Oliveira Stefan Vilges de, Romero-Alvarez Daniel, Martins Thiago Fernandes, Santos Janduhy Pereira Dos, Labruna Marcelo B, Gazeta Gilberto Salles, Escobar Luis E, Gurgel-Gonçalves Rodrigo
Programa de Pós Graduação em Medicina Tropical da Universidade de Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, CEP: 70910-900, Brasília, Brazil; Secretaria de Vigilância em Saúde do Ministério da Saúde do Brasil, Setor de Rádio TV Norte - 701 - Via W5 Norte, Edifício PO 0700, CEP: 70719-040, Brasília, Brazil; Laboratório de Referência Nacional em Vetores das Riquetsioses da Fundação Oswaldo Cruz, Av. Brasil 4365, Manguinhos, CEP: 21040-360, Rio de Janeiro, Brazil.
Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA.
Acta Trop. 2017 Dec;176:340-348. doi: 10.1016/j.actatropica.2017.07.033. Epub 2017 Sep 1.
Ticks of the Amblyomma cajennense species complex are important vectors of spotted fever in Latin America. Environmental conditions determine the geographic distribution of ticks, such that climate change could influence the distribution of tick-borne diseases. This study aimed to analyze the potential geographic distribution of A. cajennense complex ticks in a Brazil region under present-day and future climate models, assuming dispersal limitations and non-evolutionary adaptation of these tick populations to climate warming. Records of A. cajennense sensu stricto (s.s.) and Amblyomma sculptum were analyzed. Niche models were calibrated using Maxent considering climate variables for 1950-2000 and projecting models to conditions anticipated for 2050 and 2070 under two models of future climate (CCSM4 and HadGEM2-AO). Broad suitable areas for A. cajennense s.s. and A. sculptum were found in present-day climate models, but suitability was reduced when models were projected to future conditions. Our exploration of future climates showed that broad areas had novel climates not existing currently in the study region, including novel extremely high temperatures. Indeed, predicted suitability in these novel conditions would lead to biologically unrealistic results and therefore incorrect forecasts of future tick-distribution. Previous studies anticipating expansions of vectors populations due to climate change should be considered with caution as they assume that model extrapolation anticipates that species would evolve rapidly for adaptation to novel climatic conditions.
卡延钝眼蜱物种复合体的蜱虫是拉丁美洲斑点热的重要传播媒介。环境条件决定了蜱虫的地理分布，因此气候变化可能会影响蜱传疾病的分布。本研究旨在分析在当前和未来气候模型下，巴西某地区卡延钝眼蜱物种复合体蜱虫的潜在地理分布，假定这些蜱虫种群的扩散存在限制且对气候变暖无进化适应。对狭义卡延钝眼蜱和刻点钝眼蜱的记录进行了分析。使用最大熵模型（Maxent），根据1950 - 2000年的气候变量校准生态位模型，并将模型预测到未来气候的两种模型（CCSM4和HadGEM2 - AO）下2050年和2070年预期的条件。在当前气候模型中发现了狭义卡延钝眼蜱和刻点钝眼蜱的广泛适宜区域，但当模型预测到未来条件时，适宜性降低。我们对未来气候的探索表明，广大区域具有目前研究区域不存在的新气候，包括新出现的极高温度。实际上，在这些新条件下预测的适宜性会导致生物学上不现实的结果，从而对未来蜱虫分布做出错误预测。以往那些因气候变化预测病媒种群扩张的研究应谨慎看待，因为它们假定模型外推预期物种会迅速进化以适应新的气候条件。
