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In Mali the Anopheles gambiae complex consists of An. arabiensis and Mopti, Savanna and Bamako chromosomal forms of An. gambiae s.s. Previous chromosomal data suggests a complete reproductive isolation among these forms. Sequence analysis of rDNA regions led to the characterization of two molecular forms of An. gambiae, named M-form and S-form, which in Mali correspond to Mopti and to Savanna/ Bamako, respectively, while it has failed so far to show any molecular difference between Savanna and Bamako. The population structure of An. gambiae s.I. was analysed in three villages in the Bamako and Sikasso areas of Mali and the frequency of pyrethroid resistance of the knock-down resistance (kdr) type was calculated. The results show that the kdr allele is associated only with the Savanna form populations and absent in sympatric and synchronous populations of Bamako, Mopti and An. arabiensis. This is the first molecular indication of barriers to gene flow between the Bamako and Savanna chromosomal forms. Moreover, analyses of specimens collected in the Bamako area in 1987 show that the kdr allele was already present in the Savanna population at that time, and that the frequency of this allele has gradually increased since then. [ABSTRACT FROM AUTHOR]

Presents a study that inquired into the question of geographic population genetic structure for microsatellite DNA loci. Chromosomal forms of the genetic structure of Anopheles gambiae sensu stricto in Mali, West Africa; Correlation between the distances of suitable habitat and differences in microsatellite allele frequencies; Differences in microsatellite allele frequencies between populations of Anopheles gambiae in Kenya and Senegal.

Abstract Anopheles gambiae populations in west Africa are complex, being composed of multiple, sympatric subpopulations. Recent studies have failed to reveal significant genetic differences among subpopulations, stimulating a debate regarding the levels of gene flow among them. The observed homogeneity may be the consequence of substantial contemporary gene flow or it may be that reproductive isolation is complete, but too recent for the accumulation of significant levels of genic divergence. Here, we report the results of a study estimating contemporary levels of gene flow between An. gambiae subpopulations by analysing females and transferred sperm removed from their reproductive systems. A total of 251 female and associated sperm extracts was analysed from a single site in Mali. Two molecular forms of An. gambiae, the M- and S-forms, occurred in sympatry at this site. Overall, we found very strong positive assortative mating within forms, however, we did observe significant hybridization between forms. In the M subpopulation 2/195 females (1.03%) contained sperm from S-form males and in 55 S-form females we found one female containing M-form sperm (1.82%). We also identified a mated M ×S hybrid adult female. From mating frequencies, we estimate the Nem between the M- and S-form at 16.8, and from the adult hybrid frequency at 5.6. These values are consistent with our earlier estimate, based on FST for 21 microsatellite loci in which Nem = 5.8. We conclude that the general lack of genetic divergence between the M and S subpopulations of An. gambiae can be explained entirely by contemporary gene flow. [ABSTRACT FROM AUTHOR]

Abstract Background Maps of the distribution of malaria vectors are useful tools for stratification of malaria risk and for selective vector control strategies. Although the distribution of members of the Anopheles gambiae complex is well documented in Africa, a continuous map of the spatial distribution of the chromosomal forms of An. gambiae s.s. is not yet available at country level to support control efforts. Methods Bayesian geostatistical methods were used to produce continuous maps of the spatial distribution of the chromosomal forms of An. gambiae s.s. (Mopti, Bamako, Savanna and their hybrids/recombinants) based on their relative frequencies in relation to climatic and environmental factors in Mali. Results The maps clearly show that each chromosomal form favours a particular defined eco-climatic zone. The Mopti form prefers the dryer northern Savanna and Sahel and the flooded/irrigated areas of the inner delta of the Niger River. The Savanna form favours the Sudan savanna areas, particularly the South and South-Eastern parts of the country (Kayes and Sikasso regions). The Bamako form has a strong preference for specific environmental conditions and it is confined to the Sudan savanna areas around urban Bamako and the Western part of Sikasso region. The hybrids/recombinants favour the Western part of the country (Kayes region) bordering the Republic of Guinea Conakry. Conclusion The maps provide valuable information for selective vector control in Mali (insecticide resistance management) and may serve as a decision support tool for the basis for future malaria control strategies including genetically manipulated mosquitoes.

Abstract Introduction The associations between the immatures of Anopheles gambiae s.s. (Diptera: Culicidae), its M and S forms, and Anopheles arabiensis among and within larval breeding habitats in Banambani, Mali were investigated under varying conditions of water quality and rainfall. The intent was to elucidate on niche partitioning of these taxa. Methods Immatures of An. arabiensis, An. gambiae s.s., and its M and S forms were sampled every alternate day for a month in mid-rainy season from three sampling sites in each of the larval breeding habitats (rock pools, swamp, and puddles). Water quality was characterized by alkalinity, conductivity, dissolved oxygen (D.O.), nitrate, orthophosphate, pH, temperature, total dissolved solids (TDS), and turbidity. A type 3 analysis of the GENMOD model was used to examine the associations between the proportional frequencies of young (first and second instar larvae) and old (third and fourth instar larvae and pupae) or total immatures of species or forms among sampling sites within and among larval breeding habitats during a category of rainfall as influenced by water quality. Results Of the 4,174 immatures sampled, 1,300 were molecularly identified to species and forms. Significant association between the proportional frequencies of young larvae of An. arabiensis, An. gambiae s.s., its M and S forms was found among sampling sites within habitats but not among larval breeding habitats. The proportional frequencies of young larvae of M and S forms varied daily perhaps due to recruitment, mortality, and dispersal within habitats. Conductivity and TDS had significant effects when the proportional frequencies of young larvae of M and S forms among sampling sites within habitats were significantly associated. Alkalinity, D.O., orthophosphate, pH, nitrate, temperature and turbidity had no effects on niche partitioning of species and forms among sampling sites within habitats. Rainfall did not affect the frequencies of these immatures. Conclusion Conductivity and TDS have significant effects on niche partitioning of young larvae of M and S forms among sampling sites within habitats in Banambani, Mali.

