A 43-year-old man developed pneumonia after direct contact with parrots at a zoo, highlighting the under-recognised risk of psittacosis. Standard antibiotics failed to cut his fever of 40 degrees Celsius. Diagnosis of Chlamydia psittaci followed genetic testing of lung samples, and he recovered after switching to the right antibiotic.

The Case of Spherical Pneumonia

The man presented with persistent fever, fatigue and muscle pain but few respiratory symptoms. A CT scan revealed a solitary round opacity roughly 4 cm across in the right lower lung, with clear margins and surrounding ground-glass changes—an uncommon pattern called spherical pneumonia.

Routine tests for common pathogens were negative. Bronchoscopy and targeted next-generation sequencing of lung fluid detected high levels of Chlamydia psittaci DNA. He had handled ornamental parrots at a zoo about 10 days before his symptoms began, consistent with the typical incubation period of five to 14 days.

Minocycline brought his temperature down within three days, and a follow-up scan 32 days later showed the lesion almost gone.⁠

How Birds Spread the Bacterium Quietly

Psittacosis, or parrot fever, spreads mainly through inhalation of fine dust from dried bird droppings, feathers or secretions. Infected birds, including parrots and poultry, can shed the bacterium without showing obvious signs of illness. The US Centers for Disease Control and Prevention reports fewer than 10 cases annually in the United States.

In England, 13 laboratory-confirmed cases of Chlamydia psittaci or Chlamydia abortus were reported in 2025, compared with 11 in 2024. The figures may underestimate the true burden because not all infections are diagnosed or laboratory-confirmed. Children, older adults and people with weakened immunity face higher risk of severe illness.

Infection can also occur after indirect exposure to contaminated material, as people may inhale airborne particles containing the bacterium without handling birds directly.

'Psittacosis is a respiratory disease mainly spread through inhaling the dust of bird droppings. You need to breathe in the bacteria to get infected,' says Brian Labus, an infectious disease epidemiologist at the University of Nevada, Las Vegas.

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What Zoo Visitors and Bird Owners Should Know

Symptoms usually begin with fever, headache and muscle aches; a dry cough and pneumonia can follow. There are no unique clinical features that point specifically to psittacosis, so a history of any bird contact is essential.

Tetracycline antibiotics such as doxycycline or minocycline are first-line treatments. With appropriate antibiotics, death is rare—less than 1 in 100 cases. Even brief exposure to contaminated environments can infect people with no occupational link to birds.⁠

Wet droppings before cleaning to avoid aerosolising particles and wear a respirator in dusty areas. Zoo visitors should limit close contact with birds and mention any recent exposure if flu-like illness develops. The case report, published in Frontiers in Medicine on 8 June 2026, shows that encounters with healthy-looking birds can transmit a serious yet treatable infection.⁠

Health agencies monitor sporadic cases and outbreaks, including those associated with bird-related workplaces. For most people the risk stays low, yet recognising the link between bird contact and unexplained pneumonia speeds diagnosis and treatment.

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Frequently Asked Questions

  • What is psittacosis?
    Psittacosis, also known as parrot fever, is a respiratory disease caused by the bacterium Chlamydia psittaci, often spread through inhalation of dust from bird droppings.
  • How can psittacosis be prevented?
    Prevent psittacosis by avoiding close contact with birds, wetting droppings before cleaning, wearing a respirator in dusty areas, and reporting any flu-like symptoms after bird exposure.
  • What are the symptoms of psittacosis?
    Symptoms of psittacosis include fever, headache, muscle aches, dry cough, and pneumonia.
  • How is psittacosis treated?
    Psittacosis is treated with tetracycline antibiotics such as doxycycline or minocycline.