Pierre Traore

Delayed-Type Hypersensitivity to Sand Fly Saliva in Humans from a Leishmaniasis-Endemic Area of Mali Is TH1-Mediated and Persists to Midlife

Immunity to sand fly saliva in rodents induces a TH1 delayed-type hypersensitivity (DTH) response conferring protection against leishmaniasis. The relevance of DTH to sand fly bites in humans living in a leishmaniasis-endemic area remains unknown. Here, we describe the duration and nature of DTH to sand fly saliva in humans from an endemic area of Mali. DTH was assessed at 24, 48, 72, and 96 hours post bite in volunteers exposed to colony-bred sand flies. Dermal biopsies were obtained 48 hours post bite; cytokines were quantified from peripheral blood mononuclear cells (PBMCs) stimulated with sand fly saliva in vitro. A DTH response to bites was observed in 75% of individuals aged 1–15 years, decreasing gradually to 48% by age 45, and dropping to 21% thereafter. Dermal biopsies were dominated by T lymphocytes and macrophages. Abundant expression of IFN-γ and absence of TH2 cytokines establishes the TH1 nature of this DTH response. PBMCs from 98% of individuals responded to sand fly saliva. Of these, 23% were polarized to a TH1 and 25% to a TH2 response. We demonstrate the durability and TH1 nature of DTH to sand fly bites in humans living in a cutaneous leishmaniasis-endemic area. A systemic TH2 response may explain why some individuals remain susceptible to disease.

Discrepant prevalence and incidence of Leishmania infection between two neighboring villages in Central Mali based on Leishmanin skin test surveys.

Apart from a single report, the last publication of cutaneous leishmaniasis (CL) in Mali dates back more than 20 years. The absence of information on the current status of CL in Mali led us to conduct a cohort study in Kemena and Sougoula, two villages in Central Mali from which cases of CL have been recently diagnosed by Malis reference dermatology center in Bamako. In May 2006, we determined the baseline prevalence of Leishmania infection in the two villages using the leishmanin skin test (LST). LST-negative individuals were then re-tested over two consecutive years to estimate the annual incidence of Leishmania infection. The prevalence of Leishmania infection was significantly higher in Kemena than in Sougoula (45.4% vs. 19.9%; OR: 3.36, CI: 2.66–4.18). The annual incidence of Leishmania infection was also significantly higher in Kemena (18.5% and 17% for 2007 and 2008, respectively) than in Sougoula (5.7% for both years). These data demonstrate that the risk of Leishmania infection was stable in both villages and confirm the initial observation of a significantly higher risk of infection in Kemena (OR: 3.78; CI: 2.45–6.18 in 2007; and OR: 3.36; CI: 1.95–5.8 in 2008; P<0.005). The absence of spatial clustering of LST-positive individuals in both villages indicated that transmission may be occurring anywhere within the villages. Although Kemena and Sougoula are only 5 km apart and share epidemiologic characteristics such as stable transmission and random distribution of LST-positive individuals, they differ markedly in the prevalence and annual incidence of Leishmania infection. Here we establish ongoing transmission of Leishmania in Kemena and Sougoula, Central Mali, and are currently investigating the underlying factors that may be responsible for the discrepant infection rates we observed between them. Trial Registration ClinicalTrials.gov NCT00344084

Hair Care and Hair Styles in Women in Bamako, Mali

In contrast to Caucasian hair, which is fine and silky, black African hair has a dry and frizzy consistency. In both sexes, the natural hairstyle formed by the hair is used in various contexts as a means of self-expression, in particular to express female beauty. 1 Dry and frizzy hair does not easily lend itself to different methods of hair styling. Nevertheless, our hair salons produce hair styles that are impressive in aesthetic terms but which are poorly documented. 2 Hair care may also be sought for scalp problems such as pruritus, dandruff and alopecia. The types of hair care and styles available, as well as the side effects of the techniques employed, are poorly understood in Bamako. The aim of this study was to acquire a better understanding of the hair care and hair styling carried out in salons and hairdressing centers, as well as the side effects of these procedures observed in women in Bamako.

