In Central Africa, wildlife populations are increasingly influenced by humans, even in protected areas. This raises the question how spatial patterns of wildlife abundance are affected by human activities and habitat and how these patterns change over time. I address these questions by developing spatial models combined with line transect survey data in two forest sites in Central Africa. In the Odzala National Park in the Republic of Congo, I examine elephant dung abundance data in relation to human threats and protection. In the Okapi Faunal Reserve in the Democratic Republic of Congo (DRC), I developed spatio-temporal models for elephants and other forest ungulates to examine temporal changes in their densities as a result of changes in human impact in the context of a civil war that took place in the region between the two surveys. Covariates related to human influences dominated the observed patterns at both sites. In Odzala, elephant dung densities were mainly influenced by protection. They were higher inside the protected area and closer to anti-poaching patrol routes. In the Okapi Faunal Reserve, populations of all ungulate species declined severely between the two survey periods. Declines in elephant abundance were relatively higher closer to the park boundary and areas of intense human activity. After the war, elephant densities were higher in a small area in the centre of the park that may have acted as a refuge. Forest duikers also declined, but the spatial pattern of their decline was different than that of elephants. Densities dropped more in the southern part of the reserve, probably due to pre-exisisting higher levels of hunting there. Besides explaining spatial patterns of abundance, spatial modeling was shown to be useful in improving the precision of density estimates and in predicting densities across a surface in the Odzala National Park. In summary, humans overwhelmingly determined the distribution and abundance of ungulates in both sites. The civil war in DRC led to a dramatic increase in elephant poaching for ivory which caused a major decline in elephant populations. It aggravated the bushmeat hunting of duikers whose populations also declined sharply. / Science, Faculty of / Zoology, Department of / Graduate

Vegetables play a major role in the livelihoods of the rural poor in Africa. Among major constraints to vegetable production worldwide are diseases caused by a group of viruses belonging to the genus Begomovirus, family Geminiviridae. Begomoviruses are plant-infecting viruses, which are transmitted by the whitefly vector Bemisia tabaci and have been known to cause extreme yield reduction in a number of economically important vegetables around the world. Several begomoviruses have been detected infecting vegetable crops in West and Central Africa (WCA). Small single stranded circular molecules, alphasatellites and betasatellites, which are about half the size of their helper begomovirus genome, have also been detected in plants infected by begomoviruses. In WCA, B. tabaci has been associated with suspected begomovirus infections in many vegetable crops and weed species. Sequencing of viral genomes from crops such as okra resulted in the identification of two previously known begomovirus species (Cotton leaf curl Gezira virus and Okra yellow crinkle virus) as well as a new recombinant begomovirus species (Okra leaf curl Cameroon virus), a betasatellite (Cotton leaf curl Gezira betasatellite) and new alphasatellites. Tomato and pepper plants with leaf curling were shown to contain isolates of new begomoviruses, collectively referred to as West African tomato-infecting begomoviruses (WATIBs), new alphasatellites and betasatellites. To study the potential of weeds serving as begomovirus reservoirs, begomoviruses and satellites in the weed Ageratum conyzoides were characterized. Sequence analyses showed that they were infected by isolates of a new begomovirus (Ageratum leaf curl Cameroon virus) that belong to the WATIBs group, a new betasatellite (Ageratum leaf curl Cameroon betasatellite), an alphasatellite and two types of defective recombinants between a begomovirus and an alphasatellite. Putative recombinations were detected in begomovirus genomes for all four plant species studied, indicating that recombination is an important mechanism for their evolution. A close relationship between the begomoviruses infecting pepper and tomato and A. conyzoides and the detection of the same alphasatellite in them support the idea that weeds are important reservoirs for begomoviruses and their satellites. With this high diversity, recombination potential and transmission by B. tabaci, begomoviruses and ssDNA satellites pose a serious threat to crop production in West and Central Africa.

