Journal of Tropical Diseases and Parasitology ›› 2025, Vol. 23 ›› Issue (3): 160-164,188.doi: 10.20199/j.issn.1672-2302.2025.03.006

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Application of spatial zero-inflated Poisson model in spatial analysis of Brucellosis in Yunnan Province

YUAN Rui1(), LI Ke2, ZHANG Lele2, YU Binbin3, YANG Xiangdong3, WANG peng3, ZHANG Zhijie1,2()   

  1. 1. Department of Epidemiology and Health Statistics, School of Public Health, Fudan University, Shanghai 200032, China
    2. Shanghai Institute of Infectious Disease and Biosecurity
    3. Yunnan Provincial Institute for Endemic Disease Control and Prevention, Yunnan Key Laboratory of Natural Focal Disease Prevention and Control Technology
  • Received:2024-10-23 Online:2025-06-20 Published:2025-08-08
  • Contact: ZHANG Zhijie, E-mail: epistat@gmail.com

Abstract:

Objective To assess the value of spatial zero-inflated Poisson model applied to the spatial analysis of Brucellosis cases with high zero values in Yunnan Province for methodological references in analysis of the similar data in the field of public health. Methods The data on Brucellosis cases reported in Yunnan Province from January to December of 2022 were collected through the Chinese Disease Prevention and Control Information System. The global Moran’s I, local Moran’s I, and spatial scan statistics were used to analyze global and local spatial autocorrelation and detection of spatial clustering of Brucellosis cases. Traditional Poisson, zero-inflated Poisson, and spatial zero-inflated Poisson models were employed for data fitting, with the optimal model determined based on deviance information criterion (DIC) and Watanabe-Akaike information criterion (WAIC). Results In total, 1 015 cases of Brucellosis were reported in Yunnan Province from January to December of 2022. The number of cases at county-level showed a significant global spatial autocorrelation (Moran’s I=0.40, Z=8.80, P<0.01), and exhibited a serious outbreak in the eastern region of Yunnan, where a high-risk cluster was identified (RR=18.53, LLR=694.21, P<0.01). The spatial zero-inflated Poisson model demonstrated the best fit (DIC=556.055, WAIC=740.752), followed by the non-spatial zero-inflated Poisson model (DIC=815.527, WAIC=1 564.548), both outperforming the traditional Poisson model (DIC=975.799, WAIC=1 613.696). The latter two models showed biased results, leading to inaccurate parameter estimates. The posterior mean of the spatial structure random effects in the optimal model revealed significant spatial autocorrelation (Moran’s I=0.32, Z=5.92, P<0.01), whereas the non-spatial random effects indicated no significant spatial autocorrelation (Moran’s I=0.08, Z=1.52, P>0.05). Conclusion The spatial zero-inflated Poisson model, which incorporates spatial effects, can better address zero-inflated count data with spatial autocorrelation features, and reveal potential spatial structures in disease data, which may provide effective methodological support for the spatial epidemiological analysis of low-prevalence infectious diseases.

Key words: Zero-inflation, Spatial models, Spatial epidemiology, Brucellosis, Yunnan Province

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