology
The major risk factor for acquiring psittacosis is exposure to birds. Transmission can occur either by inhalation of aerosolized organisms in form of dried feces or respiratory secretions or by direct contact with birds.
Causes
Psittacosis is caused by the organism Chlamydia psittaci. Chlamydia is understood to be a Gram-negative bacterium belonging to the genus Chlamydia or Chlamydophila in the family of Chlamydiaceae together with Parachlamydiaceae, Waddliaceae and Simkaniaceae in the order Chlamydiales, class and phylum Chlamydiae. Chlamydiales are obligate intracellular infectious agents in eukaryotic cells characterized by a unique developmental replication cycle.[3]
Differential diagnosis
Psittacosis must be differentiated from other diseases that cause atypical pneumonia, febrile illness without localizing signs and extrapulmonary manifestations such as gastroenteritis, hepatitis, meningitis, or encephalitis. The three main diseases to differentiate psittacosis from are Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella infection as they tend to have similar clinical manifestations which can only be differentiated by taking appropriate histories and laboratpory investigations. There are other conditions to watch out for which may also present similar to psittacosis.
Epidemiology and demographics
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.[4]. In the united states, the incidence of psittacosis is 0.01 per 100,000 persons. The prevalence and incidence of psittacosis does not vary by gender neither is there a racial predilection for psittacosis has it has been identified in all parts of the world icluding, Africa, china, Europe and the United states.
Risk factors
Bird owners, pet shop employees, persons who work in poultry processing plants, and veterinarians are at increased risk for this infection. Typical birds involved are parrots, parakeets, and budgerigars, although other animals documented with C psittaci infection include horses,[5] cattle,[6] and koalas,[7]
Screening
Natural history, complications and prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Electrocardiogram
Chest X Ray
MRI
Echocardiography or ultrasound
Other imaging findings
Other diagnostic studies
Treatment
Medical therapy
Surgery
Primary prevention
Secondary prevention
References
- ↑ Wehrle B, Chiquet M (1990). "Tenascin is accumulated along developing peripheral nerves and allows neurite outgrowth in vitro". Development. 110 (2): 401–15. PMID 1723942.
- ↑ Vanrompay D, Butaye P, Sayada C, Ducatelle R, Haesebrouck F (1997). "Characterization of avian Chlamydia psittaci strains using omp1 restriction mapping and serovar-specific monoclonal antibodies". Res Microbiol. 148 (4): 327–33. doi:10.1016/S0923-2508(97)81588-4. PMID 9765811.
- ↑ de Rossi G, Focacci C (1979). "Early detection of craniosynostosis by 99mTc-pyrophosphate bone scanning". Radiol Diagn (Berl). 20 (3): 405–9. PMID 229510.
- ↑ "Disease Listing, Psittacosis, Technical Information | CDC Bacterial, Mycotic Diseases".
- ↑ Milton SH, Craddock GN (1970). "Failure of capsulotomy to reduce deaths from renal ischaemia". Br J Surg. 57 (5): 392. PMID 4913592.
- ↑ Silva-Zacarias, Francielle Gibson da; Alfieri, Amauri Alcindo; Spohr, Kledir Anderson Hofstaetter; Lima, Bruna Azevedo de Carvalho; Negrão, Fábio Juliano; Lunardi, Michele; Freitas, Julio Cesar de (2009). "Validation of a PCR Assay for Chlamydophila abortus rRNA gene detection in a murine model". Brazilian Archives of Biology and Technology. 52 (spe): 99–106. doi:10.1590/S1516-89132009000700014. ISSN 1516-8913.
- ↑ Weigler BJ, Girjes AA, White NA, Kunst ND, Carrick FN, Lavin MF (1988). "Aspects of the epidemiology of Chlamydia psittaci infection in a population of koalas (Phascolarctos cinereus) in southeastern Queensland, Australia". J Wildl Dis. 24 (2): 282–91. doi:10.7589/0090-3558-24.2.282. PMID 3373633.