The present study sets out to assess patterns of evolutionary diversification in central African duikers (subfamily Cephalophinae). The sampling strategy consisted of collecting geo-referenced duiker feces across 43 sites and seven countries. However, several challenges related to the use of non-invasive samples needed to be addressed prior to large scale DNA amplification. First, the best storage method for obtaining DNA from fecal samples needed to be established. Our study revealed that while silica is best for nuclear microsatellite analyses, RNAlater is the best storage medium for maximal mitochondrial amplification. Moreover, extracting DNA as early as possible always provided the best results. Second, since it is impossible to determine the species identity of duiker feces solely based on their morphology, a simple and reliable molecular method was needed. A tree-based approach based on ~650 base pairs of the control region amplified from reference samples was found to be the most reliable method to recover the identity of unknown samples. Third, for fine scale analyses of population genetic structure, a set of twelve nuclear microsatellites were assembled from existing bovid data. These microsatellites markers were chosen because they are very polymorphic, cross amplify among targeted taxa, co-amplify with combined markers of the same multiplex, and are powerful enough for individual identification. Patterns of mitochondrial and nuclear microsatellite variation were used to test two important hypotheses of diversification in the tropics: the Pleistocene refugia and the riverine barrier hypotheses. Analyses of historical and contemporary population genetic structure were carried out on the three most abundant species in our sampling area: the bay duiker (C. dorsalis), the Peter’s duiker (C. callipygus), and the blue duiker (P. monticola) using mitochondrial and nuclear markers described above. These data show that (1) southwest Nigeria and southwest Cameroon comprise genetically distinct populations in C. callipygus and P. monticola species, (2) signatures of demographic expansion for all three taxa are broadly coincident with the location of hypothesized upland refugia in Gabon and Equatorial Guinea and (3) the Sanaga, Ogooué, and Sangha rivers may constitute a partial riverine barrier and/or act as fluvial refugia for duikers.

Cette thèse a pour objet d’analyser l’ensemble des dispositions prises par la Communauté Économique des États de l’Afrique Centrale (CEEAC) qui est une organisation régionale à vocation économique, pour faire face aux menaces auxquelles elle est confrontée.Il s’agit ici, d’évaluer les forces et les faiblesses de la CEEAC dans la construction de la sécurité régionale en Afrique centrale à travers une analyse SWOT (incluant les facteurs internes et externes qui favorisent une entité et ceux qui la menacent). Ainsi, cette thèse montre que la CEEAC, dont les objectifs fondateurs n’étaient pas la sécurité au sens classique du terme, a finalement réussi à mieux développer ses capacités de défense que son intégration économique en raison de la faible complémentarité des économies nationales qui la constituent. Pour autant, je souligne les limites de cette dimension sécuritaire : l’insuffisance des moyens logistiques et financiers et le jeu de puissances extérieures. Ces insuffisances tendent à discréditer les capacités de la CEEAC en matière de sécurité et aboutissent à la réappropriation de ses responsabilités par d’autres organisations régionales locales notamment la CEMAC. / I assesses the strengths and weaknesses of ECCAS in building regional security in Central Africa through a SWOT (including internal and external factors that promote an entity and those that threaten it). Thus, this thesis shows that ECCAS, whose founding objectives were not safe in the classical sense of the term, was finally able to better develop its defense capabilities as its economic integration due to the low complementarity of national economies which up. However, I emphasize the limits of this security dimension: the lack of logistical and financial resources and the set of external powers. These shortcomings tend to discredit the capacities of ECCAS safety and result in the recovery of its responsibilities by other local regional organizations such as CEMAC.

