title: Pilot project to investigate over-wintering of free-living gastrointestinal nematode larvae of sheep in Ontario, Canada.
abstract: This study investigated the overwintering survival and infectivity of free-living gastrointestinal nematode (GIN) stages on pasture. The presence of GIN larvae was assessed on 3 sheep farms in Ontario with a reported history of clinical haemonchosis, by collecting monthly pasture samples over the winter months of 2009/2010. The infectivity of GIN larvae on spring pastures was evaluated using 16 tracer lambs. Air and soil temperature and moisture were recorded hourly. Free-living stages of Trichostrongylus spp. and Nematodirus spp. were isolated from herbage samples. Gastrointestinal nematodes were recovered from all tracer lambs on all farms; Teladorsagia sp. was the predominant species. Very low levels of Haemonchus contortus were recovered from 1 animal on 1 farm. The results suggest that Haemonchus larvae do not survive well on pasture, while Teladorsagia sp., Trichostrongylus spp. and Nematodirus spp. are able to overwinter on pasture in Ontario and are still infective for sheep in the spring.
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: Laura C
authors.initials: LC
authors.lastname: Falzon
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: Paula I
authors.initials: PI
authors.lastname: Menzies
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: John
authors.initials: J
authors.lastname: VanLeeuwen
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: Krishna P
authors.initials: KP
authors.lastname: Shakya
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: Andria
authors.initials: A
authors.lastname: Jones-Bitton
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: Jacob
authors.initials: J
authors.lastname: Avula
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: Jocelyn T
authors.initials: JT
authors.lastname: Jansen
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Falzon, Menzies, Jones-Bitton); Centre for Veterinary Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island (VanLeeuwen); Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario (Shakya, Avula, Peregrine); Veterinary Science and Policy, Ontario Ministry of Agriculture and Food, Elora, Ontario (Jansen).
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Peregrine
mesh_terms: D000821:Animal Feed / Q000469:parasitology; D000818:Animals; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000662:veterinary*; D007814:Larva; D008137:Longitudinal Studies; D009348:Nematoda / Q000302:isolation & purification*; D009349:Nematode Infections / Q000453:epidemiology / Q000662:veterinary*; D009864:Ontario / Q000453:epidemiology; D010865:Pilot Projects; D012621:Seasons; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control
references.citation: Vet Parasitol. 1993 Feb;46(1-4):197-203
references.pmid: 8484210
references.citation: J Helminthol. 2005 Dec;79(4):373-9
references.pmid: 16336722
references.citation: Vet Parasitol. 2003 Dec 1;118(1-2):79-92
references.pmid: 14651878
references.citation: Can Vet J. 1965 Oct;6(10):257-67
references.pmid: 5828182
references.citation: Vet Parasitol. 2006 Mar 31;136(3-4):367-72
references.pmid: 16406331
references.citation: Vet Parasitol. 2007 Jul 20;147(3-4):326-31
references.pmid: 17531390
references.citation: Animal. 2010 Mar;4(3):377-92
references.pmid: 22443942
references.citation: Aust Vet J. 1991 Oct;68(10):347-8
references.pmid: 1755790
references.citation: Vet Parasitol. 1997 Nov;72(3-4):247-56; discussion 257-64
references.pmid: 9460201
references.citation: Can J Comp Med. 1973 Jan;37(1):79-89
references.pmid: 4265556
references.citation: N Z Vet J. 2011 Nov;59(6):279-86
references.pmid: 22040332
references.citation: Vet Parasitol. 2006 Nov 30;142(1-2):1-15
references.pmid: 17011129
references.citation: Trop Anim Health Prod. 1993 Feb;25(1):30-2
references.pmid: 8465440
references.citation: Prev Vet Med. 2013 Jul 1;110(3-4):467-80
references.pmid: 23333408
references.citation: Vet Parasitol. 2010 Jun 24;170(3-4):244-52
references.pmid: 20236769
references.citation: N Z Vet J. 2011 Nov;59(6):272-8
references.pmid: 22040331
references.citation: N Z Vet J. 2011 Nov;59(6):287-92
references.pmid: 22040333
references.citation: Vet Parasitol. 2004 Jul 14;122(3):207-20
references.pmid: 15219362
references.citation: Vet Parasitol. 2007 Nov 30;150(1-2):128-38
references.pmid: 17920198
references.citation: Vet Parasitol. 1997 Dec 15;73(1-2):65-71
references.pmid: 9477493
references.citation: Vet Parasitol. 2013 Mar 31;193(1-3):150-62
references.pmid: 23218224