Evidence of Plasmodium vivax circulation in western and eastern regions of Senegal: implications for malaria control.

BACKGROUND: Malaria elimination in Senegal requires accurate diagnosis of all Plasmodium species. Plasmodium falciparum is the most prevalent species in Senegal, although Plasmodium malariae, Plasmodium ovale, and recently Plasmodium vivax have also been reported. Nonetheless, most malaria control tools, such as Histidine Rich Protein 2 rapid diagnosis test (PfHRP2-RDT,) can only diagnose P. falciparum. Thus, PfHRP2-RDT misses non-falciparum species and P. falciparum infections that fall below the limit of detection. These limitations can be addressed using highly sensitive Next Generation Sequencing (NGS). This study assesses the burden of the four different Plasmodium species in western and eastern regions of Senegal using targeted PCR amplicon sequencing. METHODS: Three thousand samples from symptomatic and asymptomatic individuals in 2021 from three sites in Senegal (Sessene, Diourbel region; Parcelles Assainies, Kaolack region; Gabou, Tambacounda region) were collected. All samples were tested using PfHRP2-RDT and photoinduced electron transfer polymerase chain reaction (PET-PCR), which detects all Plasmodium species. Targeted sequencing of the nuclear 18S rRNA and the mitochondrial cytochrome B genes was performed on PET-PCR positive samples. RESULTS: Malaria prevalence by PfHRP2-RDT showed 9.4% (94/1000) and 0.2% (2/1000) in Diourbel (DBL) and Kaolack (KL), respectively. In Tambacounda (TAM) patients who had malaria symptoms and had a negative PfHRP2-RDT were enrolled. The PET-PCR had a positivity rate of 23.5% (295/1255) overall. The PET-PCR positivity rate was 37.6%, 12.3%, and 22.8% in Diourbel, Kaolack, and Tambacounda, respectively. Successful sequencing of 121/295 positive samples detected P. falciparum (93%), P. vivax (2.6%), P. malariae (4.4%), and P. ovale wallikeri (0.9%). Plasmodium vivax was co-identified with P. falciparum in thirteen samples. Sequencing also detected two PfHRP2-RDT-negative mono-infections of P. vivax in Tambacounda and Kaolack. CONCLUSION: The findings demonstrate the circulation of P. vivax in western and eastern Senegal, highlighting the need for improved malaria control strategies and accurate diagnostic tools to better understand the prevalence of non-falciparum species countrywide.

Malaria prevalence and use of control measures in an area with persistent transmission in Senegal.

INTRODUCTION: In Senegal, the widespread use of vector control measures has resulted in a significant reduction in the malaria burden and led the country to consider the possibility of elimination. Given this shift and changing context, it is important to characterize the malaria burden across all age groups to guide decision-making on programmatic interventions to interrupt transmission and ultimately eradicate the disease. In Senegal, there is a lack of information on malaria prevalence among certain populations, particularly among adolescents and adults. This study sought to assess the magnitude of malaria infections in all age groups, as well as malaria associated factors in an area of persistent transmission in Senegal. METHODS: A cross-sectional household survey was conducted in four health posts (Khossanto, Mamakhona, Diakhaling and Sambrambougou), of the health district of Saraya, in November 2021, among individuals over 6 months of age. Households were selected using multistage sampling. Consented participants were screened for malaria parasites by microscopic examination of blood smears, and hemoglobin levels were measured using the Hemocue HB 301TM analyzer. Socio-demographic information of the participants, household heads, household assets, and information on ownership and use of preventive measures were collected using a structured questionnaire. Weighted generalized mixed effects logistic regression model was used to identify factors associated with microscopically confirmed malaria infection. RESULTS: A total of 1759 participants were enrolled in the study. Overall, about 21% of participants were classified as having Plasmodium infection; children aged 5-10 years old (26.6%), adolescents aged 10-19 years old (24.7%), and children under five years of age (20.5%) had higher rates of infection compared to adults (13.5%). Plasmodium falciparum accounted for 99.2% of the malaria infections, and most infections (69%) were asymptomatic. Around one-third of study participants had anemia (hemoglobin level <11.0 g/dl), with under five children bearing the highest burden (67.3%). Multivariate analysis showed that the odds of having a malaria infection were around 2 times higher among participants in Khossanto compared to Diakhaling (aOR = 1.84, 95% CI:1.06-3.20). Participants aged 5-9 years were more likely to have malaria infection compared to under five children (aOR = 1.40, 95% CI:1.02-1.91). Factors associated with anemia were P. falciparum infection (aOR = 1.36, p = 0.027), females (aOR = 2.16, p = 0.000), under-five age group (aOR = 13.01, p = 0.000). CONCLUSION: Malaria burden was considerable among adolescents and under ten children living in an area of persistent transmission, with adolescents more commonly presenting as asymptomatic. Interventions tailored to this specific group of the population are needed to better control the disease and reduce its burden.

