DESCRIPTION

• An acute febrile disease characterized by pneumonitis and other systemic symptoms
• The name is derived from the Greek word for parrot, psittakos; thus, psittacosis is often referred to as “parrot disease.”
• Also known as ornithosis

EPIDEMIOLOGY

• Birds are the major reservoir of the psittacosis pathogen.
• Nearly all domestic and wild birds may spread this infection.
• Psittacine birds (parakeets, parrots, and macaws) are the major source of disease in the United States, but pigeons and turkeys are also common culprits.
  • Infecting agent is present in bird’s nasal secretions, urine, feces, feathers, viscera, and carcasses.
  • Inhalation of aerosols of feces, urine, and secretions of infected birds is the most common route of infection.
  • Handling of plumage, bird bites, and mouth-to-beak contact are known to spread infection.
  • Birds may be healthy or sick.
• Many reported cases are the result of exposure to pet-caged birds (especially parrots and parakeets).
• The following occupations are also at increased risk for disease:
  • Workers in poultry plants
  • Duck or goose pluckers
  • Pigeon and other bird breeders
  • Pet store employees
  • Workers on farms and zoos
  • Veterinarians
  • Laboratory personnel working with Chlamydia psittaci
• Human-to-human transmission may occur but has been considered rare.

ETIOLOGY

Infection produced by C. psittaci, a gram-negative obligate intracellular pathogen

RISK FACTORS

Close human contact with birds

GENERAL PREVENTION

• Human psittacosis is a nationally notifiable disease and should be reported to public health authorities in all cases.
• Epidemiologic investigation is indicated in all suspected cases.
• Birds suspected to be infected should be killed, transported, and analyzed by qualified experts.
• Potentially contaminated living areas where bird was kept should be disinfected and aired.
• The U.S. Department of Agriculture (USDA) requires veterinary inspection of birds at the first port of entry into the United States and quarantine for a minimum of 30 days at USDA-approved facilities to ensure the birds are free of evidence of communicable diseases.
• In addition, during U.S. quarantine, psittacine birds will receive a medicated food that contains chlortetracycline for the entire quarantine period as a precautionary measure against avian chlamydiosis.
• C. psittaci is susceptible to many household disinfectants and detergents, including 1:1,000 dilutions of quaternary ammonium compounds, 1% Lysol^®, freshly prepared 1:32 dilutions of household bleach (1/2 cup per gallon), or other oxidizing agents such as accelerated hydrogen peroxide–based disinfectants.

PATHOPHYSIOLOGY

• Inhalation of aerosolized organisms into the respiratory tract
• Incubation period of 5 to 14 days; may be longer
• Spreads via bloodstream to lungs, liver, and spleen
• Lymphocytic inflammatory alveolar response

COMMONLY ASSOCIATED CONDITIONS

Pneumonitis (with a severe headache) is a common presentation.