TY - JOUR

T1 - First description of Onchocerca flexuosa infections in Danish red deer (Cervus elaphus)

AU - Nielsen, Stine T.

AU - Hansen, Mette F.

AU - Chriel, Mariann

AU - Petersen, Heidi H.

PY - 2022/2

Y1 - 2022/2

N2 - The prevalence of Onchocerca infection in wild cervids from Denmark was studied in 119 fallow deer (Dama dama), 123 red deer (Cervus elaphus), 51 roe deer (Capreolus capreolus) and eight sika deer (Cervus Nippon) shot during the hunting season from October 2017 to January 2018 from 18 geographical locations across Denmark. The carcasses were macroscopic checked for nodules, and skin samples were examined for microfilaria. All roe deer, fallow deer and sika deer were negative for Onchocerca, while 30.9% red deer were positive for either microfilaria, nodules or both. Significantly more adult red deer (50.8%; 37.6-62.4; p < 0.0001) were infected with Onchocerca than juveniles < 1 year (7.8%; 2.1-18.5), while there was an insignificant (p = 0.075) difference in prevalence observed between males (17.4%; 7.8-31.4) and females (41.7%; 30.2-53.9). Onchocerca-positive red deer were observed from 91.7% (11/12) of the sampled geographical locations. Species identification was done on adult worms from nodules taken from the lumbar region of 20 red deer of different geographical origin by sequencing the mitochondrial 12S, 16S and nad5 gene fragments. The sequences matched with previously published sequences for Onchocerca flexuosa. The high prevalence of Onchocerca infection caused by O. flexuosa in red deer in Denmark shows that Denmark has favourable vector conditions and a suitable environment for the maintenance of the parasite. To our knowledge, this is the first systematic study of Onchocerca in wild-living cervids in Denmark.

AB - The prevalence of Onchocerca infection in wild cervids from Denmark was studied in 119 fallow deer (Dama dama), 123 red deer (Cervus elaphus), 51 roe deer (Capreolus capreolus) and eight sika deer (Cervus Nippon) shot during the hunting season from October 2017 to January 2018 from 18 geographical locations across Denmark. The carcasses were macroscopic checked for nodules, and skin samples were examined for microfilaria. All roe deer, fallow deer and sika deer were negative for Onchocerca, while 30.9% red deer were positive for either microfilaria, nodules or both. Significantly more adult red deer (50.8%; 37.6-62.4; p < 0.0001) were infected with Onchocerca than juveniles < 1 year (7.8%; 2.1-18.5), while there was an insignificant (p = 0.075) difference in prevalence observed between males (17.4%; 7.8-31.4) and females (41.7%; 30.2-53.9). Onchocerca-positive red deer were observed from 91.7% (11/12) of the sampled geographical locations. Species identification was done on adult worms from nodules taken from the lumbar region of 20 red deer of different geographical origin by sequencing the mitochondrial 12S, 16S and nad5 gene fragments. The sequences matched with previously published sequences for Onchocerca flexuosa. The high prevalence of Onchocerca infection caused by O. flexuosa in red deer in Denmark shows that Denmark has favourable vector conditions and a suitable environment for the maintenance of the parasite. To our knowledge, this is the first systematic study of Onchocerca in wild-living cervids in Denmark.

KW - Onchocerca flexuosa

KW - <p>Red deer,& nbsp;Denmark</p>

KW - DNA genotyping

KW - Vector-borne

KW - Microfilaria

KW - NODULAR ONCHOCERCOSIS

KW - 1ST DESCRIPTION

KW - JAKUTENSIS

U2 - 10.1016/j.vprsr.2021.100684

DO - 10.1016/j.vprsr.2021.100684

M3 - Journal article

C2 - 35115123

VL - 28

JO - Veterinary Parasitology: Regional Studies and Reports

JF - Veterinary Parasitology: Regional Studies and Reports

SN - 2405-9390

M1 - 100684

ER -