Psittacosis

Psittacosis (Parrot fever) causes fever, cough, myalgia, and headache. It tends to have few or no upper respiratory symptoms. Most often implicated are imported psittacine birds (households, pet shops, aviaries, and pigeon lofts) and then turkeys and ducks (poultry processing and rendering workers).

CASES/YEAR
500 (US); 10,000 (Global)
CATEGORY
AGENT TYPE
Bacteria
OTHER NAMES
Ornithosis; Parrot fever; The Chlamydia family includes the following species: C. trachomatis (A-C serovar = trachoma; D-K serovar = urethritis; and L1-L3 serovar = lymphogranuloma venereum), C. pneumoniae, & C. pssitaci. [Cecil, p. 1977]
ACUITY
Acute-Severe
INCUBATION
Can be as long as 28 days; Usually 5-19 days; [Harrison ID, p. 711]
INITIAL SYMPTOMS
Fever, cough; myalgia, and headache; [ID, p. 1871] Tends to be more severe than C. chlamydiae pneumonia with high fever and few or no upper respiratory symptoms; [Cecil, p. 1982]
PRECAUTIONS
Standard; "Not transmitted from person to person." [CDC 2007 Guideline for Isolation Precautions] "Rarely, person-to-person transmission may occur during acute illness with paroxysmal coughing." [CCDM, p. 492]
COMMENTS
FINDINGS:
A common pattern is mild respiratory symptoms and extensive pneumonia demonstrated by chest x-ray. Coughing may be absent initially, and then nonproductive or minimally productive. Pulse may be slow relative to temperature elevation. Other symptoms seen in some cases are pleuritic chest pain and splenomegaly. Possible complications include encephalitis, endocarditis, hepatitis, and respiratory failure. [CCDM, p. 491-3] C. psittaci can cause conjunctivitis and keratitis. The rash may resemble the rose spots of typhoid fever. Other associated skin manifestations are erythema multiforme and erythema nodosum. [Guerrant, p. 321, 1004-5]

In an Australian series of cases, about 50% of patients had elevated liver transaminases. Pleural effusions may occur. P. psittaci is one of the rare causes of endocarditis. Some patients with severe disease have acute renal failure. [ID, p. 534-5] The main syndromes are mononucleosis-like, typhoidal, and atypical pneumonia. Symptoms present in a minority of patients include sweating, ataxia, nausea/vomiting, abdominal pain, diarrhea, constipation, sore throat, dyspnea, hemoptysis, epistaxis, arthralgia, rash, confusion, tachycardia, bradycardia, splenomegaly, and adenopathy. Anemia from hemolysis occurs in some cases. Other occasional findings are hepatitis with jaundice, reactive arthritis, cranial nerve palsies, transverse myelitis, confusion, encephalitis, meningitis, seizures, urticaria, glomerulonephritis, and bleeding diathesis. Usually normal WBC count, but 2/3 have left shift. Eosinophilia may be seen during convalescence. [PPID, p. 2320-1]

EPIDEMIOLOGY:
Most often implicated are imported psittacine birds (households, pet shops, aviaries, and pigeon lofts) and then turkeys and ducks (poultry processing and rendering workers). [CCDM, p. 491] Due to quarantine of imported birds and improved veterinary hygiene, fewer than 50 cases per year are reported in the USA. Psittacine birds (parrots and parakeets) are the type of birds most often infected. Organisms spread by direct contact or aerosols to humans from nasal secretions, excreta, tissues, and feathers. [Harrisons, p. 536] Case fatality rate up to 10% in untreated pneumonia; "Transmission from person to person has never been demonstrated." [Harrison ID, p. 711]
DIAGNOSTIC
Culture rarely done (hazardous to lab workers); Serology: (1) 4-fold rise in CF or MIF antibody against C. psittaci to at least 1:32 in paired sera or (2) IgM titer (antibody against C. psittaci) by MIF of 1:16 or greater; [Cecil, p. 1982]
SCOPE
Global
SIGNS & SYMPTOMS
  • >arthralgia
  • >fatigue, weakness
  • >fever
  • >myalgia
  • >relative bradycardia
  • E epistaxis
  • E pharyngitis
  • G abdominal pain
  • G constipation
  • G diarrhea
  • G hepatomegaly
  • G jaundice
  • G liver function test, abnormal
  • G nausea, vomiting
  • H anemia
  • H eosinophilia
  • H hemolysis
  • H lymphadenopathy
  • H splenomegaly
  • N confusion, delirium
  • N headache
  • N seizure
  • O conjunctivitis, acute
  • R chest pain
  • R cough
  • R dyspnea
  • R hemoptysis
  • R sputum production
  • S papules or plaques
  • S rash (exanthem)
  • S urticaria
  • X hilar lymphadenopathy
  • X lung infiltrates
  • X pleural effusions
  • *acute renal failure
  • *ARDS
  • *arthritis
  • *bleeding tendency
  • *cranial neuropathy
  • *encephalitis
  • *endocarditis
  • *erythema nodosum
  • *glomerulonephritis
  • *hepatitis
  • *meningitis
  • *myelitis
  • *myocarditis
  • *pancreatitis
  • *pericarditis
  • *pneumonia
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Inhalation
SOURCE
Animal Excreta, Animal Tissue
RESERVOIR
Birds and Poultry
RISK FACTORS
  • Handle animal carcasses or placentas
  • Handle infected chickens or birds
  • Victim--air release of infectious agents
  • Work in a medical or research lab
TREATMENT
Antibiotics in tetracycline group until 10-14 days after temperature returns to normal; Erythromycin is alternative when tetracycline contraindicated. [CCDM, p. 493]
DRUG LINK
REFERENCES FOR CASES/YEAR
1. (US) Published in MMWR 2011 = 2; Fewer than 50 confirmed cases per year in the US; [Harrison ID, p. 711] Use correction factor of 10 for reported diseases: 50 X 10 = 500;
2. (Global) Cases reported in England & Wales: 58 (2009), 53 (2010), 40 (2011), 27 (2012); [Public Health England website] Assumption: incidence worldwide is same as in US; Calculate: 500 X 20 = 10,000;