Epidemiologic characteristics and temporal-spatial analysis of human brucellosis in Inner Mongolia Autonomous Region and neighboring provinces, 2010-2014

Objective To investigate the epidemiologic characteristics and hot-spot areas of human brucellosis in Inner Mongolia Autonomous Region (IMAR) and neighboring provinces from 2010 to 2014, and to provide evidence for exploring the policy for human brucellosis prevention and control as well as resource allocation at regional level. Methods The epidemiologic characteristics of human brucellosis were analyzed based on the data originated from the National Notifiable Infectious Disease Reporting System(NNIDS). The spatial distribution was described by disease mapping using ArcGIS 10.3. Space-time scan statistic was used to explore the temporal-spatial clusters. Results From 2010 to 2014, the percentage of affected counties in the nine neighboring provinces rose from 66.56%(611/918)to 90.63%(832/918). There was an apparent increase in the incidence rate from 10.28/100 000 in 2010 to 12.62/100 000 in 2014, with an average annual increase of 5.27%. A seasonal incidence presents with the epidemic period from March to July. The major infected population was aged between 25 to 64 with a percentage of 91.90%. The gender ratio was 2.91:1. Farmers and herdsmen occupied 89.60% of all the cases. During the past five years, a total of 43 space-time clusters were detected, the majority of which took place from January to August and located in counties with high incidence. These clusters laid relatively steadily and expanded from the central of IMAR to more areas. Conclusions During this half decade the human brucellosis was aggravated in this region. The temporal-spatial clusters existed and laid steadily with a trend of expanding from the central of IMAR to more areas. It is necessary to consider establishment of routine surveillance and detection system for early warning of human brucellosis outbreaks. More resource should be allocated to hot-spot areas for enhancing control efforts.