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

Historically the western sahelian dry regions of Mali are known to be highly endemic for cutaneous leishmaniasis (CL) caused by Leishmania major, while cases are rarely reported from the Southern savanna forest of the country. Here, we report baseline prevalence of CL infection in 3 ecologically distinct districts of Mali (dry sahelian, north savanna and southern savanna forest areas). We screened 195 to 250 subjects from 50 to 60 randomly selected households in each of the 6 villages (four from the western sahelian district of Diema in Kayes region, one from the central district of Kolokani and one from the southern savanna district of Kolodieba, region of Sikasso). The screening consisted of: 1] A Leishmanin Skin Test (LST) for detection of exposure to Leishmania parasites; 2] clinical examination of suspected lesions, followed by validation with PCR and 3] finger prick blood sample to determine antibody levels to sand fly saliva. LST positivity was higher in the western district of Diema (49.9%) than in Kolokani (24.9%) and was much lower in Kolondieba (2.6%). LST positivity increased with age rising from 13.8% to 88% in Diema for age groups 2–5 years and 41–65 years, respectively. All eight PCR-confirmed L. major CL cases were diagnosed in subjects below 18 years of age and all were residents of the district of Diema. Exposure to sand fly bites, measured by anti-saliva antibody titers, was comparable in individuals living in all three districts. However, antibody titers were significantly higher in LST positive individuals (P<0.0001). In conclusion, CL transmission remains active in the western region of Mali where lesions were mainly prevalent among children under 18 years old. LST positivity correlated to higher levels of antibodies to sand fly salivary proteins, suggesting their potential as a risk marker for CL acquisition in Mali.

Pruritus in dermatological hospital in Bamako, Mali

Pruritus is a symptom frequently encountered in dermatology consultations. For practitioners working in a tropical environment, particularly in Africa, the diagnosis of pruritus remains a constant problem. The aim of this study was to describe the epidemioclinical aspects and the etiologies of pruritus encountered at the dermatological hospital in Bamako. We conducted a prospective survey on a cohort of patients attending the Department of Dermatology at the Centre National d’Appui (CNAM‐Ex Institut Marchoux) in the Fight against Disease over a 1‐year period (June 1, 2009–May 31, 2010). Consequently, the study included every patient, whatever their age and gender, that agreed to take part in the survey and whose main reason for attending for a consultation was “pruritus.” The clinical and biological data were entered and analyzed using Epi Info software, version 6.04 fr. A total of 232 patients (163 women, 69 men) attended because of pruritus out of 1761 overall patients (i.e., a prevalence of 13.17%). The mean age of the patients was 33 ± 19 years. Dermatological causes represented 95% of the etiologies. This work allowed us to observe the systemic causes of pruritus in the dermatological environment in Mali and greater likelihood of black women to attend because of pruritus.

Dermatitis of the folds in black Africans in Bamako, Mali

Dermatitis of the folds (intertrigo) is a frequent reason for attending consultations, particularly in Africa, where the hot and humid climate constitute an aggravating factor. It is a complex pathology with multiple and intricate etiologies. The aim of this study was to describe epidemiological and etiological aspects of dermatitis of the folds in black‐skinned subjects in Bamako (Mali). We conducted a transversal descriptive survey of cases of localized dermatitis of the folds of the skin in dermatology clinics in Bamako. In total, 141 cases of intertrigo were identified: 96 female subjects (68%) and 45 male subjects. The average age of patients was 30 ± 18 years (2–80 years). The majority of patients were seen between March and June; 52% of patients had already received treatment before the consultation. The lesions affected skin folds of the groin area and/or area between the buttocks in 95 patients (57.4%), and folds of the armpits and area under the breasts were affected in 46 cases (42.6%). Eczema, erythrasma, and fungal disease were the most frequently observed pathologies. Of interest to this study is the topographical approach that a dermatologist must adopt when diagnosing certain forms of dermatitis. In populations with specific cultural practices, apart from a thorough knowledge of these specific factors, treatment of these conditions requires certain harmful attitudes and behaviors to be abandoned.