Potentials of Glycoprotein Fraction in Successful Diagnosis of Sheep Haemonchosis

Abstract

Haemonchus contortus (H. contortus) is a pathogenic nematode of small ruminants. In sheep, H. contortus causes anemia that decreases animal productivity and can ultimately lead to death. The objective of the current study was to evaluate the immunodiagnostic efficacy of four glycoprotein fractions for detection of anti-H. contortus IgG in sheep. Four fractions were isolated from crude extract of H. contortus adult worm by Con A affinity column chromatography. Characterization of the isolated four fractions; Glucose (Gluc), Galactose (gal), N-acetyglucosamine (GlucNAc), and Lactose (Lac) by SDS-PAGE showed three bands of 83, 66 and 24 kDa in Gluc fraction and three bands of the same molecular weights in GlucNAc fraction. Gal fraction resolved into four bands of 87, 70, 36 and 27 kDa, and Lac fraction resolved into two bands at 87 and 26 KDa, compared with many bands associated with crude antigen ranged from 100 to 24 KDa. The diagnostic potency of the isolated fractions was evaluated by indirect ELISA and Western blot. The highest diagnostic potentials are associated with Gluc fraction where its 24 kDa band reacted strongly with infected serum as proved by Western blot. Indirect ELISA based on Gluc fraction using positive and negative H. contortus sheep sera and sera infected with other parasites showed 100% sensitivity and 97.05% specificity. These percentages were confirmed by Western blot. The fraction recorded Positive Predictive Value (PPV) 92%, Negative Predictive Value (NPV) 100 % and diagnostic efficacy 97.8 %. Diagnosis of natural haemonchosis using Gluc fraction by indirect ELISA showed 56.83% infection percentage in examined sample. The present study proved the potency of Gluc fraction in detection of H. contortus specific IgG in natural sheep haemonchosis by indirect ELISA.