Cervical cancer (CC) remains a real public health problem in low- and middle-income countries, where technical resources and competent personnel are insufficient. Persistent cervix infection by high-risk human papillomavirus (Hr-HPV) is the main cause of CC development. In the current study, we examined the distribution of Hr-HPV in the general healthy Malian population using cervicovaginal self- sampling. A total of 354 women were recruited, with a median age of 34 ± 11.37 years, IQR (27-43). We found that 100% of participants agreed to self-sample at the health center. For result announcement 99.2% expressed their preference to be contacted by cell phone. Furthermore, 100% of study participants showed their willingness to undergo confirmatory CC test in case of Hr-HPV test proved positive, and to receive treatment in the event of the presence of cervical lesions. The overall prevalence of Hr-HPV was 21.2% (95% CI: 17-25.8). HPV31/35/33/52/58 with 11.9% (95% CI: 8.7-15.7) and HPV39/68/56/66 with 5.9% (95% CI: 3.7-8.9) were the most common Hr-HPV subtypes. We noted that Hr-HPV genotypes were more prevalent among women under 25 years, 36.1% (N = 61). In addition, the distribution of Hr-HPV was statistically associated with age, W = 12,374, p = 0.015. Our data showed that 25.3% (N = 19) of Hr-HPV-positive women were tested positive by VIA/VILI. Among the 19 VIA/VILI-positive women, histological examination showed that 4 were CIN1, 4 were CIN2, and 2 were CIN3 grades. In addition, the median age of participants with CIN2 and CIN3 was statistically higher than the median of those with CIN1 grade, 25 years IQR (21-26.75) versus 50 years, IQR (40.25-55), W = 24, p = 0.009. In sum, end-users are very satisfied with the cervicovaginal self-sampling device for identifying HR-HPV genotypes as part of CC screening. In addition, it enables hospital practitioners to take the necessary action after triaging women according to their HR-HPV genotype., Competing Interests: Declarations. Conflict of interest: The authors have not disclosed any competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Long-term exposure to high-risk human papillomavirus (Hr-HPV) is a well-known necessary condition for development of cervical cancer. The aim of this study is to screen for Hr-HPV using vaginal self-sampling, which is a more effective approach to improve women's adherence and increase screening rates., Methods: This pilot study included a total of 100 Women living with HIV (WLWHIV), recruited from the Center for Listening, Care, Animation, and Counseling of People Living with HIV in Bamako. Hr-HPV genotyping was performed on Self-collected samples using the Cepheid GeneXpert instrument., Results: The median age of WLWHIV was 44 (interquartile range [IQR], 37-50) years. Approximately 92% of the study participants preferred self-sampling at the clinic, and 90% opted to receive result notifications via mobile phone contact. The overall prevalence of Hr-HPV among study participants was 42.6%, and the most frequent Hr-HPV sub-types observed were HPV18/45 (19.1%), HPV31/35/33/52/58 (13.8%), and HPV39/68/56/66 (12.8%), followed by HPV16 (5.3%), and HPV51/59 (5.3%). WLWHIV under 35 years of age had a higher frequency of Hr-HPV compared to their older counterparts, with rates of 30% versus 11.1% (p = 0.03). The duration of antiretroviral treatment showed an inverse association with Hr-HPV negativity, with patients on treatment for 15 (IQR, 10-18) years versus 12 (IQR = 7-14) years for Hr-HPV positive patients (95% CI [1.2-5.8], t = 3.04, p = 0.003). WLWHIV with baseline CD4 T-Cell counts below 200 exhibited a higher frequency of Hr-HPV compared to those with baseline CD4 T-Cell counts above 200 (17.9% versus 1.9%, p = 0.009). However, other demographics and clinical factors, such as marital status, age of sexual debut, parity, education, history of abortion, history of preeclampsia, and cesarean delivery, did not influence the distribution of Hr-HPV genotypes., Conclusion: Our findings indicate that WLWHIV under the age of 35 years old exhibited the highest prevalence of Hr-HPV infection, with HPV18/45 being the most prevalent subtype. Additionally, WLWHIV with baseline CD4 T-Cell counts below 200 showed the highest infection rates., (© 2024. The Author(s).)

Methylenetetrahydrofolate reductase (MTHFR) plays a major role in the metabolism of folates and homocysteine, which in turn can affect gene expression and ultimately promote the development of breast cancer. Thus, mutations in the MTHFR gene could influence homocysteine, methionine, and S-adenosylmethionine levels and, indirectly, nucleotide levels. Imbalance in methionine and S-adenosylmethionine synthesis affects protein synthesis and methylation. These changes, which affect gene expression, may ultimately promote the development of breast cancer. We therefore hypothesized that such mutations could also play an important role in the occurrence and pathogenesis of breast cancer in a Malian population. In this study, we used the PCR-RFLP technique to identify the different genotypic profiles of the C677T MTHFR polymorphism in 127 breast cancer women and 160 healthy controls. The genotypic distribution of the C677T polymorphism in breast cancer cases was 88.2% for CC, 11.0% for CT, and 0.8% for TT. Healthy controls showed a similar distribution with 90.6% for CC, 8.8% for CT, and 0.6% for TT. We found no statistical association between the C677T polymorphism and breast cancer risk for the codominant models CT and TT ( p > 0.05). The same trend was observed when the analysis was extended to other genetic models, including dominant ( p  = 0.50), recessive ( p  = 0.87), and additive ( p  = 0.50) models. The C677T polymorphism of MTHFR gene did not influence the risk of breast cancer in the Malian samples., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 Brehima Diakite et al.)

