Description

• An acute febrile disease characterized by pneumonitis and other systemic symptoms
• The name is derived from the Greek 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 a major source of disease in the United States, but pigeons and turkeys are also common culprits.
  • Infecting agent is present in bird 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.
• Most reported cases (70%) are the result of exposure to pet caged birds (especially parrots, parakeets).
• Psittacosis is mainly an occupational disease among workers in poultry plants, duck or goose pluckers, pigeon breeders, pet store employees, and workers on farms and in zoos.
• Most common mammalian source of infection is sheep.
• Person-to-person transmission is so unusual that isolation of the infected patient is likely unnecessary.

Risk Factors

Close human contact with birds and, in some cases, sheep

General Prevention

• 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.
• Pathogen is susceptible to most household disinfectants (rubbing alcohol, bleach).
• 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 receive medicated feed containing chlortetracycline for the entire quarantine period as a precautionary measure against avian chlamydiosis.
• Human psittacosis is a nationally notifiable disease and should be reported to public health authorities.

Pathophysiology

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

Etiology

• Infection produced by Chlamydophila psittaci, an obligate intracellular parasitic bacterium
• Morphologically, antigenically, and genetically different from Chlamydia species

Commonly Associated Conditions

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