Gonzalez Julia, Conway Mark, Hamer Sarah A
Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
Schubot Center for Avian Health, Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA.
Parasit Vectors. 2025 Mar 7;18(1):95. doi: 10.1186/s13071-025-06725-y.
The tropical climate and diverse vector community allows the Rio Grande Valley (RGV) of South Texas to support many vector-borne pathogen transmission cycles. It is a key area for monitoring bird ticks, since most of the migratory birds fly through this corridor to move for south tropical latitudes. Some of the tick species that infest birds in Texas can also transmit tick-borne pathogens that concern public health.
During bird banding activities in 2019-2024, ticks were collected opportunistically from local and migrant birds, as well as from outdoor recreationalists, to explore the presence of tick-borne pathogens. Applying a polymerase chain reaction (PCR)-DNA sequencing approach, ticks were tested for Ehrlichia and Rickettsia species.
Of 375 ticks, eight tick species were identified, including species regarded as locally established (Amblyomma inornatum, Amblyomma maculatum, Amblyomma mixtum, Amblyomma tenellum, and Dermacentor variabilis), neotropical species imported by migratory birds (Amblyomma geayi and Amblyomma longirostre), and for the first time in Texas, Ixodes keiransi, formerly the North American lineage of Ixodes affinis. Amblyomma tenellum was the most abundant tick species (89.3%). All ticks were screened for Ehrlichia, resulting in Ehrlichia chaffeensis detection in three A. tenellum ticks (one nymph and two adults) found on humans, and one positive for Ehrlichia ewingii in an A. inornatum nymph collected from a Clay-colored Thrush (Turdus grayi). Both bacteria can cause human ehrlichiosis, which is infrequently reported in Texas. The Rickettsia screening of ticks resulted in detection of Rickettsia amblyommatis, a potentially pathogenic spotted fever group Rickettsia, in nine ticks: eight A. inornatum ticks (one larva, five nymphs and two adults), seven of which were collected from Long-billed Thrashers (Toxostoma longirostre); and an A. longirostre engorged nymph from an Acadian Flycatcher (Empidonax virescens).
Our results highlight the importance of occupational exposure to ticks and the potential public health impact of the relatively neglected human-biting vector, A. tenellum.. There is also a critical need to investigate the fate of bird-imported A. inornatum and A. longirostre, and the pathogens they carry.
热带气候和多样的病媒群落使得德克萨斯州南部的里奥格兰德河谷（RGV）存在许多病媒传播病原体的传播循环。它是监测鸟类蜱虫的关键地区，因为大多数候鸟都飞越这条走廊前往南热带地区。在德克萨斯州，一些寄生于鸟类的蜱虫种类也能传播与公共卫生相关的蜱传病原体。
在2019年至2024年的鸟类环志活动期间，从当地鸟类、候鸟以及户外休闲者身上机会性地采集蜱虫，以探索蜱传病原体的存在情况。采用聚合酶链反应（PCR）-DNA测序方法，对蜱虫进行埃立克体和立克次体物种检测。
在375只蜱虫中，鉴定出8种蜱虫，包括被视为本地常住的种类（无饰花蜱、斑点花蜱、混合花蜱、细小花蜱和变异革蜱）、由候鸟引入的新热带种类（盖氏花蜱和长喙花蜱），以及在德克萨斯州首次发现的基兰西硬蜱，它以前是北美亲缘硬蜱的一个谱系。细小花蜱是最常见的蜱虫种类（89.3%）。对所有蜱虫进行了埃立克体筛查，在3只细小花蜱（1只若虫和2只成虫）中检测到恰菲埃立克体，这些蜱虫采自人类；在一只从灰胸鸫采集的无饰花蜱若虫中检测到尤因埃立克体呈阳性。这两种细菌都可导致人类埃立克体病，在德克萨斯州鲜有报道。对蜱虫进行立克次体筛查，在9只蜱虫中检测到斑点热群潜在致病性立克次体——安氏立克次体：8只无饰花蜱（1只幼虫、5只若虫和2只成虫），其中7只采自长嘴鶫；还有一只采自阿卡德林莺的饱血长喙花蜱若虫。
我们的数据突出了职业性接触蜱虫的重要性，以及相对被忽视的叮人病媒细小花蜱对公共卫生的潜在影响。还迫切需要调查候鸟引入的无饰花蜱和长喙花蜱及其携带的病原体的情况。