Objectives: The main objective of this study was to evaluate the effect of CYP2B6 and CYP3A4 polymorphisms on the virological and immunologic responses of HIV patients. A total of 153 HIV-positive patients were enlisted for the study., Patients and Methods: Viral load and median CD4 T cell counts were evaluated at baseline and month 6 (M6). Samples were identified using TaqMan genotyping assays., Results: The AG in CYP2B6 rs2279343 was associated with VLS compared to homozygous AA. In the dominant model, the AG/GG genotypes were associated with VLS compared to the AA genotype. Moreover, in overdominant model, the AG genotype was associated with VLS compared to AA/GG. Regarding immunological response, only the AG in SNP rs2279343 CYP2B6 was associated with an increase in CD4 cell count between baseline and M6. In CYP2B6 rs3745274, the CD4 cell count at M6 was higher than that of baseline for GG carriers and for GT carriers. In CYP3A4 rs2740574, the TC carriers showed a higher median CD4 count at M6 compared to that of the baseline count, as well as for CC carriers. The best genotypes combination associated with CD4 cell count improvement were AA/AG in SNP rs2279343 and GG/GT in SNP rs3745274., Conclusion: Our findings support the fact that CYP2B6 rs2279343 could help in the prediction of VLS and both SNPs rs3745274 and rs2279343 in CYP2B6 and CYP3A4 rs2740574 were associated with immune recovery in Malian HIV-positive patients., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

A literature review showed some discrepancies regarding the association of -592C/A with the risk of cervical cancer. To allow more precise analysis of the data by increasing the number of cases studied and more acceptable generalization by considering results from different sources, the present meta-analysis was performed on available published studies that explored the relationship between SNP -592C/A of the IL-10 gene and the risk of cervical cancer. Eleven available studies, including 4187 cases and 3311 controls, were included in this study investigating the relationship between the -592C/A polymorphism of IL-10 and cervical cancer risk. Fixed-effects or random-effects models were performed with pooled odds ratios (ORs). Heterogeneity and bias tests were performed by the inconsistency test and funnel plot, respectively. The overall analysis showed an increased susceptibility to cervical cancer with the -592C/A polymorphism of the IL-10 gene for the recessive model (OR = 1.30, 95% CI = 1.14-1.49), dominant model (OR = 1.36, 95% CI = 1.09-1.70), and additive model (OR = 1.25, 95% CI = 1.09-1.44). Regarding ethnicity, a significant association of the -592C/A polymorphism of the IL-10 gene was linked to an elevated risk of cervical cancer for all genetic models (recessive, dominant, and additive) in the Asian populations and for the recessive and additive models in Caucasians with P < 0.05. The -592C/A polymorphism of the IL-10 gene may be considered a risk factor for cervical cancer., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2022 Brehima Diakite et al.)

Abstract: Cytochrome P450 enzymes play a central role in the phase I biotransformation process of a wide range of compounds, including xenobiotics, drugs, hormones and vitamins. It is noteworthy that these enzymes are highly polymorphic and, depending on the genetic makeup, an individual may have impaired enzymatic activity. Therefore, the identification of genetic variants in these genes could facilitate the implementation of pharmacogenetic studies and genetic predisposition to multifactorial diseases. We have established the frequencies of CYP2B6 (rs3745274; rs2279343) and CYP3A4 (rs2740574) alleles and genotypes in 209 healthy Malian subjects using TaqMan drug metabolism genotyping assays for allelic discrimination. Allele frequencies were 37% for CYP2B6 rs3745274; 38% for CYP2B6 rs2279343; and 75% for CYP3A4 rs2740574 respectively. Overall, the frequencies observed in Mali are statistically comparable to those reported across Africa except North Africa. The major haplotypes in CYP2B6 rs3745274 and CYP2B6 rs2279343 were represented by GA (60.24%) followed by TG (35.36%). We noted a strong linkage disequilibrium between CYP2B6 rs3745274 and CYP2B6 rs2279343 with D' = 0.91 and r2 = 0.9. The frequencies of the genotypic combinations were 43.5% (GT/AG), 37.3% (GG/AA) and 11.5% (TT/GG) in the combination of CYP2B6-rs3745274 and CYP2B6-rs2279343; 26.8% (GT/CC), 25.4%, (GT/CT), 17.2% and GG/CT in the combination CYP2B6-rs3745274-CYP3A4-rs2740574; 26.8% (AG/CC), 23.9% (AA/CC), 19.1% (AG/CT), and 11% (AA/CT) in the combination CYP2B6-rs2279343-CYP3A4-rs2740574, respectively. The most common triple genotype was GT/AG/CC with 24.9%, followed by GG/AA/CC with 23.9%, GT/AG/CT with 16.7%, and GG/AA/CT with 10%. Our results provide new insights into the distribution of these pharmacogenetically relevant genes in the Malian population. Moreover, these data will be useful for studies of individual genetic variability to drugs and genetic predisposition to diseases., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: The effect of the p.Arg72Pro variant of the P53 gene on the risk of development ofbreast cancer remains variable in populations. However, the use ofstrategies such aspoolingage-matched controls with disease may provide a consistent meta-analysis. Our goal was to perform a meta-analysis in order to assess the association of p.Arg72Pro variant of P53 gene with the risk of breast cancer., Methods: Databases such as PubMed, Genetics Medical Literature, Harvard University Library, Web of Science and Genesis Library were used to search articles. Case-control studies with age-matched on breast cancer havingevaluated the genotype frequencies of the TP53 p.Arg72Pro polymorphism were selected. The fixed and random effects (Mantel-Haenszel) were calculated using pooled odds ratio of 95% CI to determine the risk of disease. Inconsistency was calculated to determine heterogeneity among the studies. The publication bias was estimated using the funnel plot., Results: Twenty-one publications with 7841 cases and 8876 controls were evaluated in this meta-analysis. Overall, our results suggested that TP53 p.Arg72Pro was associated with the risk of breast cancer for the dominant model (OR = 1.09, 95% CI = 1.02-1.16, P = 0.01) and the additive model (OR = 1.09, 95% CI = 1.01-1.17, P = 0.03), but not for the recessive model (OR = 1.07, 95% CI = 0.97-1.18, P = 0.19). According to the ethnic group analysis, Pro allele was associated with the risk of breast cancer in Caucasians for the dominant model and additive model (P = 0.02), and Africans for the recessive model and additive model (P = 0.03)., Conclusions: This meta-analysis found a significant association between TP53 p.Arg72Pro polymorphism and the risk of breast cancer. Individuals carrying at least one Pro allele were more likely to have breast cancer than individuals harboring the Arg allele.

