Histoplasmosis is the most common pulmonary mycosis in the United States. The responsible fungal pathogen, Histoplasma capsulatum , grows in soils contaminated with bird or bat droppings. Inhalation of dust from contaminated areas containing H. capsulatum spores is a primary route of infection. The ability to detect H. capsulatum in soil samples has been limited by the lack of fast, reliable and inexpensive methods. A polymerase chain reaction (PCR) method was developed that allows the direct detection of H. capsulatum in soil. A two-stage PCR protocol was followed employing both fungal-specific primers and nested primers specific for the internal transcribed spacer (ITS) region of the 5·8S rRNA gene of H. capsulatum . The estimated limit of detection of this method is 10 spores. In contrast to the more expensive and indirect mouse inoculum assay, which requires 6-8 weeks for sample analysis, PCR analysis of soil contaminated with H. capsulatum can be completed in less than 2 days.
Pulmonary-system-disorders; Pulmonary-system; Pulmonary-disorders; Respiratory-irritants; Respiratory-system-disorders; Fungal-diseases; Fungal-infections; Fungi; Pathogens; Soil-sampling; Dust-inhalation; Dust-analysis; Dust-exposure; Dust-sampling; Dust-particles; Analytical-methods; Laboratory-animals