A cross-sectional study of the filarial and Leishmania co-endemicity in two ecologically distinct settings in Mali

Abstract Background Filariasis and leishmaniasis are two neglected tropical diseases in Mali. Due to distribution and associated clinical features, both diseases are of concern to public health. The goal of this study was to determine the prevalence of co-infection with filarial (Wuchereria bancrofti and Mansonella perstans) and Leishmania major parasites in two ecologically distinct areas of Mali, the Kolokani district (villages of Tieneguebougou and Bougoudiana) in North Sudan Savanna area, and the district of Kolondieba (village of Boundioba) in the South Sudan Savanna area. Methods The prevalence of co-infection (filarial and Leishmania) was measured based on (i) Mansonella perstans microfilaremia count and/or filariasis immunochromatographic test (ICT) for Wuchereria bancrofti-specific circulating antigen, and (ii) the prevalence of delayed type hypersensitivity (DTH) responses to Leishmania measured by leishmanin skin test (LST). Results In this study, a total of 930 volunteers between the age of 18 and 65 were included from the two endemic areas of Kolokani and Kolondieba. In general, in both areas, filarial infection was more prevalent than Leishmania infection with an overall prevalence of 15.27% (142/930) including 8.7% (81/930) for Mansonella perstans and 8% (74/930) for Wuchereria bancrofti-specific circulating antigen. The prevalence of Leishmania major infection was 7.7% (72/930) and was significantly higher in Tieneguebougou and Bougoudiana (15.05%; 64/425) than in Boundioba (2.04%; 8/505) (χ2 = 58.66, P < 0.0001). Among the filarial infected population, nearly 10% (14/142) were also positive for Leishmania with an overall prevalence of co-infection of 1.50% (14/930) varying from 2.82% (12/425) in Tieneguebougou and Bougoudiana to 0.39% (2/505) in Boundioba (P = 0.0048). Conclusion This study established the existence of co-endemicity of filarial and Leishmania infections in specific regions of Mali. Since both filarial and Leishmania infections are vector-borne with mosquitoes and sand flies as respective vectors, an integrated vector control approach should be considered in co-endemic areas. The effect of potential interaction between filarial and Leishmania parasites on the disease outcomes may be further studied

Correction: Prevalence of Cutaneous Leishmaniasis in Districts of High and Low Endemicity in Mali.

[This corrects the article DOI: 10.1371/journal.pntd.0005141.]

Prevalence of LST positivity by age group and by study districts.

<p>Prevalence of LST positivity by age group and by study districts.</p

Images representative of active CL cases diagnosed during the study.

<p><b>A</b>: Ulcero-crusted lesion of CL (3 to 4 cm diameter) on the forearm of 8 years old girl from the village of Nafadji. <b>B</b>: Ulcerated nodule of CL (1.5 cm diameter) of the left forearm of 10 years old girl from the village of Nafadji. <b>C</b>: Superinfected and crusted lesion of CL of the right forearm of a 3 years old girl from the village of Guemou. Please note the dry and erythematous halo with an eczematization of the lesion. <b>D</b>: Ulcerated lesion of CL with black crusted lesion (covered by a local traditional powder) of leg of a 2 years boy from the village of Nafadji. <b>E</b>: Ulcerated nodule of CL of the right knee of a 13 years old boy from the village of Tinkare.</p

<i>Leishmania major</i> detection from four of the 11 tissue aspirates obtained from lesions of active CL cases.

<p>M = ladder 100bp, lanes 1–4 = samples, NC = negative control, PC = Positive Control (<i>L</i>. <i>major</i>).</p

Map of Mali showing the study sites in different districts.

<p>Map of Mali showing the study sites in different districts.</p

Prevalence of LST positivity by age group for the district of Diema (A) and for all study sites (B).

<p>Prevalence of LST positivity by age group for the district of Diema (A) and for all study sites (B).</p

Characteristics of active CL cases diagnosed during the study.

<p>Characteristics of active CL cases diagnosed during the study.</p

Optical density (OD) of antibodies against sand fly saliva measured by ELISA.

<p>A) Antibody levels in tested subjects from the 6 study villages. Sample size is shown in brackets. B) Overall antibody levels in leishmanin positive (LST+) and negative (LST-) study subjects. CTL, non-endemic controls from US healthy volunteers not exposed to <i>Leishmania</i>.</p