Ecological niche modeling as a tool for prediction of the potential geographic distribution of Bacillus anthracis spores in Tanzania

Introduction: Anthrax is caused by the spore-forming, Gram-positive bacterium Bacillus anthracis. The aim of this study was to predict the potential distribution of B. anthracis in Tanzania and produce epidemiological evidence for the management of anthrax outbreaks in the country.

Methods: The Maxent algorithm was used to predict areas at risk of anthrax outbreaks based on the occurrence and environmental data in Arusha and Kilimanjaro regions; the model was later transferred to predict the entire country. Seventy percent of the occurrence data were used to train the model, while 30% were used for model evaluation.

Results: Four regions of northern Tanzania are predicted to have a high risk for anthrax outbreaks, while the southern and western regions had low-risk areas. Soil type (56.5%), soil pH (23.7%), and isothermally (10.4%) were the most important variables for the model prediction, and the most significant soil types were solonetz, fluvisols, and lithosols.

Conclusions...

引言：炭疽由产芽孢革兰氏阳性细菌炭疽芽孢杆菌（Bacillus anthracis）引发。本研究旨在预测炭疽芽孢杆菌在坦桑尼亚的潜在分布，并为该国炭疽疫情的防控工作提供流行病学依据。
方法：本研究基于阿鲁沙与乞力马扎罗地区的炭疽发生数据及环境数据，采用最大熵（Maxent）算法预测炭疽疫情的高风险区域；随后将训练好的模型迁移至全坦桑尼亚境内开展预测。研究将70%的发生数据用于模型训练，剩余30%用于模型性能评估。
结果：模型预测坦桑尼亚北部的四个区域存在炭疽疫情高风险，而南部与西部地区则为低风险区域。对模型预测贡献度最高的环境变量依次为土壤类型（56.5%）、土壤pH值（23.7%）与等温性（10.4%），其中主要的高风险土壤类型为碱土（solonetz）、冲积土（fluvisols）与岩性土（lithosols）。
结论：……