Lane R S, Peavey C A, Padgett K A, Hendson M
Division of Insect Biology, University of California, Berkeley 94720, USA.
J Med Entomol. 1999 May;36(3):329-40. doi: 10.1093/jmedent/36.3.329.
Ixodes (Ixodes) jellisoni Cooley & Kohls, a nonhuman biting and little known tick, is one of 4 members of the I. ricinus complex in the United States. A localized population of I. jellisoni inhabiting a grassland biotope in Mendocino County, CA, was studied from 1993 to 1997. Rodent trapping in all seasons revealed that the only host of both immature and adult I. jellisoni was the heteromyid rodent Dipodomys californicus Merriam. Field investigations suggested that I. jellisoni is nidicolous in habit, and laboratory findings demonstrated that it reproduces parthenogenetically. Known parthenogenetic females (n = 4) produced an average of 530 eggs of which 74% hatched, which was comparable to the fecundity and fertility of wild-caught females (n = 8). After the transstadial molt, 57 F1 or F2 nymphs derived from 2 wild-caught or 4 laboratory-reared, unmated females produced only females. Ixodes jellisoni males were not found on 112 wild-caught D. californicus individuals that were captured an average of 2 times. Collectively, these findings suggest that I. jellisoni may be obligatorily parthenogenetic. Borrelial isolates were obtained from 85% of 58 D. californicus and 33% of 21 I. jellisoni females removed from this rodent. None of the 7 infected female ticks passed borreliae ovarially to its F1 larval progeny. Eight D. californicus and 5 I. jellisoni-derived isolates that were genetically characterized belonged to 2 restriction pattern groups of Borrelia burgdorferi s.l. Neither restriction pattern group has been assigned to a particular genospecies yet. After placement on naturally infected D. californicus, noninfected larval ticks acquired and transstadially passed spirochetes as efficiently as (group 1 borreliae) or 6 times more efficiently (group 2 borreliae) than Ixodes pacificus Cooley & Kohls. As few as 1-4 infected I. jellisoni nymphs were capable of transmitting group 1 or group 2 borreliae to naive D. californicus. We conclude that I. jellisoni is a competent vector of both restriction fragment groups when D. californicus is used as the animal model.
杰利索尼硬蜱（Ixodes jellisoni）是一种不叮咬人类且鲜为人知的蜱虫，是美国蓖麻硬蜱复合体（Ixodes ricinus complex）的4个成员之一。1993年至1997年，对加利福尼亚州门多西诺县一个栖息在草原生物群落中的杰利索尼硬蜱局部种群进行了研究。全年的啮齿动物诱捕结果显示，杰利索尼硬蜱幼虫和成虫的唯一宿主是异鼠科啮齿动物加州更格卢鼠（Dipodomys californicus Merriam）。野外调查表明，杰利索尼硬蜱有穴居习性，实验室研究结果表明它进行孤雌生殖。已知的孤雌生殖雌蜱（n = 4）平均产卵530枚，其中74%孵化，这与野生捕获雌蜱（n = 8）的繁殖力和生育力相当。在经期间蜕变后，来自2只野生捕获或4只实验室饲养的未交配雌蜱的57只F1或F2若蜱只产生雌蜱。在平均捕获2次的112只野生捕获的加州更格卢鼠个体上未发现杰利索尼硬蜱雄蜱。总体而言，这些发现表明杰利索尼硬蜱可能是专性孤雌生殖。从58只加州更格卢鼠中采集的85%以及从该啮齿动物身上采集的21只杰利索尼硬蜱雌蜱中的33%分离出了疏螺旋体。7只受感染的雌蜱均未通过卵巢将疏螺旋体传给其F1代幼虫后代。对8只加州更格卢鼠和5只杰利索尼硬蜱来源的分离株进行基因特征分析，结果表明它们属于伯氏疏螺旋体狭义种（Borrelia burgdorferi s.l.）的2个限制性模式组。这两个限制性模式组均尚未被归为特定的基因种。将未感染的幼蜱置于自然感染的加州更格卢鼠身上后，它们获取并经期间传递螺旋体的效率与太平洋硬蜱（Ixodes pacificus Cooley & Kohls）相当（第1组疏螺旋体），或者比太平洋硬蜱高6倍（第2组疏螺旋体）。少至1 - 4只受感染的杰利索尼硬蜱若蜱就能将第1组或第2组疏螺旋体传播给未感染的加州更格卢鼠。我们得出结论，以加州更格卢鼠作为动物模型时，杰利索尼硬蜱是这两个限制性片段组的有效传播媒介。
