BACKGROUND:Malaria prevention in Senegal includes the use of Seasonal Malaria Chemoprevention with sulfadoxine-pyrimethamine plus amodiaquine. Prolonged use of sulfadoxine-pyrimethamine, however, can select for mutations in the Plasmodium falciparum mutations in pfdhfr and pfdhps genes. METHODS:We analyse dried-blood-spot samples collected during therapeutic-efficacy studies in two SMC districts (Kolda, Kédougou) between 2020 and 2023. Using targeted amplicon deep sequencing we determine the prevalence of pfdhfr and pfdhps mutations by year and site. RESULTS:The pfdhfr triple mutant genotype (N51I + C59R + S108N) is near-fixed in the parasite population ( > 90 %). The pfdhps A437G mutation is also common (47-100 %). The K540E mutation is absent in 2020 and appears only sporadically thereafter-14 % of Kédougou isolates in 2021 (1/7), 5.4 % in Kolda and 2.1 % in Kédougou in 2022, and <2 % in both sites in 2023. The A581G mutation emerges in 2022 (8.1 % in Kolda) and rises to 14.9 % in Kolda and 6.5 % in Kédougou by 2023. Mutation frequencies are similar in children ≤ 5 years and 6-10 years. CONCLUSIONS:After a decade of seasonal chemoprevention, P. falciparum in southern Senegal carries multiple genetic markers associated with resistance to sulfadoxine-pyrimethamine, including a recent increase in the pfdhps A581G mutation to over 10 %. Although the sulfadoxine-pyrimethamine plus amodiaquine regimen remains clinically effective, the growing frequency of pfdhps A581G mutation warrants close monitoring.

Background: Artemisinin-based combination therapies (ACTs) remain the cornerstone of malaria treatment in Africa. However, the emergence of Plasmodium falciparum artemisinin partial resistance associated with mutations in the pfk13 gene in Southeast Asia and East Africa raises concern about its potential emergence or spread to West Africa. This study aimed to investigate whether therapeutic efficacy study (TES)-defined treatment failures in Senegal are associated with pfk13 mutations using targeted amplicon deep sequencing (TADS). Methods: A total of 182 P. falciparum isolates collected during TES conducted between 2020 and 2022 in Senegal were analyzed. These included paired Day 0 (D0)/Day of Failure (DF) samples (n=112) and additional D0 samples (n=70) analyzed in pools. The pfk13 gene was sequenced using TADS, and single nucleotide polymorphisms (SNPs) were identified and compared with WHO-validated artemisinin resistance markers. Results: Among the 182 samples, 23 SNPs were identified in the pfk13 gene, including both synonymous and non-synonymous variants. Six non-synonymous mutations (D547Y, V566L, A578S, V589I, E596D, and V637I) were detected at very low within-sample allele frequencies (<1%). None corresponded to validated or candidate artemisinin resistance-associated mutations. Analysis of paired D0/DF samples showed no enrichment or selection of pfk13 mutations in post-treatment samples, indicating that observed treatment failures were not associated with pfk13 -mediated artemisinin resistance. Conclusion: This study provides no evidence of pfk13 -mediated artemisinin resistance in Senegal between 2020 and 2022. The absence of validated resistance mutations and the lack of association between pfk13 variants and treatment failure support the continued efficacy of ACTs in this setting. These findings highlight the importance of integrating TES outcomes with genomic surveillance to detect early signals of resistance and inform malaria control strategies in West Africa.

