Histoplasmosis Risk & Prevention

Anyone can get histoplasmosis if they’ve been in an area where Histoplasma lives in the environment. Histoplasmosis is often associated with activities that disturb soil, particularly soil that contains bird or bat droppings. Certain groups of people are at higher risk for developing the severe forms of histoplasmosis:

• People who have weakened immune systems, for example, people who:
  • Have HIV/AIDS ^1–2
  • Have had an organ transplant ^2–3
  • Are taking medications such as corticosteroids or TNF-inhibitors ^2,4
• Infants⁵
• Adults aged 55 and older⁶

No. Histoplasmosis can’t spread from the lungs between people or between people and animals. However, in extremely rare cases, the infection can be passed through an organ transplant with an infected organ.⁷

It’s possible for someone who’s already had histoplasmosis to get it again, but the body’s immune system usually provides some partial protection so that the infection is less severe the second time. In people who have weakened immune systems, histoplasmosis can remain hidden in the body for months or years and then cause symptoms later (also called a relapse of infection).⁸

Yes. Pets, particularly cats, can get histoplasmosis, but it is not contagious between animals and people.⁹ Histoplasmosis in cats and dogs is similar to histoplasmosis in humans. Like humans, many cats and dogs that are exposed to Histoplasma never get sick. Cats and dogs that do develop symptoms often have symptoms that include coughing, lack of energy, and weight loss. The fungus that causes histoplasmosis grows well in soil that contains bird droppings, but birds don’t appear to be able to get histoplasmosis. If you’re concerned about your pet’s risk of getting histoplasmosis or if you think that your pet has histoplasmosis, please talk to a veterinarian.

It can be difficult to avoid breathing in Histoplasma in areas where it’s common in the environment. In areas where Histoplasma is known to live, people who have weakened immune systems (for example, by HIV/AIDS, an organ transplant, or medications such as corticosteroids or TNF-inhibitors) should avoid doing activities that are known to be associated with getting histoplasmosis, including:¹⁰

• Disturbing material (for example, digging in soil or chopping wood) where there are bird or bat droppings
• Cleaning chicken coops
• Exploring caves
• Cleaning, remodeling, or tearing down old buildings

Large amounts of bird or bat droppings should be cleaned up by professional companies that specialize in the removal of hazardous waste. Before starting a job or activity where there’s a possibility of being exposed to Histoplasma, consult the document Histoplasmosis: Protecting Workers at Risk [PDF – 39 pages].

• Surveillance. In some states, healthcare providers and laboratories are required to report histoplasmosis cases to public health authorities. Disease reporting helps government officials and healthcare providers understand how and why outbreaks occur and allows them to monitor trends in the number of histoplasmosis cases.
• Developing better diagnostic tools. The symptoms of histoplasmosis can be similar to those of other respiratory diseases. Faster, more reliable methods to diagnosis histoplasmosis are in development, which could help minimize delays in treatment, save money and resources looking for other diagnoses, and reduce unnecessary treatment for other suspected illnesses.
• Building laboratory capacity. Equipping laboratories in Latin America to be able to diagnose histoplasmosis and perform laboratory-based surveillance will help reduce the burden of HIV-associated histoplasmosis in these areas.