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Updated: Jan 1, 2026

Helminth Collection and Identification from Wildlife
Published on: December 14, 2013
Ungulate Helminth Transmission and Two Evolutionary Puzzles
James C Chubb1, Daniel Benesh2, Geoff A Parker1
1Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK.
Abstract:
Grazing mammals, ungulates, pose two evolutionary puzzles as helminth hosts. First, why do some helminths infect intermediate hosts prior to infecting ungulates, given that grazers could directly consume propagules on vegetation? Second, ungulates are large and long-lived, so why are they occasionally intermediate instead of definitive hosts, as in taeniid cestodes? We comprehensively surveyed helminth life cycles and transmission involving ungulates. We identified six transmission routes and found that ungulate helminth parasitism has evolved some 25 times. Direct egg transmission to ungulates is rare, and we suggest this is due to a transmission barrier caused by ungulate faecal avoidance. Our survey confirmed that ungulates are almost always definitive hosts, and we discuss the exceptional cases when they are not.
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