Table_2_Unveiling zoonotic threats: molecular identification of Brugia sp. infection in a lion.xlsx

Brugia malayi and B. pahangi, potential zoonotic pathogens transmitted by mosquitoes, are believed to primarily infect dogs and cats as reservoir hosts. Although previous studies have indicated nematode infections in lions, particularly in zoo environments where human contact with these reservoirs is possible, limited documentation exists regarding Brugia sp. infections in lions in Thailand. This study aims to investigate a case of Brugia infection in a lion from a zoo in Thailand. The blood sample was collected and examined from a female lion, using staining methods to morphologically identify microfilaria at the genus level. Subsequently, the PCR was employed targeting specific genes, including mitochondrial 12S rDNA, 18S rDNA, cytochrome oxidase I (COI) and Wolbachia surface protein (wsp), to confirm the species of the filarial nematode parasite. The genetic sequencing results revealed a high similarity (99–100%) to B. malayi for the 12S rDNA, 18S rDNA, COI and wsp genes. Phylogenetic analysis based on nucleotide sequences from the 12S rDNA, 18S rDNA, COI and wsp genes showed that the sequences from this study belong to different clusters. This marks the inaugural documentation of molecular identification of Brugia infection in a lion, signifying that lions could function as reservoirs for this parasite and present a potential public health risk in the region. Our research underscores the effectiveness of molecular techniques and phylogenetic analysis in discerning and comprehending the evolution of filarial parasites. Additionally, it emphasizes the significance of these methods in enhancing the diagnosis, control, and prevention of zoonotic filarial nematode infections.

马来布鲁线虫（Brugia malayi）与彭亨布鲁线虫（Brugia pahangi）是经蚊子传播的潜在人兽共患病原体，通常以犬、猫作为储存宿主。尽管既往研究已在狮子体内检出线虫感染，尤其是在动物园这类人类可与这些储存宿主发生接触的环境中，但目前关于泰国境内狮子感染布鲁线虫属（Brugia sp.）的文献记录仍较为匮乏。本研究旨在对泰国某动物园内一头狮子的布鲁线虫感染病例开展调查。研究人员从一头雌性狮子体内采集血液样本，采用染色法对微丝蚴进行形态学鉴定以确定其所属属别。随后，针对线粒体12S rDNA、18S rDNA、细胞色素氧化酶I（cytochrome oxidase I, COI）以及沃尔巴克氏体表面蛋白（Wolbachia surface protein, wsp）等特异性基因开展聚合酶链式反应（Polymerase Chain Reaction, PCR），以确认该丝虫寄生线虫的物种分类。基因测序结果显示，本研究获得的12S rDNA、18S rDNA、COI及wsp基因序列与马来布鲁线虫（Brugia malayi）的同源性达99%~100%。基于上述四个基因的核苷酸序列开展的系统发育分析结果表明，本研究的序列分属于不同的进化簇。本研究首次通过分子生物学方法在狮子体内鉴定出布鲁线虫感染，这意味着狮子可作为该寄生虫的储存宿主，并对该地区构成潜在的公共卫生风险。本研究证实了分子技术与系统发育分析在解析、阐明丝虫寄生虫演化机制方面的有效性，同时凸显了上述方法在提升人兽共患丝虫线虫感染的诊断、防控与预防水平方面的重要意义。