Boly Diop

In November 2020, an alert for a “mysterious disease” among fishermen was issued. Fishermen are particularly subjected to dermatoses due to their constant contact with seawater, fish, crustaceans, and fishing equipment that may contain harmful agents. The study aimed to examine the alert, identify the causative agent and suggest preventive and control measures. This was a cross-sectional study of dermatoses in Dakar (Senegal) from October 11 to November 30, 2020, using quantitative and qualitative methods within a ‘One Health’ approach.“ The investigation included bacterio-virological, anatomopathological and toxicological examinations. Data were analyzed using Epi info and QGIS (case mapping), We observed all confidentiality measures during the study. A total of 555 cases were diagnosed with an attack rate of 5.4% among fishermen and no deaths were reported. There was a delay in epidemic detection and notification. The epidemic was most prevalent among people from coastal areas. Average age of cases was 22 ± 9 years, and all were male and artisanal fishermen by profession. Patients presented with fever (16%), cutaneous pain (100%) and mucocutaneous lesions (100%) consisting of vesicles, papules and ulcerations localized on exposed areas of the body, external genitalia and oral mucosa, with severe cases (8%). Toxicology revealed the presence of a toxic alga ( V. rugosum ) in marine equipments. The notion of a sea trip in the 24–48 hours before the onset of the disease was found in 92%. Majority of cases (74%) did not have full personal protective equipment (PPE). The proportion of people without full protection was 83% among those who developed severe forms. People without full protection were more exposed to severe forms than those with full PPE; (OR = 1.818; 95% CI [0.829 - 3.988]). The investigation has linked the epidemic to a probable algal origin. We need to promote the use of personal protective equipment and improve the early warning and notification system.

Background: Rift Valley Fever (RVF) is a zoonotic disease affecting humans and livestock across Africa, with outbreaks influenced by ecological, animal, and social factors. In Senegal, nomadic livestock systems, endemic mosquito vectors, and mobile pastoralist communities create recurrent outbreak cycles, threatening public health, food security, and livelihoods. Early detection of animal and environmental signals is critical for timely interventions. This study analyzed the 2025 RVF outbreak in Senegal, examining its spatiotemporal dynamics and assessing the contribution of an artificial intelligence (AI)–enhanced One Health surveillance platform to early detection and national response capacity. Methodology/Principal findings: We conducted a mixed-methods study of the 2025 RVF outbreak in Senegal, integrating quantitative data from humans, animals, and environmental sources with qualitative insights from community-based surveillance. Multi-source data—including AI-generated predictions, epidemiological records, and community alerts—were analyzed alongside institutional and operational challenges. Outbreaks were characterized by widespread livestock abortions, concentrated in northern regions and shaped by livestock mobility, ecological conditions, and vector activity. The AI-based One Health platform detected early warning signals days to weeks before official confirmation. Connectivity gaps, uneven digital literacy, delayed validation, and weak cross-sector coordination constrained effectiveness of detection and response. Conclusions/Significance: Our study demonstrates that AI-enhanced, community-integrated One Health surveillance can improve early outbreak detection, but technological innovation alone is insufficient without institutional alignment, inclusive governance, and community engagement. Strengthening these systems is crucial for equitable, timely responses to zoonotic threats in agro-pastoral regions of Africa.

Human enteric viruses are common pathogens that can cause acute gastroenteritis (AGE). The largest proportion of morbidity and mortality occurs in developi

: Hepatitis E, caused by hepatitis E virus (HEV), is a highly endemic disease with a major public health impact. In Senegal, the first HEV outbreak was identified in 2014 in Kedougou, and a recent study focusing on pregnant women showed a seroprevalence of 7.8%. Apart from these data, very little is known about its burden in Senegal, and there is no specific surveillance program. We describe HEV prevalence among acute febrile jaundice patients in Senegal. A retrospective analysis using jaundice samples (2008–2020) collected through the national yellow fever surveillance program were tested for HEV by IgM/IgG ELISA and reverse transcription polymerase chain reaction (RT-PCR). Sequencing and phylogenetic analyses were performed on RT-PCR-positive samples. Statistical tools were used to analyze the HEV prevalence. In total, 2,387 samples were tested, and 174 IgG, 135 IgM/IgG, and 29 IgM positive samples were detected. Among the IgM-positive samples, 74 were positive by RT-PCR. The results showed an overall HEV prevalence of 14% in febrile jaundice patients in Senegal. Phylogenetic analyses showed the circulation of genotype 2b. Our data confirmed the HEV outbreak in Kedougou in 2014 and showed the detection of acute cases in other regions. We also detected in these regions genotype 2b, which is usually associated with large outbreaks in many African countries, suggesting a high risk of HEV outbreak occurrence in Senegal. Finally, our data showed that the yellow fever surveillance program, which is based on jaundice and already exists in many countries, could be a valuable tool for HEV surveillance.

In late September 2025, a deadly Rift Valley fever outbreak in northern Senegal caused 44 cases and 8 deaths. Sequencing confirmed lineage H persistence with three novel polymerase mutations suggesting adaptation. Ongoing concurrent One Health investigations target vectors, livestock, and human exposure to identify risk factors and strengthen control.

