Serodiagnosis of Przhevalskiana spp. Infestation in Goats Using a Competitive ELISA

Goat warble-fly infestation is one of the parasitic diseases caused by the larvae of przhevalskiana spp. It is known to be a major challenge for health and welfare in infested goats and causes high economic losses in livestock worldwide. The detection of goat grub was previously conducted by direct palpation of second and third stage larvae in the back and flank site of the live animals or visual evaluation of the carcasses in slaughterhouses. However, due to the small size of the first instar larvae of przhevalskiana (less than 1 mm during emerging from the egg), some of the infected cases were ignored and recorded as negative samples. Immunodiagnostic procedures as easy and cost-effective diagnostic methods provide early detection of myiasis in living animals (even when the larvae are still migrating or are undetectable in the animal body).This study was conducted to evaluate the competitive enzyme-linked immunosorbent assay (ELISA) system in order to detect the antibodies of przhevalskiana larvae in the goat sera. In order to prepare the larval antigen, 200 first instar larvae of przhevalskiana were collected from the subdermal region of the back and flanks of the infested goats in Khoramabad slaughterhouse, Khoramabad, Iran, from September 2017 to March 2018. Totally, 37 and 46 sera samples were taken from the infected and uninfected goats. The sensitivity and specificity at cut-off 3SD were obtained at 89.18% and 84.78%. Moreover, the measures of inter-and intra-assay coefficients of variability to express the precision or replicability of ELISA kit results were 5.33% and 2.81%, respectively.