Essa monografia tem como objetivo compreender a atuação dos ferreiros frente às transformações ocorridas no século XIX na África central. As inúmeras modificações ocorridas na região afetaram diretamente a vida dos ferreiros. A intensificação do chamado comércio legal e o acesso às áreas mais interioranas levaram ao aumento da solicitação do trabalho desses especialistas, que rapidamente se adequaram às novas demandas e souberam aproveitar as oportunidades surgidas. A introdução da metalurgia do ferro na África central proporcionou intensas modificações nas sociedades africanas, contribuindo para colocar os ferreiros num lugar privilegiado dentro das suas comunidades. O trabalho do ferreiro, além de ser exclusivamente masculino, era cercado por segredos inacessíveis à maioria. A visão de mundo baseada no equilíbrio entre homem e natureza exigia desse profissional, não apenas o conhecimento profundo do meio-ambiente, mas também das forças espirituais que o regem. Por isso, esses especialistas desempenhavam inúmeros papéis além daqueles ligados propriamente ao seu ofício, como a participação nas cerimônias de entronização e morte de chefes e, em algumas regiões, nos rituais ligados à fertilidade. / The subject of this work is to understand the role of blacksmiths within the transformations of the nineteenth century in Central Africa. The many modifications that took place in the region directly changed the way of life of the blacksmiths. The intensification of the so called legal trade in the region and the access to inland areas led to the increase request of these professionals which rapidly adequate their selves to the new demands, benefiting from the new opportunities. The introduction of iron metallurgy in Central Africa provided intense modifications in African societies and contributed to put the blacksmiths in a special place. Ironworking was exclusively masculine and surrounded by secrets hidden to most people. The African vision of world based on the balance between men and nature required from the blacksmiths not only a profound knowledge about the environment but also a vast perception of the spiritual forces that regulate it. Therefore the blacksmiths played innumerous roles besides their professional and technical assignments. They participate as key figures in inauguration and death ceremonies of chiefs and in some regions also in fertility rituals.

Essa monografia tem como objetivo compreender a atuação dos ferreiros frente às transformações ocorridas no século XIX na África central. As inúmeras modificações ocorridas na região afetaram diretamente a vida dos ferreiros. A intensificação do chamado comércio legal e o acesso às áreas mais interioranas levaram ao aumento da solicitação do trabalho desses especialistas, que rapidamente se adequaram às novas demandas e souberam aproveitar as oportunidades surgidas. A introdução da metalurgia do ferro na África central proporcionou intensas modificações nas sociedades africanas, contribuindo para colocar os ferreiros num lugar privilegiado dentro das suas comunidades. O trabalho do ferreiro, além de ser exclusivamente masculino, era cercado por segredos inacessíveis à maioria. A visão de mundo baseada no equilíbrio entre homem e natureza exigia desse profissional, não apenas o conhecimento profundo do meio-ambiente, mas também das forças espirituais que o regem. Por isso, esses especialistas desempenhavam inúmeros papéis além daqueles ligados propriamente ao seu ofício, como a participação nas cerimônias de entronização e morte de chefes e, em algumas regiões, nos rituais ligados à fertilidade. / The subject of this work is to understand the role of blacksmiths within the transformations of the nineteenth century in Central Africa. The many modifications that took place in the region directly changed the way of life of the blacksmiths. The intensification of the so called legal trade in the region and the access to inland areas led to the increase request of these professionals which rapidly adequate their selves to the new demands, benefiting from the new opportunities. The introduction of iron metallurgy in Central Africa provided intense modifications in African societies and contributed to put the blacksmiths in a special place. Ironworking was exclusively masculine and surrounded by secrets hidden to most people. The African vision of world based on the balance between men and nature required from the blacksmiths not only a profound knowledge about the environment but also a vast perception of the spiritual forces that regulate it. Therefore the blacksmiths played innumerous roles besides their professional and technical assignments. They participate as key figures in inauguration and death ceremonies of chiefs and in some regions also in fertility rituals.

Theileria parva is a complex protozoan parasite causing East Coast fever in Eastern and Central Africa. Vaccination using live parasites is an effective control measure and has been used in Zambia based on locally isolated and introduced T. parva stocks. Diversity among T. parva populations was investigated in parasites from two Zambian provinces with different disease epidemiologies and control histories. Isolates from the pre-vaccination era, local and exotic stocks used for vaccination, and one recent field isolate were cloned and passaged in vitro to study genomic stability over time. The results of the data from three genome-wide probes indicate a marked homogeneity and stability among the Zambian isolates in contrast to East African isolates. Results from Southern blot profiles and the polymorphic immunodominant molecule (PIM) sequence analysis suggest a common origin for the Zambian isolates from the pre-vaccination era, except for one isolate (Zam5) from Southern Province. This isolate showed characteristics suggesting a buffalo origin. Assays for genotype characterisation were developed using five allelic markers. Multilocus characterisation revealed identical profiles in a recent Zambian isolate from Southern Province and two components of an exotic cocktail vaccine, indicating the escape of one of the vaccine stocks in the field. Characterisation of T. parva field populations by RFLP-PCR assays after immunisation revealed the presence of dominant genotypes from those that had been used for vaccination. Circumstantial evidence for the involvement of one of the exotic vaccine parasites in epidemics in Southern Province is presented and a hypothesis formulated for the rapid spread of this genotype. Analysis of the characterisation data suggested the existence of two groups of T. parva parasites of different origin. The classic T. parva group, characterised by a dimorphism of the p150, p104 and p32 loci and the absence of a p67 insert and a buffalo-derived group which showed a polymorphism of p150, p104 and p32 and the presence of a p67 insert. There is evidence that recombination occurs, resulting in parasites that have characteristics of both groups. The relevance of these recombinant parasites in the epidemiology of the disease seems low. Characterisation of larger samples from areas of regular buffalo-cattle contact is necessary to clarify this. Sequence analysis of the most discriminative locus (PIM) was undertaken and gene conversion could be the main mechanism generating diversity. A more appropriate nomenclature for T. parva is proposed based on the growing evidence of molecular differences among isolates and stocks.

