Histoplasmosis, also called Ohio Valley disease, Central Mississippi Valley disease, Appalachian Mountain disease, and Darling's disease, is a fungal infection caused by Histoplasma capsulatum. In te United States, it occurs in 3 forms: pimary acute histoplasmosis, progressive disseminated histoplasmosis (acute disseminated or chronic disseminated disease) and chronic pulmonary histoplasmosis which produces cavitations in the lung similar to those in pulmonary tuberculosis. A fourth form, African histoplasmosis, occurs only in Africa.
Histoplasma capsulatum is found in the feces of birds and bats or in soil contaminated by their feces, such that near roosts. chicken coops, barns, caves, or underneath bridges. Transmission is through inhalation of the fungal spores or through minor skin trauma.
SYMPTOMS
Symptoms vary with each form of the disease, as follows:
- Primary acute histoplasmosis: no symptoms or similar to those of respiraory disease (cold or influenza)
- Progressive disseminated histoplasmosis causes enlarged spleen and liver, swollen lymph nodes, weight loss, fever, ulceration of the tongue, palate and larynx, which results in difficulty swallowing.
- Chronic pulmonary histoplasmosis mimics pulmonary tuberculosis and causes a produtive cough and difficulty breathing. Eventually it produces weight loss, extreme weakness and bluish coloration of the skin and mucous membranes.
DIAGNOSIS
Biopsy and other laboratory tests.
TREATMENT
Treatment consists of antifungal therapy, surgery and supportive care.
PREVENTION
Watch for early signs of histoplasmosis if you live in an area where the disease is present. If you risk occupational exposure to contaminated soil, wear a face mask.