Objectives: Breast cancer is the most prevalent cancer and the second leading cause of cancer-related deaths among women after cervical cancer in much of sub-Saharan Africa. This study aims to examine the prevalence and sociodemographic-socioeconomic factors associated with breast cancer screening among women of reproductive age in sub-Saharan Africa., Design: A weighted population-based cross-sectional study using Demographic and Health Surveys (DHS) data. We used all available data on breast cancer screening from the DHS for four sub-Saharan African countries (Burkina Faso, Ivory Coast, Kenya and Namibia). Breast cancer screening was the outcome of interest for this study. Multivariable Poisson regression was used to identify independent factors associated with breast cancer screening., Setting: Four countries participating in the DHS from 2010 to 2014 with data on breast cancer screening., Participants: Women of reproductive age 15-49 years (N=39 646)., Results: The overall prevalence of breast cancer screening was only 12.9% during the study period, ranging from 5.2% in Ivory Coast to 23.1% in Namibia. Factors associated with breast cancer screening were secondary/higher education with adjusted prevalence ratio (adjusted PR)=2.33 (95% CI: 2.05 to 2.66) compared with no education; older participants, 35-49 years (adjusted PR=1.73, 95% CI : 1.56 to 1.91) compared with younger participants 15-24 years; health insurance coverage (adjusted PR=1.57, 95% CI: 1.47 to 1.68) compared with those with no health insurance and highest socioeconomic status (adjusted PR=1.33, 95% CI : 1.19 to 1.49) compared with lowest socioeconomic status., Conclusion: Despite high breast cancer mortality rates in sub-Saharan Africa, the prevalence of breast cancer screening is substantially low and varies gradually across countries and in relation to factors such as education, age, health insurance coverage and household wealth index level. These results highlight the need for increased efforts to improve the uptake of breast cancer screening in sub-Saharan Africa., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Breast cancer, the most common tumor in women in Mali and worldwide has been linked to several risk factors, including genetic factors, such as the PIN3 16-bp duplication polymorphism of TP53. The aim of our study was to evaluate the role of the PIN3 16-bp duplication polymorphism in the susceptibility to breast cancer in the Malian population and to perform a meta-analysis to better understand the correlation with data from other populations., Methods: We analyzed the PIN3 16-bp duplication polymorphism in blood samples of 60 Malian women with breast cancer and 60 healthy Malian women using PCR. In addition, we performed a meta-analysis of case-control study data from international databases, including Pubmed, Harvard University Library, Genetics Medical Literature Database, Genesis Library and Web of Science. Overall, odds ratio (OR) with 95% CI from fixed and random effects models were determined. Inconsistency was used to assess heterogeneity between studies and publication bias was estimated using the funnel plot., Results: In the studied Malian patients, a significant association of PIN3 16-bp duplication polymorphism with breast cancer risk was observed in dominant (A1A2 + A2A2 vs. A1A1: OR = 2.26, CI 95% = 1.08-4.73; P = 0.02) and additive (A2 vs. A1: OR = 1.87, CI 95% = 1.05-3.33; P = 0.03) models, but not in the recessive model (P = 0.38). In the meta-analysis, nineteen (19) articles were included with a total of 6018 disease cases and 4456 controls. Except for the dominant model (P = 0.15), an increased risk of breast cancer was detected with the recessive (OR = 1.46, 95% CI = 1.15-1.85; P = 0.002) and additive (OR = 1.11, 95% CI = 1.02-1.19; P = 0.01) models., Conclusion: The case-control study showed that PIN3 16-bp duplication polymorphism of TP53 is a significant risk factor for breast cancer in Malian women. These findings are supported by data from the meta-analysis carried out on different ethnic groups around the world.

