Parasitic Zoonoses: One Health Surveillance in Northern Saskatchewan

Abstract

We report the results of a joint human-animal health investigation in a Dene community in northern Saskatchewan, where residents harvest wildlife (including moose, bear, elk, and fish), live in close contact with free roaming dogs, and lack access to permanent veterinary services. Fecal analysis of owned and free-roaming dogs over two consecutive years (N = 92, 103) identified several parasites of public health concern, including Toxocara canis, Diphyllobothrium spp., Echinococcus/Taenia, Cryptosporidium spp. and Giardia spp. Administration of pyrantel pamoate to a subset of dogs (N = 122) in the community in the first year was followed by reduced shedding of T. canis and other roundworms in the second year, demonstrating the potential utility of canine de-worming as a public health intervention. Using direct agglutination tests with confirmatory indirect fluorescent antibody test, 21% of 47 dogs were sero-positive for exposure to Toxoplasma gondii. Using enzyme-linked immunosorbent assay (ELISA) sero-prevalence rates in 201 human volunteers were as follows: Toxoplasma gondii (14%), Echinococcus granulosus (48%), Toxocara canis (13%) and Trichinella spp. (16%). Overall 65% of participants were sero-positive for at least one parasite. A survey administered to volunteers indicated few associations between widely accepted risk factors for parasite exposure and serological status, emphasizing the importance of environmental transmission of these parasites through soil, food, and waterborne routes.

People, Pets, and Parasites: One Health Surveillance in Southeastern Saskatchewan

“…One possibility is that dog owners have higher awareness of the risks associated with contamination of the environment with dog feces, or higher awareness of the need for hand hygiene. Results from this study did not identify gender, age, or hunting/trapping as important risk factors for E. canadensis exposure as reported previously, 6,17,25 which could be caused by the low sample size. However, our findings are similar to a related project conducted in a nearby SK community.…”

“…This study is consistent with previous findings that youth (ages 11-17) are more likely to be exposed to T. canis than adults or younger children, highlighting the importance of deworming, and keeping dogs out of areas frequented by youth, such as schoolyards and sandboxes. 24,25 Because this age group is more likely to develop ocular, rather than visceral, larval migrans, follow-up should include retinal examination. 26 Our finding of dog bite history as a risk factor for T. canis exposure has not previously been reported.…”

Biology and Systematics of Echinococcus

“…However, the limitations of serological tests used to diagnose cystic infections caused by E. canadensis have contributed to human cases being underdiagnosed Thomposn, 2015). There has been a reliance on tests developed for E. granulosus and there are known to be antigenic differences between E. canadensis and E. granulosus Schurer et al, 2013Schurer et al, , 2014. The two genotypes of E. canadensis also appear to vary in virulence in humans with G8 more pathogenic than previously considered, with two severe cases recently reported Thompson, 2015).…”

Helminths and intestinal barrier function

“…1A). Parasitic helminths typically exhibit complex life-cycles that involve one or more intermediate hosts for juvenile stages of the worm and a definite host where adults reach sexual maturity (host specificity is the basis of parasitism and while each species of parasite has a preferred definitive host there is promiscuity in the system, with implications for zoonotic disease 9 ). It is also safe to say that for every vertebrate species at least one parasitic helminth has evolved.…”