RECTAL BIOPSY IN SHEEP AND GOATS FOR MONITORING AND ANTE-MORTEM DIAGNOSIS OF SCRAPIE: NUMBER OF LYMPHOID FOLLICLES IN TWO CONSECUTIVE COLLECTIONS

Abstract This study aimed to evaluate the amount of lymphoid tissue associated with the rectal mucosa obtained by rectal biopsy and the possibility of two consecutive biopsies at different time intervals, for monitoring and ante-mortem diagnosis of scrapie. Rectal mucosa samples were collected from 56 sheep and 32 goats in two steps. In the first step, on day 0, all animals were tested and, for the second step, the animals were divided into groups and each group was subjected to collection on different dates: for sheep 7, 14, 21, and 28 days after the first one and, for goats, on days 14, 21, and 28. From 176 samples, 151 (85.8%) were collected from the rectal mucosa, and in 25 (14.2%) there was a collection failure. Considering the rectal mucosa samples (151), 56.86% of the sheep samples and 51.61% of the goat samples, on day 0, had more then ≥3 lymphoid follicles (LF). In the second collection, 58.97% of the sheep samples showed ≥ 3 LF and 33.33% of the goat samples. Comparing the number of LF of the same animals between the first and second collections, there was a significant difference (p