The Strongyloides (Nematoda) of sheep and the predominant Strongyloides of cattle form at least two different, genetically isolated populations

• Published in: Veterinary parasitology Vol. 157; no. 1; pp. 89 - 99
• Main Authors: Eberhardt, Alexander G., Mayer, Werner E., Bonfoh, Bassirou, Streit, Adrian
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.10.2008; Amsterdam; New York: Elsevier
• Subjects: Africa - epidemiology; Africa, Northern - epidemiology; animal genetics; Animals; Base Sequence; biological nomenclature; Cattle; cattle diseases; Cattle Diseases - epidemiology; Cattle Diseases - parasitology; disease prevalence; DNA, Helminth - genetics; gastrointestinal nematodes; genetic variation; Genotype; geographical variation; Host specificity; host-parasite relationships; livestock; mixed infection; molecular epidemiology; Nematoda; Nematodes; Phylogeny; population genetics; Ruminantia; Sheep; sheep diseases; Sheep Diseases - epidemiology; Sheep Diseases - parasitology; species differences; Strongyloides; Strongyloides - classification; Strongyloides - genetics; Strongyloides papillosus; Strongyloides ratti; Strongyloides stercoralis; Strongyloides vituli; strongyloidiasis; Strongyloidiasis - epidemiology; Strongyloidiasis - parasitology; Strongyloidiasis - veterinary; Germany; Africa, Northern; Africa; Nematodes; Strongyloides vituli; Strongyloides papillosus; Host specificity
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/j.vetpar.2008.07.019

Strongyloides sp. (Nematoda) are very wide spread small intestinal parasites of vertebrates that can form a facultative free-living generation. Most authors considered all Strongyloides of farm ruminants to belong to the same species, namely Strongyloides papillosus (Wedl, 1856). Here we show that, at least in southern Germany, the predominant Strongyloides found in cattle and the Strongyloides found in sheep belong to separate, genetically isolated populations. While we did find mixed infections in cattle, one form clearly dominated. This variety, in turn, was never found in sheep, indicating that the two forms have different host preferences. We also present molecular tools for distinguishing the two varieties, and an analysis of their phylogenetic relationship with the human parasite Strongyloides stercoralis and the major laboratory model species Strongyloides ratti. Based on our findings we propose that Strongyloides from sheep and the predominant Strongyloides from cattle should be considered separate species as it had already been proposed by [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l‘evolution des Anguillules parasites ( Strongyloides). Comptes rendu hebdomadaires des séances et mémoires de la Société de Biologie et de ses filiales 85, 149–152], but was largely ignored by later authors. For nomenclature, we follow [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l‘evolution des Anguillules parasites ( Strongyloides). Comptes rendu hebdomadaires des séances et mémoires de la Société de Biologie et de ses filiales 85, 149–152] and use the name S. papillosus for the Strongyloides of sheep and the name Strongyloides vituli for the predominant Strongyloides of cattle.