As climate change continues to permeate the current political discourse and its effects becomes increasingly visible, the way countries respond to the situation is crucial for determining the extent of future environmental degradation. The Paris Agreement is an attempt to mitigate and adapt to the situation, however the western values tied to it have been criticised. The effectiveness of democracy in environmental protection has been questioned, especially its ties to capitalism and individualism. This thesis uses the theory of authoritarian environmentalism to investigate this debate and see whether the claims have any legitimacy in the context of the Paris Agreement and the promises made in relation to it.     This thesis is a structured focused comparison which compares the policies and projects in three democratic and three autocratic African countries in close geographical proximity and similar environmental situations, to investigate if and in what way the type of government affects the promises made, and whether they are kept, to the Paris Agreement and its signatories. The indicators used for the thesis include policies and internationally funded projects, due to their accessibility, however it is worth noting that they only give a crude approximation of the activities and ambition in the countries, with several others having important roles.    The quality of the six countries’ Intended Nationally Determined Contributions is investigated and followed up with an evaluation of some of the projects active to examine if the countries are implementing their promised efforts, already in these early, yet important, stages of the Agreement. In addition, the theory is applied to the countries’ efforts and some conclusions are reached, including the overall good quality of the countries’ environmental work and confirming that authoritarian countries can produce quality policies, while still having lacking areas, similar to their democratic counterparts, pointing to the complexity of the topic.

Le vieillissement de la population mondiale s’accompagne de l’augmentation de la prévalence d’un certain nombre de maladies chroniques incluant la démence. Si les études épidémiologiques sur les troubles cognitifs ont été et sont encore majoritairement menées dans les pays occidentaux, peu d’entre elles sont conduites dans les pays à faible et moyen revenus, comme les pays africains, qui ne sont pourtant pas épargnés par le phénomène. Le programme EPIDEMCA, Épidémiologie des Démences en Afrique Centrale, a pour objectif principal de contribuer à une meilleure connaissance de la démence et particulièrement de la maladie d’Alzheimer en zones rurale et urbaine de deux pays d’Afrique Centrale : la République Centrafricaine (RCA) et la République du Congo (Congo). Mon travail de thèse, s’inscrivant dans le cadre de ce programme, a pour objectif général de contribuer à une meilleure connaissance des troubles cognitifs (Mild Cognitive Impairment (MCI) et démence) par l’étude du lien entre les troubles cognitifs et les facteurs psychosociaux (événement de vie stressants et trouble de la personnalité dépendante) d’une part, et nutritionnels (dénutrition et consommation alimentaire) d’autre part. Le programme EPIDEMCA est une enquête épidémiologique transversale multicentrique en population générale âgée de 65 ans et plus menée en deux phases dans une zone rurale et une zone urbaine de RCA et du Congo entre 2011 et 2012. Les diagnostics de démence et de MCI étaient posés respectivement selon les critères du DSM-IV et de Petersen. Sur 2 002 sujets ayant accepté de participer à l’enquête, le statut cognitif et l’âge étaient disponibles pour 1 772 dont 1519 étaient indemnes de troubles cognitifs, 118 étaient atteints de MCI et 135 de démence. Concernant les facteurs psychosociaux, les résultats de notre première étude ont montré que le MCI était positivement associé au nombre total d’événements vécus sur la vie entière uniquement au Congo alors qu’il l’était au nombre total d’événements survenus à partir de l’âge de 65 ans et à une maladie physique grave chez un enfant après l’âge de 65 ans dans l’échantillon total. En revanche, la démence n’était associée ni à l’accumulation d’événements de vie, ni aux événements pris séparément. Les résultats de notre deuxième étude ont montré que le MCI était associé au trouble de la personnalité