季节性动态的 Amblyomma cajennense（Fabricius，1787）在亚马逊生物群落退化地区的严格意义上，以及关于立克次体 amblyommatis 感染的说明。
Seasonal dynamics of Amblyomma cajennense (Fabricius, 1787) sensu stricto in a degraded area of the Amazon biome, with notes on Rickettsia amblyommatis infection.
机构信息
Post-Graduation Program in Health and Environment, Federal University of Maranhão, São Luís, MA, Brazil.
Pasteur Institute, São Paulo State Department of Health, São Paulo, SP, Brazil.
出版信息
Parasit Vectors. 2023 Oct 27;16(1):391. doi: 10.1186/s13071-023-05978-9.
BACKGROUND
The tick Amblyomma cajennense sensu stricto (A. cajennense s.s.) frequently parasitizes animals and humans in the Amazon biome, in addition to being a vector of Rickettsia amblyommatis. In the present study, we evaluated both the population dynamics of A. cajennense s.s. in a degraded area of the Amazon biome and the presence of rickettsial organisms in this tick population.
METHODS
The study was carried out in a rural area of the Santa Inês municipality (altitude: 24 m a.s.l.), Maranhão state, Brazil. Ticks were collected from the environment for 24 consecutive months, from June 2021 to May 2023. The region is characterized by two warm seasons: a rainy season (November-May) and a dry season (June-October). We characterized the temporal activity of A. cajennense s.s. on the vegetation by examining questing activity for each life stage (larvae, nymphs, adults [males and females]) in relation to the dry and rainy season. Ticks collected in this study were randomly selected and individually tested by a TaqMan real-time PCR assay that targeted a 147-bp fragment of the rickettsial gltA gene.
RESULTS
Overall, 1843 (62.4%) adults (52.6% females, 47.4% males), 1110 (37.6%) nymphs and 398 larval clusters were collected. All adult females and nymphs were morphologically identified as A. cajennense s.s. Larval activity was observed from April to December, with a peak from June to September (dry season); nymph abundance peaked from September to November (transition period between dry and rainy seasons); and adult ticks were abundant from October to May (spring/summer/early autumn). The infection rate by R. amblyommatis in A. cajennense s.s. ticks was at least 7% (7/99).
CONCLUSION
Our data suggest a 1-year generation pattern for A. cajennense s.s., with a well-defined seasonality of larvae, nymphs and adults in the Amazon biome. Larvae predominate during the dry season, nymphs are most abundant in the dry-rainy season transition and adults are most abundant in the rainy season. The presence of R. amblyommatis in adult ticks suggests that animals and humans in the study region are at risk of infection by this species belonging to the spotted fever group of Rickettsia.
背景
窄叶血蜱（Amblyomma cajennense sensu stricto，A. cajennense s.s.）常寄生在亚马逊生物群落中的动物和人类身上，此外还是拉氏立克次体（Rickettsia amblyommatis）的传播媒介。在本研究中，我们评估了亚马逊生物群落退化地区 A. cajennense s.s. 的种群动态，以及该蜱种群中立克次体生物的存在情况。
方法
该研究在巴西马拉尼昂州圣伊内斯市（海拔 24 米）的一个农村地区进行。从 2021 年 6 月至 2023 年 5 月，连续 24 个月从环境中收集蜱虫。该地区的气候特征是有两个温暖季节：雨季（11 月至 5 月）和旱季（6 月至 10 月）。我们通过检查每个生命阶段（幼虫、若虫、成虫[雄性和雌性]）在旱季和雨季的求偶活动，来描述 A. cajennense s.s. 在植被上的时间活动。在这项研究中收集的蜱虫被随机选择，并通过 TaqMan 实时 PCR 检测进行单独检测，该检测针对立克次体 gltA 基因的 147bp 片段。
结果
总共收集到 1843 只（62.4%）成虫（52.6%雌性，47.4%雄性）、1110 只若虫和 398 只幼虫簇。所有成年雌性和若虫均通过形态学鉴定为 A. cajennense s.s.。幼虫活动从 4 月持续到 12 月，6 月至 9 月（旱季）达到高峰；若虫数量在 9 月至 11 月（旱季和雨季之间的过渡期）达到高峰；而成年蜱虫在 10 月至 5 月（春季/夏季/初秋）最为丰富。在 A. cajennense s.s. 蜱虫中，感染拉氏立克次体的比率至少为 7%（7/99）。
结论
我们的数据表明，A. cajennense s.s. 的生成模式为 1 年 1 代，在亚马逊生物群落中，幼虫、若虫和成虫具有明显的季节性。旱季时幼虫占优势，旱季和雨季过渡期时若虫最丰富，雨季时成虫最丰富。在成年蜱虫中发现拉氏立克次体表明，该地区的动物和人类感染属于斑点热群的立克次体的风险。
Zotero 插件