Lymphatic dwelling filarioid nematodes in reindeerRangifer tarandus tarandus, (Cervidae) in Finland, identified asRumenfilaria andersoniLankester & Snider, 1982 (Nematoda: Onchocercidae: Splendidofilariinae)

Abstract

Summary :A filarioid nematode inhabiting the lymphatic vessels of the subserosal rumen and mesenteries associated with a high prevalence of its microfilariae in peripheral blood was observed in Finnish reindeer (Rangifer tarandus tarandus) in 2004 and 2006. Adult specimens were collected by dissecting lymphatic vessels from slaughtered animals, where some of the nematodes were seen through the wall of the dilated vessels as thin white winding threads obscuring the vessel. The morphology of adult worms and microfilaria is described based on light and scanning electron microscopy. These filariae belong to the subfamily Splendidofilariinae of the Onchocercidae and resemble Rumenfilaria andersoni, recovered from different host and localization, the ruminal veins of Alces alces in Canada.Comparison of paratypes of this species revealed only minor differences which were not sufficient to separate the filarioid parasitic in R. tarandus in Finland and we identify the nematode as R. andersoni. However, the findings suggest two different parasite populations. The finalizing of this taxonomic question in the future requires an integrated approach, in which the DNAbased and morphological identifications are consistent. Résumé : FILAIRES LYMPHATIQUES

A new type F Wolbachia from Splendidofilariinae (Onchocercidae) supports the recent emergence of this supergroup

“…The specimens studied were recovered from lymphatic vessels collected from reindeer in slaughter houses of Kuusamo (Finland), and identified by Laaksonen et al (2010). Madathamugadia hiepei parasitizes the gecko Chondrodactylus (=Pachydactylus) turneri (Hering-Hagenbeck et al, 2000).…”

A lymphatic dwelling filarioid nematode, Rumenfilaria andersoni (Filarioidea; Splendidofilariinae), is an emerging parasite in Finnish cervids

“…The specific identity of the mf was a mystery until adult nematodes were discovered. The adult nematodes from the lymphatic system, adjacent to the rumen, were later collected and identified, based on morphological criteria [ 10 ], in reindeer and moose during 2006.…”

“…The samples (1 ml blood/animal) were examined for the presence of Rumenfilaria mf (rmf) by the modified Knott’s technique [ 13 ] and the rmf were counted in temporary wet mounts to ten thousands. The presence and identity of mf in cervid blood circulation, was based on comparative morphological characters [ 10 ].…”

“…Subsequently, adult parasites (Figure 1 b) were found inhabiting the lymphatic vessels adjacent to the rumen of adult hosts, based on necropsies performed in December 2006. Identity of these previously unrecognized filarioids was shown, based on comparative morphology, to be Rumenfilaria andersoni Lankester and Snider, 1982 (Splendidofilariinae), a species considered to be endemic to North America and which had not been documented in Eurasian hosts and localities [ 10 ]. This nematode was originally described in one moose ( Alces americanus ) from eastern Canada.…”

“…Rumenfilaria was recently documented in Alaska where it occurs in over 70% of moose (based on mf), suggesting a broad geographic range in the Nearctic [ 12 ]. Interestingly, it has not been reported in subspecies of caribou or other high latitude ungulates, nor in other cervids including species of Cervus and Odocoileus in the temperate and boreal zone of North America, nor is it apparently known from other localities across Eurasia [ 10 , 12 ]. The detection of adult R. andersoni nematodes in reindeer represents the first lymphatic filarioid to be recognized in artiodactyles, which make our findings especially significant.…”