BACKGROUND:Chronic pulmonary aspergillosis (CPA) is a significant, yet often overlooked, sequela of pulmonary tuberculosis (TB), particularly in resource-limited settings. Data on the seroprevalence of Aspergillus infection in Senegal is absent, and diagnostic capacity is limited. This study aimed to determine the seroprevalence of Aspergillus-specific antibodies among patients with a history of TB in Senegal and to evaluate the performance of a Rapid Diagnostic Test (RDT) against an Enzyme-Linked Immunosorbent Assay (ELISA). METHODS:A cross-sectional study was conducted between April 30 to August 31, 2025 at two health centers in Senegal: Wakhinane and Yeumbeul among patients presenting with chronic respiratory symptoms. After obtaining informed consent from adult participants or from parents/guardians for minors, a blood sample was collected from each participant and tested for Aspergillus antibodies using both a rapid diagnostic test (RDT) and an ELISA. Results were classified as positive, negative, invalid, or not tested. Prevalence and agreement between the two assays were calculated using valid results only. Demographic data were collected, and descriptive statistics with test performance analyses were conducted. RESULTS:The overall seroprevalence was significantly higher by ELISA (11.9%; 38/320) than by RDT (5.5%; 11/201). Site-specific analysis revealed disparities: Wakhinane showed higher RDT positivity (4.5% vs. 1.0%), while Yeumbeul had higher ELISA positivity (13.5% vs. 11.2%). The cohort was predominantly male (66.0%) with a median age of 30 years. ROC analysis of the ELISA identified an optimal threshold that balanced sensitivity (78%) and specificity (89%). CONCLUSION:This study provided the first serological evidence of substantial Aspergillus antibody prevalence among post-TB patients in Senegal, suggesting a significant burden of undiagnosed CPA. The higher sensitivity of ELISA makes it essential for surveillance and confirmation, while the RDT's practicality offers a viable option for initial screening in peripheral clinics. These findings underscored the urgent need to integrate CPA diagnosis into routine post-TB care and to strengthen fungal diagnostic capacity in West Africa.

Abstract Background Healthcare-associated infections (HAIs) remain a major challenge in ICUs, especially in low- and middle-income countries, with limited data on bacterial colonization and antimicrobial resistance. Methods A prospective observational study was conducted in the ICU of Dalal Jamm National Hospital, Dakar, Senegal, from March 2023 to April 2024. Adult patients hospitalized >48 hours were included. Clinical data, invasive device exposure, microbiological findings, and antimicrobial susceptibility were analyzed. Nasal and rectal screening assessed bacterial colonization. Results Among 70 patients, HAI prevalence was 14.3%. Pneumonia (45%), urinary tract infections (27%), and bloodstream infections (18%) predominated, mainly associated with invasive devices. Gram-negative bacilli were most frequent, with Klebsiella pneumoniae (28%) leading. Multidrug resistance affected 46% of isolates. Gastrointestinal colonization was mainly by ESBL-producing Escherichia coli, nasal carriage by Staphylococcus aureus. Colonization-infection concordance was 20%. Conclusions HAIs remain frequent in this ICU, closely linked to invasive care and multidrug-resistant bacteria. Bacterial colonization is an important reservoir for subsequent infections.

Onchocerciasis remains a major public health problem in sub-Saharan Africa, despite decades of control efforts. In Senegal, transmission was historically focal but intense along the Gambia and Falémé river basins in the southeast of the country. Building on the legacy of the Onchocerciasis Control Programme and the African Programme for Onchocerciasis Control, Senegal implemented long-term community-directed mass drug administration (MDA) with ivermectin, aiming to interrupt local transmission and progress towards elimination. A retrospective descriptive analysis was conducted based on data from the Senegalese National Onchocerciasis Control Programme between 1998 and 2022. Annual MDA reports were used to estimate geographical and therapeutic coverage across endemic districts. Epidemiological impact was assessed through serial parasitological surveys (skin snips), entomological pool-screen PCR of Simulium blackflies, and Ov16 IgG4 ELISA performed on dried blood spots collected from children aged 5–9 years in the Gambia and Falémé river basins. These data were interpreted against WHO thresholds for stopping MDA and for verification of elimination. From 1998 onwards, geographical coverage rapidly reached 100

