Jean-Pierre Quéré

An epidemiological and ecological study of human alveolar echinococcosis transmission in south Gansu, China.

Human alveolar echinococcosis (AE) is usually a rare, highly pathogenic zoonotic disease, transmitted across the northern hemisphere between fox and rodent hosts. In China the first cases were described in 1965; however very few epidemiological studies have been undertaken since. Following identification in 1991 of a serious focus of human AE in south Gansu province, detailed village-based community and ecological studies were carried out between 1994 and 1997. Hepatic ultrasound mass screening with serological testing (five tests) identified 84/2482 new AE cases (3%). An overall prevalence of 4.1% (135/3331) was recorded for the area when previous cases were also included. Based on a seropositive result only, without an ultrasound scan indication, no additional AE cases were identified. Of the evolutive AE cases, 96% were seropositive in at least one test, while up 15-20% of individuals who exhibited hepatic calcified lesions and 12-15% exhibiting hepatic nodular lesions were seropositive for specific Em2 or Em18 antibodies. Village (n=31) human AE prevalence rates varied from 0 to 15.8%. Questionnaire analysis indicated that total number of dogs owned over a period was a risk factor (P<0.006), but not a history of red fox hunting (P>0.6). Rodent ecology studies revealed an association between density indices of voles (Microtus limnophilus) and village AE prevalence rates, on the one hand, and village landscape characterised by a ratio of scrub/grassland to total area above 50% (P<0.005). Long-term transmission of Echinococcus multilocularis and risk of zoonotic infection of south Gansu farmers may be related ultimately to a process of deforestation driven by agriculture. This in turn probably results in creation of optimal peri-domestic habitats for rodents that serve as intermediate host species (such as M. limnophilus) and subsequent development of a peri-domestic cycle involving dogs.

Population dynamics of fossorial water vole (Arvicola terrestris scherman): a land use and landscape perspective

Abstract This study investigates the effect of land use, and landscape composition and structure on the population dynamics of fossorial water vole (Arvicola terrestris scherman Shaw). Water vole populations were monitored from 1989 to 1994 in the Doubs department, France, by using index methods. Land use patterns were studied based on agriculture and forestry data from the French Ministry of Agriculture collected in 1956, 1970, 1979 and 1988. Grassland quality and landscape structure were studied based on field transects, combined with the assessment of landscape structure from maps at 1:25,000 scale. Outbreaks of water vole populations occurred as a wave, spreading from epicentres over more than 2500 km2. The propagation speed was in excess of 10 km/yr. On a regional level (n × 10 km) and over 5 years and more, density variation patterns of water vole were linked to the ratio of ploughed land and of permanent grassland to farmland. At a sectional scale (n × 1 km), forests and uncultivated lands had a dampening effect both on the outbreaks and on their duration. The evolution of farmlands from 1956 to 1988 was apparently the major cause of increase in density variations of water vole. Therefore, land use and landscape management could be a way to control water vole outbreaks, and their effects are discussed.

Interactions between landscape changes and host communities can regulate Echinococcus multilocularis transmission

An area close to the Qinghai-Tibet plateau region and subject to intensive deforestation contains a large focus of human alveolar echinococcosis while sporadic human cases occur in the Doubs region of eastern France. The current review analyses and compares epidemiological and ecological results obtained in both regions. Analysis of rodent species assemblages within quantified rural landscapes in central China and eastern France shows a significant association between host species for the pathogenic helminth Echinococcus multilocularis, with prevalences of human alveolar echinococcosis and with land area under shrubland or grassland. This suggests that at the regional scale landscape can affect human disease distribution through interaction with small mammal communities and their population dynamics. Lidickers ROMPA hypothesis helps to explain this association and provides a novel explanation of how landscape changes may result in increased risk of a rodent-borne zoonotic disease.

