Effects of sub-zero storage temperatures on endoparasites in canine and equine feces.
Abstract: Fecal samples from wild and domestic carnivores are routinely frozen for three days at -80°C to kill eggs of Echinococcus spp., following recommendations from the World Health Organization (WHO) and World Organization for Animal Health (OIE). This is done to decrease the risk of zoonotic infection with these pathogenic cestodes. In addition, it is often necessary to freeze fecal samples collected for research prior to batch processing by a limited number of personnel, especially large numbers of samples or those collected in remote locations. The effect of freezing on the recovery of endoparasite eggs, cysts and oocysts from fecal samples is not well documented, even in hosts for which veterinary diagnostic submissions are relatively common. In this study, fecal samples from naturally infected dogs and horses were split into four treatment groups: fresh; -80°C for 3 days; -20°C for 30 days; and -80°C for 3 days followed by -20°C for an additional 30 days. Temperatures and times were chosen to simulate diagnostic and research protocols currently in place. Helminth eggs and sporocysts of Sarcocystis spp. were counted using a quantitative double centrifugation sucrose fecal flotation (modified Stoll egg count). Repeated measures ANOVA was used to detect differences in egg/sporocyst counts between the treatment groups for Sarcocystis spp. sporocysts, taeniid eggs (Taenia and/or Echinococcus spp.), ascarid eggs (Parascaris equorum, Toxocara canis, Toxascaris leonina), and strongylid type eggs (Uncinaria stenocephala, and equine strongylids, most likely cyathostomins). Counts for P. equorum and strongylid type eggs (both equine and canine) decreased significantly following freezing. Post-freezing, some samples that had been positive on fresh examination became negative for Parascaris and strongylid eggs. This study suggests that protocols requiring freezing artificially lowers recovery of eggs of Parascaris and strongylid nematodes in fecal surveys; however, recovery rates for eggs of other helminth species as well as sporocysts of Sarcocystis spp. were relatively robust compared to the freshly tested fecal samples. This is reassuring for large scale fecal surveys needed for fecal egg count reduction analyses following treatment, and for surveillance in wildlife and remote human and animal populations.
Copyright © 2014 Elsevier B.V. All rights reserved.
Publication Date: 2014-05-16 PubMed ID: 24880644DOI: 10.1016/j.vetpar.2014.05.008Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research examines how different sub-zero storage temperatures impact the detectability of endoparasite eggs, cysts, and oocysts in canine and equine feces, revealing that freezing procedures can impede the recovery of certain parasite eggs.
Background
- The study begins by highlighting the routine practice of freezing fecal samples from both wild and domestic carnivores. The purpose of this is to destroy eggs from Echinococcus spp., reducing their zoonotic infection risk.
- It furthermore points out the necessity of freezing fecal samples for research purposes, especially in cases when a large number of samples are collected in distant locations.
Objective and Methodology
- The primary aim of this research was to assess the impact of freezing on the recovery of endoparasite eggs, cysts, and oocysts in dog and horse fecal samples.
- Fecal samples from naturally infected dogs and horses were divided into four groups: fresh; chilled at -80°C for 3 days; chilled at -20°C for 30 days; and finally cooled at -80°C for 3 days, then kept at -20°C for an additional 30 days.
- These temperature settings and durations were selected to imitate diagnostic and research protocols currently employed.
- A repetitive measures ANOVA statistical test was deployed to determine any noticeable differences in egg/sporocyst counts among the different testing groups.
Findings
- The research discovered a significant decrease in counts for P. equorum and strongylid-type eggs (both equine and canine) following the freezing process.
- Additionally, some samples that had initially tested positive on fresh examination were found to be negative for Parascaris and strongylid eggs post-freezing.
Conclusion
- The study concludes that freezing procedures could artificially lower the number of Parascaris and strongylid nematode eggs recovered in fecal samples.
- On the brighter side, the recovery rates for eggs of other types of helminth, together with sporocysts of Sarcocystis spp., were quite resilient in comparison to the fresh samples.
- This could be positive news for vast-scale fecal studies necessary for post-treatment fecal egg count reduction analyses, and for wildlife and remote human and animal population monitoring.
Cite This Article
APA
Schurer J, Davenport L, Wagner B, Jenkins E.
(2014).
Effects of sub-zero storage temperatures on endoparasites in canine and equine feces.