Predicting the age of field Anopheles mosquitoes using mass spectrometry and deep learning.

Mosquito-borne diseases like malaria are rising globally, and improved mosquito vector surveillance is needed. Survival of Anopheles mosquitoes is key for epidemiological monitoring of malaria transmission and evaluation of vector control strategies targeting mosquito longevity, as the risk of pathogen transmission increases with mosquito age. However, the available tools to estimate field mosquito age are often approximate and time-consuming. Here, we show a rapid method that combines matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry with deep learning for mosquito age prediction. Using 2763 mass spectra from the head, legs, and thorax of 251 field-collected Anopheles arabiensis mosquitoes, we developed deep learning models that achieved a best mean absolute error of 1.74 days. We also demonstrate consistent performance at two ecological sites in Senegal, supported by age-related protein changes. Our approach is promising for malaria control and the field of vector biology, benefiting other disease vectors like Aedes mosquitoes.

Distribution and dynamics of Anopheles gambiae s.l. larval habitats in three Senegalese cities with high urban malaria incidence.

Urban malaria has become a challenge for most African countries due to urbanization, with increasing population sizes, overcrowding, and movement into cities from rural localities. The rapid expansion of cities with inappropriate water drainage systems, abundance of water storage habitats, coupled with recurrent flooding represents a concern for water-associated vector borne diseases, including malaria. This situation could threaten progress made towards malaria elimination in sub-Saharan countries, including Senegal, where urban malaria has presented as a threat to national elimination gains. To assess drivers of urban malaria in Senegal, a 5-month study was carried out from August to December 2019 in three major urban areas and hotspots for malaria incidence (Diourbel, Touba, and Kaolack) including the rainy season (August-October) and partly dry season (November-December). The aim was to characterize malaria vector larval habitats, vector dynamics across both seasons, and to identify the primary eco- environmental entomological factors contributing to observed urban malaria transmission. A total of 145 Anopheles larval habitats were found, mapped, and monitored monthly. This included 32 in Diourbel, 83 in Touba, and 30 in Kaolack. The number of larval habitats fluctuated seasonally, with a decrease during the dry season. In Diourbel, 22 of the 32 monitored larval habitats (68.75%) were dried out by December and considered temporary, while the remaining 10 (31.25%) were classified as permanent. In the city of Touba 28 (33.73%) were temporary habitats, and of those 57%, 71% and 100% dried up respectively by October, November, and December. However, 55 (66.27%) habitats were permanent water storage basins which persisted throughout the study. In Kaolack, 12 (40%) permanent and 18 (60%) temporary Anopheles larval habitats were found and monitored during the study. Three malaria vectors (An. arabiensis, An. pharoensis and An. funestus s.l.) were found across the surveyed larval habitats, and An. arabiensis was found in all three cities and was the only species found in the city of Diourbel, while An. arabiensis, An. pharoensis, and An. funestus s.l. were detected in the cities of Touba and Kaolack. The spatiotemporal observations of immature malaria vectors in Senegal provide evidence of permanent productive malaria vector larval habitats year-round in three major urban centers in Senegal, which may be driving high urban malaria incidence. This study aimed to assess the presence and type of anopheline larvae habitats in urban areas. The preliminary data will better inform subsequent detailed additional studies and seasonally appropriate, cost-effective, and sustainable larval source management (LSM) strategies by the National Malaria Control Programme (NMCP).

Hepatocellular carcinoma surveillance among people living with hepatitis B in Senegal (SEN-B): insights from a prospective cohort study.

