title: Nonlinear effect of climate on plague during the third pandemic in China.
abstract: Over the years, plague has caused a large number of deaths worldwide and subsequently changed history, not the least during the period of the Black Death. Of the three plague pandemics, the third is believed to have originated in China. Using the spatial and temporal human plague records in China from 1850 to 1964, we investigated the association of human plague intensity (plague cases per year) with proxy data on climate condition (specifically an index for dryness/wetness). Our modeling analysis demonstrates that the responses of plague intensity to dry/wet conditions were different in northern and southern China. In northern China, plague intensity generally increased when wetness increased, for both the current and the previous year, except for low intensity during extremely wet conditions in the current year (reflecting a dome-shaped response to current-year dryness/wetness). In southern China, plague intensity generally decreased when wetness increased, except for high intensity during extremely wet conditions of the current year. These opposite effects are likely related to the different climates and rodent communities in the two parts of China: In northern China (arid climate), rodents are expected to respond positively to high precipitation, whereas in southern China (humid climate), high precipitation is likely to have a negative effect. Our results suggest that associations between human plague intensity and precipitation are nonlinear: positive in dry conditions, but negative in wet conditions.
authors.affiliation: State Key Laboratory of Integrated Management on Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Liu
authors.forename: Leif Chr
authors.initials: LC
authors.lastname: Stige
authors.forename: Tamara
authors.initials: T
authors.lastname: Ben Ari
authors.forename: Xiye
authors.initials: X
authors.lastname: Fang
authors.forename: Kung-Sik
authors.initials: KS
authors.lastname: Chan
authors.forename: Shuchun
authors.initials: S
authors.lastname: Wang
authors.forename: Nils Chr
authors.initials: NC
authors.lastname: Stenseth
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002681:China / Q000453:epidemiology; D002980:Climate; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D010930:Plague / Q000453:epidemiology* / Q000266:history