Comparison of the effects of infection with Trichostrongylus colubriformis, T. vitrinus and T. rugatus in Merino lambs

Impact of gastrointestinal parasitic nematodes of sheep, and the role of advanced molecular tools for exploring epidemiology and drug resistance - an Australian perspective

“…In Australia, the three most common species are T. colubriformis , T. vitrinus , and T. rugatus [20]. The main pathogenic effects are caused by the exsheathed L3s of T. vitrinus , which burrow between the enterocytes of intestinal villi and lead to the formation of intra-epithelial tunnels [21]. Young nematodes develop in these tunnels 10–12 days following infection.…”

“…circumcincta and T. axei in the abomasum, and T. colubriformis and T. vitrinus in the small intestine, of which the latter species has the highest pathogenicity [21] and predominates in this environment [25,29]. In the Australian winter rainfall zones, these parasites are associated with death in weaners and productivity losses through all classes of sheep [10].…”

Linear distribution of nematodes in the gastrointestinal tract of tracer lambs

“…It has been reported that both T. colubriformis and T. vitrinus are confined only in the small intestine, and the majority of the adult worms are localized in the first part of the intestine (Taylor and Kilpatrick 1980;Beveridge et al 1989;Wagland et al 1996;Ziam et al 1999). In our work, we discovered more T. colubriformis in the ileum and jejunum rather than in the duodenum (53.78% individualsTables 3 and 4), T. vitrinus was found in the duodenum in 93.33% of infected lambs and in 90% of cases, T. vitrinus was found in the jejunum and ileum (Tables 3, 4).…”

Immune-mediated responses account for the majority of production loss for grazing meat-breed lambs during Trichostrongylus colubriformis infection

“…It is possible that differences in the relative importance of immune and direct components involved in the response to GIN infection do genuinely differ between species and in pathogenicity within species. Morley (2006) reported that immunosuppression had little effect on the production loss associated with H. contortus infection, while Beveridge et al (1989) concluded that T. vitrinus was more pathogenic than T. colubriformis and T. rugatus. Greater reductions in VFI were observed for T. vitrinus, in addition to a significant decrease in plasma albumin concentration, possibly resulting from increased plasma loss into the lumen of the gastrointestinal tract.…”

“…Approximately 8 m of the small intestine was collected, as the predominant site of predilection for T. colubriformis is within the anterior 4 m (Beveridge et al, 1989). The abomasum and small intestine were washed and mucosal linings scraped with the entire contents and washings collected.…”