Psittacosis overview: Difference between revisions
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==Overview== | ==Overview== | ||
Psittacosis is a [[zoonosis|zoonotic]] [[infectious diseases|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, [[Veterinarian|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== | ==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. <ref name="pmid1723942">{{cite journal| author=Wehrle B, Chiquet M| title=Tenascin is accumulated along developing peripheral nerves and allows neurite outgrowth in vitro.| journal=Development | year= 1990 | volume= 110 | issue= 2 | pages= 401-15 | pmid=1723942 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1723942 }} </ref> | 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.<ref name="pmid1723942">{{cite journal| author=Wehrle B, Chiquet M| title=Tenascin is accumulated along developing peripheral nerves and allows neurite outgrowth in vitro.| journal=Development | year= 1990 | volume= 110 | issue= 2 | pages= 401-15 | pmid=1723942 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1723942 }} </ref> | ||
==Classification== | ==Classification== | ||
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==Pathophysiology== | ==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. The exact molecular details of bacterial uptake are not well understood, it is speculated that chlamydial cell contact is a two-step process; Reversible binding followed by irreversible attachment. The key to understanding the pathogenesis of [[C. psittaci]] is that frequent and repeated episodes of reinfection are needed for the development of severe disease. Several studies also highlighted the critical importance of host microfilaments, microtubules and microtubule motor | The major [[risk factor]] for acquiring psittacosis is exposure to birds. [[Transmission (medicine)|Transmission]] can occur either by inhalation of aerosolized organisms in form of dried feces or [[Respiratory system|respiratory]] secretions or by direct contact with birds. The exact molecular details of [[bacterial]] uptake are not well understood, it is speculated that [[chlamydial]] cell contact is a two-step process; Reversible binding followed by irreversible attachment. The key to understanding the [[pathogenesis]] of [[C. psittaci]] is that frequent and repeated episodes of reinfection are needed for the development of severe [[disease]]. Several studies also highlighted the critical importance of host [[microfilaments]], [[microtubules]] and [[Microtubule-associated protein|microtubule motor protein]]<nowiki/>s ([[kinesin]] and [[dynein]]) for uptake and [[intracellular]] development of [[C. psittaci]] and other [[Chlamydia infection|chlamydia spp]]. As with other [[intracellular]] [[zoonoses]] such as [[Q fever]] and [[brucellosis]], the clinical conditions associated with [[psittacosis]] have been seen in many [[organ systems]] such as [[pulmonary]], [[hepatic]], [[central nervous system]] etc. | ||
==Causes== | ==Causes== | ||
Psittacosis is caused by the organism Chlamydia psittaci. Chlamydia is understood to be a [[Gram-negative bacteria|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 (biology)|class]] and [[Phylum (biology)|phylum]] [[Chlamydiae]]. [[Chlamydiales]] are [[Obligate intracellular parasite|obligate intracellular]] infectious agents in [[eukaryotic]] cells characterized by a unique developmental replication cycle.<ref name="pmid229510">{{cite journal| author=de Rossi G, Focacci C| title=Early detection of craniosynostosis by 99mTc-pyrophosphate bone scanning. | journal=Radiol Diagn (Berl) | year= 1979 | volume= 20 | issue= 3 | pages= 405-9 | pmid=229510 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=229510 }} </ref> | Psittacosis is caused by the [[organism]] [[Chlamydia psittaci]]. [[Chlamydia]] is understood to be a [[Gram-negative bacteria|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 (biology)|class]] and [[Phylum (biology)|phylum]] [[Chlamydiae]]. [[Chlamydiales]] are [[Obligate intracellular parasite|obligate intracellular]] infectious agents in [[eukaryotic]] cells characterized by a unique developmental replication cycle.<ref name="pmid229510">{{cite journal| author=de Rossi G, Focacci C| title=Early detection of craniosynostosis by 99mTc-pyrophosphate bone scanning. | journal=Radiol Diagn (Berl) | year= 1979 | volume= 20 | issue= 3 | pages= 405-9 | pmid=229510 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=229510 }} </ref> | ||
==Differential diagnosis== | ==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 laboratory investigations. There are other conditions to watch out for which may also present similar to psittacosis. | 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 [[Laboratory information system|laboratory investigations]]. There are other conditions to watch out for which may also present similar to psittacosis. | ||
