Éditeur(s) : HAL CCSD
Résumé : International audience
Space technologies have been used increasingly for assessing the risk of infection by vector-borne diseases, providing tools for delimiting the distribution of vectors. As rodent-borne diseases are a growing concern in Thailand since the emergence of leptospirosis starting in 1998, this study was set up to determine the hazard, related to the potential presence of the main rodent with medical importance, Bandicota indica (Bechstein, 1800), the great bandicoot rat, widely distributed in the country. It was conducted in Nakhon Pathom province (west of Bangkok, Thailand) following a large rodent sampling. Habitats of Bandicota indica were delimited using a Landsat 5 Thematic Mapper image and Multiscope remote sensing software (Fleximage, France). Environmental variables, related to its ecology, were identified by describing the place and surroundings of each capture. An extrapolation to the entire province could generate the potential distribution of Bandicoot rats. This delineation helped at first to improve further sampling ofBandicota indica and adapt the model to other study areas. Furthermore it allowed developing researches on the dynamics of rodents and the risk of transmission of rodent-borne diseases.
Natural History Journal of Chulalongkorn University

ird-00714409
http://hal.ird.fr/ird-00714409
http://hal.ird.fr/ird-00714409/document
IRD : fdi:010045886

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The Black Rat (Rattus rattus) spread out of Asia to become one of the world's worst agricultural and urban pests, and a reservoir or vector of numerous zoonotic diseases, including the devastating plague. Despite the global scale and inestimable cost of their impacts on both human livelihoods and natural ecosystems, little is known of the global genetic diversity of Black Rats, the timing and directions of their historical dispersals, and the risks associated with contemporary movements. We surveyed mitochondrial DNA of Black Rats collected across their global range as a first step towards obtaining an historical genetic perspective on this socioeconomically important group of rodents. We found a strong phylogeographic pattern with well-differentiated lineages of Black Rats native to South Asia, the Himalayan region, southern Indochina, and northern Indochina to East Asia, and a diversification that probably commenced in the early Middle Pleistocene. We also identified two other currently recognised species of Rattus as potential derivatives of a paraphyletic R.rattus. Three of the four phylogenetic lineage units within R. rattus show clear genetic signatures of major population expansion in prehistoric times, and the distribution of particular haplogroups mirrors archaeologically and historically documented patterns of human dispersal and trade. Commensalism clearly arose multiple times in R. Rattus and in widely separated geographic regions, and this may account for apparent regionalism in their associated pathogens. Our findings represent an important step towards deeper understanding the complex and influential relationship that has developed between Black Rats and humans, and invite a thorough re-examination of host-pathogen associations among Black Rats.
PLoS ONE

ird-00714383
http://hal.ird.fr/ird-00714383
http://hal.ird.fr/ird-00714383/document
DOI : 10.1371/journal.pone.0026357
IRD : fdi:010055548

Éditeur(s) : HAL CCSD
Résumé : International audience
Hantaviruses' distribution is reassessed after performing a cladistic analysis on 93 strains isolated from rodents, and one used as out-group: Thottapalayam isolated from a shrew. While most hantaviruses found in wild animals were collected in northern Asia, Europe, North America, and South America, only Thottapalayam and Thailand were found in South and Southeastern Asia. Thottapalayam is highly divergent from the other known hantaviruses and may represent the emerging tip of a different lineage. Serological surveys carried out to detect evidence of Hantavirus in human populations revealed positive samples not only in West and Central Africa but also in Thailand, with a first case recently confirmed. This suggests that Hantaan-related viruses may infect humans out of their well-documented range. Thus, if rodents are probably the primary reservoir, other mammals may be involved in the cycle of hantaviruses. Additional work is needed out of the traditional areas where hantaviruses have been recorded. New viruses, different hosts, and different human syndromes may be discovered in the future mainly in Southeastern Asia and in Africa where Muridae rodents are present and highly diversified.
Annals New York Academy of Sciences

ird-00714427
http://hal.ird.fr/ird-00714427
http://hal.ird.fr/ird-00714427/document
DOI : 10.1196/annals.1373.004
IRD : fdi:010045640