Drug resistance in Plasmodium falciparum threatens to undermine malaria control and elimination efforts. Senegal is a malaria-endemic country that has implemented successive antimalarial and chemopreventive drug-based strategies for two decades. Sulfadoxine-pyrimethamine (SP) is used for chemoprevention in Senegal for intermittent preventive treatment in pregnancy (since 2004) and SP plus amodiaquine (AQ) is used for seasonal malaria chemoprevention (SMC, since 2013). Using whole genome sequence (WGS) data from malaria patient samples from health facilities across Senegal (2006 – 2022), we observed near fixation of Pfdhfr triple mutant and fluctuation in Pfdhps and Pfcrt mutation frequencies over time. It is unclear how these mutations influence drug resistance and fitness phenotypes in natural isolates; therefore, we evaluated natural parasite isolates with different Pfcrt, Pfmdr1, Pfdhps , and Pfdhfr haplotypes. Parasites were culture-adapted and phenotyped for antimalarial drug susceptibility and competitive growth (fitness). Pfcrt CVIET + A220S + Q271E + N326S + R371I and Pfcrt CVIET + A220S + Q271E + I356T + R371I mutants were significantly more resistant to monodesethyl-amodiaquine (md-AQ) compared to Pfcrt wild-type (WT) and Pfcrt CVIET + A220S + Q271E + R371I mutants. Pfdhfr triple mutants were significantly more pyrimethamine (PYR) resistant than Pfdhfr WT and revealed a range of phenotypes, but this was not explained by Pfgch1 copy-number. Pfdhps A437G parasites were significantly more sulfadoxine (SDX) resistant compared to Pfdhps wild-type and Pfdhps S436A mutants, suggesting that A437G is a key mutation for SDX resistance. Competitive growth assays between Pfdhfr-Pfdhps mutants revealed that Pfdhps mutations do not always result in fitness costs. Ongoing phenotypic assessment and genetic validation of these mutations in a Senegalese background is necessary to assess the impact of drug pressure, identify evolving genetic determinants of drug resistance, and provide molecular markers for ongoing surveillance to monitor and guide the use of drug-based interventions. AUTHOR SUMMARY Drug resistance is a major concern for both preventing and treating malaria, especially in Africa where most malaria cases and deaths occur. Since 2013, Senegal has been giving children under 10 years old a combination of sulfadoxine-pyrimethamine plus amodiaquine to prevent malaria during the transmission season, called Seasonal Malaria Chemoprevention (SMC), and plans to continue expanding its use. However, there is evidence from genetic surveillance that drug resistance mutations are present in Senegal which could render this antimalarial drug combination ineffective. Here we use natural P. falciparum isolates obtained from Senegalese patients that represent the extant parasite population to evaluate the consequences of evolving mutations on antimalarial drug resistance and fitness phenotypes. This study is one of the first to use natural parasites to assess the impact of naturally derived mutations on drug resistance and fitness phenotypes. Our results provide evidence that certain combinations of drug resistance mutations impact both parasite drug resistance and fitness, and therefore need to be closely monitored and can inform optimal antimalarial combinations for the prevention or treatment of malaria. This work informs the ongoing evolution of resistance and fitness phenotypes in malaria endemic settings that are introducing new multi first line therapies (MFTs) and SMC interventions that have been used for decades in Senegal. Our approach creates a framework for using genetic surveillance data to form a hypothesis, which can then be phenotypically tested by measuring the resistance and fitness levels of genetically diverse natural parasite isolates. ### Competing Interest Statement The authors have declared no competing interest. Gates Foundation, https://ror.org/0456r8d26, INV-003442, INV-049909, OPP1156051 National Institute of Allergy and Infectious Diseases, https://ror.org/043z4tv69, R21AI141843, 5R01AI099105, 5R01AI169892

The investigation of the fungal etiologies of otomycoses is a rare occurrence in Senegal. The present study aspires to ascertain the profile of these mycoses within the confines of Ziguinchor. Conducted from 3 February 2021 to 31 August 2022, this retrospective descriptive study encompassed a total of 82 patients presenting with clinically suspected otomycosis within the otolaryngology (ENT) department of the Ziguinchor Peace Hospital (ZPH). In this study, two samples were collected from the external auditory canal (EAC) of each patient using sterile swabs. These samples were first observed by direct microscopy and then cultured at 30 °C on Sabouraud chloramphenicol with or without cycloheximide. The identification of the isolates was based on their macroscopic, microscopic, and physiological characteristics. The mycological examination was positive in 70 patients, with a prevalence of 85.37%. The most prevalent fungal isolates were Aspergillus section Nigri (30%), Aspergillus section Flavi (20%), and Candida albicans/Candida dubliniensis (10%). Of the clinical signs examined, auricular pruritus (p = 1.7033 × 10−6) was the only one to demonstrate a positive correlation with the onset of otomycosis. These results indicate that fungal agents play a significant role in the pathogenesis of otitis externa, underscoring the importance of mycological diagnosis in ensuring optimal patient management.

