Chlamydophila psittaci

Background

• 6 avian serovars (A-F) and 2 mammalian isolates (WC and M56)
• Reservoirs: birds (465 species), duck, geese, turkeys, cattle, muskrats
• Transmission: inhalation from aerosolized urine, feather dust, feces, dried feces, eye secretions. Person-to-person transmission is possible but rare.
• Incubation period usually 5-14 days but can be up to 1 month
• All transmittable to humans with potential for severe disease

Clinical Features

• High fever (up to 40.5C)
• Common: Bradycardia, chills, headache, myalgia, nonproductive staccato cough
• Less common: vomiting, abdominal pain, diarrhea, trace hemoptysis
• Extrapulmonary complications: myocarditis, endocarditis, icterus, encephalitis, ARDS, MODs

Differential Diagnosis

Causes of Pneumonia

Bacteria

• Gram-positive
  • Streptococcus pneumoniae
  • Staphylococcus aureus
• Gram-negative
  • Haemophilus influenzae
  • Klebsiella pneumoniae
  • Escherichia coli
  • Pseudomonas aeruginosa
  • Moraxella catarrhalis
• Atypical pneumonia
  • Chlamydophila pneumoniae
  • Chlamydophila psittaci
  • Mycoplasma pneumoniae
  • Coxiella burnetti
  • Legionella pneumophila

Viral

• Common
  • Influenza
  • Respiratory syncytial virus
  • Parainfluenza
• Rarer
  • Adenovirus
  • Metapneumovirus
  • Severe acute respiratory syndrome (SARS)
  • Middle east respiratory syndrome coronavirus (MERS)
• Cause other diseases, but sometimes cause pneumonia
  • Herpes simplex virus
  • Varicella-zoster (VZV)
  • Measles
  • Rubella
  • Cytomegalovirus
  • Smallpox
  • Dengue

Fungal

• Histoplasmosis
• Coccidioidomycosis
• Blastomycosis
• Pneumocystis jirovecii pneumonia (PCP)
• Sporotrichosis
• Cryptococcosis
• Aspergillosis
• Candidiasis

Parasitic

• Ascariasis
• Schistosomiasis
• Toxoplasma gondii

Lower Respiratory Zoonotic Infections

• Psittacosis
• Anthrax (Bacillus anthracis)
• Brucellosis (Brucella species)
• Q fever (C. burnetti)
• Pasteurellosis (Pasteurella multocida)
• Melioidosis (Burkholderia pseudomallei)
• Rocky Mountain Spotted Fever (R. rickettsii)
• Pulmonic Plague (Yersinia pestis)
• Influenza A
• Hantavirus

Evaluation

Workup

• CBC-leukopenia in 25% of cases
• Chemistry
• CRP
• LFT
• CXR-usually lower lobe consolidation
• Sputum culture

Evaluation

• Pneumonia is atypical - nonproductive cough, lobar or interstitial infiltrates on CXR.

Management

• Doxycycline 100mg PO Q12h x 10-14 days OR
• Azithromycin 500mg PO Qday x 7 days

Disposition

• Generally may be discharged

See Also

• Psittacosis

References

Authors

Ross Donaldson, Silas Chiu, Michael Holtz, Daniel Eggeman, Neil Young