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Dugbe virus (DUGV) is a tick-borne arbovirus first isolated in Nigeria in 1964. It has been detected in many African countries using such diverse methods as serological tests, virus isolation, and molecular detection. In Senegal, reports of DUGV isolates mainly occurred in the 1970s and 1980s. Here, we report a contemporary detection of three novel DUGV isolates upon screening of a total of 2877 individual ticks regrouped into 844 pools. The three positive pools were identified as Amblyomma variegatum, the main known vector of DUGV, collected in the southern part of the country (Kolda region). Interestingly, phylogenetic analysis indicates that the newly sequenced isolates are globally related to the previously characterized isolates in West Africa, thus highlighting potentially endemic, unnoticed viral transmission. This study was also an opportunity to develop a rapid and affordable protocol for full-genome sequencing of DUGV using nanopore technology. The results suggest a relatively low mutation rate and relatively conservative evolution of DUGV isolates.

Crimean–Congo hemorrhagic fever (CCHF), the most widespread tick-borne viral human infection, poses a threat to global health. In this study, clinical samples collected through national surveillance systems were screened for acute CCHF virus (CCHFV) infection using RT-PCR and for exposure using ELISA. For any CCHF-positive sample, livestock and tick samples were also collected in the neighborhood of the confirmed case and tested using ELISA and RT-PCR, respectively. Genome sequencing and phylogenetic analyses were also performed on samples with positive RT-PCR results. In Eastern Senegal, two human cases and one Hyalomma tick positive for CCHF were identified and a seroprevalence in livestock ranging from 9.33% to 45.26% was detected. Phylogenetic analyses revealed that the human strain belonged to genotype I based on the available L segment. However, the tick strain showed a reassortant profile, with the L and M segments belonging to genotype I and the S segment belonging to genotype III. Our data also showed that our strains clustered with strains isolated in different countries, including Mauritania. Therefore, our findings confirmed the high genetic variability inside the CCHF genotypes and their introduction to Senegal from other countries. They also indicate an increasing CCHF threat in Senegal and emphasize the need to reinforce surveillance using a one-health approach.

Background Crimean‐Congo haemorrhagic fever (CCHF), a disease of medical and veterinary importance in several countries including Senegal, is transmitted by ticks or exposure to infected body fluids. Severe human cases of CCHF were recently observed across Senegal suggesting modification of the endemicity area and the tick fauna. Objective This study aims to investigate some aspects associated with the bioecology of ticks infesting livestock and their infection with CCHF virus (CCHFV) across three bioclimatic areas of Senegal. Methods Ticks were collected between October 2020 and November 2022, from randomly selected cattle, goats and sheep in the Sahelian, Sudano‐Sahelian and Sudanian zones. They were screened for CCHFV RNA by RT‐PCR. Results A total of 3632 animals were examined, and 35.3% (95% CI: 33.8–36.9) were found tick‐infested. The overall tick infestation rate was 81.7% (95% CI: 78.1–84.9) in cattle, 30.3% (95% CI: 28.2–32.5) in sheep and 24.1% (95% CI: 21.8–26.5) in goats. TIR differed per age, gender, host species and bioclimatic area. Overall, 7734 ticks belonging to 12 species and 3 genera were collected. The most abundant species included Rhipicephalus evertsi (32.7%) and Hyalomma impeltatum (20.1%). CCHFV was detected in 6 of the 1709 tested pools with an overall minimum infection rate (MIR) of 0.8‰. Infected ticks (H. impeltatum and H. rufipes) were collected mainly from the anogenital areas of sheep and cattle in the Sahelian and Sudano‐Sahelian zones. Conclusion These updated data on ticks and CCHFV vectors in Senegal will be useful for the prevention and control of tick‐borne diseases. Ticks were collected between October 2020 and November 2022, from cattle, goats and sheep in the Sahelian, Sudano‐Sahelian and Sudanian zones, and tested for CCHFV infection. A total of 3632 animals were examined and 35.3% (95% CI: 33.8–36.9) found tick‐infested. CCHFV was detected in six tested pools with an overall minimum infection rate of 0.8‰. Infected ticks (H. impeltatum and H. rufipes) were collected mainly from the anogenital areas of sheep and cattle in the Sahelian and Sudano‐Sahelian zones.