BACKGROUND: Chronic hepatitis B virus (HBV) infection is the predominant cause of hepatocellular carcinoma in west Africa, yet data on the incidence of HBV-related hepatocellular carcinoma remain scarce. We aimed to describe the uptake and early outcomes of systematic ultrasound-based hepatocellular carcinoma screening in SEN-B, which is a prospective HBV cohort in Senegal. METHODS: In this prospective cohort study, we included treatment-naive, HBsAg-positive individuals who were referred to the two infectious diseases clinics (the Department of Tropical and Infectious Diseases and Ambulatory Treatment Center) at Fann University Hospital of Dakar, Senegal, between Oct 1, 2019, and Oct 31, 2022. All participants resided within the Dakar region. Participants underwent abdominal ultrasound, transient elastography, and clinical and virological assessments at inclusion and every 6 months. Liver lesions at least 1 cm in diameter on ultrasound were assessed using four-phase CT, MRI, or liver biopsy. Adherence to hepatocellular carcinoma surveillance was measured using the proportion of time covered, calculated by dividing the cumulative months covered by abdominal ultrasound examinations by the overall follow-up time, defined as the number of months from the date of cohort entry until the last recorded visit, hepatocellular carcinoma diagnosis, or death. Optimal adherence was defined as a proportion of time covered of 100%. FINDINGS: Overall, 755 (99·6%) of 758 participants had at least one abdominal ultrasound performed. The median age of the enrolled participants was 31 years (IQR 25-39), 355 (47·0%) of 755 participants were women, and 82 (10·9%) had a family history of hepatocellular carcinoma. 15 (2·0%) of 755 individuals were HBeAg positive, 206 (27·3%) of 755 individuals had HBV DNA of more than 2000 IU/mL, and 27 (3·6%) of 755 had elastography-defined liver cirrhosis. Of ten (1·3%) participants with a focal lesion at least 1 cm at initial assessment, CT or MRI ruled out hepatocellular carcinoma in nine, whereas imaging and subsequent liver biopsy confirmed one patient with hepatocellular carcinoma. Two further patients with hepatocellular carcinoma were diagnosed at study presentation due to the presence of portal thrombosis on ultrasound. Excluding the three participants with hepatocellular carcinoma identified at baseline, 752 participants were eligible for screening every 6 months. Median follow-up time was 12 months (IQR 6-18) and the median number of ultrasounds per patient was 3 (2-4). During 809·5 person-years of follow-up, one incident hepatocellular carcinoma was reported, resulting in an incidence rate of 1·24 cases per 1000 person-years (95% CI 0·18-8·80). Overall, 702 (93·0%) of 755 participants showed optimal hepatocellular carcinoma surveillance, but this proportion decreased to 77·8% (42 of 54 participants) after 24 months. INTERPRETATION: Hepatocellular carcinoma screening is feasible in HBV research cohorts in west Africa, but its longer-term acceptability needs to be evaluated. Long-term hepatocellular carcinoma incidence data are crucial for shaping tailored screening recommendations. FUNDING: Swiss National Science Foundation, the Swiss Cancer Research Foundation, the National Cancer Institute, and Roche Diagnostics. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

The Tools for Integrated Management of Childhood Illness (TIMCI) study protocol: a multi-country mixed-method evaluation of pulse oximetry and clinical decision support algorithms.

Effective and sustainable strategies are needed to address the burden of preventable deaths among children under-five in resource-constrained settings. The Tools for Integrated Management of Childhood Illness (TIMCI) project aims to support healthcare providers to identify and manage severe illness, whilst promoting resource stewardship, by introducing pulse oximetry and clinical decision support algorithms (CDSAs) to primary care facilities in India, Kenya, Senegal and Tanzania. Health impact is assessed through: a pragmatic parallel group, superiority cluster randomised controlled trial (RCT), with primary care facilities randomly allocated (1:1) in India to pulse oximetry or control, and (1:1:1) in Tanzania to pulse oximetry plus CDSA, pulse oximetry, or control; and through a quasi-experimental pre-post study in Kenya and Senegal. Devices are implemented with guidance and training, mentorship, and community engagement. Sociodemographic and clinical data are collected from caregivers and records of enrolled sick children aged 0-59 months at study facilities, with phone follow-up on Day 7 (and Day 28 in the RCT). The primary outcomes assessed for the RCT are severe complications (mortality and secondary hospitalisations) by Day 7 and primary hospitalisations (within 24 hours and with referral); and, for the pre-post study, referrals and antibiotic. Secondary outcomes on other aspects of health status, hypoxaemia, referral, follow-up and antimicrobial prescription are also evaluated. In all countries, embedded mixed-method studies further evaluate the effects of the intervention on care and care processes, implementation, cost and cost-effectiveness. Pilot and baseline studies started mid-2021, RCT and post-intervention mid-2022, with anticipated completion mid-2023 and first results late-2023. Study approval has been granted by all relevant institutional review boards, national and WHO ethical review committees. Findings will be shared with communities, healthcare providers, Ministries of Health and other local, national and international stakeholders to facilitate evidence-based decision-making on scale-up.Study registration: NCT04910750 and NCT05065320.

