Motloung R F, Chaisi M E, Sibiya M S, Nyangiwe N, Shivambu T C
Foundational Biodiversity Science, South African National Biodiversity Institute, Private Bag x101, Pretoria, South Africa.
Foundational Biodiversity Science, South African National Biodiversity Institute, Private Bag x101, Pretoria, South Africa; Department of Veterinary Tropical Diseases, University of Pretoria, P/Bag X04, Onderstepoort, Pretoria 0110, South Africa.
Vet Parasitol. 2025 Aug;338:110528. doi: 10.1016/j.vetpar.2025.110528. Epub 2025 Jun 28.
Predicting the potential distribution of disease vectors is crucial for vector management and disease transmission surveillance. This study aims to assess changes in the geographic projection of the ecological niche of ticks of veterinary, public health, and economic importance in South Africa, and to predict areas suitable for their establishment under current and future climate scenarios. We used a suite of six algorithms within the ensemble modelling framework of the biomod2 package in R version 4.4.2 to produce species distribution models for current (2021-2040) and future (2041-2060) climate scenarios. Six bioclimatic variables, representing a range of biophysical and anthropogenic factors, were used in combination with tick presence-only occurrence data submitted to SANBI's Integrated Publishing Toolkit by tick species experts. The model outputs indicate that all 10 tick species will likely experience range shifts over time (2021-2060). All species are projected to gain significant portions of suitable ranges in the future. Notably, Rhipicephalus microplus is predicted to gain the most, with a 14 % increase in its suitable range in South Africa. This predicted range expansion could potentially disrupt ecological balances in the ecosystems it is likely to occupy. Native species such as Amblyomma hebraeum and Hyalomma rufipes are predicted to expand their ranges by 10 and 9 %, respectively, while others may gain less than 6 % of their potential ranges The overall predicted range expansion could also introduce new disease dynamics, potentially leading to increased pathogen transmission, host switching and higher incidences of diseases in humans and animals in currently unaffected areas. The study provides baseline information to support ongoing monitoring and adaptive management strategies to mitigate the negative impacts associated with ticks on ecosystems, public health, and agriculture. The results will help inform tick control programs in South Africa and other similar environments. South Africa must adopt a comprehensive One Health approach to tick management to address the challenges posed by invasive species like R. microplus, which threaten livestock health and have significant veterinary and economic impacts.
预测病媒的潜在分布对于病媒管理和疾病传播监测至关重要。本研究旨在评估南非具有兽医、公共卫生和经济重要性的蜱虫生态位地理分布的变化，并预测在当前和未来气候情景下适合其生存的区域。我们在R版本4.4.2的biomod2包的集成建模框架内使用了六种算法，以生成当前（2021 - 2040年）和未来（2041 - 2060年）气候情景下的物种分布模型。六个生物气候变量，代表一系列生物物理和人为因素，与蜱虫物种专家提交给南非国家生物多样性研究所综合出版工具包的仅存在蜱虫的出现数据相结合使用。模型输出表明，所有10种蜱虫物种可能会随着时间推移（2021 - 2060年）发生分布范围的变化。预计所有物种在未来都会获得相当大比例的适宜分布范围。值得注意的是，微小牛蜱预计获得的适宜分布范围增加最多，在南非其适宜分布范围增加了14%。这种预测的分布范围扩大可能会破坏其可能占据的生态系统中的生态平衡。本地物种如希伯来花蜱和红足璃眼蜱预计其分布范围将分别扩大10%和9%，而其他物种可能获得的潜在分布范围增加不到6%。总体预测的分布范围扩大还可能引入新的疾病动态，可能导致病原体传播增加、宿主转换以及当前未受影响地区人类和动物疾病发病率升高。该研究提供了基线信息，以支持正在进行的监测和适应性管理策略，以减轻蜱虫对生态系统、公共卫生和农业的负面影响。研究结果将有助于为南非和其他类似环境中的蜱虫控制计划提供信息。南非必须采取全面的“同一个健康”方法来管理蜱虫，以应对像微小牛蜱这样的入侵物种带来的挑战，这些物种威胁家畜健康并产生重大的兽医和经济影响。
