Patterns of shedding of cryptosporidial oocysts by ewes and lambs kept indoors

Abstract

This study was carried out to determine the pattern of shedding of cryptosporidial oocysts by lambs and their dams kept indoors from lambing to weaning in Botucatu, São Paulo State, Brazil. A group of 20 Ile de France ewes in late pregnancy was housed in a facility with concrete floor. The concrete floor was cleaned daily and vigorously washed three times per week. Lambing occurred in August and September/2001. Fecal samples were taken from ewes and lambs on the day of the lambing, 4, 8, 16, 32 and 64 days after lambing. Samples were processed using a centrifuge-sedimentation technique in ether. Fecal smears were stained with auramine O and by Ziehl-Neelsen modified technique. The overall percentages of fecal samples of lambs and ewes positives for Crypostosporidium oocysts were 26.7% and 31.9%, respectively (P>;0.05). Four of the 20 lambs and two of the 20 ewes did not shed oocysts in any of the faecal samples examined. The highest percentage of positive samples occurred in 4-day-old lambs. In ewes a peak in the percentage of positive samples occurred 4 days after lambing. Despite the relative high rate of animal shedding oocysts in feces, the cryptosporidial infection was asymptomatic in all ewes and lambs.