Glutathione S-transferase genes, known to be highly polymorphic, are implicated in the process of phase II metabolism of many substrates, including xenobiotics, anticancer and anti-infective drugs. The detoxification activity is linked to individual genetic makeup. Therefore, the identification of alleles and genotypes in these genes within a population may help to better design genetic susceptibility and pharmacogenetic studies. We performed the present study to establish the frequencies of the GSTM1, GSTT1, and GSTP1 c. 313A > G (rs1695) polymorphisms in 206 individuals of the Malian healthy population. GSTM1 and GSTT1 were genotyped by using multiplex polymerase chain reaction, whereas genotypes of GSTP1 were identified by polymerase chain reaction followed by restriction fragment length polymorphism. The frequencies of GSTM1-null and GSTT1-null genotypes were respectively 24.3 and 41.3%. The observed genotype frequencies for GSTP1 were 25.73% homozygous wild-type AA, 49.03% heterozygous AG and 25.24% homozygous mutant GG. The frequency of GSTP1-A allele was 50.24% versus 49.76% for the GSTP1-G allele. The distribution of these three genes was homogeneous between men and women (p > 0.05). We found no statistical association between the presence of a particular profile of GSTM1 or GSTT1 with the genotypes of GSTP1 (p > 0.05). Nevertheless, we noticed that the majority of the individuals harboring the GSTM1-present or the GSTT1-present harbor also the GSTP1-AG genotype. In addition, the triple genotype GSTM1-present/GSTT1-present/AG was the most frequent with 25.2%. Our findings will facilitate future studies regarding genetic associations of multifactorial diseases and pharmacogenetic, thus opening the way to personalized medicine in our population.

Purpose: To report cases of sexually transmitted infections (STIs) in consultation and evaluate syndromic management., Patients and Methods: We carried out a prospective and descriptive study in patients who had consulted for STI at the urology department of the Gabriel Toure University Hospital from April 2013 to March 2014., HIV cases were not included. The syndromic approach was used., Results: We obtained the following results: 460 cases of STI (Dysuria, Cystitis, Scrotal swelling, Prostatitis). The sex ratio was 20.52 in favor of the male sex. The age group 23-32 years was the most affected, and non-married single patients were the most represented. The majority were Bambara. All cases were diagnosed clinically. Additional tests were requested to confirm the diagnosis. In terms of syndromic management, probabilistic antibiotic therapy was applied to each type of STI. Antibiotic therapy was rehabilitative with an effective therapeutic response in 61.61% of cases for prostatitis, 98.60% for urethritis, 100% for scrotal swelling, 90.78% for cystitis., Conclusion: Management of STIs using the syndromic approach is an option in countries where laboratory diagnosis is not always available., (Le comitée de rédaction se réserve le droit de revoyer aux auteurs avant toute soumission à l'avis des lecteurs les manuscrits qui ne seraient pas conformes à ces modalités de présentation. En outre il leur conseille de sonserver un examplaire du manuscrit, des figures et des tableaux.)

Background: Maps of the distribution of malaria vectors are useful tools for stratification of malaria risk and for selective vector control strategies. Although the distribution of members of the Anopheles gambiae complex is well documented in Africa, a continuous map of the spatial distribution of the chromosomal forms of An. gambiae s.s. is not yet available at country level to support control efforts., Methods: Bayesian geostatistical methods were used to produce continuous maps of the spatial distribution of the chromosomal forms of An. gambiae s.s. (Mopti, Bamako, Savanna and their hybrids/recombinants) based on their relative frequencies in relation to climatic and environmental factors in Mali., Results: The maps clearly show that each chromosomal form favours a particular defined eco-climatic zone. The Mopti form prefers the dryer northern Savanna and Sahel and the flooded/irrigated areas of the inner delta of the Niger River. The Savanna form favours the Sudan savanna areas, particularly the South and South-Eastern parts of the country (Kayes and Sikasso regions). The Bamako form has a strong preference for specific environmental conditions and it is confined to the Sudan savanna areas around urban Bamako and the Western part of Sikasso region. The hybrids/recombinants favour the Western part of the country (Kayes region) bordering the Republic of Guinea Conakry., Conclusion: The maps provide valuable information for selective vector control in Mali (insecticide resistance management) and may serve as a decision support tool for the basis for future malaria control strategies including genetically manipulated mosquitoes.

To explore the feasibility of field sites for malaria vaccine trials, we conducted a prospective study of clinical malaria incidence during two consecutive transmission seasons in children and young adults living in two areas of Mali with different entomologic inoculation rates (EIRs). Approximately 200 subjects (3 months to 2 years of age) were enrolled per site and followed weekly. Malaria smears were performed monthly in all participants and when symptoms or signs of malaria were present. In Sotuba (annual EIR < 15 infective bites per person), the incidence of clinical malaria was comparable across all age groups but varied significantly between the 2 years. In contrast, in Donéguébougou (annual EIR > 100 infective bites per person), incidence rates decreased significantly with increasing age but remained stable between years. Our results suggest that, although the age distribution of clinical malaria depends on transmission intensity, the total burden of disease may be similar or higher in settings of low transmission.