: Crimean–Congo hemorrhagic fever (CCHF) is a lethal zoonotic disease transmitted through tick bites and contact with infected animals or humans. As CCHF continues to expand worldwide, we report on the first severe outbreak in Senegal (Podor, Saint-Louis region) in 2022. We conducted a comprehensive outbreak investigation after a confirmed CCHF human case in Podor. This included sample collections from humans, animals, and ticks from the household and surrounding area. Human and animal samples were tested by ELISA for antibodies to CCHF virus and by reverse transcription polymerase chain reaction (RT-PCR) for CCHF virus RNA, whereas tick samples underwent CCHF RT-PCR only. Positive RT-PCR samples underwent viral genome sequencing for genetic characterization. We determined three CCHF human cases, with two deaths, as well as virus circulation in 11 ticks and in livestock, with an overall seroprevalence of 42.5%. CCHF IgG antibodies were detected in human contact cases, showing its prior prevalence in the area. Phylogenetic analyses revealed high genetic diversity within CCHF genotypes, with existence of reassortants and cocirculation of two different isolates from various origins in Mboyo and Nenette villages, where human cases were detected. The data showed a correlation between the strains identified in humans and ticks in each village, showing two independent emergences in Podor. The outbreak in Podor was probably because of the high abundance of animal hosts in this sylvopastoral area, the diversity of tick populations with the presence of the main CCHF vectors, and the increasing prevalence of CCHF virus. The surveillance in this area needs to be strengthened.

Monkeypox (Mpox) is a zoonotic viral infection caused by a virus of the Orthopoxvirus genus. In response to global alerts, efforts in epidemiological surveillance and infection control have intensified, following WHO recommendations for enhanced monitoring, contact tracing, and the implementation of appropriate public health measures. This study aimed to assess the epidemiological surveillance of Mpox in Senegal in 2024. This was a retrospective, cross-sectional, descriptive, and analytical study conducted over a four-month period (from July 14 to November 10, 2024). The study population included all cases sampled as part of Mpox surveillance in Senegal during this period. Key strengths in the response included the adaptation to the IDSR Kit, training of personnel at all levels on the IDSR strategy, case definition and monitoring training, development of surveillance procedures, presence of focal points for surveillance, a diversified network of reference laboratories, and the use of an electronic case notification platform. A total of 56.25% of the initially planned priority activities were completed. During the surveillance period, 100 suspected Mpox cases were reported, corresponding to 6 cases per 1 million inhabitants. Biological samples were collected from all patients. At the time of the study, no confirmed cases of Mpox were detected. Alternative viral diagnoses were established in 32% of cases—most frequently varicella-zoster virus. Co-infections were observed in 4 patients (12.5%). The median delay between symptom onset and result availability was 7 days. Symptom duration had a median of 3 days, and the median interval from consultation to result delivery was 2 days. Longer delays were significantly observed in remote or hard-to-reach areas. Overall, patient-related delays were significantly longer than surveillance-related delays (p = 0.002). Strengthening epidemiological surveillance improves sample processing times and response effectiveness. This enhancement should be prioritized in border areas and hard-to-reach regions.

This study assesses Senegal’s performance against the 7-1-7 approach, a benchmark for outbreak preparedness, focusing on infectious disease detection, notification, and response from 2022 to 2023. Using secondary national surveillance data, the analysis included socio-demographic, clinical, and laboratory information, with data visualized using ArcGIS. Findings showed a median detection period of 12 days, twice the recommended duration, due to factors like healthcare-seeking behavior and lab processing times. Notification was relatively efficient, with a median of 1 day post-lab confirmation. However, delays in activating the national Emergency Operations Center (EOC) were noted. Despite limitations such as incomplete arbovirus data and an unstructured response data system, the study highlights the need to align current surveillance indicators with the 7-1-7 metrics, digitalize the notification system, and empower additional laboratories. These interventions are essential for improving public health responses, enhancing health outcomes, and increasing community resilience in Senegal.

The Chikungunya virus, a mosquito-borne alphavirus, continues to pose a significant public health challenge with its capacity to cause widespread outbreaks. In 2023, Senegal experienced a major outbreak, initially emerging in the Kedougou region and subsequently spreading to Tambacounda. This study aimed to monitor the molecular evolution of Chikungunya virus using real-time genomic surveillance during the epidemic progression. A total of fourteen human samples blood collected from Chikungunya suspected cases in Tambacounda were analyzed. Whole genome sequencing revealed that the outbreak strain belonged to the West African genotype, closely related to strains from the Kedougou 2023 outbreak. Phylogenetic analysis highlighted three distinct genetic groups within the 2023 strains, with notable genetic variations between the Kedougou and Tambacounda clusters. Specifically, two amino acid mutations, A13T in the non-structural protein 1 (nsP1) and K270R in the structural E2 glycoprotein, were identified in the Tambacounda strains, suggesting potential adaptive changes. Our findings demonstrate the rapid evolution of Chikungunya virus in eastern Senegal, emphasizing the necessity for continuous genomic surveillance to detect emerging variants and understand their implications for virus transmissibility and virulence. This study underscores the critical role of genomic analysis in managing viral outbreaks and informing public health strategies.