Éditeur(s) : HAL CCSD Kasetsart University
Résumé : http://www.ceropath.org/references/rodent_protocols_book
Technical book
"Protocols for field and laboratory rodent studies" present the best practices for the studies of rodents and rodent-borne pathogens and parasites from the field to the laboratory. It aims at covering the different steps of rodent studies: 1) Trapping, 2) Dissection and preparation of tissue samples for pathogens screening, 3) Identification of species, 4) Isolation of helminths, 5) Preparing rodent specimens for collections. This book gathers accurate recommendations and techniques, based on those generally accepted in the literature and adapted from the experience of the different authors during rodent surveys and laboratory work. Its presentation is designed to work in the fields with a clear and colorful organization of each chapter, with: inserts providing definitions and recommendations, protocols detailed step by step, and an emphasis on illustrations with several photographs. This book is a publication generated by the CERoPath project (Community Ecology of Rodents and their Pathogens in a changing environment, www.ceropath.org) funded by the French Ministry of Research from 2008 to 2011.
http://hal.ird.fr/ird-00714514

ird-00714514
http://hal.ird.fr/ird-00714514
http://hal.ird.fr/ird-00714514/document
IRD : fdi:010056183

Éditeur(s) : HAL CCSD American Society of Tropical Medicine and Hygiene
Résumé : International audience
We investigated infection of rodents and shrews by Leptospira spp. in two localities of Cambodia (Veal Renh, Kaev Seima) and in four types of habitat (forests, non-flooded lands, lowland rain-fed paddy fields, houses) during the wet and the dry seasons. Habitat preference was common, and rodent and shrew species were found only in houses or in rain-fed paddy fields or in forests. Among 649 small mammals trapped belonging to 12 rodent species and 1 shrew species, 71 of 642 animals tested were carriers of Leptospira according to the 16S ribosomal RNA marker used. Rodent infection was higher in low-slope locations, corresponding to rain-fed paddy fields, especially in the rainy season and in Kaev Seima. Rodents (Rattus exulans) and shrews (Suncus murinus) inhabiting households showed significantly low levels of infections, whereas rodents living in and near to forests (shrubby wasteland, orchards) showed high levels of infection.
American Journal of Tropical Medicine and Hygiene

pasteur-00808144
https://hal-riip.archives-ouvertes.fr/pasteur-00808144
DOI : 10.4269/ajtmh.2012.11-0349
PUBMED : 22665613

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
While the effects of deforestation and habitat fragmentation on parasite prevalence or richness are well investigated, host-parasite networks are still understudied despite their importance in understanding the mechanisms of these major disturbances. Because fragmentation may negatively impact species occupancy, abundance and co-occurrence, we predict a link between spatiotemporal changes in habitat and the architecture of host-parasite networks. For this, we used an extensive data set on 16 rodent species and 29 helminth species from seven localities of South-East Asia. We analysed the effects of rapid deforestation on connectance and modularity of helminth-parasite networks. We estimated both the degree of fragmentation and the rate of deforestation through the development of land uses and their changes through the last 20 to 30years in order to take into account the dynamics of habitat fragmentation in our statistical analyses. We found that rapid fragmentation does not affect helminth species richness per se but impacts host-parasite interactions as the rodent-helminth network becomes less connected and more modular. Our results suggest that parasite sharing among host species may become more difficult to maintain with the increase of habitat disturbance.
ISSN: 0021-8790

hal-01355307
https://hal.archives-ouvertes.fr/hal-01355307
DOI : 10.1111/1365-2656.12368
IRD : fdi:010064927

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 Thai Society of Higher Education Institutes on Environment
Résumé : International audience
Due to the high level of endemic species that they support and the high threats they are facing, such as unsustainable limestone quarrying, hunting and urbanization, limestone karsts are recognized as biodiversity hotspots needing urgent protection. The first aim of our study was to investigate the mammal rodent diversity of Thai limestone karsts. Our second aim was to examine the diversity at a finer scale than the species level (intraspecific biodiversity) using phylogeographic approaches. Therefore, we studied the phylogeographic structure of a threatened rodent, endemic to limestone karsts of Thailand, the Murinae Leopoldamys neilli. We sampled 76 limestone karsts in whole Thailand and live-trapped 444 rodents including 115 Leopoldamys neilli. Our study revealed an important rodent diversity in Thai limestone karsts. Besides endemic rodent species, karsts also host typical forest species to which they provide forest refugia in deforested regions. At the intraspecific level, our study revealed an unexpected high level of genetic differentiation within the rodent species L. neilli. As each limestone area of Thailand is characterized by a particular genetic lineage of L. neilli, the destruction of these karsts would lead to the disappearance of unique intraspecific strains not found elsewhere. Our results highlight the importance of protecting limestone habitats to preserve not only their interspecific but also intraspecific rodent diversity that is highly threatened as more than 20% of limestone karsts in Thailand have already been quarried. Management plans of limestone, a non-renewable resource, should urgently take into account this high biological importance of karsts.
The 1st EnvironmentAsia International Conference on "Environmental Supporting in Food and Energy Security: Crisis and Opportunity"
Bangkok, Thailand

ird-00714455
http://hal.ird.fr/ird-00714455
http://hal.ird.fr/ird-00714455/document
IRD : fdi:010056152

Éditeur(s) : HAL CCSD
Résumé : International audience
Background: Comparative analysis, which aims at investigating ecological and evolutionary patterns among species, may help at targeting reservoirs of zoonotic diseases particularly in countries presenting high biodiversity. Here, we developed a simple method to target rodent reservoirs using published studies screening microparasite infections. Methods: We compiled surveys of microparasites investigated in rodents trapped in Thailand. The data comprise a total of 17,358 rodents from 18 species that have been investigated for a total of 10 microparasites (viruses, bacteria and protozoans). We used residual variation of microparasite richness controlled for both rodent sample size and pathogens' screening effort to identify major rodent reservoirs and potential risky habitats. Results: Microparasite species richness was positively related to rodent sample size and pathogens' screening effort. The investigation of the residual variations of microparasite species richness showed that several rodent species harboured more pathogens than expected by the regression model. Similarly, higher pathogen richness than expected was observed in rodents living in non-flooded lands, forests and paddy fields. Conclusion: Our results suggest to target some rodent species that are not commonly investigated for pathogen screening or surveillance such as R. andamanensis or B. savilei, and that non-flooded lands and forests should be more taken into caution, whereas much surveys focused on paddy rice fields and households.
Infection Ecology and Epidemiology

ird-00714369
http://hal.ird.fr/ird-00714369
http://hal.ird.fr/ird-00714369v2/document
DOI : 10.3402/iee.v2iO.18637
IRD : fdi:010055557

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