First description of Onchocerca jakutensis (Nematoda: Filarioidea) in red deer ( Cervus elaphus ) in Switzerland

Abstract

Twenty-seven species of the genus Onchocerca (Nematoda; Filarioidea) can cause a vector-borne parasitic disease called onchocercosis. Most Onchocerca species infect wild and domestic ungulates or the dog, and one species causes river blindness in humans mainly in tropical Africa. The European red deer (Cervus e. elaphus) is host to four species, which are transmitted by blackflies (simuliids) or biting midges (ceratopogonids). Two species, Onchocerca flexuosa and Onchocerca jakutensis, produce subcutaneous nodules, whereas Onchocerca skrjabini and Onchocerca garmsi live free in the hypodermal serous membranes. During the hunting season, September 2013, red deer (n = 25), roe deer (Capreolus c. capreolus, n = 6) and chamois (Rupicapra r. rupicapra, n = 7), all shot in the Grisons Region (Switzerland) were investigated for the presence of subcutaneous nodules which were enzymatically digested, and the contained Onchocerca worms were identified to species by light and scanning electron microscopy as well as by PCR/sequencing. In addition, microfilariae from skin samples were collected and genetically characterized. Neither nodules nor microfilariae were discovered in the roe deer and chamois. Adult worms were found in 24% of red deer, and all of them were identified as O. jakutensis. Two morphologically different microfilariae were obtained from five red deer, and genetic analysis of a skin sample of one red deer indicated the presence of another Onchocerca species. This is the first report of O. jakutensis in Switzerland with a prevalence in red deer similar to that in neighbouring Germany.

Sarcocystis infection in red deer (Cervus elaphus) with eosinophilic myositis/fasciitis in Switzerland and involvement of red foxes (Vulpes vulpes) and hunting dogs in the transmission

“…(Filarioidea; Onchocercidae) nematodes were associated with greenish discolouration and oedema of subcutaneous tissues in cervids ( Laaksonen et al, 2017 ) and domestic species ( Solismaa et al, 2008 ). Adult Onchocerca worms are localised free or in nodules in subcutaneous tissues and produce microfilariae in these sites ( Bosch et al, 2016 ; Boijsen et al, 2017 ). Dead or dying adult worms or microfilariae may trigger inflammatory reactions characterized by infiltration of eosinophilic granulocytes and multifocal nodular lymphoplasmacytic aggregations around them, followed by calcification and fibrosis ( Solismaa et al, 2008 ).…”

“…Four Onchocerca species were described in red deer in Central Europe (i.e. O. skrjabini and O. garmsi free in subcutaneous tissues, and O. flexuosa and O. jakutensis in subcutaneous nodules) ( Bosch et al, 2016 ; Boijsen et al, 2017 ), and O. jakutensis infection was reported in 26% of red deer of the Grisons region ( Bosch et al, 2016 ). Although the occurrence of Onchocerca spp.…”

A survey of Onchocerca fasciata infection in camels (Camelus bactrianus) with notes on morphology

“…flexuosa , Wedl, 1856; O . jakutensis , Guvanov, 1964) [9–11], wolves and dogs ( O . lupi , Rodonaja, 1967) [12].…”

Onchocerca jakutensis ocular infection in Poland: a new vector-borne human health risk?

“…To the best of our knowledge, we report the first case of O. jakutensis ocular infection. Onchocerca jakutensis is a common parasite of red deer detected in the Russian Federation [9], Switzerland [10], Italy [1], Germany [11], the Czech Republic [12], the Slovak Republic [12] and Poland [9]. A study by Demiaszkiewicz [13] has shown that O. jakutensis parasitize red deer in several regions of Poland, among others, in the south-west part, where patient described in the present report lives.…”