Background: Attempts over the last three decades to reconstruct the phylogenetic history of the Anopheles gambiae species complex have been important for developing better strategies to control malaria transmission., Methodology: We used fingerprint genotyping data from 414 field-collected female mosquitoes at 42 microsatellite loci to infer the evolutionary relationships of four species in the A. gambiae complex, the two major malaria vectors A. gambiae sensu stricto (A. gambiae s.s.) and A. arabiensis, as well as two minor vectors, A. merus and A. melas., Principal Findings: We identify six taxonomic units, including a clear separation of West and East Africa A. gambiae s.s. S molecular forms. We show that the phylogenetic relationships vary widely between different genomic regions, thus demonstrating the mosaic nature of the genome of these species. The two major malaria vectors are closely related and closer to A. merus than to A. melas at the genome-wide level, which is also true if only autosomes are considered. However, within the Xag inversion region of the X chromosome, the M and two S molecular forms are most similar to A. merus. Near the X centromere, outside the Xag region, the two S forms are highly dissimilar to the other taxa. Furthermore, our data suggest that the centromeric region of chromosome 3 is a strong discriminator between the major and minor malaria vectors., Conclusions: Although further studies are needed to elucidate the basis of the phylogenetic variation among the different regions of the genome, the preponderance of sympatric admixtures among taxa strongly favor introgression of different genomic regions between species, rather than lineage sorting of ancestral polymorphism, as a possible mechanism.

In Mali, anopheline mosquito populations increase sharply during the rainy season, but are barely detectable in the dry season. This study attempted to identify the dry season mosquito breeding population in and near the village of Bancoumana, Mali, and in a fishing hamlet 5 km from this village and adjacent to the Niger River. In Bancoumana, most larval habitats were human made, and dried out in January-February. In contrast, in the fishing hamlet, productive larval habitats were numerous and found mainly during the dry season (January-May) as the natural result of drying riverbeds. Adult mosquitoes were abundant during the dry season in the fishermen hamlet and rare in Bancoumana. To the extent that the fishermen hamlet mosquito population seeds Bancoumana with the advent of the rainy season, vector control in this small hamlet may be a cost-effective way to ameliorate malaria transmission in the 40-times larger village.

Irrigation for rice cultivation increases the production of Anopheles gambiae, the main vector of malaria in Mali. Mosquito abundance is highly variable across villages and seasons. We examined whether rice cultivation patterns mapped using remotely sensed imagery can account for some of this variance. We collected entomologic data and mapped land use around 18 villages in the two cropping seasons during two years. Land use classification accuracy ranged between 70% and 86%. The area of young rice explained 86% of the inter-village variability in An. gambiae abundance in August before the peak in malaria transmission. Estimating rice in a 900-meter buffer area around the villages resulted in the best correlation with mosquito abundance, larger buffer areas were optimum in the October and dry season models. The quantification of the relationship between An. gambiae abundance and rice cultivation could have management applications that merit further study.

The type of water management and drainage system could be a potential reason for variation in malaria transmission in rice cultivation areas. To investigate this we have compared the population dynamics of Anopheles mosquitoes (Diptera, Culicidae) in rice plots with controlled and uncontrolled water depth, i.e. casiers and hors-casiers, respectively in the Office du Niger, Mali. We also compared malaria transmission in areas with mixed and casiers plots. Larval collection was performed fortnightly with the standard WHO dipping technique. Adult Anopheles were collected both by pyrethrum spray and landing catches. During the dry season rice cultivation cycle, the larval density in the hors-casier was significantly higher than in the casier plots. The larval peak in the casier plots was considerably smaller than the one in the hors-casier. During the rainy season, no significant difference was observed between the two plot types. However, larval densities begin to rise approximately one month earlier in the casier then in the hors-casier plots, and continued to increase trough the rice development phases until the grain filling/maturation phase, declining thereafter. In contrast, in the hors-casier rice plots larval density increased throughout the rice development. This difference was not significantly reflected in the adult vector density and man biting rate. However, high relative frequencies of Anopheles funestus, survival and entomological inoculation rates of An. gambiae s.l. were observed in the mixed plot sector.

Studies aimed at monitoring the spread of knockdown resistance to pyrethroids (kdr) in time and space are particularly useful for detecting barriers to gene flow among the chromosomal and molecular forms of Anopheles gambiae. We used a recently developed polymerase chain reaction assay to estimate changes in kdr frequency that occurred in several mixed-form populations from Mali, West Africa, in the past decade. We found that the kdr allele significantly increased in frequency in most populations but was still absent from the M molecular form. Importantly, within the S molecular form, kdr was detected for the first time in the Bamako chromosomal form. These results provide important insights on the patterns of spread and emergence of pyrethroid knockdown resistance in West Africa.

The genome sequences for many insects vector of human diseases are now available and promise the development of a set of new, powerful tools that can be used to develop innovative approaches to control these diseases. The African continent, which is the most severely affected by vector borne diseases, lacks adequate infrastructures and personal resources required for rational use of genomic information. To fill this gap, the African Center for Training in Functional Genomics of Insect vectors of Human Disease (AFRO VECTGEN) was initiated by WHO/TDR and the Department of Medical Entomology and Vector Ecology (DMEVE) of the Malaria Research and Training Center (MRTC) in Mali. The aim of the AFRO VECTGEN program is to train young scientists in functional genomics who will ultimately use genome sequence data for research on insect vector of human disease. The program could trigger collaborative research and will benefit from an existing vector biology network in Mali, which was built around research grants funded by the National Institutes of Health, USA and WHO/TDR.