Vet Parasitol, 204(3-4), 310-315.
https://doi.org/10.1016/j.vetpar.2014.05.008 Publication
Researcher Affiliations
- Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada. Electronic address: jschurer@gmail.com.
- Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
- Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
- Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
MeSH Terms
- Animals
- Centrifugation
- Dogs
- Feces / parasitology
- Female
- Freezing
- Helminthiasis, Animal / parasitology
- Helminths / physiology
- Horses
- Humans
- Ovum
- Parasite Egg Count / veterinary
- Parasites / physiology
- Protozoan Infections, Animal / parasitology
- Temperature
- Zoonoses
Grant Funding
- Canadian Institutes of Health Research
Citations
This article has been cited 11 times.- Toresson L, Spillmann T, Pilla R, Ludvigsson U, Hellgren J, Olmedal G, Suchodolski JS. Clinical Effects of Faecal Microbiota Transplantation as Adjunctive Therapy in Dogs with Chronic Enteropathies-A Retrospective Case Series of 41 Dogs. Vet Sci 2023 Apr 3;10(4).
- Marchiori E, Obber F, Celva R, Marcer F, Danesi P, Maurizio A, Cenni L, Massolo A, Citterio CV, Cassini R. Comparing copromicroscopy to intestinal scraping to monitor red fox intestinal helminths with zoonotic and veterinary importance. Front Vet Sci 2022;9:1085996.
- Bouchard É, Schurer JM, Kolapo T, Wagner B, Massé A, Locke SA, Leighton P, Jenkins EJ. Host and geographic differences in prevalence and diversity of gastrointestinal helminths of foxes (Vulpes vulpes), coyotes (Canis latrans) and wolves (Canis lupus) in Québec, Canada. Int J Parasitol Parasites Wildl 2021 Dec;16:126-137.
- Morandi B, Mazzone A, Gori F, Alvarez Rojas CA, Galuppi R, Deplazes P, Poglayen G. New Insights Into the Peculiar World of the Shepherd-Dog Parasites: An Overview From Maremma (Tuscany, Italy). Front Vet Sci 2020;7:564164.
- Jenkins E, Backwell AL, Bellaw J, Colpitts J, Liboiron A, McRuer D, Medill S, Parker S, Shury T, Smith M, Tschritter C, Wagner B, Poissant J, McLoughlin P. Not playing by the rules: Unusual patterns in the epidemiology of parasites in a natural population of feral horses (Equus caballus) on Sable Island, Canada. Int J Parasitol Parasites Wildl 2020 Apr;11:183-190.
- Nakhodkin SS, Pshennikova VG, Dyachkovskaya PS, Barashkov NA, Nikanorova AA, Teryutin FM, Melnichuk OA, Crubézy E, Fedorova SA, Magnaval JF. A serological survey of echinococcosis, toxocariasis and trichinellosis among rural inhabitants of Central Yakutia. Int J Circumpolar Health 2019 Dec;78(1):1603550.
- Seltmann A, Webster F, Martins Ferreira SC, Czirják GÁ, Wachter B. Age-specific gastrointestinal parasite shedding in free-ranging cheetahs (Acinonyx jubatus) on Namibian farmland. Parasitol Res 2019 Mar;118(3):851-859.
- Al-Sabi MNS, Rääf L, Osterman-Lind E, Uhlhorn H, Kapel CMO. Gastrointestinal helminths of gray wolves (Canis lupus lupus) from Sweden. Parasitol Res 2018 Jun;117(6):1891-1898.
- Norris LJ, Watral V, Kent ML. Survival of Bacterial and Parasitic Pathogens from Zebrafish (Danio rerio) After Cryopreservation and Thawing. Zebrafish 2018 Apr;15(2):188-201.
- Grauer JA, Frair JL, Schuler KL, Lejeune M, Kramer DW, Fuller AK. Moose Survival and Habitat-Associated Risk of Endoparasites. Ecol Evol 2025 Dec;15(12):e72721.
- Moriyoshi M, Hayashi N, Nonaka N, Nakao R, Yamanaka M, Tsubota T, Shimozuru M. Patterns of intestinal parasite prevalence in brown bears (Ursus arctos) revealed by a 3-year survey on the Shiretoko peninsula, Hokkaido, Japan. Int J Parasitol Parasites Wildl 2025 Apr;26:101048.
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