No English title available

• Main Author: Mélade, Julien
• Other Authors: Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Université de La Réunion (UR)-Institut National de la Santé et de la Recherche Médicale (INSERM)-IRD-Centre National de la Recherche Scientifique (CNRS), Université de la Réunion, Koussay Dellagi, Hervé Pascalis
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2015
• Subjects: Wild fauna; Zoonoses; Biodiversity; Lyssaviruses; Paramyxoviruses; “host-Switch”; Faune sauvage; Biodiversité; Lyssavirus; Paramyxovirus; « Host-Switch »; [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases; [SDV.EE.SANT]Life Sciences [q-bio]/Ecology; environment/Health; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BBM]Life Sciences [q-bio]/Biochemistry; Molecular Biology; Rattus rattus
• Online Access: https://theses.hal.science/tel-01326944; https://theses.hal.science/tel-01326944/document; https://theses.hal.science/tel-01326944/file/2015lare0030_JMelade_dif.pdf

Since many decades, the wild fauna has been incriminated as an important reservoir of many zoonotic pathogens (Nipah, Hendra, Ebola, Hantaan viruses etc.) at risk for humans. Tropical and subtropical islands of the South West Indian Ocean (SWIO) are part of the 34 areas of the world recognized as "hotspot" of biodiversity. They are characterized by a strong wildlife endemism especially on Madagascar. The multi-island structure of the SWIO region, the diversity of its biotopes and its biogeographical human disparities, offer a unique opportunity to investigate "in natura" the evolutionary dynamics of infectious agents and the host-virus relationships. Our research has focused on two models of negative RNA viruses, paramyxoviruses and lyssaviruses. The first virus model allowed us to address issues related to the dynamics of viral transmission within a host community, in particular, bats and small terrestrial mammals of Madagascar and to identify the driving factors, especially bio-ecological factors associated with their hosts, affecting the dynamic of transmission and of viral diversification. The second model allowed us to describe on the islands of the SWIO, the intense circulation of bats lyssaviruses in this multi-island system which bats are endemic to this region. Overall, our investigations highlighted (i) intense viral exchanges ("host-switch") between bats, endemic terrestrial small mammals and introduced rodents from Madagascar, (ii) the role of these mammals as major viral reservoir and (iii) the key role played by Rattus rattus as viral spreader. Furthermore, we identified both the phenomenon of "host-switch" as the major macro-evolutionary mechanism among bat paramyxoviruses from Madagascar and the importance of biotic and abiotic factors in shaping the transmission dynamics and viral diversification. La faune sauvage a été depuis longtemps incriminée dans la survenue de zoonoses et joue le rôle de réservoir d'agents pathogènes (virus Nipah, Hendra, Ebola, Hantaan etc.) pour l'homme. Les îles ...