Histoplasma Seropositivity in TB Patients in The Gambia: Evidence to Drive Research on a High-Priority Fungal Pathogen

BACKGROUND: Inclusion of Histoplasma in the World Health Organization's first Fungal Priority Pathogens List under “high-priority” fungal species highlights the need for robust surveillance of Histoplasma spp. in endemic and underrepresented regions. Despite increasing reports of histoplasmosis in Africa, data on the burden of this fungal disease are sparse in The Gambia. This baseline study examined the human seroprevalence of anti-Histoplasma antibody in a TB patient group in The Gambia, explored associations between seropositivity and demographic and clinical variables, and proposes future research directions. METHODS: Biobanked plasma samples were selected from active TB cases with variable HIV infection status. Latex agglutination tests were performed on samples from 52 study participants to detect the presence of anti-Histoplasma antibodies. Potential risk factors for Histoplasma exposure were explored using logistic regression analysis. RESULTS: The sample seroprevalence of anti-Histoplasma antibody was 28.8% (n = 15/52; 95% CI, 17.1%–43.1%). Multivariable logistic regression analysis identified a statistically significant association between Histoplasma seropositivity and age (odds ratio, 0.91; 95% CI, 0.84–0.98; P = .008). CONCLUSIONS: This baseline study provides evidence of Histoplasma seropositivity in TB patients in The Gambia and explores risk factors for exposure. The small sample size and use of the LAT in TB and HIV-positive patient groups are significant study limitations. Future research directions are proposed to ascertain the burden of Histoplasma in general and patient populations and explore the context-specific risk factors for exposure and infection in The Gambia.