Heat waves in the West African Sahel: nature, drivers and predictabilty

The Sahel in West Africa is a vast semi-arid region stretching from the Atlantic coast to the Red Sea and marks a transition between the Guinean forests and the Sahara desert, home to several millions of people. It is a climatologically hot region with a peak of heat observed in boreal spring before the summer monsoon. However, heatwave research in the region is still in its infancy despite that, as in most regions of the globe, high temperatures have escalated over recent decades as a result of climate change. This thesis builds knowledge on the characteristics, physical understanding and predictability of heatwaves in the Sahel at the weather and intraseasonal scales. These timescales have received little attention from previous work despite being important for operational risk management. The analyses are built on two main datasets including the fifth generation of the European reanalyses (ERA5) and the hindcast of the ECMWF ensemble extended-range forecastings system (ENS-ext). Sahelian intraseasonal heatwaves are overall short-lived with mean duration between three and five days. Record-breaking events can nonetheless last up to two weeks in some locations. Heatwaves in the Sahel are also characterised by low frequencies of occurrence with typically one to two events a year across most of the region. On the other hand, they are very severe in intensity given that the mean state of the atmosphere is already hot. The eastern and central parts of the Sahel are the most affected by heatwaves in terms of duration, frequency and intensity whereas the proximity to the Atlantic Ocean attenuates extreme heat events in western Sahel. The physical quantification of heat can be done in considering temperature only or adding other environmental variables to build multivariate thermal indices. The upstream choice of thermal index for heatwave study is important in the Sahel. Indeed, heatwaves sampled using different indices show only moderate synchronicity between them. Besides, the Sahel is characterised by a low concomitance between daytime and nighttime heatwave events, which is a relieving factor when it comes to the impact on health. Regarding the thermodynamic processes, heat advection and greenhouse effect of moisture are found to be the main underlying causes. Both these processes are made possible by a significant perturbation of the low-level flow, favouring a transport of hotter or more humid air masses towards Sahelian locations. At the large-scale, this circulation anomaly is often associated with convective anomalies in the Guinean region of West Africa, where convection is at its peak during the spring season. Consequently, the link between heatwaves in the Sahel and tropical modes of variability including the Madden Julian Oscillation (MJO) and the equatorial Rossby (ER) and Kelvin waves (EK), which are important drivers of the Guinean convection, was investigated. The examination reveals that the probability and, to a lesser extent, intensity of Sahelian heatwaves are significantly modulated by the passage of tropical modes over the West African domain. Depending on their convective phases, i.e. either enhanced or suppressed, they can increase or decrease heatwave probability in the region. The modulation is sensitive to the diurnal period and geographical location with nighttime heatwaves more impacted by the modes over eastern Sahel and daytime heatwaves more affected over western Sahel. Among the investigated modes, the MJO was found to have the greatest impact on heatwaves owing to its larger spatial extension and longer periodicity. The skill of Sahelian heatwave prediction by numerical models was assessed using ENS-ext which is regularly considered as one of the best forecasting systems at the intraseasonal scales. Significant skill was found in the first two to three weeks of the forecast. Longer predictability can be achieved using a “flexible” evaluation i.e. tolerating errors within a given temporal window, especially at the longest lead-times, where even approximate indication of heatwave occurrence is valuable for targeted anticipatory actions. With increasing lead-times, heatwaves are found to be more predictable at night than at day. Interestingly, ENS-ext is able, on one hand, to relatively well predict the local activity of tropical modes over West Africa and, on the other hand, to simulate their observed impact on Sahelian heatwaves. Furthermore, heatwave prediction skill is higher when tropical modes are active, implying that they are good sources of heatwave predictability. As a result, in the future, more precision and longer predictability can be obtained for heatwave prediction in the Sahel in view of the continual improvement in the representation of convection and tropical modes by models. Given its findings, this thesis has many implications for heatwave risk management in the Sahel across a range of sectors including, but not limited to, health, labour productivity, water and energ

Implémentation du Field Epidemiology Training Programme Frontline au Burkina Faso, 2016 à 2019: leçons apprises et Défis: Implementation of the Frontline Field Epidemiology Training Programme in Burkina Faso, 2016 to 2019: Lessons Learned and Challenges

