Blastocystis lives in moist soil enriched with decomposing organic debris. Endemic in parts of the south-central, south-eastern and mid-western United States. Microfoci in Central and South America and parts of Africa.

Causes

Inhalation of airborne conidia (spores) after disturbance of contaminated soil.

Risk Factors

Persons in areas with endemic disease with exposures to wooded sites (e.g., farmers, forestry workers, hunters, and campers).

Symptoms

Symptomatic infection (50% of cases) usually presents as a flu-like illness with fever, chills, productive cough, myalgia, arthralgia and pleuritic chest pain. Some patients fail to recover and develop chronic pulmonary infection or widespread disseminated infection (affecting the skin, bones, and genitourinary tract). Occasionally affects the meninges.

Diagnosis

Clinical tests needed to confirm infection type.

Treatment

Dependent on type and severity of infection.

References:

Bradsher RW, Chapman SW, Pappas PG. Blastomycosis. Infect Dis Clin North Am 2003; 17: 21-40.

Cano MV, Ponce-de-Leon GF, Tippen S, et al. Blastomycosis in Missouri: epidemiology and risk factors for endemic disease. Epidemiol Infect 2003; 131: 907-914.

Chapman SW, Bradsher RW, Campbell GD, et al. Practice guidelines for the management of patients with blastomycosis. Clin Infect Dis 2000; 30: 679-683.