ABSTRACTBackgroundAlthough tinea capitis (TC) is most commonly diagnosed in children, several studies have also shown that it is far from unusual in adults.ObjectivesTo determine the frequency and risk factors of TC in adults in Dakar, Senegal.Patients and MethodsA cross‐sectional study including all patients who visited the Parasitology and Mycology Lab at Aristide Le Dantec University Hospital for suspicion of TC was conducted from 1 January 2015 to 31 December 2019. The diagnosis was performed using conventional techniques.ResultsIn sum, 458 adults were included. The majority (89%) were female. The patients' mean age was 35 ± 12 years (ranges: 18–84). Of the 458, 92 (20%) were confirmed with TC. The frequency trend, by year, showed a significant decrease ranging from 26.3% in 2015 to 19.2% in 2019. By sex, females (20.5%) were more affected than males (17.6%). According to age, the elderly present the highest infestation rate (36.4%). TC was diagnosed alone in 91.3%. T. soudanense (57.6%) was the most common species, followed by M. audouinii (34.8%).ConclusionTC is frequent among adults in Senegal, particularly in women, and the main causal agent is T. soudanense. Its duration seems to indicate a chronic form previously acquired between 1 and 10 years ago. Thus, early management will be essential to avoid epidemic proportions.

Background:Rapid Diagnostic Tests (RDTs) remain the frontline tool for malaria diagnosis, but their performance in detecting low-density infections is variable and poorly characterized at the population level. Objective:This study aimed to evaluate the diagnostic performance of HRP2-based RDTs by integrating high-throughput bead-based HRP2 quantification into school-based malaria surveys. Methods:A cross-sectional study was conducted in three Senegalese districts (Diourbel, Tambacounda, and Kédougou), enrolling 3,748 school-aged children. All participants were tested using RDTs, and dried blood spots were analyzed with a multiplex bead-based HRP2 assay. A Gaussian mixture model was used to classify HRP2 positivity, and logistic regression assessed the relationship between HRP2 concentration and RDT outcome. Results:The overall RDT positivity rate was 7.2%, with marked heterogeneity across districts (Diourbel: 3.0%, Kédougou: 15.9%, Tambacounda: 7.6%). HRP2 concentration was the strongest predictor of RDT positivity (aOR: 14.55 per log10 increase, 95% CI: 11.14-19.00). RDT limits of detection (LOD95) varied significantly: 3.9 ng/mL in Tambacounda, 121.2 ng/mL in Kédougou, and 204.3 ng/mL in Diourbel. Conclusion:RDTs remain a useful surveillance tool, particularly in moderate- to high-transmission settings. However, reduced sensitivity at lower antigen concentrations in hypo-endemic areas highlights the value of complementary high-sensitivity assays for elimination-focused strategies. Future research should explore the application of these integrated diagnostic approaches in regions without seasonal malaria chemoprophylaxis intervention.

The relatively mild impact of COVID-19 in sub-Saharan Africa has raised questions about the role of pre-existing immunity in the region. One hypothesis for this unexpected observation is the presence of pre-existing cross-protective immunity, potentially induced by prior exposure to seasonal and zoonotic coronaviruses. However, the prevalence and functional relevance of such antibodies in the Senegalese population are not fully known. To investigate this, we conducted a cross-sectional seroprevalence study using 822 plasma samples collected in Senegal before (2017-2019) and during (2020-2022) the pandemic, across regions of high (Kédougou) and low (Thiès) malaria endemicity. Samples were screened for anti-SARS-CoV-2 spike 1 IgG using enzyme-linked immunosorbent assay (ELISA), and a subset of the pre-pandemic IgG-positive samples was further tested for neutralizing activity using a surrogate virus neutralization test (sVNT). Pre-pandemic SARS-CoV-2 IgG positivity was 39.1% [34.6 - 43.7]. No significant differences were observed in terms of age, sex, region, or malaria status. However, only 5.1% of pre-pandemic IgG-positive samples showed neutralizing activity, with 1.3% [0.1 - 6.7] in Kédougou and 9.2% [4.5 - 17.8] in Thiès. During the pandemic, IgG seroprevalence increased from the baseline around 40% in 2020 (37.3 % [27.7 - 48.1] in Kedougou and 50%[29.03 - 70.9%] in Thies), peaking near 99% of the study population by 2022 with 98.2% [93.8 - 99.5] in Kedougou and 98.8% [93.6 - 99.7] in Thies. These results indicate widespread pre-pandemic cross-reactivity to SARS-CoV-2 in Senegal, likely driven by exposure to related coronaviruses. However, their poor neutralizing activity implies limited cross-protection. These findings highlight the need for further investigation into the origins, nature, and immunological significance of these cross-reactive antibody responses.

