Human induced changes on landscape can alter the biotic and abiotic factors that influence the transmission of vector-borne parasites. To examine how infection rates of vector-transmitted parasites respond to changes on natural landscapes, we captured 330 Blue-black Grassquits (Volatinia jacarina) in Brazilian biomes and assessed the prevalence and diversity of avian haemosporidian parasites (Plasmodium and Haemoproteus) across avian host populations inhabiting environment under different disturbance and climatic conditions. Overall prevalence in Blue-black Grassquits was low (11%) and infection rates exhibited considerable spatial variation, ranging from zero to 39%. Based on genetic divergence of cytochrome b gene, we found two lineages of Haemoproteus (Parahaemoproteus) and 10 of Plasmodium. We showed that Blue-black Grassquit populations inhabiting sites with higher proportion of native vegetation cover were more infected across Brazil. Other landscape metrics (number of water bodies and distance to urban areas) and climatic condition (temperature and precipitation) known to influence vector activity and promote avian malaria transmission did not explain infection probability in Blue-black Grassquit populations. Moreover, breeding season did not explain prevalence across avian host populations. Our findings suggest that avian haemosporidian prevalence and diversity in Blue-black Grassquit populations are determined by recent anthropogenic changes in vegetation cover that may alter microclimate, thus influencing vector activity and parasite transmission.

人类引起的景观变化可以改变影响媒介传播寄生虫传播的生物和非生物因素。为了检查载体传播的寄生虫的感染率如何响应自然景观的变化，我们在巴西生物群落中捕获了330个蓝黑色草蝇（Volatinia jacarina），并评估了禽寄主种群中禽血孢子虫（疟原虫和嗜血杆菌）的流行和多样性。在不同干扰和气候条件下的居住环境。蓝黑色草场的总体患病率很低（11％），感染率表现出很大的空间变化，范围从零到39％。基于细胞色素b的遗传差异基因，我们发现了血红蛋白（Parahaemoproteus）的两个谱系和疟原虫的10个谱系。我们发现，在巴西各地，居住于具有较高原始植被覆盖率的地点的蓝黑色Grassquit种群受到更多感染。已知会影响媒介活动并促进禽类疟疾传播的其他景观指标（水体数量和到市区的距离）和气候条件（温度和降水）不能解释蓝黑色草鼠种群的感染可能性。而且，繁殖季节不能解释禽类宿主种群的流行情况。我们的研究结果表明，蓝黑色草种种群中禽血友病的流行和多样性是由最近植被覆盖的人为变化决定的，该变化可能会改变小气候，从而影响病媒的活动和寄生虫的传播。