dépendante au Congo comme en RCA, alors que la démence ne l’était seulement au Congo.Du côté nutritionnel, notre troisième étude a montré une association significative entre la démence (mais pas le MCI) et les trois indicateurs de dénutrition utilisés (IMC inférieur à 18,5 kg/m2, périmètre brachial inférieur à 24 cm et circonférence musculaire brachiale (CMB) inférieure au 5ème percentile d’une population de référence) en RCA. Au Congo, le MCI était associé seulement à la CMB inférieure au 5ème percentile alors que la démence ne l’était à aucun indicateur. Notre quatrième étude a, quant à elle, trouvé qu’en RCA, les troubles cognitifs étaient associés à une consommation modérée d’alcool dans l’échantillon total ainsi qu’à une faible consommation d’oléagineux en zone rurale. Au Congo, en revanche, ils n’étaient associés à aucun groupe d’aliments ni même à la consommation d’alcool. Les travaux de cette thèse ont permis de contribuer à l’amélioration des connaissances sur l’épidémiologie des troubles cognitifs en Afrique centrale. Il n’en demeure pas moins que nos résultats ne sont qu’exploratoires et devront être confirmés par des études ultérieures, nécessaires préalables à la planification d’actions pertinentes et ciblées susceptibles de réduire le risque. / With the aging of the world population, prevalence of non-communicable diseases including dementia is increasing. While epidemiological studies on cognitive impairments have been mainly conducted in high-income countries, a few have been carried out in low-and middle-income countries, including African countries, not exempt from this phenomenon. The EPIDEMCA program, Epidemiology of Dementia in Central Africa, is aimed at contributing to a better understanding of dementia and Alzheimer's disease in rural and urban areas in two countries of Central Africa: the Central African Republic (CAR) and the Republic of Congo (ROC). This PhD thesis, which is part of this program, focuses on the relationship between cognitive disorders (Mild Cognitive Impairment (MCI) and dementia) and psychosocial factors (stressful life events and dependent personality disorder) on the one hand, and nutritional factors (undernutrition and dietary consumption) on the other.The EPIDEMCA program is a cross-sectional multicenter population-based epidemiological study carried out among people aged 65 years and over in rural and urban areas of CAR and ROC between 2011 and 2012 using a two-phase design. DSM-IV and Petersen criteria were required for a diagnosis of dementia and MCI, respectively. Among 2002 subjects who agreed to participate in the study, cognitive status and reliable age were available for 1772 people: 1519 were free of cognitive impairment, 118 suffered from had MCI and 135 from had dementia. As regards the psychosocial factors, our first study showed that MCI was positively associated with the total number of events experienced throughout a life span in Congo only, and, with the total number of events from the age of 65 onwards and with a child’s severe physical disease after the age of 65 in the total sample. On the contrary, dementia was associated with neither the accumulation of stressful life events nor individual events. Results of our second study showed that MCI was associated with the dependent personality disorder in Congo and CAR, while dementia was associated with this disorder in Congo only. Regarding nutritional factors, our third study showed a significant association between dementia (but not MCI) and the three markers of undernutrition used (BMI inferior to 18.5 kg/m2, mid-upper arm circumference inferior to 24 cm and arm muscle circumference (AMC) below the 5th percentile of a reference population) in CAR. In Congo, MCI was associated with only the AMC<5th percentile while dementia with none of markers. Our fourth study found that cognitive disorders were associated with light alcohol intake and a low consumption of oilseeds in rural areas only. In Congo, cognitive disorders were associated with neither food groups nor alcohol consumption. This PhD thesis has contributed to improve the knowledge available on the epidemiology of cognitive disorders in Central Africa. Nevertheless, our results are solely exploratory and require to be confirmed by further studies, prerequisites for relevant and targeted interventions with a view to reduce the risk.

