Specific IgG response. Specific IgG anti-rFhGST-S1were measured using the ELISA method as described previously [46] . A total of 10 mg/ml of rFhGST-S1 was used to coat microtitre plates, 100 ml/well of goat sera diluted in blocking buffer and rabbit antigoat IgG peroxidase conjugated (whole molecule -Sigma) diluted in blocking buffer at 1:10000. Serum pools were from ten experimentally infected goats and ten uninfected goats as positive and negative controls, respectively. All samples were analysed in duplicate. Results were expressed as antibody titre (Log10).