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Introduction: Patients with COVID_19 infection have been shown to have an increased thrombotic risk, due to activation of coagulation secondary to sepsis. Objective: To study biological markers correlated with blood clotting disorders in hospitalized patients with COVID_19. Method: This was a retrospective descriptive and analytical cross-sectional study conducted at the Mali Hospital between September 2020 and January 2021. The markers being biologically monitored were: PT, ACT, INR, D-dimer and Troponin-I. Result: A total of 134 patients were enrolled in our study. Male was in the majority than female with 62.68% male and 37.31% female. The age group from 20 to 50 years was the most represented, at 58.21%. Biological markers showed plasma D-dimer concentration > 0.5 μL, PT ˂ 70, INR > 3; an ACT > 40 seconds and a Troponin > 0.1 μL for 76.11%, 10.44%, 15.67%, 16.41% and 1.49% of the study population respectively. The rate of cured patients was 94.02% and that of deceased patients was 5.97%, with all deceased patients having a high D-dimer level. Conclusion: Blood clotting disorders and elevated D-Dimer are important biomarkers predicting complications of COVID_19 infection.

Background - Although schistosomiasis is a public health issue in Mali, little is known about the genetic profile. The purpose of this study was to analyze the genetic profile of the schistosomes of Schistosoma haematobium group in school aged children in various sites of Mali. Methods - Urine samples were collected from 07 to 21 November 2021 and subjected to a filtration method for the presence S. haematobium eggs. The study took place in two schistosomiasis endemic villages, qualified as hotspots according to the World Health Organization (WHO) definition Fangouné Bamanan and Diakalel in Kayes’ region. Molecular biology (Cox1 and ITS2/18S) was used as eggs taxonomic parameters. Results - A total of 789 miracidium were collected individually from 63 school aged children and stored on Whatman Find The Agent (FTA) cards for molecular analysis. After genotyping for species and hybrid identification using rapid diagnostic multiplex mitochondrial Cox1 Polymerase chain reaction (PCR) and Amplification-refractory mutation system -ARMS_PCR analysis of the nuclear Internal Transcribed spacer - ITS2 and 18S regions, 338 (42.8%) and 45) (57.2%) of miracidium revealed S. bovis and S. haematobium profiles for Cox1, respectively; 749 (94.9%) and 40 (5.1%) revealed S. haematobium and S. haematobium/S. curassoni profiles for ITS/18S genes, respectively. There was a significant difference in the Cox1 and ITS2/18S profiles distribution between the two villages (pSb_ShxSc) with 2.3%); (Sb_ShxSh with 40,9%) ; (Sh_ShxSc with 2.8%) and one pure profile [Sh_ShxSh with 54.5%) were identified. The hybrid Sb_ShxSh appeared to be more frequent in Fangouné Bamanan (68%) whereas Sh_Sh/Sc was lightly represented in Diakalel (5.8%). Conclusions - Our findings show for the first time the presence of introgressive hybridization between S. haematobium and S. bovis/S. curassoni in humans at a large scale. More studies are needed on population genetics of schistosomes at the human and animal interface to evaluate the parasite’s gene flow and its consequences on epidemiology of the disease as well as the transmission to humans.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which triggered the ongoing pandemic, was first discovered in China in late 2019. SARS-CoV-2 is a respiratory virus responsible for coronavirus disease 2019 (COVID-19) that often manifests as a pneumonic syndrome. In the context of the pandemic, there are mixed views on the data provided by epidemiologists and the information collected by hospital clinicians about their patients. In addition, the literature reports a large proportion of patients free of pneumonia vs a small percentage of patients with severe pneumonia among confirmed COVID-19 cases. This raises the issue of the complexity of the work required to control or contain the pandemic. We believe that an integrative and pluralistic approach will help to put the analyses into perspective and reinforce collaboration and creativity in the fight against this major scourge. This paper proposes a comprehensive and integrative approach to COVID-19 research, prevention, control, and treatment to better address the pandemic. Thus, this literature review applies a pluralistic approach to fight the pandemic.

