Histoplasmosis and Mexican Caves
A Fungus Which Grows in Bat Guano Threatens Cave Explorers in Mexico
Jan 1, 2009
Histoplasmosis is an infection caused by inhaling spores from a fungus called Histoplasma capsulatum. This fungus prospers in bird or bat guano and therefore, in the USA, the disease is associated with chicken coops and caves, especially in the Ohio Valley and some parts of Texas.
Histoplasmosis in Mexico
In Mexico, it poses a serious problem to anyone entering a cave in areas which have a mild or tropical climate. The fungus is invisible to the naked eye. Its spores are less than one micron in size, far too small to be seen but so light they can easily be wafted to any part of a cave by air currents.
Stirring up the dust on a dry cave floor is a sure way to increase the possibility of inhaling the spores, but even breathing the air in a wet cave can be risky.
Symptoms of Histoplasmosis
Once the spores enter the lungs, they begin to grow. In Mexico, a typical incubation period is eleven days. During this time, the exposed individual normally has no symptoms. On the eleventh day, the victim may develop a hacking cough, chest pains and a high, intermittent fever. After two weeks of this, the body often manages to encapsulate the spores and the individual feels better.
Unfortunately, not all people react the same way. Some might experience nothing more than a light cough while others may be incapacitated for months and a few may find themselves in grave danger of death. It is, therefore, critically important to consult a doctor familiar with histoplasmosis.
Doctors who have never seen a case, might easily misdiagnose histoplasmosis as an ailment caused by bacteria or a virus, rather than a fungus. In extreme cases, a fungicide may be prescribed, whereas in light cases, patients normally recover with no treatment except plenty of rest.
A simple skin test indicates whether one is histoplasmosis positive or negative. A positive reading often means that cavers are somewhat immune to future attacks but this again may vary widely from individual to individual.
In-Cave Prevention of Histoplasmosis
Masks of all sorts have been tested, but only those which tightly adhere to the skin were found effective. These same masks, however, literally suffocate the wearer in Mexico’s typically warm caves and prevent oral communication. Rumors claim that imbibing strong spirits before entering a cave may inhibit the growth of the spores in the lungs, but scientifically sound proof is lacking.
Therefore, the most effective prevention technique would seem to be avoiding Mexican caves altogether.
While that may work in some parts of Mexico, studies carried out by the Mexican Social Security Institute in 1986 indicate that the very soil of the state of Jalisco. in western Mexico, is rich in Histoplasma capsulatum spores, for which reason local cavers have bestowed on Jalisco the dubious honor of being “The Histo Capital of the World.”
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