Validation of an in-house Sarcosystis fusiformis Glycoprotein-based ELISA for The Serodiagnosis of Sarcocystosis in Buffaloes

El Shanawany, Eman E.; Ata, Emad B.; Hassan, Soad E.; Abdel-Rahman, Eman H.

doi:10.21608/ejvs.2025.410864.3019

Validation of an in-house Sarcosystis fusiformis Glycoprotein-based ELISA for The Serodiagnosis of Sarcocystosis in Buffaloes

Document Type : Original Article

Authors

33 El Buhouth St، Ad Doqi, Dokki, Cairo Governorate 12622

10.21608/ejvs.2025.410864.3019

Abstract

Sarcocystosis is an important parasitic disease with a significant economic impact. This study aimed to perform molecular identification of Sarcocystis species in Egyptian buffaloes and developing a diagnostic antigen for detecting sarcocystis infection. A total of 174 serum samples were collected from Egyptian buffaloes (Bubalus bubalis) in private farms and slaughterhouses to obtain random, positive, and negative sera, along with tissue infected samples. DNA extracted from sarcocysts was used for molecular identification using 18s and ITS-specific primers, followed by sequencing and phylogenetic analysis. Antigen purification was achieved using Concanavalin-A (Con-A) affinity column chromatography. The purified fraction was used for detection of Sarcosystis antibodies in serum samples using ELISA. Molecular identification revealed the presence of Sarcocystis (S) fusiformis as the sole detected species with an identity percentage of 99.8%. This species is closely related to the strains found in Egypt and is part of a different phylogenetic cluster from other Sarcosystis species. The purified SF-GlcNAc-based ELISA demonstrated high diagnostic performance, with a sensitivity of 95.56%, specificity of 82.5%, and overall accuracy of 89.4% based on receiver operating characteristic (ROC) analysis. Compared to crude whole-cyst antigen-based ELISA (68.89% sensitivity, 67.5% specificity, and 68.24% accuracy), SF-GlcNAc-based ELISA demonstrated better diagnostic performance. Furthermore, the SF-GlcNAc antigen showed minimal cross-reactivity (12%) with sera from toxoplasmosis cases, achieving 88% relative specificity. In conclusion, S. fusiformis was the only Sarcocystis species detected, and the developed SF-GlcNAc-based ELISA proved to be an accurate, cost-effective, and reliable tool for the serodiagnosis of bovine sarcocystosis, offering a promising approach for disease control.

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