Spatiotemporal expansion of human brucellosis in Shaanxi Province, Northwestern China and model for risk prediction

Abstract

Background Human brucellosis imposes a heavy burden on the health and economy of endemic regions. Since 2011, China has reported at least 35,000 human brucellosis cases annually, with more than 90% of these cases reported in the northern. Given the alarmingly high incidence and variation in the geographical distribution of human brucellosis cases, there is an urgent need to decipher the causes of such variation in geographical distribution. Method We conducted a retrospective epidemiological study in Shaanxi Province from January 1, 2005 to December 31, 2018 to investigate the association between meteorological factors and transmission of human brucellosis according to differences in geographical distribution and seasonal fluctuation in northwestern China for the first time. Results Human brucellosis cases were mainly distributed in the Shaanbei upland plateau before 2008 and then slowly extended towards the southern region with significant seasonal fluctuation. The results of quasi-Poisson generalized additive mixed model (GAMM) indicated that air temperature, sunshine duration, rainfall, relative humidity, and evaporation with maximum lag time within 7 months played crucial roles in the transmission of human brucellosis with seasonal fluctuation. Compared with the Shaanbei upland plateau, Guanzhong basin had more obvious fluctuations in the occurrence of human brucellosis due to changes in meteorological factors. Additionally, the established GAMM model showed high accuracy in predicting the occurrence of human brucellosis based on the meteorological factors. Conclusion These findings may be used to predict the seasonal fluctuations of human brucellosis and to develop reliable and cost-effective prevention strategies in Shaanxi Province and other areas with similar environmental conditions.

Changes in the epidemiological characteristics of human brucellosis in Shaanxi Province from 2008 to 2020

“…Human brucellosis had an apparent north-to-south geographic expansion trend. Similarly, previous reports concerning the spatiotemporal expansion of brucellosis in Shaanxi Province showed that human cases slowly extended towards the southern region, with significant seasonal fluctuations 10 . Moreover, the incidence rate has declined in previously epidemic northern Shaanxi regions (Yulin, Yan'an, and Weinan Cities), in contrast to the yearly increases in some emerging Guanzhong and southern Shaanxi epidemic regions, such as Hancheng and Xianyang.…”

“…The latest study focuses on the spatial and temporal distributions and model for risk prediction of human brucellosis in Shaanxi Province between 2005 and 2018. This study showed that human brucellosis cases were mainly distributed in the Shaanbei upland plateau before 2008 and then slowly extended towards the southern region with significant seasonal fluctuations 10 . Multiple climatic factors (air temperature, sunshine duration, rainfall and relative humidity, etc.)…”

“…Multiple climatic factors (air temperature, sunshine duration, rainfall and relative humidity, etc.) have potent pertinence to the transmission of human brucellosis with seasonal fluctuations 10 . However, comprehensive analysis of the epidemic situation, incidence rate of regions, specific demographic and seasonality features of human brucellosis, and characterization of the species/biovars, geographic distribution and genetic profile of Brucella strains isolated in this province is necessary to formulate targeted control measures.…”

Epidemic characteristics and transmission risk prediction of brucellosis in Xi'an city, Northwest China

“…Moreover, the high incidence of HB is concentrated in northern China, with an apparent shift in the geographic expansion from northern traditional livestock regions to more urban southern inland areas (16). Our previous study conducted in Shaanxi Province demonstrated similar conclusions regarding the spatiotemporal distribution of HB (17). Owing to rapid and sometimes uncontrolled urbanization, people may face closer encounters with infected animals (18).…”

Seroprevalence trend of human brucellosis and MLVA genotyping characteristics of Brucella melitensis in Shaanxi Province, China, during 2008–2020

“…Shaanxi Province is located in northern China and is adjacent to many northern regions with a high incidence rate of human brucellosis (Liang et al., 2020). The human brucellosis cases were mainly distributed in the Shaanbei upland plateau before 2008 and then slowly extended towards the southern regions, with significant seasonal fluctuation (Z. Yang, Pang, et al., 2020). Understanding seroprevalence in the human population is an important step for identifying the high‐prevalence regions and formulating targeted measures of control and prevention of human brucellosis (Liu et al., 2020).…”