Introduction: Dans le contexte de l'agenda de la sécurité mondiale de la santé lancé en 2015. The Centers for Disease Control and Prevention (CDC Atlanta) a initié le renforcement de capacités des acteurs dans l'épidémiologie de terrain Frontline (FETP). Pour l'implémentation du programme, des réunions, une évaluation de base, le recrutement et formation de mentors, sélection et formation de participants en utilisant l'approche « One Health », travaux de terrain, supervision et interviews de sortie ont été menés. Au Burkina Faso ce programme a commencé en avril 2016. L'objectif de cette étude était de décrire le processus d'implémentation, les défis et les leçons apprises. Méthodes: Une étude transversale rétrospective qualitative à visée descriptive conduite d'avril 2016 à septembre 2019 incluant tous les participants. Des interviews et une revue documentaire avaient été réalisés. Résultats: L'évaluation de base avait montré un besoin dans le renforcement des capacités pour le système de surveillance. Au total 22 mentors formés. Fin décembre 2019, neuf cohortes (100%) formées dont 6 (75%) avec approche « One Health ». Au total 210 participants devraient être formés sans distinction de sexe, ainsi 267 capacités (127%). Sur les 267 formés, 22 femmes (8%). Deux qui n'ont pas achevé la formation (0,7%), un décès (0,3%). Au total 1040 travaux réalisés. Les défis restent le suivi post formation, les mutations des agents formés et la pérennisation. Conclusion: L'implémentation de FETP Frontline au Burkina Faso a été effective et a fait face à plusieurs défis et des leçons apprises ont été tirées. Il est recommandé la poursuite de ces formations pour le renforcement des capacités des acteurs de la surveillance. Introduction: In the context of the global health security agenda launched in 2015, the Center for Disease Control and Prevention (CDC Atlanta) initiated capacity building for stakeholders in Frontline Field Epidemiology (FETP). To implement the programme, meetings, a baseline assessment, recruitment and training of mentors, selection and training of participants using the "One Health" approach, fieldwork, supervision and exit interviews were conducted. In Burkina Faso this programme started in April 2016. The objective of this study was to describe the implementation process, challenges and lessons learned. Methods: A retrospective qualitative descriptive cross-sectional study conducted from April 2016 to September 2019 including all participants. Interviews and a literature review were conducted. Results: The baseline assessment showed a need in capacity building for the surveillance system. In total 22 mentors trained. By the end of December 2019, nine cohorts (100%) trained, of which six (75%) with a "One Health" approach. A total of 210 participants should be trained regardless of gender, thus 267 were trained (127%). Of the 267 trained, 22 were women (8%). Two did not complete the training (0.7%), one died (0.3%). A total of 1,040 works were completed. The challenges remain post-training follow-up, transfers of trained agents and sustainability. Conclusion: The implementation of FETP Frontline in Burkina Faso was effective, faced several challenges and lessons were learned. It is recommended that these training sessions be continued in order to strengthen the capacities of surveillance actors

Knowledge, attitudes and practices about rabies prevention and control: A community survey in five health districts of Burkina Faso

Rabies is a deadly viral disease that affects humans and animals. It is transmitted by rabid animals, through bite, scratch or licking. Almost 99% of human cases are caused by dogs. In Burkina Faso, nearly 5,000 bites cases are recorded annually. This cross-sectional investigation was conducted with the objective of assessing the knowledge, attitudes and practices of people regarding rabies and preventive measures in five health districts, Burkina Faso. Using a structured questionnaire, the survey was conducted in households to capture data on participants’ knowledge, attitudes and practices of rabies control. Through a house-to-house approach, the questionnaire was administrated to 320 household members. The results indicated that 36.9% of the participants had high level knowledge of rabies, 80% perceived it as a fatal disease, 76.4% of participant’s reported attitudes were negative and 58.9% of them reported uncorrect practices. The knowledge level of rabies was significantly associated with health district, area of household location, participant’s age, their level of education, previous history with rabies and information channels used by household (p<0.05). However, the health district, the area of household location, the level of education and the knowledge level had significant association with attitudes of participants with regard to rabies (p<0.05). Concerning health behaviours, health district of respondents and their previous history with rabies showed significant association with practices regarding bite cases management (p<0.05). In addition, people health seeking behaviors were significantly associated with their levels of knowledge regarding rabies, their perceptions and attitudes towards the disease (p<0.05). National rabies control stakeholders should address the knowledge gaps through mass awareness campaigns providing key information regarding the risks of contamination and the recommended practices to prevent avoidable deaths

Dog ownership, demographics, owners’ knowledge of rabies, and factors associated with canine rabies vaccination in urban and rural areas of Dedougou, Burkina Faso

Rabies is a prioritized zoonotic disease in Burkina Faso and is known as a major zoonotic disease with high public health importance. This investigation was conducted to assess community knowledge, dog ecology and demographics, and factors associated with dog vaccination against rabies in the urban and rural areas of Dedougou. Three hundred and sixteen (316) dog-owning households were surveyed in the rural and urban areas of Dedougou using a semi-structured questionnaire. Among participants, 55.7% lived in rural area, and 59.8% were farmers. Only 34.5% of participants had satisfactory knowledge of rabies. About 22% were aware of the required age of dogs’ primo vaccination against rabies while 55.7% knew the frequency of booster vaccination. Participants living in households with less than five persons were significantly more likely to be aware of rabies than those living in households with the higher number of persons (P<0.05). Participants who were aware of rabies were more likely to vaccinate their dogs compared to those who were not aware of rabies (P<0.05). In total, 2930 persons were recorded in visited households with 60.6% from rural area, and an average household size of 9.27 persons. Three hundred and thirty seven dogs were found in surveyed households’ and 54.9% were from rural area. In overall, a dog per human ratio of 1:8.7 was determinated. Regarding dog ownership practices, the majority of respondents reported that they provided their dogs with water (84.5%) and food (84.8%). This research reported supplementary data on dog ecology and rabies, which could be useful for rabies control planning in Burkina Faso