International audience; The circulation of Zika virus (ZIKV) in Mali has not been clearly characterized. Therefore, we conducted a serologic survey of 793 asymptomatic volunteers >15 years of age (2016), and 637 blood donors (2013) to assess the seroprevalence of ZIKV infection in 2 ecoclimatic regions of Mali, tropical savannah and warm semiarid region, using ELISA and seroneutralization assays. The overall seroprevalence was ≈12% and increased with age, with no statistical difference between male and female participants. In the warm semiarid study sites we detected immunological markers of an outbreak that occurred in the late 1990s in 18% (95% CI 13%-23%) of participants. In tropical savannah sites, we estimated a low rate of endemic transmission, with 2.5% (95% CI 2.0%-3.1%) of population infected by ZIKV annually. These data demonstrate the circulation of ZIKV in Mali and provide evidence of a previously unidentified outbreak that occurred in the late 1990s.

Background - Schistosomiasis is a water-based parasitic disease caused by blood flukes of the genus Schistosoma. Mass Drug Distribution (MDD) with Praziquantel is periodically recommended in schistosomiasis-endemic countries to prevent morbidity. In Mali, schistosomiasis still remains endemic, especially in Senegal and Niger rivers basin, although the strategy has been adopted since 2005. Our study aimed to assess the impact of annual school-based MDD. Materials and methods – The study was conducted at twelve sentinel sites across Kayes and Koulikoro regions. A cross-sectional study design was performed in April 2018 after four-or five-years post treatment with praziquantel (PZQ) depending on the statute of sites. At baseline (2014-2015) and for the control year (2018), 734 (386 boys and 347 girls) and 1708 (844 boys and 864 girls) school children of 7-14 years of age, were successfully examined respectively. Infections with Schistosoma haematobium and S. mansoni were diagnosed with the urine filtration and the Kato-Katz method respectively. Results – From eight schools treated in 2014, the four annual rounds of MDD with PZQ were associated with a significant decrease in S. haematobium prevalence in five sites (p and a significant increase in one site (p). Of them, the prevalence of high-intensity (≥50 eggs/10mL of urine) significantly decreased in four previous sites but not in Diakalele where it increased ((pIn all the four sites treated in 2015, S. haematobium prevalence increased significantly in Kokoun and Samaya (P). The heavy infection increased slightly in Dougourakoro and Samaya (P>0.05). The prevalence of S. mansoni significantly decreased in three sites (p), increased in three and remains zero in the six others sites. Conclusion – Our findings show that five of the twelve sentinel sites have achieved the criterion of elimination of schistosomiasis due to Schistosoma haematobium as a major public health problem (Prevalence of heavy infection

Small mammals are the natural reservoirs for many zoonotic pathogens. Using molecular tools, we assessed the prevalence of bacteria and protozoans in small mammals and their ectoparasites in Faladje, Bougouni, and Bamoko, Mali. A total of 130 small mammals belonging to 10 different species were captured, of which 74 (56.9%) were infested by ectoparasites, including Laelaps echidnina, Xenopsylla cheopis, Amblyomma variegatum, Rhipicephalus sanguineus sensu lato, and Haemaphysalis spp. nymphs. DNA of Bartonella was found in 14/75 (18.7%), 6/48 (12.5%), and 3/7 (42.8%) small mammals from Faladje, Bougouni, and Bamako, respectively. In Faladje, Bartonella DNA was detected in 31/68 (45.6%) of L. echidnina and 14/22 (63.6%) of X. cheopis. In Bougouni, it was found in 2/26 (7.7%) of L. echidnina and 10/42 (23.8%) of X. cheopis. The sequences of Bartonella obtained from small mammals were close to those of Bartonella mastomydis, Bartonella elizabethae, and uncultured Bartonella spp. In Faladje, Coxiella burnetii DNA was detected in 64.4% (29/45) of Haemaphysalis spp. ticks, 4.5% (2/44) of Mastomys erythroleucus, 12.5% (1/8) of Praomys daltoni, and 1.5% (1/68) of L. echidnina. We found DNA of Wolbachia in X. cheopis from Faladje and DNA of Rickettsia africae and Ehrlichia ruminantium in Am. variegatum from Bougouni. The results of our study show that several small mammal species harbor and may serve as potential reservoirs of Bartonella spp., likely to play a major role in the maintenance, circulation, and potential transmission of bacteria in Mali. The pathogenicity of these bacteria for humans or animals remains to be demonstrated.