Le vieillissement de la population est en train de devenir un enjeu de politique majeur. Il a pour conséquence une augmentation de la prévalence des maladies non transmissibles, dont les démences. La démence est un problème de santé publique dans le monde et en Afrique subsaharienne. Elle est assimilée à un véritable « tsunami Alzheimer », du fait du nombre croissant de personnes atteintes de démence. Dans 50% des cas, elles peuvent être prises en charge dans les établissements d’hébergement pour personnes âgées dépendantes ou par des soignants professionnels en ambulatoire dans les pays à revenus élevés. Dans les pays à revenus moyens ou faibles, leur prise en charge est dite informelle et est réalisée par les aidants informels ni formés ni encouragés. Ces aidants ont des liens de parenté de type filiation, alliance et germanité. En Afrique subsaharienne, les maladies mentales sont riches en représentations socioculturelles péjoratives et dévalorisantes. L’objectif principal était de décrire les facteurs socio-économiques et familiaux du processus de stigmatisation dont sont victimes les personnes atteintes de démence en zones urbaine et rurale en République du Congo. Une étude ethnologique a été menée grâce à une immersion de trois mois sur le terrain. Les entretiens non directifs menés en langues locales (Lingala, Kituba, Mbochi, Téké, Lari) et officielle (Français), complétés par des observations participantes, ont permis de recueillir toutes les données. Elles étaient transcrites littéralement avant leur classement en thèmes. Les aidants informels étaient essentiellement des belles-filles et petites-filles. Ces dernières ont été considérées comme des pourvoyeuses des soins informels d’une durée estimée entre 10 à 15 heures par jour, contre les belles-filles, considérées comme des maltraitantes, pour une disponibilité de 2 à 6 heures par jour. L’irrégularité de revenus des aidants informels associés aux représentations socioculturelles des personnes atteintes de démence entraînaient d’abord leur prise en charge par les églises syncrétiques, comportant des diètes strictes pour les séances d’exorcisme. Le deuxième recours était les guérisseurs traditionnels utilisant les plantes médicinales, les incantations-prières et les scarifications. Quelques personnes atteintes de démence ont été accusées de sorcellerie et condamnées en public devant une juridiction coutumière, cette accusation constituant la forme majeure de stigmatisation. En République du Congo comme en Afrique subsaharienne, la maladie se construit à partir de noyaux de symboles puisés dans la culture. / The aging population is becoming a major political issue. It results in an increase in the prevalence of non-communicable diseases including dementia. Dementia is a major public health problem worldwide and in sub-Saharan Africa. It is assimilated to a real "Alzheimer tsunami", because of the growing number of people with dementia. In 50% of cases, they are taken care of in residential care facilities for dependent elderly people or by ambulatory professionals in high-income countries. By cons, in low and middle incomes countries, their taken care is informal, provided by informal caregivers who are neither trained nor encouraged, having links of kinship as filiation, alliance and germanic with people with dementia. In sub- Saharan Africa, mental illnesses are rich in pejorative and demeaning sociocultural representations. The main objective was to describe socio-economic and family factors in the process of stigmatization of people with dementia in urban and rural areas in the Republic of Congo. An ethnological study was conducted in three months’ immersion on the ground. Non-directive interviews conducted in the local (Lingala, Kituba, Mbochi, Teke and Lari) and official languages (French) and complemented by participant observation were used to collect all the data. They were literally transcribed before their classification into themes. Informal caregivers were mainly daughters-in-law and granddaughters. The latter were considered as purveyors of informal care to an estimated duration between 10 to 15 hours a day, against daughters-in-law considered abusers and available between 2 to 6 hours per day. The irregular income of informal caregivers associated with the socio-cultural representations of people with dementia first led to their care by the syncretic churches, with strict diets for exorcism sessions. The second resort was traditional healers using medicinal plants, prayers-incantations and scarifications. Some people with dementia were accused of witchcraft and condemned in public in front of a customary jurisdiction. This accusation of witchcraft was the major form of stigmatization. In the Republic of Congo as in sub-Saharan Africa, the disease is constructed from nuclei of symbols from culture.