Le travail présenté dans ce manuscrit traite des mécanismes d'émergence des maladies infectieuses. Une première partie du texte est consacrée à la réflexion menée sur ces processus, et à leurs conséquences pour la gestion des maladies. Dans une deuxième partie nous exposons les travaux de modélisation réalisés ; l’objectif est de tester si des changements dans l'expression d'une infection peuvent être expliqués par la dynamique de circulation de l'agent infectieux dans la population hôte, à travers la protection de groupe. Nous montrons que l'apparition de la maladie de Carré chez les lions du Serengeti peut être due à une perte d’immunité de groupe suite à l’extinction du virus. Nous étudions ensuite les conséquences sur le patron épidémique d'une protection partiellement croisée entre souches. Enfin, nous intégrons à cette problématique la structure spatiale de la population hôte, pour expliquer des observations faites sur les systèmes lagomorphes/lagovirus en France. / The study presented here aims to suggest and to test several mechanisms to explain how infectious diseases impact could increase, in relation to microparasite circulation and loss of herd protection. We first introduce the main characteristics of host/microparasite interaction and display some knowledge about emerging infectious diseases, and their consequences for diseases control. Stochastic modelling is then used to study epidemic patterns under several hypotheses and for different host/parasite systems: i) we explain canine distemper emergence in Serengeti lions through a break in virus circulation and the resulting loss of herd immunity; ii) we study the consequences of partial crossprotection induced in hosts by different strains in a small homogeneous host population; and iii) we extend this study to spatially structured host populations to explain data observed in lagomorphs/lagoviruses in France.

Le travail présenté dans ce manuscrit traite des mécanismes d'émergence des maladies infectieuses. Une première partie du texte est consacrée à la réflexion menée sur ces processus, et à leurs conséquences pour la gestion des maladies. Dans une deuxième partie nous exposons les travaux de modélisation réalisés ; l'objectif est de tester si des changements dans l'expression d'une infection peuvent être expliqués par la dynamique de circulation de l'agent infectieux dans la population hôte, à travers la protection de groupe. Nous montrons que l'apparition de la maladie de Carré chez les lions du Serengeti peut être due à une perte d'immunité de groupe suite à l'extinction du virus. Nous étudions ensuite les conséquences sur le patron épidémique d'une protection partiellement croisée entre souches. Enfin, nous intégrons à cette problématique la structure spatiale de la population hôte, pour expliquer des observations faites sur les systèmes lagomorphes/lagovirus en France.

The Mara River Basin (MRB) is endowed with pristine biodiversity, socio-cultural heritage and natural resources. The purpose of my study is to develop and apply an integrated water resource allocation framework for the MRB based on the hydrological processes, water demand and economic factors. The basin was partitioned into twelve sub-basins and the rainfall runoff processes was modeled using the Soil and Water Assessment Tool (SWAT) after satisfactory Nash-Sutcliff efficiency of 0.68 for calibration and 0.43 for validation at Mara Mines station. The impact and uncertainty of climate change on the hydrology of the MRB was assessed using SWAT and three scenarios of statistically downscaled outputs from twenty Global Circulation Models. Results predicted the wet season getting more wet and the dry season getting drier, with a general increasing trend of annual rainfall through 2050. Three blocks of water demand (environmental, normal and flood) were estimated from consumptive water use by human, wildlife, livestock, tourism, irrigation and industry. Water demand projections suggest human consumption is expected to surpass irrigation as the highest water demand sector by 2030. Monthly volume of water was estimated in three blocks of current minimum reliability, reserve (>95%), normal (80–95%) and flood (40%) for more than 5 months in a year. The assessment of water price and marginal productivity showed that current water use hardly responds to a change in price or productivity of water. Finally, a water allocation model was developed and applied to investigate the optimum monthly allocation among sectors and sub-basins by maximizing the use value and hydrological reliability of water. Model results demonstrated that the status on reserve and normal volumes can be improved to ‘low’ or ‘moderate’ by updating the existing reliability to meet prevailing demand. Flow volumes and rates for four scenarios of reliability were presented. Results showed that the water allocation framework can be used as comprehensive tool in the management of MRB, and possibly be extended similar watersheds.