Pulse oximetry and clinical decision support algorithms show potential for supporting healthcare providers to identify and manage severe illness among children under-five attending primary care in resource-constrained settings, whilst promoting resource stewardship but scale-up has been hampered by evidence gaps.This study design article describes the largest scale evaluation of these interventions to date, the results of which will inform country- and global-level policy and planning .

Success in vaccination programming through community health workers: a qualitative analysis of interviews and focus group discussions from Nepal, Senegal and Zambia.

OBJECTIVES: Community health workers are essential to front-line health outreach throughout low-income and middle-income countries, including programming for early childhood immunisation. Understanding how community health workers are engaged for successful early childhood vaccination among countries who showed success in immunisation coverage would support evidence-based policy guidance across contexts. DESIGN: We employed a multiple case study design using qualitative research methods. SETTING: We conducted research in Nepal, Senegal and Zambia. PARTICIPANTS: We conducted 207 interviews and 71 focus group discussions with 678 participants at the national, regional, district, health facility and community levels of the health systems of Nepal, Senegal and Zambia, from October 2019 to April 2021. We used thematic analysis to investigate contributing factors of community health worker programming that supported early childhood immunisation within each country and across contexts. RESULTS: Implementation of vaccination programming relied principally on the (1) organisation, (2) motivation and (3) trust of community health workers. Organisation was accomplished by expanding cadres of community health workers to carry out their roles and responsibilities related to vaccination. Motivation was supported by intrinsic and extrinsic incentives. Trust was expressed by communities due to community health worker respect and value placed on their work. CONCLUSION: Improvements in immunisation coverage was facilitated by community health worker organisation, motivation and trust. With the continued projection of health worker shortages, especially in low-income countries, community health workers bridged the equity gap in access to vaccination services by enabling wider reach to underserved populations. Although improvements in vaccination programming were seen in all three countries-including government commitment to addressing human resource deficits, training and remuneration; workload, inconsistency in compensation, training duration and scope, and supervision remain major challenges to immunisation programming. Health decision-makers should consider organisation, motivation and trust of community health workers to improve the implementation of immunisation programming.

Health workforce strategies during COVID-19 response: insights from 15 countries in the WHO Africa Region.

INTRODUCTION: The COVID-19 pandemic unveiled huge challenges in health workforce governance in the context of public health emergencies in Africa. Several countries applied several measures to ensure access to qualified and skilled health workers to respond to the pandemic and provide essential health services. However, there has been limited documentation of these measures. This study was undertaken to examine the health workforce governance strategies applied by 15 countries in the World Health Organization (WHO) Africa Region in responding to the COVID-19 pandemic. METHODS: We extracted data from country case studies developed from national policy documents, reports and grey literature obtained from the Ministries of Health and other service delivery agencies. This study was conducted from October 2020 to January 2021 in 15 countries - Angola, Burkina Faso, Chad, Eswatini, Ghana, Guinea, Guinea Bissau, Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal and Togo. RESULTS: All 15 countries had national multi-sectoral bodies to manage the COVID-19 response and a costed national COVID-19 response plan. All the countries also reflected human resources for health (HRH) activities along the different response pillars. These activities included training for health workers, and budget for the recruitment or mobilization of additional health workers to support the response, and for provision of financial and non-financial incentives for health workers. Nine countries recruited additional 35,812 health workers either on a permanent or temporary basis to respond to the COVID-19 with an abridged process of recruitment implemented to ensure needed health workers are in place on time. Six countries redeployed 3671 health workers to respond to the COVID-19. The redeployment of existing health workers was reported to have impacted negatively on essential health service provision. CONCLUSION: Strengthening multi-sector engagement in the development of public health emergency plans is critical as this promotes the development of holistic interventions needed to improve health workforce availability, retention, incentivization, and coordination. It also ensures optimized utilization based on competencies, especially for the existing health workers.

