Essoham Ataba

Background: Despite concerted global efforts, urogenital schistosomiasis remains an important public health challenge in sub-Saharan Africa. Understanding the local dynamics of this disease is crucial for effectively planning interventions to eliminate urogenital schistosomiasis as a public health concern. This study, conducted in southern Togo, aimed to comprehensively describe the epidemiology of Schistosoma haematobium infection among school-aged children after more than a decade of control using preventive chemotherapy. Methods: A cross-sectional study was conducted from July to August 2022 among children aged 5 to 14 years in selected villages across three districts of the Plateaux region of Togo. Coordinates of each surveyed household were recorded, and sociodemographic data were gathered using a pre-tested questionnaire. Urine samples were visually examined for macrohematuria and tested for microhematuria. Urine filtration was performed to quantify S. haematobium eggs. Results: In total, 3146 households were enrolled, and 6400 school-aged children provided urine samples. The overall prevalence of macrohematuria was 4.48% (95% CI [4.21–4.75]) and of microhematuria was 16.11% (95% CI [15.65–16.57]), while 15.0% (95% CI [14.55–15.45]), of children were S. haematobium egg-positive. Prevalence varied across villages and districts, with Ogou district exhibiting the highest prevalence by all three indicators. The prevalence of heavy-intensity infection ranged from 0.92% (95% CI [0.69–1.15]) in the Est-Mono district to 12.91% (95% CI [12.3–13.52]) in the Ogou district, averaging 3.40% (95% CI [2.95–3.85]) in the Anié district. Conclusions: This study highlights geographic variability in the distribution of S. haematobium , even after more than a decade of PC. The detailed data provided can support the development of more targeted treatment strategies, focusing on areas where S. haematobium remains prevalent. This approach may accelerate progress toward achieving the WHO goal of eliminating schistosomiasis as a public health concern. Graphical

: In areas where malaria is endemic and microscopes are unavailable, rapid diagnostic tests (RDTs) are essential tools for early diagnosis and prompt and effective treatment. However, HRP2-based RDTs are threatened by the emergence of Plasmodium falciparum parasites that do not carry the pfhrp2 or pfhrp3 gene, leading to false-negative results. Therefore, the aim of this study was to evaluate the performance of the ParaHIT RDT together with the proportion of pfhrp2/3 gene–deleted P. falciparum parasites in Togo. The performance of RDTs compared with microscopy and polymerase chain reaction (PCR) was determined using capillary blood collected by finger prick during a cross-sectional study conducted from September 2021 to January 2022 in children aged 6–59 months at two sentinel sites. Blood spots were collected for molecular analysis. Amplicons from the target regions (exon 2 of hrp2 and hrp3 genes) were generated by multiplex nested PCR and sequenced using Illumina’s MiSeq protocol. A total of 278 samples were analyzed for ParaHIT RDT evaluation. The sensitivity and specificity of the RDT test compared with microscopy were 96.4% and 85.7%, respectively, which increased to 97.9% and 90.7%, respectively, when compared with PCR. Of the microscopically and PCR-positive P. falciparum samples, 138 were sequenced to detect pfhrp2/3 deletions. None of the parasites had a single pfhrp2 deletion or a single pfhrp3 deletion. The ParaHIT RDT demonstrated an acceptable level of performance in this evaluation, confirming the use of HRP2-based RDTs for the detection of P. falciparum infection in areas where microscopy is not available in Togo.

