University of the Free State, Bloemfontein, 9301, South Africa.
School of Biology and Environmental Sciences, University of Mpumalanga, Mbombela, 1201, South Africa.
Parasitol Res. 2023 Oct;122(10):2393-2404. doi: 10.1007/s00436-023-07941-0. Epub 2023 Aug 16.
Prevalence studies of avian haemosporidian parasites frequently use microscopy and the nested polymerase chain reaction (PCR) protocols for detecting infections. Newer PCR protocols to detect parasites are being developed, with the distinct advantage of reducing screening cost and time, as well as increasing efficiency and sensitivity. The detection ability of microscopy and nested PCR was compared against a real-time PCR (qPCR) protocol using genomic DNA extracted from 240 bird blood samples collected from three starling species (Cape Starling, the Greater Blue-eared Starling, and the Wattled Starling; family Sturnidae) in the Kruger national park, South Africa. All three protocols successfully detected avian haemosporidian parasites with the qPCR having a considerable edge against the other two methods. Fifteen unique cytochrome b lineages were identified of which seven were new lineages. Microscopy and nested PCR recorded similar prevalence (32.92% and 35.42% respectively). The qPCR protocol used here, although more sensitive (52.92% prevalence), is not able to differentiate between parasite genera but provides the opportunity to screen a large number of samples in large-scale studies within a specific region. This study recommends the development and adoption of new molecular protocols with increased sensitivity and accuracy in prevalence studies. Nevertheless, microscopy remains essential for the morphological description of parasites and for distinguishing between abortive and successful chronic infections. The PCR-based method displays the detection of the parasitic genome but does not reveal whether parasites have or will develop into a successful infection.
在检测鸟类血孢子虫寄生虫的流行情况时，通常使用显微镜检查和巢式聚合酶链反应（PCR）检测感染。目前正在开发新的 PCR 检测方法，这些方法具有降低检测成本和时间、提高效率和灵敏度等明显优势。本研究采用实时 PCR（qPCR）方法，对提取自南非克鲁格国家公园三种椋鸟（黑脸椋鸟、蓝耳椋鸟和凤头椋鸟）240 份血液样本的基因组 DNA 进行了检测，将其与显微镜检查和巢式 PCR 进行了比较。所有三种方法都成功地检测到了鸟类血孢子虫寄生虫，qPCR 比其他两种方法具有明显优势。鉴定出了 15 种独特的细胞色素 b 谱系，其中 7 种是新的谱系。显微镜检查和巢式 PCR 的检测结果相似（分别为 32.92%和 35.42%）。虽然本研究使用的 qPCR 方法更为敏感（患病率为 52.92%），但无法区分寄生虫属，只能在特定区域的大规模研究中筛选大量样本。本研究建议开发和采用新的分子检测方法，提高检测的灵敏度和准确性。然而，显微镜检查仍然是寄生虫形态学描述和区分失败和成功慢性感染的必要手段。基于 PCR 的方法只能检测寄生虫的基因组，但不能显示寄生虫是否已经或将会发展成成功的感染。