Land use patterns and types of common vole (Microtus arvalis) population kinetics

Abstract Various observed patterns of common vole ( Microtus arvalis ) population kinetics have been classified into five types according to two criteria: the time period of changes in abundance (season or year) and the presence or absence of local extinction. Some types may be subdivided into categories depending on the duration of population fluctuations. They can be ordinate along a gradient correlated to the importance of permanent grassland in farmland and we suggest that this correlation is mainly due to the fact that a major predator ( Mustela nivalis ) can use grassy landscape elements as refuges and easily disrupt population kinetics from low abundance and smooth variations to large amplitude cycles with pullulation periods. Thus major shifts in land use patterns towards a dominance of grassland can enhance the abundance of a pest species such as the common vole. Local extinctions and recolonization as observed in type IV are characteristics of metapopulation. Further field data of local vole populations will be very useful in the development of predictive models.

Effect of landscape structure on Common Vole (Microtus arvalis) distribution and abundance at several space scales

This paper aims to answer the following question: are the fluctuations of abundance of Common Vole (Microtus arvalis) specific to different types of landscapes? The research was carried out in landscapes where grassland was dominant. The sampling method was based upon a partition in both landscape types and landscape units. Tracking of vole indices was used to evaluate their relative abundance. Six landscape transects were sampled during two successive years. Results show that population variation and diffusion of demographic states are closely related to landscape types. The possible causes of this are discussed. The landscape units can be used as global variables to assess outbreak risk and landscape design can be used to prevent them.

Divergent evolutionary processes associated with colonization of offshore islands

Oceanic islands have been a test ground for evolutionary theory, but here, we focus on the possibilities for evolutionary study created by offshore islands. These can be colonized through various means and by a wide range of species, including those with low dispersal capabilities. We use morphology, modern and ancient sequences of cytochrome b (cytb) and microsatellite genotypes to examine colonization history and evolutionary change associated with occupation of the Orkney archipelago by the common vole (Microtus arvalis), a species found in continental Europe but not in Britain. Among possible colonization scenarios, our results are most consistent with human introduction at least 5100 bp (confirmed by radiocarbon dating). We used approximate Bayesian computation of population history to infer the coast of Belgium as the possible source and estimated the evolutionary timescale using a Bayesian coalescent approach. We showed substantial morphological divergence of the island populations, including a size increase presumably driven by selection and reduced microsatellite variation likely reflecting founder events and genetic drift. More surprisingly, our results suggest that a recent and widespread cytb replacement event in the continental source area purged cytb variation there, whereas the ancestral diversity is largely retained in the colonized islands as a genetic ‘ark’. The replacement event in the continental M. arvalis was probably triggered by anthropogenic causes (land‐use change). Our studies illustrate that small offshore islands can act as field laboratories for studying various evolutionary processes over relatively short timescales, informing about the mainland source area as well as the island.

A relict bank vole lineage highlights the biogeographic history of the Pyrenean region in Europe.

The Pyrenean region exhibits high levels of endemism suggesting a major contribution to the phylogeography of European species. But, to date, the role of the Pyrenees and surrounding areas as a glacial refugium for temperate species remains poorly explored. In the current study, we investigated the biogeographic role of the Pyrenean region through the analyses of genetic polymorphism and morphology of a typical forest‐dwelling small mammal, the bank vole (Myodes glareolus). Analyses of the mitochondrial cytochrome b gene and the third upper molar (M3) show a complex phylogeographic structure in the Pyrenean region with at least three distinct lineages: the Western European, Spanish and Basque lineages. The Basque lineage in the northwestern (NW) Pyrenees was identified as a new clearly differentiated and geographically localized bank vole lineage in Europe. The average M3 shape of Basque bank voles suggests morphological differentiation but also restricted genetic exchanges with other populations. Our genetic and morphological results as well as palaeo‐environmental and fossils records support the hypothesis of a new glacial refugium in Europe situated in the NW Pyrenees. The permissive microclimatic conditions that prevailed for a long time in this region may have allowed the survival of temperate species, including humans. Moreover, local differentiation around the Pyrenees is favoured by the opportunity for populations to track the shift of the vegetation belt in altitude rather than in latitude. The finding of the Basque lineage is in agreement with the high level of endemic taxa reported in the NW Pyrenees.