Rift Valley Fever virus (RVFV) is a mosquito-borne zoonotic pathogen, that causes significant morbidity and mortality in livestock, including high abortion rates in pregnant animals and elevated case fatality in neonates, representing a major threat to both animal and human health. Vaccination is the most effective countermeasure to reduce RVFV’s impact. In this study, we designed a veterinary DNA vaccine encoding a consensus RVFV glycoprotein precursor (GPC), optimized for expression in sheep. The construct was evaluated for immunogenicity in mice and sheep and for protective efficacy in sheep raised under natural field conditions in Senegal, West Africa. The vaccine induced robust humoral responses characterized by high neutralizing antibody titers in both mice and sheep. Under natural exposure, vaccinated sheep showed reduced infection rates (3.2%) compared with controls (14.3%), and neutralizing antibody responses persisted for more than one year. Importantly, the vaccine was well tolerated, including in pregnant animals, with no adverse outcomes such as abortions or fetal abnormalities. These findings demonstrate that a DNA-based RVFV vaccine can elicit durable immunity and provide protection in livestock under real-world conditions. This study highlights the potential of DNA vaccines as a safe, effective, and affordable alternative to existing veterinary vaccines and supports their further development as a key strategy to reduce RVFV transmission and improve animal and human health outcomes in endemic regions.

Crimean-Congo haemorrhagic fever virus (CCHFV) occurs sporadically in Senegal, with a few human cases each year. This active circulation of CCHFV motivated this study which investigated different localities of Senegal to determine the diversity of tick species, tick infestation rates in livestock and livestock infections with CCHFV. The samples were collected in July 2021 from cattle, sheep and goats in different locations in Senegal. Tick samples were identified and pooled by species and sex for CCHFV detection via RT-PCR. A total of 6135 ticks belonging to 11 species and 4 genera were collected. The genus 'Hyalomma' was the most abundant (54%), followed by 'Amblyomma' (36.54%), 'Rhipicephalus' (8.67%) and 'Boophilus' (0.75%). The prevalence of tick infestation was 92%, 55% and 13% in cattle, sheep and goats, respectively. Crimean-Congo haemorrhagic fever virus (CCHFV) was detected in 54/1956 of the tested pools. The infection rate was higher in ticks collected from sheep (0.42/1000 infected ticks) than those from cattle (0.13/1000), while all ticks collected from goats were negative. This study confirmed the active circulation of CCHFV in ticks in Senegal and highlights their role in the maintenance of CCHFV. It is imperative to take effective measures to control tick infestation in livestock to prevent future CCHFV infections in humans.

A Crimean-Congo Hemorrhagic Fever Virus (CCHFV) survey in Agnam (North Senegal) permits the detection of three isolates in ticks. These isolates belong genetically to multiple genotypes (I, II, III) and clustered with strains from Uganda, Sudan, Mauritania, and Senegal. The role of ticks in CCHF emergence and widespread is highlighted.

Tick-borne pathogens (TBPs) are expanding globally, with their impact on public health expected to rise due to climate change. Immunizing livestock offers a cost-effective alternative or adjunct to human vaccination. We evaluated two DNA vaccines, one targeting Crimean-Congo hemorrhagic fever virus (CCHFV) and another targeting Hyalomma tick infestation. The Hyalomma -targeting vaccine was designed to disrupt tick feeding by targeting midgut proteins essential for blood digestion and survival; however, its direct role in preventing CCHFV transmission remains unconfirmed. Here, we demonstrate that two doses of the CCHFV vaccine significantly reduced the risk of CCHFV infection in naturally exposed sheep. We further investigated whether the Hyalomma vaccine provided cross-protection against Wad Medani virus (WMV) and Rickettsia conorii , two TBPs endemic to Senegal. Sheep were vaccinated intramuscularly with two doses of DNA vaccine, followed by electroporation, and monitored under natural farming conditions in an endemic region of Senegal. Natural infection with CCHFV, WMV, and R. conorii was assessed longitudinally using pathogen-specific IgG seroconversion as the primary endpoint. The Hyalomma vaccine reduced WMV acquisition, whereas its effect on R. conorii was less pronounced. These findings underscore the potential of veterinary vaccines to mitigate multiple TBPs and reinforce their established role in reducing tick-borne diseases.

The mosquito-borne disease caused by the Rift Valley Fever Virus (RVFV) is a viral hemorrhagic fever that affects humans and animals. In 1987, RVFV emerged in Mauritania, which caused the first RVFV outbreak in West Africa. This outbreak was shortly followed by reported cases in humans and livestock in Senegal. Animal trade practices with neighboring Mauritania suggest northern regions of Senegal are at high risk for RVF. In this study, we aim to conduct a molecular and serological survey of RVFV in humans and livestock in Agnam (northeastern Senegal) by RT-PCR (reverse transcription real-time polymerase chain reaction) and ELISA (Enzyme-Linked Immunosorbent Assay), respectively. Of the two hundred fifty-five human sera, one (0.39%) tested RVFV IgM positive, while fifty-three (20.78%) tested positive for RVFV IgG. For animal monitoring, out of 30 sheep recorded and sampled over the study period, 20 (66.67%) showed seroconversion to RVFV IgG antibodies, notably during the rainy season. The presence of antibodies increased significantly with age in both groups (p < 0.05), as the force of RVF infection (FOI), increased by 16.05% per year for humans and by 80.4% per month for livestock sheep. This study supports the usefulness of setting up a One Health survey for RVF management.

