Table_2_Molecular characteristics and zoonotic potential of enteric protists in domestic dogs and cats in Egypt.DOCX

IntroductionDomestic dogs and cats can be a source of human infection by a wide diversity of zoonotic pathogens including parasites. Genotyping and subtyping tools are useful in assessing the true public health relevance of canine and feline infections by these pathogens. This study investigated the occurrence, genetic diversity, and zoonotic potential of common diarrhea-causing enteric protist parasites in household dogs and cats in Egypt, a country where this information is particularly scarce.
MethodsIn this prospective, cross-sectional study a total of 352 individual fecal samples were collected from dogs (n = 218) and cats (n = 134) in three Egyptian governorates (Dakahlia, Gharbeya, and Giza) during July–December 2021. Detection and identification of Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. were carried out by PCR and Sanger sequencing. Basic epidemiological variables (geographical origin, sex, age, and breed) were examined for association with occurrence of infection by enteric protists.
Results and discussionThe overall prevalence rates of Cryptosporidium spp. and G. duodenalis were 1.8% (95% CI: 0.5–4.6) and 38.5% (95% CI: 32.0–45.3), respectively, in dogs, and 6.0% (95% CI: 2.6–11.4) and 32.1% (95% CI: 24.3–40.7), respectively, in cats. All canine and feline fecal samples analyzed tested negative for E. bieneusi and Blastocystis sp. Dogs from Giza governorate and cats from Dakahlia governorate were at higher risk of infection by Cryptosporidium spp. (p = 0.0006) and G. duodenalis (p = 0.00001), respectively. Sequence analyses identified host-adapted Cryptosporidium canis (n = 4, one of them belonging to novel subtype XXe2) and G. duodenalis assemblages C (n = 1) and D (n = 3) in dogs. In cats the zoonotic C. parvum (n = 5) was more prevalent than host-adapted C. felis (n = 1). Household dogs had a limited (but not negligible) role as source of human giardiasis and cryptosporidiosis, but the unexpected high frequency of zoonotic C. parvum in domestic cats might be a public health concern. This is the first molecular-based description of Cryptosporidium spp. infections in cats in the African continent to date. Molecular epidemiological data provided here can assist health authorities and policy makers in designing and implementing effective campaigns to minimize the transmission of enteric protists in Egypt.

引言
家养犬与猫可作为多种人畜共患病原（包括寄生虫）的人类感染来源。基因分型与亚型分型工具，可用于评估此类病原引发的犬猫感染的真实公共卫生意义。本研究针对埃及家养犬与猫体内常见的致腹泻肠道原生动物寄生虫，调查其感染情况、遗传多样性与人畜共患潜力；埃及在该领域的相关研究信息尤为匮乏。
材料与方法
本项前瞻性横断面研究于2021年7月至12月期间，在埃及3个省（达卡利亚省、盖勒尤卜省和吉萨省）采集了352份个体粪便样本，其中犬样本218份、猫样本134份。通过聚合酶链反应（PCR）与桑格测序（Sanger sequencing），完成隐孢子虫属（Cryptosporidium spp.）、十二指肠贾第虫（Giardia duodenalis）、比氏肠胞虫（Enterocytozoon bieneusi）以及芽囊原虫属（Blastocystis sp.）的检测与鉴定。同时分析了地理来源、性别、年龄与品种等基础流行病学变量与肠道原生动物感染发生的相关性。
结果与讨论
犬群中隐孢子虫属与十二指肠贾第虫的总体感染率分别为1.8%（95%置信区间：0.5–4.6）与38.5%（95%置信区间：32.0–45.3）；猫群中二者的总体感染率分别为6.0%（95%置信区间：2.6–11.4）与32.1%（95%置信区间：24.3–40.7）。所有纳入分析的犬、猫粪便样本的比氏肠胞虫与芽囊原虫属检测结果均为阴性。来自吉萨省的犬与来自达卡利亚省的猫，分别具有更高的隐孢子虫属感染风险（p=0.0006）与十二指肠贾第虫感染风险（p=0.00001）。序列分析显示，犬体内存在宿主适应性的犬隐孢子虫（Cryptosporidium canis，n=4，其中1株属于新型亚型XXe2），以及十二指肠贾第虫的C聚集群（n=1）与D聚集群（n=3）。猫体内的人畜共患微小隐孢子虫（C. parvum，n=5）感染率高于宿主适应性的猫隐孢子虫（C. felis，n=1）。家养犬作为人类贾第虫病与隐孢子虫病感染源的作用有限，但仍不可忽视；而家养猫体内出人意料的高比例人畜共患微小隐孢子虫感染，可能构成公共卫生隐患。本研究为截至目前非洲大陆首次基于分子生物学手段对猫隐孢子虫属感染的报道。本研究提供的分子流行病学数据，可助力埃及卫生主管部门与政策制定者设计并实施有效防控策略，以最大限度降低肠道原生动物的传播风险。