ResumeAu Mali la leishmaniose cutanee (LC) est bien decrite en milieu rural, mais sa transmission n’est pas encore etablie en milieu urbain. L’objectif de l’etude etait de decrire la faune phlebotomienne a Bamako et dans ses environs. Les pieges CDC et adhesifs servaient a collecter les phlebotomes en 2011 et 2012 a Bamako. Les pieges etaient places dans le district de Bamako repartis en 30 zones (200 m × 200 m) a l’aide des images de satellite SPOT-5. La delimitation des zones etait basee sur les facteurs ecologiques (relief, hydrographie, couverture vegetale) et anthropologiques (nature des maisons, depots d’ordure). Les pieges etaient places en 2011 a Sotuba, zone periurbaine, puis a Doneguebougou et Banambani, deux villages environnants de Bamako. Au total 122 phlebotomes etaient collectes 27 (22,13 %) a Banambani, 12 (9,83 %) a Doneguebougou, 2 (1,63 %) a Sotuba et 81 (66,39 %) a Bamako. La densite des phlebotomes en novembre etait plus elevee, avec 48 specimens captures (39,3 %), que celle d’avril, ...

Background Even if rainfall and temperature are factors classically associated to malaria, little is known about other meteorological factors, their variability and combinations related to malaria, in association with river height variations. Furthermore, in suburban area, urbanization and growing population density should be assessed in relation to these environmental factors. The aim of this study was to assess the impact of combined environmental, meteorological and hydrological factors on malaria incidence through time in the context of urbanization. Methods Population observational data were prospectively collected. Clinical malaria was defined as the presence of parasites in addition to clinical symptoms. Meteorological and hydrological factors were measured daily. For each factors variation indices were estimated. Urbanization was yearly estimated assessing satellite imaging and field investigations. Principal component analysis was used for dimension reduction and factors combination. Lags between malaria incidences and the main components were assessed by cross-correlation functions. Generalized additive model was used to assess relative impact of different environmental components, taking into account lags, and modelling non-linear relationships. Change-point analysis was used to determine transmission periods within years. Results Malaria incidences were dominated by annual periodicity and varied through time without modification of the dynamic, with no impact of the urbanization. The main meteorological factor associated with malaria was a combination of evaporation, humidity and rainfall, with a lag of 3 months. The relationship between combined temperature factors showed a linear impact until reaching high temperatures limiting malaria incidence, with a lag 3.25 months. Height and variation of the river were related to malaria incidence (respectively 6 week lag and no lag). Conclusions The study emphasizes no decreasing trend of malaria incidence despite accurate access to care and control strategies in accordance to international recommendations. Furthermore, no decreasing trend was showed despite the urbanization of the area. Malaria transmission remain increase 3 months after the beginning of the dry season. Addition to evaporation versus humidity/rainfall, nonlinear relationship for temperature and river height and variations have to be taken into account when implementing malaria control programmes.

International audience; Ticks are considered the second vector of human and animal diseases after mosquitoes. Therefore, identification of ticks and associated pathogens is an important step in the management of these vectors. In recent years, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising method for the identification of arthropods including ticks. The objective of this study was to improve the conditions for the preparation of tick samples for their identification by MALDI-TOF MS from field-collected ethanol-stored Malian samples and to evaluate the capacity of this technology to distinguish infected and uninfected ticks. A total of 1,333 ticks were collected from mammals in three distinct sites from Mali. Morphological identification allowed classification of ticks into 6 species including Amblyomma variegatum, Hyalomma truncatum, Hyalomma marginatum rufipes, Rhipicephalus (Boophilus) microplus, Rhipicephalus evertsi evertsi and Rhipicephalus sanguineus sl. Among those, 471 ticks were randomly selected for molecular and proteomic analyses. Tick legs submitted to MALDI-TOF MS revealed a concordant morpho/molecular identification of 99.6%. The inclusion in our MALDI-TOF MS arthropod database of MS reference spectra from ethanol-preserved tick leg specimens was required to obtain reliable identification. When tested by molecular tools, 76.6%, 37.6%, 20.8% and 1.1% of the specimens tested were positive for Rickettsia spp., Coxiella burnetii, Anaplasmataceae and Borrelia spp., respectively. These results support the fact that MALDI-TOF is a reliable tool for the identification of ticks conserved in alcohol and enhances knowledge about the diversity of tick species and pathogens transmitted by ticks circulating in Mali.