Creating culturally-informed protocols for a stunting intervention using a situated values-based approach (WeValue InSitu): a double case study in Indonesia and Senegal.

International development work involves external partners bringing expertise, resources, and management for local interventions in LMICs, but there is often a gap in understandings of relevant local shared values. There is a widespread need to better design interventions which accommodate relevant elements of local culture, as emphasised by recent discussions in global health research regarding neo-colonialism. One recent innovation is the concept of producing 'cultural protocols' to precede and guide community engagement or intervention design, but without suggestions for generating them. This study explores and demonstrates the potential of an approach taken from another field, named WeValue InSitu, to generate local culturally-informed protocols. WeValue InSitu engages stakeholder groups in meaning-making processes which 'crystallize' their envelope of local shared values, making them communicable to outsiders.Our research context is understanding and reducing child stunting, including developing interventions, carried out at the Senegal and Indonesia sites of the UKRI GCRF Action Against Stunting Hub. Each national research team involves eight health disciplines from micro-nutrition to epigenetics, and extensive collection of samples and questionnaires. Local culturally-informed protocols would be generally valuable to pre-inform engagement and intervention designs. Here we explore generating them by immediately following the group WeValue InSitu crystallization process with specialised focus group discussions exploring: what local life practices potentially have significant influence on the environments affecting child stunting, and which cultural elements do they highlight as relevant. The discussions will be framed by the shared values, and reveal linkages to them. In this study, stakeholder groups like fathers, mothers, teachers, market traders, administrators, farmers and health workers were recruited, totalling 83 participants across 20 groups. Themes found relevant for a culturally-informed protocol for locally-acceptable food interventions included: specific gender roles; social hierarchies; health service access challenges; traditional beliefs around malnutrition; and attitudes to accepting outside help. The concept of a grounded culturally-informed protocol, and the use of WeValue InSitu to generate it, has thus been demonstrated here. Future work to scope out the advantages and limitations compared to deductive culture studies, and to using other formative research methods would now be useful.

A social acceptability scale: Validation in the context of government measures to curb the COVID-19 pandemic in Senegal.

INTRODUCTION: In March 2020, the government of Senegal introduced a curfew, a ban on travel between regions, the closure of markets, and a ban on attending places of worship to contain the spread of the COVID-19 pandemic. As part of research into the response to COVID-19, we developed a scale to measure the social acceptability of these measures. METHODS: We used Sekhon's theoretical framework of acceptability (TFA) to formulate the content of the scale items. We assessed the homogeneity of the scale using Cronbach's Alpha and average interitem correlations. We measured the dimensional properties of the scale using rating scale models. We tested the sensitivity of the scale to sociodemographic characteristics using mixed linear regressions and rating scale models. RESULTS: The final scale consisted of seven items corresponding to the constructs of acceptability. Analysis performed on data from 813 individuals showed that the scale has satisfactory statistical properties (Cronbach's α > 0.8, Loevinger's coefficient>0.3, intraclass correlation>0.4). CONCLUSION: This scale was one of the first to test the TFA. The small number of items was advantageous for use under challenging data collection contexts. Measuring the acceptability of public health interventions with this tool can help in their design and implementation.

Health workforce incentives and dis-incentives during the COVID-19 pandemic: experiences from Democratic Republic of Congo, Nigeria, Senegal, and Uganda.