==Epidemiology and demographics== | ==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.<ref name="urlDisease Listing, Psittacosis, Technical Information | CDC Bacterial, Mycotic Diseases">{{cite web |url=http://www.cdc.gov/ncidod/dbmd/diseaseinfo/psittacosis_t.htm |title=Disease Listing, Psittacosis, Technical Information | CDC Bacterial, Mycotic Diseases |format= |work= |accessdate=}}</ref> | 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.<ref name="urlDisease Listing, Psittacosis, Technical Information | CDC Bacterial, Mycotic Diseases">{{cite web |url=http://www.cdc.gov/ncidod/dbmd/diseaseinfo/psittacosis_t.htm |title=Disease Listing, Psittacosis, Technical Information | CDC Bacterial, Mycotic Diseases |format= |work= |accessdate=}}</ref> 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. It has been identified in all parts of the world including Africa, China, Europe and the United states. | ||
==Risk factors== | ==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,<ref name="pmid4913592">{{cite journal| author=Milton SH, Craddock GN| title=Failure of capsulotomy to reduce deaths from renal ischaemia. | journal=Br J Surg | year= 1970 | volume= 57 | issue= 5 | pages= 392 | pmid=4913592 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=4913592 }} </ref> cattle,<ref name="Silva-ZacariasAlfieri2009">{{cite journal|last1=Silva-Zacarias|first1=Francielle Gibson da|last2=Alfieri|first2=Amauri Alcindo|last3=Spohr|first3=Kledir Anderson Hofstaetter|last4=Lima|first4=Bruna Azevedo de Carvalho|last5=Negrão|first5=Fábio Juliano|last6=Lunardi|first6=Michele|last7=Freitas|first7=Julio Cesar de|title=Validation of a PCR Assay for Chlamydophila abortus rRNA gene detection in a murine model|journal=Brazilian Archives of Biology and Technology|volume=52|issue=spe|year=2009|pages=99–106|issn=1516-8913|doi=10.1590/S1516-89132009000700014}}</ref> and koalas,<ref name="pmid3373633">{{cite journal| author=Weigler BJ, Girjes AA, White NA, Kunst ND, Carrick FN, Lavin MF| title=Aspects of the epidemiology of Chlamydia psittaci infection in a population of koalas (Phascolarctos cinereus) in southeastern Queensland, Australia. | journal=J Wildl Dis | year= 1988 | volume= 24 | issue= 2 | pages= 282-91 | pmid=3373633 | doi=10.7589/0090-3558-24.2.282 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3373633 }} </ref>but they have not been documented to transmit the infection to humans. | Bird owners, pet shop employees, persons who work in poultry processing plants, and [[Veterinarian|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,<ref name="pmid4913592">{{cite journal| author=Milton SH, Craddock GN| title=Failure of capsulotomy to reduce deaths from renal ischaemia. | journal=Br J Surg | year= 1970 | volume= 57 | issue= 5 | pages= 392 | pmid=4913592 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=4913592 }} </ref> cattle,<ref name="Silva-ZacariasAlfieri2009">{{cite journal|last1=Silva-Zacarias|first1=Francielle Gibson da|last2=Alfieri|first2=Amauri Alcindo|last3=Spohr|first3=Kledir Anderson Hofstaetter|last4=Lima|first4=Bruna Azevedo de Carvalho|last5=Negrão|first5=Fábio Juliano|last6=Lunardi|first6=Michele|last7=Freitas|first7=Julio Cesar de|title=Validation of a PCR Assay for Chlamydophila abortus rRNA gene detection in a murine model|journal=Brazilian Archives of Biology and Technology|volume=52|issue=spe|year=2009|pages=99–106|issn=1516-8913|doi=10.1590/S1516-89132009000700014}}</ref> and koalas,<ref name="pmid3373633">{{cite journal| author=Weigler BJ, Girjes AA, White NA, Kunst ND, Carrick FN, Lavin MF| title=Aspects of the epidemiology of Chlamydia psittaci infection in a population of koalas (Phascolarctos cinereus) in southeastern Queensland, Australia. | journal=J Wildl Dis | year= 1988 | volume= 24 | issue= 2 | pages= 282-91 | pmid=3373633 | doi=10.7589/0090-3558-24.2.282 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3373633 }} </ref>but they have not been documented to transmit the [[infection]] to humans. | ||
==Screening== | ==Screening== | ||
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==Natural history, complications and prognosis== | ==Natural history, complications and prognosis== | ||
Psittacosis, if left untreated presents as a flu like symptom or an [[atypical pneumonia]] in most cases. In the first week of psittacosis the symtoms mimic [[typhoid fever]] | Psittacosis, if left untreated presents as a [[Flu|flu like symptom]] or an [[atypical pneumonia]] in most cases. In the first week of psittacosis the symtoms mimic [[typhoid fever|typhoid fever,]] prostrating high [[fever]]s, [[arthralgia]]s, [[diarrhea]], [[conjunctivitis]], [[epistaxis]] and [[leukopenia]]. [[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 (patient information)|coma]] can result in severe cases. The second week is more akin of [[acute]] [[Bacteremia|bacteraemic]] [[pneumococcal pneumonia]] with continuous high [[fever]]s, [[cough]] and [[dyspnea]]. Some complications include [[respiratory failure]], [[acute tubular necrosis]], [[hemolytic anemia]], [[endocarditis]], [[hepatitis]], [[encephalitis]] and in some fatal cases death. | ||
==Diagnosis== | ==Diagnosis== | ||
===History and Symptoms=== | ===History and Symptoms=== | ||