Genetic differentiation between the largely sympatric molecular forms M and S of Anopheles gambiae appears mostly limited to division 6 and part of division 5 of the X chromosome. This region is adjacent to the centromere and includes the rDNA that was used to define these forms. This localized differentiation between populations that experience gene flow strongly suggests that this region contains genes responsible for reproductive isolation. Regions adjacent to centromeres are known to experience less recombination in several species and it has recently been suggested that low recombination rates can facilitate the accumulation and maintenance of isolation genes in partially isolated populations. Therefore, we measured the recombination rate in division 5D/6 directly and estimate that it is at least 16-fold reduced across this region compared to the remainder of the X chromosome. Additionally, sequence data from four loci from field-collected mosquitoes from several West African countries show very strong differentiation between the molecular forms in division 5D/6, whereas none was observed in two loci elsewhere on the X chromosome. Furthermore, genetic variation was substantially lower in division 5D/6 compared to the two reference loci, and the inferred genealogies of the division 5D/6 genes show patterns consistent with selective sweeps. This suggests that the reduced recombination rate has increased the effect of selection on this region and that our data are consistent with the hypothesis that reduced recombination rates can play a role in the accumulation of isolation genes in the face of gene flow.

Introduction: The associations between the immatures of Anopheles gambiae s.s. (Diptera: Culicidae), its M and S forms, and Anopheles arabiensis among and within larval breeding habitats in Banambani, Mali were investigated under varying conditions of water quality and rainfall. The intent was to elucidate on niche partitioning of these taxa., Methods: Immatures of An. arabiensis, An. gambiae s.s., and its M and S forms were sampled every alternate day for a month in mid-rainy season from three sampling sites in each of the larval breeding habitats (rock pools, swamp, and puddles). Water quality was characterized by alkalinity, conductivity, dissolved oxygen (D.O.), nitrate, orthophosphate, pH, temperature, total dissolved solids (TDS), and turbidity. A type 3 analysis of the GENMOD model was used to examine the associations between the proportional frequencies of young (first and second instar larvae) and old (third and fourth instar larvae and pupae) or total immatures of species or forms among sampling sites within and among larval breeding habitats during a category of rainfall as influenced by water quality., Results: Of the 4,174 immatures sampled, 1,300 were molecularly identified to species and forms. Significant association between the proportional frequencies of young larvae of An. arabiensis, An. gambiae s.s., its M and S forms was found among sampling sites within habitats but not among larval breeding habitats. The proportional frequencies of young larvae of M and S forms varied daily perhaps due to recruitment, mortality, and dispersal within habitats. Conductivity and TDS had significant effects when the proportional frequencies of young larvae of M and S forms among sampling sites within habitats were significantly associated. Alkalinity, D.O., orthophosphate, pH, nitrate, temperature and turbidity had no effects on niche partitioning of species and forms among sampling sites within habitats. Rainfall did not affect the frequencies of these immatures., Conclusion: Conductivity and TDS have significant effects on niche partitioning of young larvae of M and S forms among sampling sites within habitats in Banambani, Mali.

The main vector of malaria in sub-Saharan Africa, Anopheles gambiae, is subdivided into five chromosomal forms. Three of them (i.e., BAMAKO, SAVANNA, and MOPTI) are found in sympatry in Mali, where MOPTI can be distinguished from the other two forms based on differences in the ribosomal DNA locus. However, no molecular markers are available to distinguish BAMAKO from SAVANNA. We examined the banding patterns of 139 amplified fragment length polymorphism primer combinations in an attempt to identify diagnostic differences between SAVANNA and BAMAKO. Despite screening > 10,000 bands, no diagnostic differences were found. However, additional AFLP analyses indicated that BAMAKO is genetically differentiated from SAVANNA, with a significant Phi(st) value of 0.072. This could indicate that gene flow between these forms is restricted in at least some portion of the genome and the lack of identifiable fixed differences between the two forms is probably due to their recent origin.

Anophelism without malaria has long been recognized. In large irrigation projects, such as that around Niono, Mali, villages in irrigated areas sometimes have more anopheline vectors of malaria than adjacent nonirrigated villages, but overall malaria prevalence is substantially less. One hypothesized explanation for this is high anopheline densities lead to smaller adults, who do not live so long and hence are less efficient at transmitting the disease. We analyzed serial collections from 18 villages in an irrigated area of Mali, measuring correlations between mosquito densities and survival rates, zoophilic rates, and vectorial capacity over the villages and times. Adult density was inversely related to anthropophily and adult survival and its relationship with vectorial capacity was positive at low mosquito densities, flat at intermediate densities, and negative at high densities. This may partly explain why malaria prevalence is low in irrigated villages with high Anopheles density.

We compared malaria indicators among sympatric groups to study human heterogeneities in the response to Plasmodium falciparum malaria infection. Four cross-sectional surveys and two longitudinal surveys in two sympatric ethnic groups (Dogon and Fulani) in Mali were carried out from 1998 to 2000. Spleen and parasite rates were evaluated during the cross-sectional surveys and disease incidence was assessed during longitudinal surveys. In spite of similar sociocultural factors and entomologic inoculation rates between ethnic groups, the Fulani had a significantly higher spleen enlargement rate, lower parasite rate, and were less affected by the disease than the Dogon group, whose frequency of hemoglobin C was higher than that recorded among the Fulani group. The Fulani group had significantly higher levels of IgG and IgE against crude malaria antigen than the Dogon group, suggesting a role of anti-malaria antibodies in the immune protection seen in this group.