BACKGROUND: The COVID-19 pandemic presented a myriad of challenges for the health workforce around the world due to its escalating demand on service delivery. A motivated health workforce is critical to effectual emergency response and in some settings, incentivizing health workers motivates them and ensures continuity in the provision of health services. We describe health workforce experiences with incentives and dis-incentives during the COVID-19 response in the Democratic Republic of Congo (DRC), Senegal, Nigeria, and Uganda. METHODS: This is a multi-country qualitative research study involving four African countries namely: DRC, Nigeria, Senegal, and Uganda which assessed the workplace incentives instituted in response to the COVID-19 pandemic. Key informant interviews (n = 60) were conducted with staff at ministries of health, policy makers and health workers. Interviews were virtual using the telephone or Zoom. They were audio recorded, transcribed verbatim, and analyzed thematically. Themes were identified and quotes were used to support findings. RESULTS: Health worker incentives included (i) financial rewards in the form of allowances and salary increments. These motivated health workers, sustaining the health system and the health workers' efforts during the COVID-19 response across the four countries. (ii) Non-financial incentives related to COVID-19 management such as provision of medicines/supplies, on the job trainings, medical care for health workers, social welfare including meals, transportation and housing, recognition, health insurance, psychosocial support, and supervision. Improvised determination and distribution of both financial and non-financial incentives were common across the countries. Dis-incentives included the lack of personal protective equipment, lack of transportation to health facilities during lockdown, long working hours, harassment by security forces and perceived unfairness in access to and inadequacy of financial incentives. CONCLUSION: Although important for worker motivation, financial and non-financial incentives generated some dis-incentives because of the perceived unfairness in their provision. Financial and non-financial incentives deployed during health emergencies should preferably be pre-determined, equitably and transparently provided because when arbitrarily applied, these same financial and non-financial incentives can potentially become dis-incentives. Moreover, financial incentives are useful only as far as they are administered together with non-financial incentives such as supportive and well-resourced work environments. The potential negative impacts of interventions such as service delivery re-organization and lockdown within already weakened systems need to be anticipated and due precautions exercised to reduce dis-incentives during emergencies.

Seasonal variation of asymptomatic viral and bacterial nasopharyngeal carriage in rural Senegal.

BACKGROUND: The surveillance of respiratory pathogens in rural areas of West Africa has, to date, largely been focussed on symptoms. In this prospective study conducted prior to the COVID-19 pandemic, we aimed to assess the asymptomatic prevalence of respiratory pathogen carriage in a group of individuals living in a rural area of Senegalese. METHODS: Longitudinal follow up was performed through monthly nasopharyngeal swabbing during the dry season and weekly swabbing during the rainy season. We enrolled 15 individuals from the village of Ndiop. A total of 368 nasopharyngeal swabs were collected over a one-year period. We investigated the prevalence of 18 respiratory viruses and eight respiratory bacteria in different age groups using singleplex and multiplex PCR. RESULTS: In total, 19.56% of the samples (72/368) were positive for respiratory viruses and 13.60% of the samples (50/368) were positive for respiratory bacteria. Coronaviruses (19/72, 26.39%), adenoviruses (17/72, 23.61%), rhinoviruses (14/72, 19.44%), Streptococcus pneumoniae (17/50, 34%), and Moraxella catarrhalis (15/50, 30%) were the most frequently detected viruses. Interestingly, the carriage of respiratory pathogens was shown to be more frequent during the rainy season, as pluviometry was shown to be positively associated with the occurrence of respiratory viruses such as influenza (P = .0078, r2 =.523) and RSV (P = .0055, r2 =.554). CONCLUSIONS: Our results show a non-negligible circulation of respiratory pathogens in a rural area in Senegal (West Africa) with an underestimated proportion of asymptomatic individuals. This study highlights the fact that the circulation of viruses and bacteria in the community has been overlooked.

Military affected by the first wave of COVID-19 in Senegal: stress and resilience factors during care.

COVID-19 had a psychological impact on the population, particularly those affected. Our objective was to investigate stress and resilience factors in the Senegalese soldiers affected during the first wave of COVID-19. Our retrospective and qualitative study included military personnel listed as contacts, suspects, or positive cases and supported by the Armed Forces Psychological Support Program during the period of isolation. The stress factors were health-related, sociological, and occupational. The conditions and the experience of isolation, stigmatization, and suspension of their professional projects were concerns for the soldiers. They had relied on personal, familial, and professional resources to cultivate resilience during the quarantine. Isolation during the pandemic showed psychological consequences, the foundations of which have been found in our study.

Advancing access to care: An assessment of the prehospital system in Senegal.

BACKGROUND: Most low- and middle-income countries do not have a mature prehospital system limiting access to definitive care. This study sought to describe the current state of the prehospital system in Senegal and offer recommendations aimed at improving system capacity and population access to definitive care. METHODS: Structured interviews were conducted with key informants in various regions throughout the country using qualitative and quantitative techniques. A standardized questionnaire was generated using needs assessment forms and system frameworks. Descriptive statistics were performed for quantitative data analysis, and qualitative data was consolidated and presented using ATLAS.ti. RESULTS: Two (20%) of the studied regions, Dakar and Saint-Louis, had a mature prehospital system in place, including dispatch centers and teams of trained personnel utilizing equipped ambulances. 80% of the studied regions lacked an established prehospital system. The vast majority of the population relied on the fire department for transport to a healthcare facility. The ambulances in rural regions were not part of a formal prehospital system, were not equipped with life-support supplies, and were limited to inter-facility transfers. CONCLUSIONS: While Dakar and Saint-Louis have mature prehospital systems, the rest of the country is served by the fire department. There are significant opportunities to further strengthen the prehospital system in rural Senegal by training the fire department in basic life support and first aid, maintaining cost efficiency, and building on existing national resources. This has the potential to significantly improve access to definitive care and outcomes of emergent illness in the Senegalese community.