Polyparasitism is common in the developing world, and interactions that alter disease severity may occur. We previously demonstrated that infection with Schistosoma hematobium was associated with protection against Plasmodium falciparum infection in children who were 4 to 8 years old. In this study, we determined whether underlying helminth infections affected the cytokine responses to acute falciparum malaria. A total of 338 schistosomiasis-positive [Sch(+)] children who were 4 to 14 years old were matched by age, residence, and sex with 338 schistosomiasis-negative [Sch(−)] children and monitored for a malaria transmission season (25 weeks). Serologic cytokine levels were measured at the time of the first clinical malaria episode and in children who did not contract malaria. Elevated background levels of interleukin-6 (IL-6) (37.1 pg/ml versus 10.9 pg/ml [ P = 0.04]), IL-4 (27.7 pg/ml versus 6.9 pg/ml [ P = 0.02]), IL-10 (18.2 pg/ml versus 7.2 pg/ml [ P < 0.001]), and gamma interferon (18.2 pg/ml versus 4.7 pg/ml [ P = 0.006]) were noted in Sch(+) children compared to Sch(−) children without malaria. IL-6 and IL-10 levels were elevated in association with acute malaria, but the levels appeared to be blunted in Sch(+) children compared to Sch(−) children who were 4 to 8 years old (for IL-6, 96.2 pg/ml versus 137.2 pg/ml [ P = 0.08]; for IL-10, 195.9 pg/ml versus 282.2 pg/ml [ P = 0.06]). The level of IL-10 was similarly lower in Sch(+) children than in Sch(−) children who were 9 to 14 years old (91.2 pg/ml versus 141.2 pg/ml [ P = 0.03]). IL-4 levels were inversely correlated with the time until the first malaria infection in both the Sch(+) children ( P < 0.001) and the Sch(−) children ( P < 0.001) who were 4 to 8 years old. We postulate that the Th2-enriched environment induced by schistosomiasis protects against malaria and alters the cytokine milieu during an actual infection.

Plasmodium falciparum and Schistosoma haematobium are co-endemic parasitic diseases with worldwide distribution. Evidence suggests interactions occur between helminthic and malaria infections, although it is unclear whether this effect is beneficial or harmful to the host. Malian children 4-14 years of age with asymptomatic S. haematobium infection (SP) (n = 338) were prospectively matched by age, sex, and residence to children without schistosomiasis (SN) (n = 338) who were cleared of occult intestinal parasites, and followed-up for one malaria transmission season (25 weeks). The time to the first clinical malaria infection, incidence of malaria episodes, and parasitemia were recorded. Age associated protection from malaria in children with schistosomiasis was observed. SP children (4-8 years of age) compared with SN children demonstrated delayed time to first clinical malaria infection (74 versus 59 days; P = 0.04), fewer numbers of malaria episodes (1.55 versus 1.81 infections; P = 0.03) and lower geometric mean parasite densities (6,359 versus 9,874 asexual forms/mm(3); P = 0.07) at first infection. No association between schistosomiasis and P. falciparum malaria was observed in children 9-14 years of age. We conclude that underlying schistosomiasis is associated with protection against clinical falciparum malaria in an age-dependent manner.

Background Schistosomiasis is classically described as a rural disease that occurs in areas with poor sanitary conditions. However, over recent decades, there has been an expansion of schistosomiasis foci towards urban areas faced with a rapid and disordered urbanization. In Bamako, Mali, the impact of environmental change on vector-borne diseases such as schistosomiasis is not well known. This study sought to identify the presence of schistosomiasis transmission hotspots in Bamako. Using this perspective, we aimed to describe the risk factors of the endemization and maintenance of schistosomiasis. Materials and methods A cross-sectional study was carried out in the six municipalities (communes) in Bamako. Environmental information was obtained from earth observation satellites in order to maximize ecological contrasts. Twenty-nine blocks of 200 m x 200 m were identified. We selected a school inside or nearest to each block for urine and stool samples examination. The study cohort was school children aged between eight and 15 years. The Kato-Katz technique and filtration were used for Schistosoma mansoni and S. haematobium ova research in stools and urine, respectively. The schools and snail breeding sites were georeferenced. Four malacological surveys were conducted between October 2011 and February 2012. Bivariate analysis was used to identify independent predictors of being infected with schistosomiasis. Results The prevalence rate of S. haematobium was 14.7% (n = 1,761) and that of S. mansoni 1.5% (n = 1,491). Overall, the urinary form was endemic in 76.6% of schools. The infection significantly varied between the municipalities (p

