Diagnostic capacity for cutaneous fungal diseases in the African continent.

BACKGROUND: Cutaneous fungal infections are very common, especially in poorer communities and with intercurrent HIV infection. Determining the fungal pathogen in skin-related fungal neglected tropical diseases (NTDs) determines optimal therapy. We undertook a country survey across many African countries to determine the diagnostic capacity for skin fungal diseases. METHODS: A detailed questionnaire was delivered to country contacts to collect data on availability, frequency, and location of testing for key diagnostic procedures and followed up with 2 rounds of validation by video call and by confirmation of individual country data confirmation by email. RESULTS: Of 47 countries with data, seven (15%) and 21 (45%) do not offer skin biopsy in the public or private sector, respectively, but 22 (46%) countries do it regularly, mostly in university hospitals. Direct microscopy is often performed in 20 of 48 (42%) countries in the public sector and not done in 10 (21%). Fungal cultures are often performed in 21 of 48 (44%) countries in the public sector but not done in nine (20%) or 21 (44%) in either public or private facilities. Histopathological examination of tissue is frequently used in 19 of 48 (40%) countries but not in nine (20%) countries in the public sector. The cost of diagnostics to patients was a major limiting factor in usage. CONCLUSION: Major improvements in the availability and use of diagnostic tests for skin, hair, and nail fungal disease are urgently needed across Africa.

False-negative rapid diagnostic tests for malaria and deletion of the histidine-rich repeat region of the hrp2 gene.

We identified 480 persons with positive thick smears for asexual Plasmodium falciparum parasites, of whom 454 had positive rapid diagnostic tests (RDTs) for the histidine-rich protein 2 (HRP2) product of the hrp2 gene and 26 had negative tests. Polymerase chain reaction (PCR) amplification for the histidine-rich repeat region of that gene was negative in one-half (10/22) of false-negative specimens available, consistent with spontaneous deletion. False-negative RDTs were found only in persons with asymptomatic infections, and multiplicities of infection (MOIs) were lower in persons with false-negative RDTs (both P < 0.001). These results show that parasites that fail to produce HRP2 can cause patent bloodstream infections and false-negative RDT results. The importance of these observations is likely to increase as malaria control improves, because lower MOIs are associated with false-negative RDTs and false-negative RDTs are more frequent in persons with asymptomatic infections. These findings suggest that the use of HRP2-based RDTs should be reconsidered.