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Pet Birds Pose Threat to People With Weak Immune Systems

Woman Dies After Contracting Cockatoo Transmitted Fungal Infection

From the WebMD Archives

Feb. 1, 2000 (New York) - The case of a 72-year-old woman who died after contracting a rare fungal infection, apparently from a pet cockatoo, is a good example of why patients with compromised immune systems should not have pet birds, according to a new report.

The woman had undergone a kidney transplant several years earlier and was taking medication to suppress her immune system. She had the umbrella cockatoo for seven years, but she was not involved in its care nor did she live on the same floor as the bird. "However, she passed the cage several times per week," the authors write. Thirty-nine days after contracting a cryptococcus infection, the woman died.

The type of fungus involved in the infection, Cryptococcus neoformans, has been linked to birds in the past, so researchers turned an eye toward the woman's pet.

They found that the bird's droppings did indeed contain the yeast-like Cryptococcus neoformans, which can cause infections of the brain and central nervous system, skin, bones, and urinary tract.

After culturing the fungi from the woman, the scientists found that it matched the strain in the cockatoo's droppings. Fumes from bird droppings can become released into the air by sweeping and other disturbances. The researchers therefore suspected that the woman contracted the infection by inhalation.

This is the first case of human Cryptococcus neoformans infection in which the fungus was found in the patient's immediate environment and the two strains were found to be "indistinguishable," write the authors, whose report appears in the current issue of the Annals of Internal Medicine. However, they write, "We cannot conclusively prove transmission from birds to humans because we cannot exclude the possibility that both the patient and the bird were infected by an unidentified third source."

"If you have a bird in the home, it does not mean that you are going to get the infection. Plenty of individuals with compromised immunity have birds but don't get it. Still, caution is for the wise," says lead researcher Arturo Casadevall, MD, PhD, an associate professor of medicine at the Albert Einstein College of Medicine in the Bronx, N.Y. "The important message is that people should be cautious and think about the possibility that birds in the household can be a source of infection with Cryptococcus neoformans," he tells WebMD.

According to information cited in the study, Cryptococcus neoformans has been found in 26% of canaries, 18.4% of carrier pigeons, 1.7% of budgerigars, and 1.2% of psittacines.

It is for these reasons that caution is strongly advised, Mahmoud Ghannoum, PhD, director of the Center for Medical Mycology at Case Western Reserve University in Cleveland, tells WebMD.

"Pigeons are known carriers of Cryptococcus neoformans, and it has been shown that, especially in New York City, there is some association between infections among individuals with the AIDS virus," says Ghannoum, who is also a professor of dermatology at Case Western Reserve.

Acknowledging that it can be tough to avoid pigeons, especially in New York City, people with compromised immune systems should never play with the pigeons and avoid them when and where they can, he advises.

Vital Information:

  • Researchers report that a 72-year old woman apparently contracted alife-threatening fungal infection from a pet cockatoo.
  • It is suspected that the fungus was released into the air from the bird'sdroppings and that the fumes were inhaled by the woman.
  • People who have HIV or are taking medications that suppress the immunesystem may be at risk of infection transmitted from household birds.