Animal trypanosomosis eliminated in a major livestock production region in Senegal following the eradication of a tsetse population.

African animal trypanosomosis (AAT) was one of the main disease-related constraints to the development of intensive livestock production systems in the Niayes region of Senegal, a 30 km wide strip of land along the coast between Dakar and Saint-Louis. To overcome this constraint, the Government of Senegal initiated an area-wide integrated pest management programme combining chemical control tactics with the sterile insect technique to eradicate a population of the tsetse fly Glossina palpalis gambiensis Vanderplank, 1949 (Diptera, Glossinidae) in this area. The project was implemented following a phased conditional approach, and the target area was divided into three blocks treated sequentially. This study aims to assess the temporal dynamics of the prevalence of Trypanosoma spp. during the implementation of this programme. Between 2009 and 2022, 4,359 blood samples were collected from cattle and screened for trypanosomes using both the buffy coat and ELISA techniques, and PCR tests since 2020. The seroprevalence decreased from 18.9% (95%CI: 11.2-26.5) in 2009 to 0% in 2017-2022 in block 1, and from 92.9% (95%CI: 88.2-97) in 2010 to 0% in 2021 in block 2. The parasitological and serological data confirm the entomological monitoring results, i.e., that there is a high probability that the population of G. p. gambiensis has been eradicated from the Niayes and that the transmission of AAT has been interrupted in the treated area. These results indicate the effectiveness of the adopted approach and show that AAT can be sustainably removed through the creation of a zone free of G. p. gambiensis.

Title: Trypanosomose animale éliminée dans une importante région de production d'élevage au Sénégal suite à l'éradication d'une population de glossines. Abstract: La trypanosomose animale africaine (TAA) était l'une des principales contraintes pathologiques au développement de systèmes de production animale intensifs dans les Niayes du Sénégal, une bande de terre large de 30 km longeant la côte entre Dakar et Saint-Louis. Pour surmonter cette contrainte, le Gouvernement du Sénégal a lancé un programme de lutte intégrée à l'échelle de la zone combinant lutte chimique et technique de l'insecte stérile pour éradiquer une population de Glossina palpalis gambiensis Vanderplank, 1949 (Diptera, Glossinidae). Le projet a été mis en œuvre selon une approche conditionnelle progressive, et la zone cible a été divisée en trois blocs, traités de manière séquentielle. L'objectif de cette étude était d'évaluer la dynamique temporelle de la prévalence de Trypanosoma spp. au cours de la mise en œuvre du programme. Entre 2009 et 2022, 4 359 échantillons de sang ont été prélevés sur des bovins et ont fait l'objet d'un dépistage des trypanosomes à l'aide des techniques du buffy-coat et ELISA, ainsi que de test PCR depuis 2020. Dans le bloc 1, la séroprévalence est passée de 18,9 % (IC 95 % : 11,2­26,5) en 2009 à 0 % entre 2017­2022 et de 92,9 % (IC 95 % : 88,2-97) en 2010 à 0 % en 2021 pour le block 2. Les données parasitologiques et sérologiques confirment les résultats du suivi entomologique selon lesquels il est très probable que la population de Glossina palpalis gambiensis soit éradiquée des Niayes, et que la transmission de la TAA a été interrompue dans la zone traitée. Elles indiquent l'efficacité de l'approche adoptée, et montrent que la TAA peut être durablement éliminée grâce à la création d'une zone exempte de G. p. gambiensis.

Evaluating the performance of Plasmodium falciparum genetic metrics for inferring National Malaria Control Programme reported incidence in Senegal.

