Association of eumycetoma and schistosomiasis

Abstract

Eumycetoma is a morbid chronic granulomatous subcutaneous fungal disease. Despite high environmental exposure to this fungus in certain regions of the world, only few develop eumycetoma for yet unknown reasons. Animal studies suggest that co-infections skewing the immune system to a Th2-type response enhance eumycetoma susceptibility. Since chronic schistosomiasis results in a strong Th2-type response and since endemic areas for eumycetoma and schistosomiasis do regionally overlap, we performed a serological case-control study to identify an association between eumycetoma and schistosomiasis. Compared to endemic controls, eumycetoma patients were significantly more often sero-positive for schistosomiasis (p = 0.03; odds ratio 3.2, 95% CI 1.18-8.46), but not for toxoplasmosis, an infection inducing a Th1-type response (p = 0.6; odds ratio 1.5, 95% CI 0.58-3.83). Here, we show that schistosomiasis is correlated to susceptibility for a fungal disease for the first time.

Figure 1. Endemic regions of mycetoma, Schistosoma haematomium and Schistosoma mansoni in Sudan.

The area from which our sera were collected is encircled. The cities of Khartoum, New Halfa and Kassala are indicated.

Figure 2. Percentage of eumycetoma patients and matched controls with positive serology for schistosomiasis and toxoplasmosis.

Percentage of eumycetoma patients and matched controls with positive serology for schistosomiasis (panel A) and toxoplasmosis (panel B). Eumycetoma patients were significantly more often sero-positive for schistosomiasis when compared to matched controls (p<0.05; Chi square test).

Figure 3. Median fluorescence intensity of Madurella mycetomatis TCTP in various groups.

Median fluorescence intensity (MFI) values reflecting levels of antigen-specific IgG for recombinant Madurella mycetomatis his-tagged TCTP in eumycetoma patients with positive Schistosoma-serology (mycetoma+ Schistosoma+), eumycetoma patients without positive Schistosoma-serology (mycetoma+ Schistosoma−), healthy endemic controls with positive Schistosoma-serology (mycetoma− Schistosoma+), healthy endemic controls without positive Schistosoma-serology (mycetoma− Schistosoma−) and Dutch controls. Each symbol represents a single patient or control. Horizontal Lines indicate median levels of anti-Madurella antibodies. Significance was calculated with the Mann-Whitney test. Only antibody levels measured in Dutch controls were significantly lower than any other group (all p<0.01).