Laboratory of Medical Zoology, Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan.
School of Veterinary Medicine, Nippon Veterinary and Life Science University, Tokyo, Japan.
Microbiol Spectr. 2021 Dec 22;9(3):e0099021. doi: 10.1128/Spectrum.00990-21. Epub 2021 Nov 3.
Pallas's squirrel (Callosciurus erythraeus) was introduced in Japan in the 1930s and has since established itself in several areas across the country. Although wild Sciuridae populations have been demonstrated to be potential reservoirs for zoonotic enteric protozoa, epidemiological studies of such pathogens in Japan are scarce. Here, we examined 423 fecal samples from Pallas's squirrels captured in Kanagawa Prefecture, Japan, using PCR and DNA sequencing to determine the occurrence of spp., Enterocytozoon bieneusi, and . The overall prevalence of spp., E. bieneusi, and was 4.3% (18/423 samples), 13.0% (55/423 samples), and 44.0% (186/423 samples), respectively. The prevalence of and E. bieneusi was significantly higher in spring (60.1% and 17.4%, respectively) than in winter (27.6% and 8.6%, respectively [0.01]). Sequence analysis of spp., targeting the partial small subunit ribosomal RNA gene (SSU rDNA), showed 100% identity (541/541 bp) to Cryptosporidium ubiquitum, and analysis of the gp60 gene showed 99.76% (833/835 bp) identity to C. ubiquitum subtype XIIh. The sequences of the ribosomal internal transcribed spacer region of E. bieneusi and the partial SSU rDNA of were identified as E. bieneusi genotype SCC-2 and subtype 4, respectively. This study confirmed the presence of C. ubiquitum, E. bieneusi, and in Pallas's squirrels in Kanagawa Prefecture. Because Pallas's squirrels inhabit urban areas, living close to humans, the species may serve as a potential source of infection in human populations. Pallas's squirrel is designated a "regulated organism" under the Invasive Alien Species Act in Japan, and municipal authorities are introducing control measures to reduce its populations. It has been suggested that wild mammals may play a role in contaminating the environment with zoonotic pathogens. The present study detected the enteric pathogens Cryptosporidium ubiquitum, Enterocytozoon bieneusi, and in the feces of Pallas's squirrels inhabiting Kanagawa Prefecture, Japan. These pathogens persist in the environment and contaminate soils and water, which may potentially infect humans. Because Pallas's squirrels in Kanagawa Prefecture are found in urban areas, where they are in close contact with human populations, continued monitoring of zoonotic diseases among squirrel populations will be important for evaluating the significance of wildlife in pathogen transmission.
花鼠（Callosciurus erythraeus）于 20 世纪 30 年代被引入日本，此后已在全国多个地区定居。尽管野生松鼠科动物已被证明是人畜共患肠道原生动物的潜在宿主，但日本对这些病原体的流行病学研究很少。在这里，我们使用 PCR 和 DNA 测序检查了来自日本神奈川县的 423 份花鼠粪便样本，以确定 spp.、肠微孢子虫和 的发生情况。 spp.、E. bieneusi 和 的总流行率分别为 4.3%（18/423 样本）、13.0%（55/423 样本）和 44.0%（186/423 样本）。 和 E. bieneusi 的流行率在春季（分别为 60.1%和 17.4%）明显高于冬季（分别为 27.6%和 8.6%[0.01]）。针对部分小亚单位核糖体 RNA 基因（SSU rDNA）的 spp.的序列分析显示与隐孢子虫 ubiquitum 完全一致（541/541bp），而对 gp60 基因的分析显示与隐孢子虫 ubiquitum 亚型 XIIh 的一致性为 99.76%（833/835bp）。肠微孢子虫的核糖体内部转录间隔区和 的部分 SSU rDNA 序列被鉴定为肠微孢子虫基因型 SCC-2 和 亚型 4。本研究证实了神奈川县花鼠中存在隐孢子虫 ubiquitum、肠微孢子虫和 。由于花鼠栖息在城市地区，与人类生活密切相关，因此该物种可能成为人类感染的潜在来源。花鼠在日本被《外来入侵物种法》指定为“受管制的生物”，市政当局正在采取控制措施减少其数量。有研究表明，野生动物可能在污染环境中的人畜共患病原体方面发挥作用。本研究在日本神奈川县栖息的花鼠粪便中检测到肠道病原体隐孢子虫 ubiquitum、肠微孢子虫和 。这些病原体在环境中持续存在，并污染土壤和水，可能潜在感染人类。由于神奈川县的花鼠生活在城市地区，与人类密切接触，因此对松鼠种群中人畜共患病的持续监测对于评估野生动物在病原体传播中的意义非常重要。