Arthritogenic alphaviruses such as chikungunya (CHIKV) and o'nyong-nyong (ONNV) viruses have shown capacity to cause widespread epidemics, with recurrent and sporadic outbreaks occurring throughout sub-Saharan Africa. We analyzed the seroprevalence for CHIKV and ONNV in 470 non-febrile subjects from three regions in Senegal (Sindia, 2018; Thies, 2018; and Kedougou, 2022/2023) using retrospective samples. We assessed the presence of anti-CHIKV IgG and neutralizing antibody titers against CHIKV and ONNV via enzyme-linked immunosorbent assay (ELISA) and microneutralization tests, respectively, and determined risk factors of CHIKV and ONNV exposure by binary logistic regression. The overall alphavirus seroprevalence based on an anti-CHIKV virus like particle (VLP) IgG ELISA was 38.5%, with rates varying geographically: Kedougou (48.6%), Thies (31.9%), and Sindia (14.9%). Neutralizing antibody titers revealed CHIKV and ONNV seroprevalence rates of 7.4% and 9.8%, respectively, with significant variations by region and age group. Cross-reactivity analysis showed that 82.9% of CHIKV cases exhibited a neutralizing response to ONNV, while 71.7% of ONNV cases cross-neutralized CHIKV. Residents of Thies had significantly higher odds of CHIKV infection (aOR, 3.147; 95% CI: 1.164-8.510) while ONNV infection was more likely in Kedougou (aOR, 3.888; 95% CI: 1.319-11.466). Furthermore, older age (> 40 years) was a significant risk factor both CHIKV (aOR, 2.094; 95% CI: 0.846-5.185) and ONNV infection (aOR, 2.745; 95% CI: 1.212-6.216). Our study confirms the co-circulation of CHIKV and ONNV in Senegal, highlighting their geographic and demographic distribution. These findings underscore the need for continued surveillance, alphavirus testing, and tailored public health strategies to mitigate their impact in Senegal.

West Africa serves as a critical region for the co-circulation of mosquito-borne flaviviruses, which often precipitate sporadic outbreaks. This study investigated the seropositivity to dengue virus serotypes 1-4 (DENV-1-4), Zika virus (ZIKV), yellow fever virus (YFV), and West Nile virus (WNV) in three regions of Senegal: Sindia, Thies, and Kedougou. We retrospectively analyzed 470 serum samples for flavivirus immunoglobulin G (IgG) using a DENV-2 envelope (E) ELISA. Our findings revealed an overall flavivirus seroprevalence of 37.23%. Among the DENV-2 E IgG positive samples, the proportion of subjects with IgG to DENV-1-4, ZIKV, YFV, or WNV NS1 was 57.14%, 12.57%, 80.57%, and 17.14%, respectively, with 66.86% harboring neutralizing antibodies against two or more flaviviruses. We also identified that residents in Sindia (ZIKV, aOR, 9.428; 95% CI: 1.882-47.223 and WNV, aOR, 6.039; 95% CI: 1.855-19.658) and Kedougou (ZIKV, aOR, 7.487; 95% CI: 1.658-33.808 and WNV, aOR, 1.142; 95% CI: 0.412-3.164) were at significant risk for ZIKV and WNV exposure. This study underscores the complexity of flavivirus epidemiology in West Africa and the necessity for enhanced surveillance to inform public health strategies.

Rhino-orbital-cerebral mucormycosis (ROCM) is an invasive mycosis caused by fungi of the order Mucorales. It mainly affects patients with uncontrolled diabetes. This case report concerns a 27-year-old woman with diabetic ketoacidosis who presented with a large erythematous plaque localised in the right orbitofrontal region with exophthalmos and patches of necrosis that rapidly led to death within 3 days before the diagnosis of ROCM due to Rhizopus oryzae, the causal agent. So, without rapid diagnosis and swift management, ROCM results in a potential fatality.