Background: Due to the burden of schistosomiasis (SCH) and soil-transmitted helminths (STH), Togo Ministry of Health launched a program for Preventive Chemotherapy Neglected Tropical Diseases (PC-NTDs) in 2009, initiating integrated mass drug administration (MDA) the following year for the three PC-NTDs: SCH, STH and onchocerciasis. Significant reduction of infection across the country was noted in 2015 during the first impact assessment, following 5 years of high-coverage MDA implemented at the sub-district level for SCH and district level for STH. After another 5 years of effective MDA, a second survey was conducted in 2021 to re-evaluate the situation of SCH and STH. Methods: A cross-section of school-aged children was taken across ten districts of Togo. A total of 302 schools in 92 sub-districts were sampled, with 24 school-aged children per school resulting in 7248 children surveyed. Urine samples were tested by haemastix® for Schistosoma haematobium, with urine filtration for the presence of eggs conducted on haematuria-positive samples. Stool samples were collected in a subset of 34 sub-districts in seven out of the ten surveyed districts, where STH and Schistosoma mansoni endemicity was high during the 2015 impact assessment. Duplicate (two) Kato-Katz analysis was performed for each stool sample. Sociodemographic and school-level water, sanitation and hygiene information was also collected. Results: Overall, SCH prevalence was 5.90% (95% CI: 5.4–6.5), with 5.09% (95% CI: 4.64–5.67) for S. haematobium and 2.56% (95% CI: 1.98–3.29) for S. mansoni. STH prevalence was 19.7% (95% CI: 18.2–21.4), with 19.6% (95% CI: 18.1–21.3) hookworm, 0.08% (95% CI: 2.2–5.8) Trichuris trichiura and 0.04% (95% CI: 0.01–0.33) Ascaris lumbricoides. Compared to baseline, a significant reduction in both SCH (22.2% to 5.90%) and STH (29.2% t0 19.7%) prevalence was observed. Children aged 5–9 years were less infected than older peers aged 10–14 years: 4.76% vs. 7.53% (P < 0.01) for SCH and 17.2% vs. 23.0% (P < 0.01) for STH. Conclusions: After 10 years of high coverage integrated MDA, Togo has achieved low prevalence SCH infection through the sub-district MDA implementation with considerable infection heterogeneity within sub-districts. As STH infection has not reached a level where the infections are not a public health problem, the sub-district treatment strategy could also be adopted in addition to improvement of treatment coverage among preschool age children and hygiene and sanitation practices. Graphical

Hyperreactive onchocerciasis (HO) is characterized by a severe skin inflammation with elevated Th17-Th2 combined responses. We previously demonstrated the anthelminthic activity of Aframomum melegueta (AM), Xylopia aethiopica (XA) and Khaya senegalensis (KS) used by traditional healers to treat helminthiasis in the endemic area of Togo. However, their effect on severe onchocerciasis is poorly investigated. The present study aimed to investigate the anti-Th17 and anti-Th2 effects of hydro-ethanolic extracts of AM, XA and KS during HO. Onchocerca volvulus-infected individuals were recruited in the Central region of Togo in 2018. Isolated peripheral blood mononuclear cells (PBMCs) from both generalized onchocerciasis (GEO) and HO forms were activated with anti-CD3 and anti-CD28 monoclonal antibodies in the presence or absence of the hydro-ethanolic extracts of AM, XA and KS as well as their delipidated, deproteinized and deglycosylated fractions. After 72 hours, cytokines were assayed from cell culture supernatants. Then, flow cytometry was used to investigate the effects of the extracts on cell activation, proliferation, intracellular cytokines and T cells transcription factors. The production of both Th17 and Th2 cytokines IL-17A and IL-5 were significantly inhibited upon T-cell receptor (TCR) activation in the presence of the hydro-ethanolic extracts of AM, XA and KS in HO individuals’ PBMCs in vitro. AM and XA inhibited CD4⁺RORC2⁺IL-17A⁺ and CD4⁺GATA3⁺IL-4⁺ cell populations induction. This inhibition was not Th1 nor Treg-dependent since both IFN-γ and IL-10 were also inhibited by the extracts. AM and XA did not interfere with T cell activation and proliferation for their inhibitory pathways. Lipid and protein compounds from AM and XA were associated with the inhibition of IL-17A. This study showed that in addition to their anthelminthic effects, hydro-ethanolic extracts of Aframomum melegueta, Xylopia aethiopica and Khaya senegalensis could downregulate both Th17 and Th2 responses and prevent the severe skin disorder observed.

Plasmodium resistance to antimalarial drugs is an obstacle to the elimination of malaria in endemic areas. This situation is particularly dramatic for Africa, which accounts for nearly 92% of malaria cases worldwide. Drug pressure has been identified as a key factor in the emergence of antimalarial drug resistance. Indeed, this pressure is favoured by several factors, including the use of counterfeit forms of antimalarials, inadequate prescription controls, poor adherence to treatment regimens, dosing errors, and the increasing use of other forms of unapproved antimalarials. This resistance has led to the replacement of chloroquine (CQ) by artemisinin-based combination therapies (ACTs) which are likely to become ineffective in the coming years due to the uncontrolled use of Artemisia annua in the sub-Saharan African region for malaria prevention and COVID-19. The use of Artemisia annua for the prevention of malaria and COVID-19 could be an important factor in the emergence of resistance to Artemisinin-based combination therapies.