Data from: Range expansion and increasing Borrelia burgdorferi infection of the tick Ixodes scapularis (Acari: Ixodidae) in Iowa, 1990-2013

A passive surveillance program monitored ticks submitted by the public in Iowa from 1990–2013. Submitted ticks were identified to species and life stage, and Ixodes scapularis Say nymphs and adults were tested for the presence of Borrelia burgdorferi. An average of 2.6 of Iowa’s 99 counties submitted first reports of I. scapularis per year over the surveillance period, indicating expansion of this tick species across the state. The proportion of vector ticks infected by B. burgdorferi increased over time between 1998 and 2013. In 2013, 23.5% of nymphal and adult I. scapularis were infected with B. burgdorferi, the highest proportion of any year. Active surveillance was performed at selected sites from 2007–2009. Ixodes scapularis nymphs collected at these sites were tested for the presence of B. burgdorferi, Anaplasma phagocytophilum, and spotted fever group Rickettsia spp. (likely representing Rickettsia buchneri). Nymphs tested were 17.3% positive for B. burgdorferi, 28.9% for A. phagocytophilum, and 67.3% for Rickettsia spp. The results of these surveillance programs indicate an increasing risk of disease transmission by I. scapularis in Iowa.

1990—2013年，一项被动监测计划对艾奥瓦州民众提交的蜱虫样本开展监测。所有提交的蜱虫均完成物种鉴定与虫期判定，并对肩突硬蜱（Ixodes scapularis Say）的若虫和成虫开展伯氏疏螺旋体（Borrelia burgdorferi）检测。监测期内，艾奥瓦州99个县中，年均有2.6个县首次提交肩突硬蜱的监测报告，表明该蜱虫物种正在全州范围内逐步扩散。1998年至2013年间，该媒介蜱虫的伯氏疏螺旋体感染率随时间持续上升。2013年，肩突硬蜱若虫与成虫的伯氏疏螺旋体感染率达23.5%，为所有监测年份中的最高值。2007—2009年，研究团队在选定监测点位开展主动监测。在此期间采集的肩突硬蜱若虫样本被用于检测伯氏疏螺旋体、嗜吞噬细胞无形体（Anaplasma phagocytophilum）以及斑点热群立克次体（spotted fever group Rickettsia spp.，推测为布氏立克次体Rickettsia buchneri）。检测结果显示，受检若虫的伯氏疏螺旋体阳性率为17.3%、嗜吞噬细胞无形体阳性率为28.9%，斑点热群立克次体阳性率为67.3%。上述两项监测计划的结果表明，艾奥瓦州由肩突硬蜱介导的疾病传播风险正持续升高。