The hallmark of psittacosis is a flu-like reaction with a history of exposure to birds. However, history of exposure to birds may not always be present. Psittacosis is characterized by a wide range in both disease severity and in spectrum of clinical features, but it typically presents with [[fever]], prominent [[headache]], [[myalgia]], and a nonproductive cough. The mainstay of diagnostic testing is [[serology]], although molecular techniques are increasingly utilized. | The hallmark of psittacosis is a [[Flu|flu-like]] reaction with a history of exposure to [[birds]]. However, history of exposure to birds may not always be present. Psittacosis is characterized by a wide range in both [[disease]] severity and in spectrum of clinical features, but it typically presents with [[fever]], prominent [[headache]], [[myalgia]], and a [[Cough|nonproductive cough]]. The mainstay of diagnostic testing is [[serology]], although [[molecular]] techniques are increasingly utilized. | ||
===Physical Examination=== | ===Physical Examination=== | ||
Physical examination in a patient with psittacosis includes [[rose spots]] rashes on the skin which 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]]. | [[Physical examination]] in a patient with psittacosis includes [[rose spots]] rashes on the skin which 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]]. | ||
===Laboratory Findings=== | ===Laboratory Findings=== | ||
Exposure history is | Exposure history is paramount to [[diagnosis]]. [[Complete blood count]] shows [[leukopenia]], [[thrombocytopenia]] and moderately elevated [[liver]] enzymes. Culture of [[C. psittaci]] is demanding, requires a level 3 laboratory isolation facility because of the risk of laboratory transmission and is rarely performed. [[Serology]] is the most widely available method for laboratory diagnosis of [[C. psittaci]] [[infection]]. [[Complement fixation]], [[Immunofluorescence|microimmunofluorescence]], and [[EIA]] the most commonly used techniques. | ||
===Electrocardiogram=== | ===Electrocardiogram=== | ||
There are no electrocardiogram findings associated with psittacosis. However, bradycardia may be noticed on electrocardiogram. | There are no [[electrocardiogram]] findings associated with psittacosis. However, [[bradycardia]] may be noticed on [[electrocardiogram]]. | ||
===Chest X Ray=== | ===Chest X Ray=== | ||
X rays show lobar consolidation, patchy infiltrates, a diffuse whiteout of lung field or [[Pleural effusion|pleural effusions]]. | [[Chest X ray|Chest X rays]] show [[Consolidation (medicine)|lobar consolidation]], patchy infiltrates, a diffuse whiteout of lung field or [[Pleural effusion|pleural effusions]]. | ||
===CT scan=== | ===CT scan=== | ||
On high resolution CT, infiltrates may be nodular and surrounded by ground glass opacity.<sup>[[Psittacosis CT#cite note-pmid19465839-1|[1]]]</sup> | On high resolution [[Computed tomography|CT]], infiltrates may be nodular and surrounded by [[Ground glass opacification on CT|ground glass opacity]].<sup>[[Psittacosis CT#cite note-pmid19465839-1|[1]]]</sup> | ||
===MRI=== | ===MRI=== | ||
There are no MRI findings associated with psittacosis. | There are no [[MRI]] findings associated with psittacosis. | ||
===Echocardiography or ultrasound=== | ===Echocardiography or ultrasound=== | ||
There are no echocardiography or ultrasound findings associated with psittacosis. | There are no [[echocardiography]] or [[ultrasound]] findings associated with psittacosis. | ||
===Other imaging findings=== | ===Other imaging findings=== | ||
| Line 68: | Line 68: | ||
===Medical therapy=== | ===Medical therapy=== | ||
The infection is treated with [[tetracyclines]]. 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. Since [[tetracyclines]] are contraindicated during pregnancy and infancy and so preferred treatment is [[Azithromycin]]. | The [[infection]] is treated with [[tetracyclines]]. 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. Since [[tetracyclines]] are contraindicated during [[pregnancy]] and infancy and so preferred treatment is [[Azithromycin]]. | ||
===Surgery=== | ===Surgery=== | ||
| Line 74: | Line 74: | ||
===Primary prevention=== | ===Primary prevention=== | ||
Avoid exposure to birds that may carry this bacteria, such as imported parakeets. Medical problems that lead to a weak immune system increases the risk for this disease and should be treated appropriately. | Avoid exposure to birds that may carry this [[bacteria]], such as imported parakeets. Medical problems that lead to a weak immune system increases the risk for this [[disease]] and should be treated appropriately. | ||
=== Secondary prevention === | === Secondary prevention === | ||
Revision as of 20:47, 24 July 2017
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Psittacosis Microchapters |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Omodamola Aje B.Sc, M.D. [2]
Overview
Psittacosis 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. 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
There is no established classification system for psittacosis.