Background: Despite the progress made in the control of Neglected Tropical Diseases (NTD), schistosome and soil-transmitted helminth infections are far from being effectively managed in many parts of the world. Chemotherapy, the key element of all control strategies, is faced with some difficulties in terms of access to treatment. Our study aims to describe the factors involved in the success or failure of the community-directed intervention (CDI) approach through control programmes, which aims to achieve consistent high coverage at affordable and sustainable costs in endemic areas. Methods: The CDI approach was carried out from December 2007 to October 2008 in ten villages of the district of Diema, Mali. At inclusion, each child part of the study’s sample was interviewed and submitted for a physical examination. The study focused on: data collection, treatment of the eligible population, evaluation of the treatment coverage, performance of community drug distributors (CDDs), and the involvement and perception of populations. Results: A total of 8,022 eligible people were studied with a mean coverage rate of 76.7%. Using multiple regression, it was determined that receiving praziquantel as treatment was associated with five factors: belonging to the Fulani or Moorish ethnic minority versus the Bambara/Soninke, use of the central versus the house-to-house drug distribution mode, the ratio of the population to the number of CDDs, the lack of supervision and belonging to the age group of 15 years or above (p

Background Regulatory T cells (Tregs) suppress host immune responses and participate in immune homeostasis. In co-infection, secondary parasite infections may disrupt the immunologic responses induced by a pre-existing parasitic infection. We previously demonstrated that schistosomiasis-positive (SP) Malian children, aged 4–8 years, are protected against the acquisition of malaria compared to matched schistosomiasis-negative (SN) children. Methods and Findings To determine if Tregs contribute to this protection, we performed immunologic and Treg depletion in vitro studies using PBMC acquired from children with and without S. haematobium infection followed longitudinally for the acquisition of malaria. Levels of Tregs were lower in children with dual infections compared to children with malaria alone (0.49 versus 1.37%, respectively, P = 0.004) but were similar months later, during a period with negligible malaria transmission. The increased levels of Tregs in SN subjects were associated with suppressed serum Th1 cytokine levels, as well as elevated parasitemia compared to co-infected counterparts. Conclusions These results suggest that lower levels of Tregs in helminth-infected children correlate with altered circulating cytokine and parasitologic results which may play a partial role in mediating protection against falciparum malaria.

Millions of humans are exposed to schistosome infections, which cause severe kidney and liver disease and 280,000 deaths annually. Th2-mediated immunity is critical to human defenses against this pathogen and susceptibility to infection is controlled by a major genetic locus that includes IL4, IL5, and IL13 genes. These observations led us to evaluate whether certain polymorphisms in IL4, IL5, or IL13 determine schistosome infection. The study was performed in two Dogon villages where Schistosoma haematobium is endemic. Schistosome infections were evaluated by counting eggs and measuring worm Ags in urine. Genetic polymorphisms were determined by restriction enzyme analysis or by primer extension and denaturing high-performance liquid chromatography analysis. Associations were tested using family-based association tests and logistical regression analysis. The alleles IL13-1055C (p = 0.05) and IL13-591A (p = 0.01) are shown, by family-based association test, to be preferentially transmitted to children with the 10% highest infections. A logistic regression analysis that included IL13-1055 G/G, G/T and T/T genotypes, age, gender, and village of residency, applied to the whole study population, showed that subjects bearing the IL13-1055T/T genotype were on average much less infected than individuals with other genotypes. Previous studies on asthma indicated that the IL13-1055T allele increased gene transcription, which is in agreement with the fact that this cytokine enhances resistance to infection by schistosome in humans.

Background. Schistosoma haematobium infection causes severe urinary disease and considerable mortality. The factors that determine disease progression from mild to severe stages are not fully understood. Methods. Here we describe a cross-sectional epidemiological study of kidney and bladder diseases in 2 Dogon populations with different exposure to S. haematobium infection. Results. Early and high exposure resulted in more-severe disease, especially among young subjects, without clear evidence of a more-rapid development of immunity. Nevertheless, 50%-60% of subjects of all age classes in both villages showed no evidence of disease. Kidney and bladder disease peaked biphasically among young subjects and adults >25 years old. The first peak corresponded with infections of maximum intensity, whereas the second peak occurred among adults with infections of very low intensity. Kidney disease was correlated with circulating anodic antigen concentration in serum, whereas bladder disease was correlated with egg count and eosinophil cationic protein concentration in urine. Kidney and bladder disease did not correlate. Severe kidney disease was more frequent in certain families. Conclusions. The frequency of urinary disease is increased by infections acquired early during life, is regulated by strong clinical immunity in certain subjects, and may be dependent on hereditary factors. Kidney and bladder disease may involve different mechanisms of pathogenesis, which may differ between children and adults.

