Toaleb Nagwa I, Shaapan Raafat M, Elaadli Haitham, Abdel Megeed Kadria N, Aboelsoued Dina
Parasitology and Animal Diseases Department, Veterinary Research Institute, National Research Centre, El Buhouth St., Dokki, Giza, Egypt.
Zoonotic Diseases Department, Veterinary Research Institute, National Research Centre, El Buhouth St., Dokki, Giza, Egypt.
BMC Vet Res. 2025 Jul 22;21(1):482. doi: 10.1186/s12917-025-04933-3.
Meat infection with the coccidian protozoan zoonotic Sarcocystis spp. causes public health hazards and high economic loss. The current study aimed to investigate molecular identification, cyst histological examination and seroprevalence of Sarcocystis spp. in water buffaloes slaughtered in the main abattoirs of 6 Egyptian Governorates; Cairo, Giza, Beni-suef, Al-Sharqia, Qalyubia, and El-Beheira. Each buffalo was visually inspected for the presence of Sarcocystis macrocysts and blood samples were collected. Out of 900 examined water buffaloes (Bubalus bubalis), 246 (27.3%) were found to be infected based on macroscopic examination. Histological examination of the macrocyst revealed metrocytes close to the cyst's edge and elongated curving basophilic bradyzoites occupying most of the cyst. Depending on age, we categorized naturally infected buffaloes into 3 groups: young (< 2 y.), adult (2-5 y.) and old (5-10 y.). The highest infection rate was observed in older buffaloes aged 5-10 years, meanwhile female animals exhibited a higher prevalence of infection compared to males. The esophagus had the highest presence of Sarcocystis compared to other organs. Using PCR based on 18S rRNA gene and sequencing, we isolated 3 Sarcocystis species from infected tissues: S. buffalonis, S. fusiformis and S. hirsuta-like. The prepared whole cyst antigen of S. fusiformis was characterized by 9 major polypeptides (140, 120, 78, 66, 53, 39, 32, 24 and 19 kDa) on 10% SDS-PAGE. Using western blotting, we identified 2 common immunogenic reactive bands (66 and 32 kDa) against naturally infected buffalo sera and hyperimmune rat sera. Additionally, sarcocystosis positive seroprevalence rate was 46.4% (418/900) with a sensitivity of 97.6% and specificity of 100% using indirect ELISA based on S. fusiformis whole cyst antigen. In conclusion, this study highlights the molecular identification, cyst histological examination and seroprevalence of Sarcocystis sp. among buffaloes in Egypt. ELISA using the S. fusiformis whole cyst antigen could be adapted to detect antibodies to Sarcocystis sp., in live animals, with an acceptable specificity and sensitivity.
肉类感染球虫类原生动物人畜共患的肉孢子虫属会造成公共卫生危害和巨大经济损失。本研究旨在调查埃及6个省（开罗、吉萨、贝尼苏韦夫、东部省、盖勒尤卜省和布海拉省）主要屠宰场宰杀的水牛中肉孢子虫属的分子鉴定、包囊组织学检查及血清流行率。对每头水牛进行肉眼检查，查看是否存在肉孢子虫大包囊，并采集血样。在900头被检查的水牛（水牛属）中，基于宏观检查发现246头（27.3%）被感染。对大包囊进行组织学检查发现，包囊边缘附近有滋养母细胞，细长弯曲的嗜碱性缓殖子占据了包囊的大部分区域。根据年龄，我们将自然感染的水牛分为3组：幼年（<2岁）、成年（2 - 5岁）和老年（5 - 10岁）。在5 - 10岁的老年水牛中观察到最高感染率，同时雌性动物的感染率高于雄性。与其他器官相比，食道中肉孢子虫的存在率最高。基于18S rRNA基因进行PCR和测序，我们从感染组织中分离出3种肉孢子虫：水牛肉孢子虫、梭形肉孢子虫和类刚毛刺肉孢子虫。在10%十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳上，梭形肉孢子虫制备的全包囊抗原由9种主要多肽（140、120、78、66、53、39、32、24和19 kDa）组成。使用蛋白质印迹法，我们鉴定出针对自然感染水牛血清和超免疫大鼠血清的2条常见免疫反应条带（66和32 kDa）。此外，使用基于梭形肉孢子虫全包囊抗原的间接ELISA法，肉孢子虫病血清阳性流行率为46.4%（418/900），敏感性为97.6%，特异性为100%。总之，本研究突出了埃及水牛中肉孢子虫的分子鉴定、包囊组织学检查及血清流行率。使用梭形肉孢子虫全包囊抗原的ELISA法可用于检测活体动物中肉孢子虫的抗体，具有可接受的特异性和敏感性。