Epidemiology of alveolar echinococcosis in Xinjiang Uygur autonomous region, China: a preliminary analysis

The Xinjiang Uygur autonomous region (XUAR) in north-western China is known to be endemic for Echinococcosis multilocularis, the causative agent of human alveolar echinococcosis (HAE). Despite regular reports of HAE cases in their region, very little is known about the local epidemiology of the disease or the transmission of E. multilocularis. The epidemiology of HAE in Xinjiang has now been investigated by the analysis of data collected from the medical records of 157 clinical cases who had attended the four main hospitals in the region. These data indicate that the disease is relatively common in the Altai, western Junggar, and Tianshan mountain ranges, whereas the Tarim and Junggar basins are likely to be of low endemicity. The prevalence of the disease in the Kunlun mountains is not clear. Semi-nomadic groups, especially those of Kazakh or Mongol origin, have a higher risk of infection than other ethnic groups. Prevalence of the disease in humans appears to be correlated with aspects of the local climate, such as annual precipitation and temperature. Red foxes, Microtinae, Ochotona spp. and Marmota spp. may be important hosts of E. multilocularis in the XUAR, sustaining the transmission cycles of the parasite.

Dietary response of Barn Owls (Tyto alba) to large variations in populations of common voles (Microtus arvalis) and European water voles (Arvicola terrestris)

The diet of the Barn Owl (Tyto alba (Scopoli, 1769)) was studied over an 8-year period in the Jura mountains of France, during two population surges of its main rodent prey (common voles (Microtus arvalis (Pallas, 1778)) and European water voles (Arvicola terrestris (L.,1758))), allowing us to test whether T. alba is an opportunistic predator as is often cited in the literature or exhibits more complex patterns of prey selection as is reported in arid environments. Small mammals were sampled by trapping and index methods. We observed (i) significant correlations between the proportions of A. terrestris and M. arvalis and woodland rodents in the diet and their respective densities in the field; (ii) interactions between populations of A. terrestris and M. arvalis, indicating that the proportion of each species in diet was affected by the density of the other; (iii) proportions of red-toothed shrews (genus Sorex (L., 1758)) in the diet did not correlate with their abundance in the field, indicating that those species were likely to be preyed upon when others were no longer available. This confirms that T. alba is generally opportunistic; however, prey selection of a focal species (e.g., Sorex spp., grassland species) can be affected by the density or availability of the other prey species

Small-mammal assemblage response to deforestation and afforestation in central China

Abstract Deforestation is a major environmental issue driving the loss of animal and plant species. Afforestation has recently been promoted to conserve and restore Chinese forest ecosystems. We investigated the distribution of small-mammal assemblages in an area where forest and associated deforestation habitats dominate, and in an agricultural area where afforestation is ongoing in the Loess Plateau of southern Ningxia Autonomous Region, P.R. China. Multiple trapping was used. Assemblages were defined based on the multinomial probability distribution and information theory. Species turnover between assemblages of deforested and afforested habitats was high, although no clear effect on species richness was observed. The two assemblages described along the deforestation gradient displayed higher diversity, whereas diversity was lower in assemblages identified in afforested habitats where Cricetulus longicaudatus, a known agricultural pest in various areas of China, clearly dominated. The threatened Sorex cylindricauda and Eozapus setchuanus were recorded along the deforestation gradient but not in plantations. Therefore, habitats present along a deforestation succession in this part of Ningxia sustain a high diversity of small mammals and include species of conservation concern. At the present stage of its process (maximum 15 years), afforestation in southern Ningxia favours the dominance of an agricultural pest.