Random amplified polymorphic DNA (RAPD) markers were used to assess distribution and genetic diversity of Schistosoma haematobium populations within their bulinid intermediate hosts in Mali. Naturally infected snails (Bulinus truncatus and B. globosus) were collected at four sites in the Bamako district. S. haematobium cercariae from single snails were used to infect mice and genotypes of the resultant adult worms were characterized using RAPD markers. Diversity indices were calculated at the scale of one snail, both within and among sites. One third of the molluscs harboured multiple miracidial infections (the maximum number equal to five) with slightly overdispersed distributions in three sites and a random distribution at one site. Similarity indices revealed significantly less variation among populations compared to within populations, indicative of the absence of distinct S. haematobium populations within the Bamako district. RAPD markers represent an accurate tool for determining genetic diversity and amount of gene flow among parasite populations contained within different individual snails and among intermediate host populations.

The effect of age, previous intensity of infection, and exposure on reinfection with Schistosoma haematobium after treatment was studied in a cohort of 468 subjects six years of age and over living in an irrigation scheme area in Mali. Prevalence and intensity of S. haematobium infection were measured each year between 1989 and 1991, but the reinfection study period was restricted to the last year of the follow-up. Observations were made at the principal water contact sites where the number of Bulinus truncatus shedding furcocercous cercariae was recorded. A cumulative index of exposure taking into account time, duration and type of contact, and malacologic data was calculated for each subject. Univariate analysis showed that the reinfection risk decreased with age and increased with exposure and pretreatment intensity. These results were confirmed by fitting a logistic model that showed that this risk was seven times lower among those 15 years of age and older than among the 6–14-year-old children, while linear trends with exposure to infection and pretreatment intensity were significant. This study supports the concept of an age-acquired resistance to reinfection and is in favor of a predisposition to infection that raises the question of a genetic factor controlling susceptibility/resistance to S. haematobium infection.

Given their prevalence in recent years, earnings management and financial restatements have been at the center of much of the discussion surrounding corporate malfeasance. This study builds a probability model for predicting the likelihood of earnings restatements by analyzing the trends in and the deviations from the industry averages of the return on assets, accounts receivable turnover, net profit margin, and operating cash flow to net income measures. Data are obtained for a sample of 104 firms (restating as well as non-restating) for the 2000 to 2001 period. The results suggest that deviations from the industry average of the accounts receivable turnover and the variability in the cash flow to net income provide good barometers for detecting fraudulent accounting. Potential restating firms have higher accounts receivable turnover rates than their industry counterparts and downward trends in their cash flow to net income, so an increase (decrease) in the accounts receivable turnover (operating cash flow to net income) significantly increases the likelihood of a restatement, at least in the current study.

Background Mass chemotherapy with praziquantel is the main control strategy for schistosomiasis in Mali. However, in the national control programme for schistosomiasis and soil-transmitted helminthiasis, infants and preschool-aged children are overlooked in preventive chemotherapy campaigns. We therefore determined the prevalence and intensity of urinary schistosomiasis in children between the ages 1-4 years in three villages across Diema health district, a rural community with endemic schistosomiasis in Mali. For Schistosoma haematobium diagnosis, a single urine sample of 10 ml obtained from each child was subjected to the standard urine filtration method. Results Of the 338 children examined 173 (51.2%) were infected. Both prevalence and intensity of infection varied significantly between communities (p < 0.01). There was no significant difference (p = 0.94) in infection rates between boys (51.2%) and girls (50.3%). Likewise, prevalence did not significantly increase with age (p = 0.86). The overall geometric mean of Williams (GMw) was 18.41 eggs/10 ml urine, with no significant association (p = 0.91) between boys (17.48 eggs/10 ml urine) and girls (19.69 eggs/10 ml urine). However, the GMw significantly increased with age (p = 0.04). Infection of preschool children would occur through early exposure to infected water bodies through both passive and active process. Conclusion Our study showed that preschool children living closely to lakes across in Mali are at high risk to be infected by schistosomiasis and contributed largely to the transmission; therefore schistosomiasis control interventions should also target infants in addition to school children and adults in endemic areas.