Paracoccidioidin sensitization in Guyana — a prelimary skin test survey in hospitalized patients and laboratory workers

Abstract

Thirty-one percent of a group of 49 hospitalized patients or laboratory workers in Guyana showed positive intradermal paracoccidioidin tests in the presence of negative histoplasmin reactions. In 2 patients (4%), the intradermal reactions to paracoccidioidin were greater than 10 mm in diameter. The prevalence of positive reactors in a selected population suggests that paracoccidioidomycosis may be endemic in Guyana although no clinical case has been reported from the country. A further survey in a larger, unselected population would lead to a clearer understanding of the problem.

Paracoccidioidomycosis: an update

“…The first recorded attempt to demonstrate DTH in patients with paracoccidioidomycosis was that of Fonseca and Area-Leao, who intradermally injected a mycelial filtrate into two patients, both of whom proved reactive (109). Since then, numerous investigators have employed exocellular and intracellular P. brasiliensis antigens to study skin reactivity in both infected patients and healthy populations (14,75,85,92,136,179,180,210,267,296). In 1961, Fava-Netto and Raphael (101) reported the use of the polysaccharide antigen (intracellular and cytoplasmic) for skin testing.…”

Paracoccidioidomycosis: an update.

“…Since then, numerous investigators have employed exocellular and intracellular P. brasiliensis antigens to study skin reactivity in both infected patients and healthy populations (14,75,85,92,136,179,180,210,267,296).…”

Preparation of species-specific murine monoclonal antibodies against the yeast phase of Paracoccidioides brasiliensis

“…Paracoccidioidomycosis is a major systemic mycosis in Central and South America (7,12,25). The causative agent is the thermally dimorphic fungus Paracoccidioides brasiliensis.…”

“…Antibodies to P. brasiliensis can be detected by a number of serological techniques such as immunodiffusion (3,21), complement fixation (18), indirect immunofluorescence (1, 16,24), immunoelectrophoresis, and enzyme-linked immunosorbent assay (ELISA) (5,19). However, antigenic similarities between the dimorphic fungi result in serological cross-reactivities when existing P. brasiliensis antigens are used in these tests, particularly between P. brasiliensis and Histoplasma capsulatum (12,16), often leading to false-positive results. There is a similar problem in using existing antigens as skin test reagents to study the epidemiology of the infection (5,12,18,21).…”

“…However, antigenic similarities between the dimorphic fungi result in serological cross-reactivities when existing P. brasiliensis antigens are used in these tests, particularly between P. brasiliensis and Histoplasma capsulatum (12,16), often leading to false-positive results. There is a similar problem in using existing antigens as skin test reagents to study the epidemiology of the infection (5,12,18,21).…”