Infections of Moniezia expansa (Rudolphi, 1810) in Sheep During the Wet and Dry Seasons on St. Croix, U.S. Virgin Islands

Abstract

The sheep tapeworm, Moniezia expansa, occurred in 100% of lambs and wethers during the wet warm season (15 Jun–15 Dec) on the U.S. Virgin Island of St. Croix in 1999. In total, 924 mm of precipitation was measured during this period. In the early dry season and mid-dry season, the percentage of lambs and wethers infected was 25 and 44%, respectively. In total, 424 mm of rainfall was measured during this period (16 Dec 1999–15 Jun 2000). During the transition from wet to dry seasons, prevalence was lower in ewes (peaking at 29.6%) than in offspring. In lambs and wethers, prevalence increased to 58% and then declined to 44.4%. Temperature averaged 25°C during the wet season and 29.4°C during the dry season. Eggs per gram of feces (EPG), determined by the modified McMaster method, followed a similar pattern, peaking at 1,698 EPG in the wet season, 2,008 EPG in the early dry season, and 939 EPG in the mid-dry season. Infections were heavier and of greater duration in the wet season. The study started in September 1999 and ended in August 2000.