title: Drivers of Echinococcus multilocularis transmission in China: small mammal diversity, landscape or climate?
abstract: BACKGROUND
  Human alveolar echinococcocosis (AE) is a highly pathogenic zoonotic disease caused by the larval stage of the cestode E. multilocularis. Its life-cycle includes more than 40 species of small mammal intermediate hosts. Therefore, host biodiversity losses could be expected to alter transmission. Climate may also have possible impacts on E. multilocularis egg survival. We examined the distribution of human AE across two spatial scales, (i) for continental China and (ii) over the eastern edge of the Tibetan plateau. We tested the hypotheses that human disease distribution can be explained by either the biodiversity of small mammal intermediate host species, or by environmental factors such as climate or landscape characteristics.
  
  
  RESULTS
  The distributions of 274 small mammal species were mapped to 967 point locations on a grid covering continental China. Land cover, elevation, monthly rainfall and temperature were mapped using remotely sensed imagery and compared to the distribution of human AE disease at continental scale and over the eastern Tibetan plateau. Infection status of 17,589 people screened by abdominal ultrasound in 2002-2008 in 94 villages of Tibetan areas of western Sichuan and Qinghai provinces was analyzed using generalized additive mixed models and related to epidemiological and environmental covariates. We found that human AE was not directly correlated with small mammal reservoir host species richness, but rather was spatially correlated with landscape features and climate which could confirm and predict human disease hotspots over a 200,000 km(2) region.
  
  
  CONCLUSIONS
  E. multilocularis transmission and resultant human disease risk was better predicted from landscape features that could support increases of small mammal host species prone to population outbreaks, rather than host species richness. We anticipate that our study may be a starting point for further research wherein landscape management could be used to predict human disease risk and for controlling this zoonotic helminthic.
authors.affiliation: Chrono-environment, University of Franche-Comte, CRNS, Besançon, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Giraudoux
authors.forename: Francis
authors.initials: F
authors.lastname: Raoul
authors.forename: David
authors.initials: D
authors.lastname: Pleydell
authors.forename: Tiaoying
authors.initials: T
authors.lastname: Li
authors.forename: Xiuming
authors.initials: X
authors.lastname: Han
authors.forename: Jiamin
authors.initials: J
authors.lastname: Qiu
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.forename: Hu
authors.initials: H
authors.lastname: Wang
authors.forename: Akira
authors.initials: A
authors.lastname: Ito
authors.forename: Philip S
authors.initials: PS
authors.lastname: Craig
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D044822:Biodiversity; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D002980:Climate; D004197:Disease Reservoirs; D004444:Echinococcosis, Hepatic / Q000453:epidemiology* / Q000635:transmission*; D048210:Echinococcus multilocularis / Q000302:isolation & purification*; D005260:Female; D005843:Geography; D006801:Humans; D008297:Male; D008322:Mammals / Q000145:classification; D008875:Middle Aged; D012307:Risk Factors; D055815:Young Adult