Department of Biology, Georgia Southern University, 4324 Old Register Road, Statesboro, Georgia 30460.
University of Nebraska State Museum, University of Nebraska-Lincoln, Lincoln, Nebraska 68588.
J Parasitol. 2022 Mar 1;108(2):192-198. doi: 10.1645/21-101.
Grouse and ptarmigan (Galliformes) harbor fairly diverse helminth faunas that can impact the host's health, including filarial nematodes in the genus Splendidofilaria. As host and parasite distributions are predicted to shift in response to recent climate change, novel parasites may be introduced into a region and impose additional stressors on bird populations. Limited information is available on the prevalence of filariasis in Alaska galliforms. To date, no molecular surveys have been completed. Past studies relied on examining blood smears or total body necropsies, which are time-consuming and may not detect filarial parasites with low prevalence in hosts. Therefore, we developed a TaqMan probe-based real-time PCR assay targeting the cytochrome c oxidase 1 gene (COI) of Splendidofilaria to decrease processing times and increase sensitivity as well as provide baseline data on the diversity of filariid infections in galliform species in Alaska. We screened a combined total of 708 galliform samples (678 unique individual birds) from different tissues (blood, muscle, and lung) for the presence of filarial DNA across the state of Alaska. Real-time PCR screening revealed an overall prevalence of filarial infection of 9.5% across species: Bonasa umbellus (0%, n = 23), Dendragapus fuliginosus (0%, n = 8), Falcipennis canadensis (26.8%, n = 198), Lagopus lagopus (2.6%, n = 274), Lagopus leucura (0%, n = 23), Lagopus muta (3%, n = 166), and Tympanuchus phasianellus (12.5%, n = 16). We observed microfilarial infections throughout most of Alaska except in Arctic regions and the Aleutian Islands where viable vectors may not be present.
松鸡和雷鸟（鸡形目）拥有相当多样化的寄生虫群，这些寄生虫可能会影响宿主的健康，包括 Splendidofilaria 属的丝虫。随着寄生虫和宿主的分布预计会因最近的气候变化而发生变化，新的寄生虫可能会被引入一个地区，并给鸟类种群带来额外的压力。关于阿拉斯加鸡形目寄生虫病的流行情况，我们的了解有限。迄今为止，还没有完成分子调查。过去的研究依赖于检查血液涂片或全身剖检，这些方法既费时又可能无法检测到宿主中流行率低的丝虫寄生虫。因此，我们开发了一种基于 TaqMan 探针的实时 PCR 检测方法，该方法针对 Splendidofilaria 的细胞色素 c 氧化酶 1 基因（COI），以减少处理时间、提高检测灵敏度，并提供阿拉斯加鸡形目物种中丝状感染多样性的基线数据。我们对来自不同组织（血液、肌肉和肺）的总共 708 只鸡形目样本（678 个独特个体）进行了实时 PCR 筛查，以检测阿拉斯加境内是否存在丝状 DNA。实时 PCR 筛查显示，在所有物种中，寄生虫感染的总流行率为 9.5%：Bonasa umbellus（0%，n=23），Dendragapus fuliginosus（0%，n=8），Falcipennis canadensis（26.8%，n=198），Lagopus lagopus（2.6%，n=274），Lagopus leucura（0%，n=23），Lagopus muta（3%，n=166），和 Tympanuchus phasianellus（12.5%，n=16）。我们观察到微丝蚴感染遍布阿拉斯加的大部分地区，除了北极地区和阿留申群岛，那里可能没有存活的媒介。
