Diagnosis of experimentally infected sheep hydatidosis through antigen detection in serum and urine, with coagglutination [Co.A] test

ABSTRACT

To evaluate coagglutination test in the serum and urine of sheep for diagnosing of hydatidosis. Experimental study. Two rabbits, three dogs and nineteen sheep. Ovine hydatid cysts from affected livers and lungs, were collected from Ahwaz abattoir [Khozestan province, Iran]. The hydatid fluid [HF] and protoscolces were aseptically obtained in lab. Hydatid fluid was centrifuged and injected to rabbits in two steps. After then, rabbit hyperimmune sera were collected. Furthermore, each dog was given 15,000 viable protoscoleces. Less than two months later, dogs were autopsied after euthanasia and all Echinococcus granulosus worms were collected and their eggs were released. Almost, 2000 eggs were orally administred to each [N= 13]. The six other sheep were kept as control. All sheep were bled each week and their urine samples were collected fortnight. All sera and urine samples were examined with coagglutination [Co.A] test. While sensitivity of coagglutination test, was nil during five weeks of post-infection [p.i.], its values showed a biphasic pattern. While, it increased up to 23% in the sixth week and after then up to 100% in the 12th and 13th week of p.i. it decreased in the following weeks. Specificity of test was 100% throughout the experiment. While examination of urine in the affected sheep resulted in positive reaction from 6th week of p.i, its sensitivity and the sensitivity gradually increased up to 100% at 12th week of p.i. Furthermore, specificity of the test for urine of non-infected sheep remained 100%. These results suggest that the time of appearance of hydatid antigens in serum and urine is approximately alike. While positive results are very valuable, negative ones do not rule out hydatidosis