This case study investigates perspectives and changes in gender roles in household activities from a gender (in)equality context in Tarime, northern Tanzania. The participants in this study part-took in a previous project called the Serengeti-Mara Ecosystem Project (SEMA) which aimed to integrate gender perspectives and sustainable livelihoods in rural parts of Tarime. Women in these areas often bear the primary responsibilities of caring for the household. The area is also controlled by male authority, and women are daily exposed to oppression and physical violence. Statistically, girls in the study area often miss the chance to higher education since boys are prioritized. Instead, girls risk the chances of early marriage and are exposed to female genital multination. So far, there has been little research on gender roles in household activities in these areas. Therefore, this case study strived to provide such material for future project operations. The main goal of this study was to investigate gender equality in households, focusing on how women and men describe norms linked to equality and gender roles in households, if norms and roles have changed after the project and if so, which circumstances have led to such a change. Both men and women were interviewed through semi-structured interviews, focus group interviews and informal interviews. The empirical data was later analyzed through the lens of the social role theory. Research findings showed that women are still living subordinate to men and unequal distribution of household duties still exists. However, education on equal rights and women empowerment from the SEMA project has changed people's perspectives on the matter, inspiring both women and men to fight for a sustainable change. The study explores root causes that hinder the implementation of equal rights. This study can contribute to more understanding of cultural traditions and finding new ways to sustain the implantation of equal rights. / Nyckelord: Fallstudie, könsroller, Tarime, norra Tanzania, ojämlikhet mellan könen, genusperspektiv, Serengeti-Mara Ecosystem Project (SEMA), hållbar försörjning, förtryck, fysiskt våld, kvinnlig könsstympning, hushållsaktiviteter, utbildning, jämställdhetDenna fallstudie undersöker perspektiv och förändringar i könsroller i hushållsaktiviteter i Tarime, norra Tanzania. Deltagarna i denna studie deltog i ett tidigare projekt kallat Serengati-Mara Ecosystem Project (SEMA) som syftade till att integrera genusperspektiv och hållbar försörjning på landsbygden i Tarime. Kvinnor i dessa områden bär ofta det primära ansvaret att ta hand om hushållet. Studieområdet kontrolleras också av manlig auktoritet och kvinnor utsätts dagligen för förtryck och fysiskt våld. Statistiskt sett saknar många flickor högre utbildning eftersom pojkarna är de främsta prioriterade. I stället ligger fokus på att flickor ska bli bortgifta och undergå kvinnlig könsstympning. Hittills har det gjorts lite forskning om könsroller i hushållsaktiviteter inom dessa områden. Därför strävade denna fallstudie efter att tillhandahålla sådant material för framtida projektverksamhet. Huvudmålet med denna studie var att undersöka jämställdhet i hushållen, med fokus på hur kvinnor och män beskriver normer kopplade till jämställdhet och könsroller i hushållen, om normer och roller har förändrats efter projektet och vilka omständigheter som i så fall har lett till sådan förändring. Både män och kvinnor intervjuades genom semistrukturerade intervjuer och fokusgruppsintervjuer. Den empiriska datan analyserades senare genom teorin om sociala roller. Forskningsresultat visade att kvinnor fortfarande lever under manligt styrande och att det fortfarande finns en ojämn fördelning av hushållsuppgifter. Utbildning om lika rättigheter och kvinnors egenmakt från SEMA-projektet har dock förändrat människors perspektiv på frågan, och inspirerat både kvinnor och män att kämpa för en hållbar förändring. Studien utforskar grundorsaker som hindrar genomförandet av lika rättigheter. Denna studie kan bidra till mer förståelse för kulturella traditioner och hitta nya sätt att upprätthålla införandet av lika rättigheter.