BACKGROUND: Genetic surveillance of the Plasmodium falciparum parasite shows great promise for helping National Malaria Control Programmes (NMCPs) assess parasite transmission. Genetic metrics such as the frequency of polygenomic (multiple strain) infections, genetic clones, and the complexity of infection (COI, number of strains per infection) are correlated with transmission intensity. However, despite these correlations, it is unclear whether genetic metrics alone are sufficient to estimate clinical incidence. METHODS: This study examined parasites from 3147 clinical infections sampled between the years 2012-2020 through passive case detection (PCD) across 16 clinic sites spread throughout Senegal. Samples were genotyped with a 24 single nucleotide polymorphism (SNP) molecular barcode that detects parasite strains, distinguishes polygenomic (multiple strain) from monogenomic (single strain) infections, and identifies clonal infections. To determine whether genetic signals can predict incidence, a series of Poisson generalized linear mixed-effects models were constructed to predict the incidence level at each clinical site from a set of genetic metrics designed to measure parasite clonality, superinfection, and co-transmission rates. RESULTS: Model-predicted incidence was compared with the reported standard incidence data determined by the NMCP for each clinic and found that parasite genetic metrics generally correlated with reported incidence, with departures from expected values at very low annual incidence (< 10/1000/annual [‰]). CONCLUSIONS: When transmission is greater than 10 cases per 1000 annual parasite incidence (annual incidence > 10‰), parasite genetics can be used to accurately infer incidence and is consistent with superinfection-based hypotheses of malaria transmission. When transmission was < 10‰, many of the correlations between parasite genetics and incidence were reversed, which may reflect the disproportionate impact of importation and focal transmission on parasite genetics when local transmission levels are low.

Quality assessment of malaria microscopic diagnosis at the Aristide Le Dantec University Hospital of Dakar, Senegal, in 2020.

BACKGROUND: Following WHO guidelines, microscopy is the gold standard for malaria diagnosis in endemic countries. The Parasitology-Mycology laboratory (LPM) is the National Reference Laboratory and is currently undergoing ISO 15189 accreditation. In this context, we assessed the performance of the laboratory by confirming the reliability and the accuracy of results obtained in accordance with the requirements of the ISO 15189 standards. This study aimed to verify the method of microscopic diagnosis of malaria at the LPM, in the Aristide Le Dantec hospital (HALD) in Dakar, Senegal. METHODS: This is a validation/verification study conducted from June to August 2020. Twenty (20) microscopic slides of thick/thin blood smear with known parasite densities (PD) selected from the Cheick Anta Diop University malaria slide bank in Dakar were used for this assessment. Six (6) were used to assess microscopists' ability to determine PD and fourteen (14) slides were used for detection (positive vs negative) and identification of parasites. Four (4) LPM-HALD microscopists read and recorded their results on prepared sheets. Data analysis was done with Microsoft Excel 2010 software. RESULTS: A minimum threshold of 50% concordance was used for comparison. Of the twenty (20) slides read, 100% concordance was obtained on eight (8) detection (positive vs negative) slides. Four (4) out of the six (6) parasite density evaluation slides obtained a concordance of less than 50%. Thirteen (13) out of the fourteen (14) identification slides obtained a concordance greater than 50%. Only one (1) identification slide obtained zero agreement from the microscopists. For species identification a concordance greater than 80% was noted and the microscopists obtained scores between 0.20 and 0.4 on a scale of 0 to 1 for parasite density reading. The microscopists obtained 100% precision, sensitivity, specificity and both negative and positive predictive values. CONCLUSION: This work demonstrated that the microscopic method of malaria diagnosis used in the LPM/HALD is in accordance with the requirements of WHO and ISO 15189. Further training of microscopists may be needed to maintain competency.

Reemergence of Sylvatic Dengue Virus Serotype 2 in Kedougou, Senegal, 2020.

In 2020, a sylvatic dengue virus serotype 2 infection outbreak resulted in 59 confirmed dengue cases in Kedougou, Senegal, suggesting those strains might not require adaptation to reemerge into urban transmission cycles. Large-scale genomic surveillance and updated molecular diagnostic tools are needed to effectively prevent dengue virus infections in Senegal.

Case Management of Imported Crimean-Congo Hemorrhagic Fever, Senegal, July 2023.

We report an imported Crimean-Congo hemorrhagic fever case in Senegal. The patient received PCR confirmation of virus infection 10 days after symptom onset. We identified 46 patient contacts in Senegal; 87.7% were healthcare professionals. Strengthening border crossing and community surveillance systems can help reduce the risks of infectious disease transmission.