Parasitic nematodes of the genusSyphaciaSeurat, 1916 infecting Muridae in the British Isles, and the peculiar case ofSyphacia frederici

Abstract

SUMMARYSyphacia stroma(von Linstow, 1884) Morgan, 1932 andSyphacia fredericiRoman, 1945 are oxyurid nematodes that parasitize two murid rodents,Apodemus sylvaticusandApodemus flavicollis,on the European mainland. OnlyS. stromahas been recorded previously inApodemusspp. from the British Isles. Despite the paucity of earlier reports, we identifiedS. fredericiin four disparate British sites, two in Nottinghamshire, one each in Berkshire and Anglesey, Wales. Identification was based on their site in the host (caecum and not small intestine), on key morphological criteria that differentiate this species fromS. stroma(in particular the tail of female worms) and by sequencing two genetic loci (cytochrome C oxidase 1 gene and a section of ribosomal DNA). Sequences derived from both genetic loci of putative BritishS. fredericiisolates formed a tight clade with sequences from continental worms known to beS. frederici, clearly distinguishing these isolates fromS. stromawhich formed a tight clade of its own, distinct from clades representative ofSyphacia obvelatafromMusandS. murisfromRattus. The data in this paper therefore constitute the first record ofS. fredericifrom British wood mice, and confirm the status of this species as distinct from bothS. obvelataandS. stroma.