Bat Guano’s Hidden DangerImage of a flying southern long nosed bat

Ask almost anyone, and you will hear that bats can be dangerous because they carry rabies (although beneficial for insect control). Histoplasmosis, however, is a lesser-known risk and one that is not as easy to avoid. Histoplasmosis is a disease that you can get from bat guano exposure (bat droppings). Bats carry a high number of parasites and diseases that make them hazardous to your health. Potential health threats from bat bites includes rabies, and there is also the possibility of getting histoplasmosis and other bat diseases from bat guano. Similar to other animals, bats will do what they can to keep themselves and home safe. They will bite any potential predators to eliminate the animals that pose a risk to them. The bat’s bites alone are not fatal to larger animals; so they inject their blood into them when they bite. As a result, some diseases such as rabies can get into the animal’s blood. The rabies disease is harmful, not easily treated, and can also be fatal. A quick list of common questions we get about histoplasmosis is provided below.

Histoplasmosis, what is it?

It is an infectious disease caught in the histoplasma capsulatum fungus by inhaling the spores. These spores are present because of guano. Although the lung disease is not contagious person to person, it can affect a wide range of humans who may not even know that they are at risk. Infection takes place when airborne spores are inhaled, especially after a roost has been disturbed. Most infections are mild and produce either no symptoms or a disease-like minor influenza, like chest pain. On occasion, high fever, blood abnormalities, pneumonia, and even death can be caused by the disease. Up to 80 percent of people show evidence of previous infection in some areas, including portions of Illinois.

Should I worry about my risk of infection?

Histoplasmosis can be obtained by anyone. However, there are certain people whose professions make the risk of exposure greater than others. Chimney cleaners, building workers, gardeners, HVAC installers or repair workers, roofers and, of course, spelunkers are included in that group (cave explorers). However, in reality, anyone who comes across the fungus, particularly those with a weakened immune system, can get histoplasmosis.

But I have never touched a bat or have been bitten. So how could I have gotten it?

It is easier than you might have thought. Bats become infected with histoplasmosis and the histoplasma capsulatum fungus is found in their feces (or guano). This fungus grows in an attic occupied by bats, in the soil where the droppings land, or in the droppings themselves. Then the fungus keeps growing, just waiting for you or me to come along to clean the old barn, the attic, or other places where the spores are lying now. Or sometimes, humans disturb the dirt, causing the spores to become airborne (cleaning up the garden, sweeping out an empty building, or doing other seemingly harmless dirty work). Humans then become infected with histoplasmosis when we breathe that air and the real trouble begins.

How do I know if I’ve got it?

The disease first affects the lungs, and within the first few days, those with the disease often have no or very mild symptoms. On average, many sufferers complain of flu-like symptoms about 10 days after exposure: fever, chest pain, abdominal pain, loss of appetite, dry cough, headache, shortness of breath, vision impairment, and possibly pain in the joints and muscles. You may have been exposed to the illness because of the vague symptoms and do not know it. The disease may run its course in many cases, and you’ll think you’ve simply had a flu case. However, some cases cause severe infection, resulting in long-term disease, often resembling tuberculosis in nature. And some cases are fatal if not treated. You may be more likely to get histoplasmosis if you have a weakened immune system (are undergoing chemotherapy, have AIDS, etc.) or are a heavy smoker. And if you’ve had it in the past, after another exposure, you are subject to re-infection or reactivation of the illness. Other risk factors include the elderly, those with immune systems that are compromised, and the very young.

How can I avoid getting it?

Avoid areas that may house the fungus when cleaning an old attic or building, especially if there are accumulations of bird or bat droppings. If you have to work there, spray a mist of water over contaminated sites. This will help keep the dust down (and thus the spores). Wear disposable or protective clothing and specially designed face masks that can filter particulate matter of 1 milli-micron in diameter if you have to work around a contaminated area. Keep hands and skin covered. Keep bats and birds from nesting in building areas such as barns and in the attic or eaves of your house. Note that before cleanup can begin, you may have to have your home or building cleared of bats and/or bird roosts. If that is the case, it is best to have this done by a business specializing in bat control. To minimize the risk of getting or spreading the disease, they will know the proper ways to control the spores and have suitable clothing and equipment.