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. The exact molecular details of bacterial uptake are not well understood, it is speculated that chlamydial cell contact is a two-step process; Reversible binding followed by irreversible attachment. The key to understanding the pathogenesis of C. psittaci is that frequent and repeated episodes of reinfection are needed for the development of severe disease. Several studies also highlighted the critical importance of host microfilaments, microtubules and microtubule motor proteins (kinesin and dynein) for uptake and intracellular development of C. psittaci and other chlamydia spp. As with other intracellular zoonoses such as Q fever and brucellosis, the clinical conditions associated with psittacosis have been seen in many organ systems such as pulmonary, hepatic, central nervous system etc.
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.[2]
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 laboratory 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.[3] 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. It has been identified in all parts of the world including 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,[4] cattle,[5] and koalas,[6]but they have not been documented to transmit the infection to humans.
Screening
According to the USPSTF, there is insufficient evidence to recommend routine screening for psittacosis.
Natural history, complications and prognosis
Psittacosis, if left untreated presents as a flu like symptom or an atypical pneumonia in most cases. In the first week of psittacosis the symtoms mimic typhoid fever, prostrating high fevers, arthralgias, diarrhea, conjunctivitis, epistaxis and leukopenia. 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 dyspnea. Some complications include respiratory failure, acute tubular necrosis, hemolytic anemia, endocarditis, hepatitis, encephalitis and in some fatal cases death.
Diagnosis
History and Symptoms
The hallmark of psittacosis is a flu-like reaction with a history of exposure to birds. However, history of exposure to birds may not always be present. Psittacosis is characterized by a wide range in both disease severity and in spectrum of clinical features, but it typically presents with fever, prominent headache, myalgia, and a nonproductive cough. The mainstay of diagnostic testing is serology, although molecular techniques are increasingly utilized.
Physical Examination
Physical examination in a patient with psittacosis includes rose spots rashes on the skin which 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.
Laboratory Findings
Exposure history is paramount to diagnosis. Complete blood count shows leukopenia, thrombocytopenia and moderately elevated liver enzymes. Culture of C. psittaci is demanding, requires a level 3 laboratory isolation facility because of the risk of laboratory transmission and is rarely performed. Serology is the most widely available method for laboratory diagnosis of C. psittaci infection. Complement fixation, microimmunofluorescence, and EIA the most commonly used techniques.
Electrocardiogram
There are no electrocardiogram findings associated with psittacosis. However, bradycardia may be noticed on electrocardiogram.
Chest X Ray
Chest X rays show lobar consolidation, patchy infiltrates, a diffuse whiteout of lung field or pleural effusions.
CT scan
On high resolution CT, infiltrates may be nodular and surrounded by ground glass opacity.[1]
MRI
There are no MRI findings associated with psittacosis.
Echocardiography or ultrasound
There are no echocardiography or ultrasound findings associated with psittacosis.
Other imaging findings
There are no other imaging findings associated with psittacosis.
Other diagnostic studies
Biopsy, culture and serology have been found useful in the diagnosis of psittacosis.
Treatment
Medical therapy
The infection is treated with tetracyclines. 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. Since tetracyclines are contraindicated during pregnancy and infancy and so preferred treatment is Azithromycin.
Surgery
Surgical intervention is not recommended for the management of psittacosis.
Primary prevention
Avoid exposure to birds that may carry this bacteria, such as imported parakeets. Medical problems that lead to a weak immune system increases the risk for this disease and should be treated appropriately.
Secondary prevention
There are no secondary preventive measures available for psittacosis.
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.
- ↑ 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.