Monje L D, Costa F B, Colombo V C, Labruna M B, Antoniazzi L R, Gamietea I, Nava S, Beldomenico P M
Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL)/Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, S3080, Argentina (
Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo, 05508-270, Brazil (
J Med Entomol. 2016 May;53(3):660-665. doi: 10.1093/jme/tjv250. Epub 2016 Jan 21.
Several cases of human rickettsiosis caused by Rickettsia parkeri were recently documented in the Paraná River delta of Argentina, where the tick vector is Amblyomma triste Koch. As cattle suffer recurrent A. triste infestations, they are at risk of becoming infected with R. parkeri Herein we investigated the dynamics of R. parkeri and its A. triste vector in a herd of beef cattle. Cattle were followed for 18 mo and samples were analyzed for the presence of antibodies against four Rickettsia species (R. parkeri, Rickettsia bellii, Rickettsia amblyommii, and Rickettsia felis) and also for the presence of rickettsial DNA. Additionally, cattle were examined for attached ticks and questing adult ticks were collected. All ticks were analyzed for the presence of rickettsial DNA. No evidence of rickettsemia was found in any cow, but the high R. parkeri infection rate documented in A. triste both questing in the study area (13.9%) and feeding on cattle (19.8%) and the identification of antibodies against R. parkeri antigen in 90% of cattle are evidence that infection is taking place. Altogether, our data suggest that A. triste ticks are capable of naturally exposing cattle to R. parkeri However, the progress of R. parkeri infection and its impact on bovine health and production remain to be established.
最近在阿根廷巴拉那河三角洲记录了几例由帕克立克次体引起的人类立克次体病病例，该地的蜱传播媒介是特氏钝眼蜱（Amblyomma triste Koch）。由于牛群反复受到特氏钝眼蜱的侵扰，它们有感染帕克立克次体的风险。在此，我们调查了一群肉牛中帕克立克次体及其特氏钝眼蜱传播媒介的动态情况。对牛群进行了18个月的跟踪，并分析样本中针对四种立克次体物种（帕克立克次体、贝利立克次体、钝眼蜱立克次体和猫立克次体）的抗体存在情况以及立克次体DNA的存在情况。此外，检查牛身上附着的蜱，并收集正在寻找宿主的成年蜱。对所有蜱进行立克次体DNA存在情况的分析。在任何一头母牛中均未发现立克次体血症的证据，但在研究区域内正在寻找宿主的特氏钝眼蜱（感染率为13.9%）和寄生在牛身上的特氏钝眼蜱（感染率为19.8%）中记录到的高帕克立克次体感染率，以及90%的牛中针对帕克立克次体抗原的抗体鉴定结果，均证明感染正在发生。总之，我们的数据表明，特氏钝眼蜱能够使牛自然接触帕克立克次体。然而，帕克立克次体感染的进展及其对牛健康和生产的影响仍有待确定。