Malaria control projects based on the introduction and spread of transgenes into mosquito populations depend on the extent of isolation between those populations. On the basis of the distribution of paracentric inversions, Anopheles gambiae has been subdivided into five subspecific chromosomal forms. Estimating gene flow between and within these forms of An. gambiae presents a number of challenges. We compared patterns of genetic divergence (F(ST)) between sympatric populations of the Bamako and Mopti forms at five sites. We used microsatellite loci within the j inversion on chromosome 2, which is fixed in the Bamako form but absent in the Mopti form, and microsatellites on chromosome 3, a region void of inversions. Estimates of genetic diversity and F(ST)'s suggest genetic exchanges between forms for the third chromosome but little for the j inversion. These results suggest a role for the inversion in speciation. Extensive gene flow within forms among sites resulted in populations clustering according to form despite substantial gene flow between forms. These patterns underscore the low levels of current gene flow between chromosomal forms in this area of sympatry. Introducing refractoriness genes in areas of the genome void of inversions may facilitate their spread within forms but their passage between forms may prove more difficult than previously thought.

Severe anemia is one of the major complications of malaria in Africa. We studied 2 populations, one in a village and the second in a periurban area in Mali, to understand the preventable factors in the disease. The 2 correlates of disease were parasitemia above 100 000 parasitized red blood cells per microliter (0.1 x 10(12)/L) and a low baseline hemoglobin level. All cases of moderate to severe anemia occurred in children under 3.2 years of age. Raising the baseline hemoglobin level and lowering peak parasitemia in infants and young children may reduce the incidence of severe anemia resulting from malarial infection.

We observed the survivorship and distribution of larvae and pupae of Anopheles gambiae s.l. Giles immature stages in three habitats (rock pools, swamp, and puddles) in Banambani village. Mali, West Africa, during the mid-rainy season of 2000. Horizontal life tables were constructed for immatures in the laboratory. Times spent in the various immature stages were determined, and laboratory survival was measured. Vertical life tables were obtained from each habitat. We found large day-to-day variation for age class composition within habitats across days. The swamp samples had small but statistically significant different distributions in some instar stages compared with rock pools and puddles as affected by precipitation history. There were obviously unstable age distributions in the swamp and puddles and to some extent in rock pools. There were more individuals in some later age classes than in earlier ones. The daily survival estimates using an exponential decay model were 0.807 in rock pools, 0.899 in the swamp, 0.818 in puddles, and 0.863 in the overall village. Possible reasons for the departure from stable age distribution were cannibalism, predation and other complex interactions, rainfall effects, sampling bias, and differences in physicochemical properties of the water in the habitats.

Recent advances have demonstrated that, in the absence of postmating barriers to hybridization, reproductive isolation between different forms of Anopheles gambiae sensu stricto is maintained by strong assortative mating. The forms of An. gambiae s.s. and the sister species An. arabiensis commonly form mixed swarms in which they mate. This raises the question as to how individuals recognize mates of their own species or form within swarms. It has been proposed that wingbeat frequency is used as a cue to discriminate potential mates. This has important implications for prospective genetic control programs. We used a photosensor to record the transient waveforms generated by individuals An. arabiensis and from the M and S molecular forms of An. gambiae s.s. as they flew through a beam of light. We found no significant between-species or between-form differences in the fundamental harmonic--equivalent to wingbeat frequency--either in males or females collected from sympatric populations in Mali, West Africa. However, there were significant differences in the amplitude of the first and third harmonics in females and of the first and second harmonics in males. Whereas these results suggest some morphological or behavioral differences between species and forms, the extensive overlap in the distributions of harmonic amplitudes does not point to them as reliable cues for assortative mating. Combining all waveforms parameters into a discriminant analysis did not yield characteristic scores either for males or females. Thus, our results do not support the wingbeat hypothesis of premating isolation in the An. gambiae complex.

Seven cross-sectional entomological surveys were carried out from September 1995 to February 1998 in three irrigated rice growing villages and three villages without irrigated agriculture in the area surrounding Niono, located 350km north-east of Bamako, Mali. The transmission pattern differed markedly between the two zones. In the irrigated zone, the transmission of malaria was fairly constant over the seasons at a low level. In the non-irrigated zone, transmission was mostly below detection level during the dry season, whereas it was high toward the end of the rainy season. In the irrigated zone, high densities of mosquitoes were correlated with low anthropophily, low sporozoite indices and probably low survival rates. In the non-irrigated zone, mosquito densities were lower and these relationships were less pronounced. Differential use of mosquito nets in the two zones may have been an important factor in the observed differences in transmission. The presence of cattle may also have played an important role. Two mosquito-catching methods (human landing catch and spray catch) were compared.

We investigated the frequencies of single and multiple matings in field-collected female Anopheles gambiae by conducting microsatellite DNA analyses on the sperm contained within their spermatheca. Amplifcation by a polymerase chain reaction (PCR) at four loci allowed the detection of sperm extracts exhibiting more than two alleles per locus, thereby revealing the occurrence of multiple inseminations. Polyandry was found in six of 239 females examined, or 2.5% of the samples. Previous analyses of the molecular form of the sperm and female extracts using a PCR-based diagnostic procedure showed that two of these multiple inseminations involved cross-mating between two chromosomal/molecular forms of An. gambiae s.s. Thus polyandry occurred within-form in 1.7% of examined females while other multiple inseminations may be linked to processes of reproductive isolation between forms of An. gambiae.