Centro de Parasitologia Veterinária, Escola de Veterinária e Zootecnia, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Vet Parasitol. 2021 Aug;296:109506. doi: 10.1016/j.vetpar.2021.109506. Epub 2021 Jun 25.
The present study evaluated over two years the seasonal dynamics of Rhipicephalus microplus in a Cerrado biome of midwestern Brazil (Goiânia, Goiás) and correlated the current climatic conditions (environmental temperature, insolation, rainfall, relative humitidy and saturation deficit of the atmosphere) of this site with 30 years ago. In addition, the data collected in the present research were compared with climatic conditions data and R. microplus population dynamics conducted by our group in other regions (Formiga, Minas Gerais and Jaboticabal, São Paulo) within the same biome. For the parasitic phase dynamics, R. microplus females (4.5-8.0 mm) counts were performed on tick natural infested cows kept in Panicum maximum paddocks. To verify the larvae dynamics on pasture the flannel dragg technique on natural infested pasture was performed, and the height of the grass was measured. Five peaks of engorged R. microplus females on animals and larvae infestations on pastures were observed. Being three and two peaks during the rainy and dry season of the year, respectively. Insolation (r = 0.8758; P = 0.00009; R² = 0.7670), rainfall (r = -0.8572; P = 0.0002; R² = 0.7348), maximum environmental temperature in summer (r = 0.9999; P < 0.0087; R² = 0.9988) and the saturation deficit of the atmosphere in autumn (r = -0.9789; P = 0.0211; R² = 0.9582) influenced the seasonal dynamics of R. microplus larvae on pastures. While the forage height did not influence the number of larvae found on pasture (r = 0.1545; P = 0.7682; R² = 0.0239). The comparison between the climatic data of the last 30 years with the current climatological data (2012 to 2019) in the state of Goiás, and the comparison with R. microplus population dynamics from other two locations in the same biome indicated that the increase of the environmental temperature due to the global warming possibly is a determining factor which increase the number of one or up two tick annual peaks. In addition, this climatic variable was responsible for increase the population density of ticks on pastures and animals observed in July/winter of the present study, in comparison to other regions with the same biome, as discussed in this work.
本研究在巴西中西部塞拉多生物群落（戈亚尼亚，戈亚斯州）评估了 Rhpicephalus microplus 的季节性动态超过两年，并将该地点当前的气候条件（环境温度、光照、降雨量、相对湿度和大气饱和亏缺）与 30 年前进行了相关比较。此外，本研究收集的数据与我们小组在同一生物群落的其他地区（米纳斯吉拉斯州的福米加和圣保罗州的雅博蒂巴）进行的气候条件数据和 R. microplus 种群动态进行了比较。对于寄生阶段的动态，在潘库姆最大牧场中饲养的自然感染牛身上对雌性 R. microplus（4.5-8.0 毫米）进行了计数。为了验证牧场幼虫的动态，对自然感染的牧场进行了绒布拖拽技术，同时测量了草的高度。在动物上观察到五次饱血的 R. microplus 雌性高峰期和牧场上的幼虫感染。其中，雨季和旱季各有三个和两个高峰期。光照（r=0.8758；P=0.00009；R²=0.7670）、降雨量（r=-0.8572；P=0.0002；R²=0.7348）、夏季环境最高温度（r=0.9999；P<0.0087；R²=0.9988）和秋季大气饱和亏缺（r=-0.9789；P=0.0211；R²=0.9582）影响了牧场上 R. microplus 幼虫的季节性动态。而饲草高度并不影响牧场上发现的幼虫数量（r=0.1545；P=0.7682；R²=0.0239）。将过去 30 年的气候数据与当前（2012 年至 2019 年）戈亚斯州的气候数据进行比较，并与同一生物群落的其他两个地点的 R. microplus 种群动态进行比较，结果表明，由于全球变暖导致环境温度升高可能是增加每年一个或两个蜱虫高峰数量的决定因素。此外，与本工作中讨论的其他具有相同生物群落的地区相比，这一气候变量导致了本研究 7 月/冬季牧场上和动物身上蜱虫种群密度的增加。