Background:While malaria elimination efforts in West African countries focus primarily on Plasmodium falciparum, non-falciparum malaria species could replace P. falciparum if their elimination is neglected. It is within this malaria control and elimination context that this article reviews the circulation of non-falciparum malaria species in the West African region. Methods:Non-falciparum related articles with a focus on the West African sub-region, published between 2000 and 2024, were selected using internet search engines Google Search, PubMed Central®, and the National Library of Medicine. The methodologies, including the study type, period, population, clinical symptoms, and diagnostic techniques used, plus the frequency of non-falciparum species, were reviewed. Results:A total of 31 articles about non-falciparum malaria were reviewed, including 2 (6.5%) each from Benin, Burkina Faso, and Ivory Coast, 4 (12.9%) each from Ghana and Nigeria, 5 (16.1%) from Mali, 3 (9.7%) from Niger, and 9 (29.0%) from Senegal. Of the 31 reviewed papers, P. falciparum was reported in 29 (93.5%), P. malariae in 25 (80.6%), P. ovale in 24 (77.4%), P. vivax in 11 (35.5%). Overall, 17 (54.8%) of the review papers used RDTs including 12 (70.6%) PfHRP2-based RDTs, and 5 (29.4%) of the malaria Ag P.f/Pan-based RDTs. Conclusion:This review describes and provides a better understanding of the circulation of non-falciparum malaria species in West Africa. In addition, it underscores the need to adapt malaria diagnostics by using more sensitive techniques, and to modify control strategies to investigate asymptomatic Plasmodium infections.

Mycetoma can be caused either by fungi or aerobic Actinomycetes. A precise identification of the causal agents is critical for the therapeutic outcome. Thus, this study aimed to identify the pathogens of mycetoma using 16S/ITS rRNA gene polymerase chain reaction (PCR) followed by Sanger sequencing directly on grains. In sum, 32 samples including 15 black grains, 12 red grains, and five white/yellow grains collected from patients with mycetoma at the Aristide Le Dantec University Hospital in Dakar, Senegal, between October 2014 and September 2020 were submitted to PCR/sequencing. For black grain eumycetoma, the ITS rRNA region was targeted. Similarly, the 16S rRNA gene was targeted for red grain actinomycetoma. These two regions were targeted in parallel for white/yellow grains, which could be of either bacterial or fungal origin. The age of the patients ranged from 14 to 72 years with a mean age of 36 ± 14 years. Thirteen (86

Drug resistance in Plasmodium falciparum is a major threat to malaria control efforts. Pathogen genomic surveillance could be invaluable for monitoring current and emerging parasite drug resistance. Data from two decades (2000–2020) of continuous molecular surveillance of P. falciparum parasites from Senegal were retrospectively examined to assess historical changes in malaria drug resistance mutations. Several known drug resistance markers and their surrounding haplotypes were profiled using a combination of single nucleotide polymorphism (SNP) molecular surveillance and whole genome sequence based population genomics. This dataset was used to track temporal changes in drug resistance markers whose timing correspond to historically significant events such as the withdrawal of chloroquine (CQ) and the introduction of sulfadoxine-pyrimethamine (SP) in 2003. Changes in the mutation frequency at Pfcrt K76T and Pfdhps A437G coinciding with the 2014 introduction of seasonal malaria chemoprevention (SMC) in Senegal were observed. In 2014, the frequency of Pfcrt K76T increased while the frequency of Pfdhps A437G declined. Haplotype-based analyses of Pfcrt K76T showed that this rapid increase was due to a recent selective sweep that started after 2014. The rapid increase in Pfcrt K76T is troubling and could be a sign of emerging amodiaquine (AQ) resistance in Senegal. Emerging AQ resistance may threaten the future clinical efficacy of artesunate-amodiaquine (ASAQ) and AQ-dependent SMC chemoprevention. These results highlight the potential of molecular surveillance for detecting rapid changes in parasite populations and stress the need to monitor the effectiveness of AQ as a partner drug for artemisinin-based combination therapy (ACT) and for chemoprevention.