Crimean-Congo hemorrhagic fever virus (CCHFV) is widespread in Asia, Europe, and Africa. In Senegal, sporadic cases of CCHFV have been reported since 1960. Bordering Mauritania in northeastern Senegal, Agnam is an arid area in the region of Matam where CCHFV is endemic, which harbors a pastoralist community. Given the drought conditions of Agnam, inhabitants are in constant movement with their animals in search of pasture, which brings them into contact with pathogens such as arboviruses. To identify CCHFV in this area, we established a One Health site in order to analyze animal livestock, ticks and human samples collected over a one-year period by qRT-PCR and ELISA. Our analysis showed one (1/364) patient carried anti-CCHFV IgM and thirty-seven carried anti-CCHFV IgG (37/364). In livestock, anti-CCHFV IgG was detected in 13 (38.24%) of 34 sentinel sheep. The risk of CCHFV infection increased significatively with age in humans (p-value = 0.00117) and sheep (p-value = 1.18 × 10−11). Additional risk factors for CCHFV infection in sheep were dry seasons (p-value = 0.004) and time of exposure (p-value = 0.007). Furthermore, we detected a total of three samples with CCHFV RNA within Rhipicephalus evertsi evertsi and Rhipicephalus guilhoni tick species. Our results highlighted the usefulness of a One Health survey of CCHFV in pastoral communities at risk of arboviruses.

ObjectivesPublic awareness and the dissemination of tailored information to lay populations are essential for highly endemic countries like Senegal to achieve hepatitis B elimination targets by 2030. In Senegal, despite its high prevalence, hepatitis B has not received sufficient attention in health communication campaigns compared with other health issues like HIV. We aimed to explore knowledge and perceptions surrounding hepatitis B virus (HBV), as well as the influence of digital media on the information accessed by individuals living with HBV in Senegal.DesignWe employed a mixed-methods approach combining qualitative semistructured interviews conducted with people living with HBV enrolled in the Senegalese hepatitis B cohort (SEN-B), with a quantitative content analysis of online news coverage focused on HBV within the online media of Senegal.SettingA referral University hospital in Dakar, Senegal.Participants29 individuals aged >18 years presenting with a positive hepatitis B surface antigen (HBsAg) with a median age of 40 years (IQR 27–54), of whom 51.7% were female.Outcomes and analysisQualitative interviews were conducted between December 2019 and October 2021, and we employed purposive sampling to select participants enrolled in SEN-B. Thematic analysis facilitated a systematic synthesis of respondents’ narratives. All data analyses were performed using Atlas.ti (V.22). For content analysis of online media news collected from September 2019 to May 2022, a structured data extraction form was developed to collect relevant information from the selected online news articles. Data on readers’ comments spaces were extracted using an inductive approach and were processed using thematic analyses. The quantitative data issued from content analysis were exported to Stata SE V.17.0 (StataCorp) for statistical analysis.ResultsWe observed a generalised lack of knowledge about HBV among participants, some of whom had never heard of the virus prior to their screening. Incomprehension regarding the disease contributed to feelings of fear and anxiety, leading participants to express various concerns about their personal health status, transmission, cure and treatment(s). The presence of rumours surrounding the disease further underscored the limited awareness of HBV revealing the marginal recognition of HBV as a significant societal concern. In many cases, the absence of effective health communication strategies at the national level resulted in individuals turning to traditional and online media for information, which often intensified their fears and concerns about HBV. An analysis of Senegalese media coverage about HBV included 157 articles published between 2009 and 2022. 55.4% (87/157) of these publications appeared in July, coinciding with World Hepatitis Day, while 65.0% (102/157) focused on general HBV epidemiology and activities led by the National Hepatitis Programme. Online media also served as informal spaces where unaccredited actors within the health sector promoted treatments lacking official verification. Additionally, the reactions’ spaces provided a venue for the exchange of information, though without any guarantee of its accuracy.ConclusionsFacilitating collaboration and engagement between health communication stakeholders and communities is crucial for effectively disseminating structured information and culturally appropriate messages, ultimately contributing to raising awareness of HBV.