Defining parasite biodiversity at high latitudes of North America: new host and geographic records for Onchocerca cervipedis (Nematoda: Onchocercidae) in moose and caribou

• Published in: Parasites & Vectors
• Main Authors: Verocai Guilherme G, Lejeune Manigandan, Beckmen Kimberlee B, Kashivakura Cyntia K, Veitch Alasdair M, Popko Richard A, Fuentealba Carmen, Hoberg Eric P, Kutz Susan J
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2012
• Subjects: Alces; Caribou; Legworm; North America; Onchocerca cervipedis; Moose; Rangifer; Subarctic; Vector-borne diseases; Infectious and parasitic diseases; RC109-216; Yukon; Northwest Territories; Canada; Rangifer tarandus; Alaska
• Online Access: https://doi.org/10.1186/1756-3305-5-242; https://doaj.org/article/39bb03d5c2744dc2904fc6b75b77d6e0

Abstract Background Onchocerca cervipedis is a filarioid nematode of cervids reported from Central America to boreal regions of North America. It is found primarily in subcutaneous tissues of the legs, and is more commonly known as ‘legworm’. Blackflies are intermediate hosts and transmit larvae to ungulates when they blood-feed. In this article we report the first records of O. cervipedis from high latitudes of North America and its occurrence in previously unrecognized host subspecies including the Yukon-Alaska moose ( Alces americanus gigas) and the Grant’s caribou ( Rangifer tarandus granti ). Methods We examined the subcutaneous connective tissues of the metacarpi and/or metatarsi of 34 moose and one caribou for parasitic lesions. Samples were collected from animals killed by subsistence hunters or animals found dead in the Northwest Territories (NT), Canada and Alaska (AK), USA from 2005 to 2012. Genomic DNA lysate was prepared from nematode fragments collected from two moose. The nd5 region of the mitochondrial DNA was amplified by PCR and sequenced. Results Subcutaneous nodules were found in 12 moose from the NT and AK, and one caribou from AK. Nematodes dissected from the lesions were identified as Onchocerca cervipedis based on morphology of female and male specimens. Histopathological findings in moose included cavitating lesions with multifocal granulomatous cellulitis containing intralesional microfilariae and adults, often necrotic and partially mineralized. Lesions in the caribou included periosteitis with chronic cellulitis, eosinophilic and lymphoplasmacytic infiltrate, and abundant granulation associated with intralesional adult nematodes and larvae. Sequences of the nd5 region (471bp), the first generated for this species, were deposited with Genbank (JN580791 and JN580792). Representative voucher specimens were deposited in the archives of the United States National Parasite Collection. Conclusions The geographic range of O. cervipedis is broader than previously thought, and extends into ...