Histoplasmosis is caused by infection with the dimorphic soil
fungus Histoplasma capsulatum. Histoplasmosis is in any parts of
the world with warm humid soil and large migratory bird
populations. It is the most common pulmonary and systemic
mycosis of humans. Even under the most adverse conditions,
ordinary soil teems with life. One square meter of plain dirt
can contain more than 10,000 varieties of bacteria and fungi and
up to 1,000 species of protozoa, nematodes and earthworms. Most
soil organisms are highly beneficial, but a few can be
dangerous, and some can even be deadly. One of these is the
fungus Histoplasma capsulatum, which in humans and other animals
causes a lung disease called histoplasmosis. It's transmitted
through airborne spores that you breathe into your lungs when
you work in or around soil that contains the fungus. Farmers,
landscapers, construction workers and people who have contact
with birds or bats are especially at risk. Most people with
histoplasmosis never develop signs and sympto