Predicting the transmission risk of visceral leishmaniasis in Gansu Province based on an ecological niche model / 中华地方病学杂志

ABSTRACT

Objective:To analyze and predict the transmission risk of visceral leishmaniasis in Gansu Province based on an ecological niche model, providing a basis for the development of precise prevention and control measures and epidemic surveillance.Methods:The information of reported cases of visceral leishmaniasis in Gansu Province from 2015 to 2021 were collected from the National Infectious Disease Reporting Information Management System, and the longitude and latitude coordinates of the distribution points of cases and the data of 19 climate variables, 5 geographical variables and 2 socio-economic variables within the region were obtained. Based on an ecological niche model, a model for predicting the transmission risk of visceral leishmaniasis was constructed using the maximum entropy algorithm (MaxEnt), and its performance was evaluated by the area under the receiver operating characteristic curve (AUC). Then the importance of each environmental variable of the model was evaluated, and the distribution area of visceral leishmaniasis transmission risk in Gansu Province was predicted.Results:A total of 368 cases of visceral leishmaniasis were reported in Gansu Province from 2015 to 2021, of which 89.13% (328/368) were from Longnan City and Gannan Tibetan Autonomous Prefecture (Gannan Prefecture). The number of cases peaked in 2017 (79 cases, 21.47%). The model had high prediction accuracy (AUC = 0.985). The results of model analysis showed that the important climate variable affecting the distribution of visceral leishmaniasis was the average temperature in the coldest quarter (contribution value of 3.1), the geographical variables were land use type (contribution value of 52.6) and vegetation cover type (contribution value of 8.5), and the socio-economic variable was population size (contribution value of 14.3). The distribution results of transmission risk showed that high, medium and low risk areas exhibited a gradual transition from the southern part to the northwest part of Gansu Province. The high risk areas were mainly located in the central and southern parts of Longnan City and the southern part of Gannan Prefecture, accounting for 0.18% of the total area of the province. Medium and low risk areas accounted for 0.48% and 2.47% of the total area of the province, respectively; and areas with no risk accounted for 96.87%.Conclusions:The ecological niche model predicts that the spread of visceral leishmaniasis in Gansu Province is characterized by point like dispersion and local high aggregation distribution. It is necessary to strengthen monitoring and prevention and control of high-risk areas such as Longnan City and Gannan Prefecture.