Clams and potential foodborne <i>Toxoplasma gondii</i> in Nunavut, Canada

Fung, Rebecca; Manore, Anna J. W.; Harper, Sherilee L.; Sargeant, Jan M.; Shirley, Jamal; Caughey, Amy; Shapiro, Karen

doi:10.1111/zph.12822

Cited by 9 publications

(4 citation statements)

References 29 publications

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“…Sources of infection with T. gondii for marine animals are thought to be oocysts washed into the sea through water runoff and transported by marine currents [34,[60][61][62]. Marine mammals could get infected by consuming filter feeding fish and invertebrates acting as mechanical reservoirs of oocysts [63,64]. We also detected a higher seroprevalence and tissue prevalence in foxes in southern QC (65%) versus sub-Arctic QC (31%).…”

Section: Discussionmentioning

confidence: 72%

Are foxes (Vulpes spp.) good sentinel species for Toxoplasma gondii in northern Canada?

et al. 2022

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Background In changing northern ecosystems, understanding the mechanisms of transmission of zoonotic pathogens, including the coccidian parasite Toxoplasma gondii, is essential to protect the health of vulnerable animals and humans. As high-level predators and scavengers, foxes represent a potentially sensitive indicator of the circulation of T. gondii in environments where humans co-exist. The objectives of our research were to compare serological and molecular assays to detect T. gondii, generate baseline data on T. gondii antibody and tissue prevalence in foxes in northern Canada, and compare regional seroprevalence in foxes with that in people from recently published surveys across northern Canada. Methods Fox carcasses (Vulpes vulpes/Vulpes lagopus, n = 749) were collected by local trappers from the eastern (Labrador and Québec) and western Canadian Arctic (northern Manitoba, Nunavut, and the Northwest Territories) during the winters of 2015–2019. Antibodies in heart fluid were detected using a commercial enzyme-linked immunosorbent assay. Toxoplasma gondii DNA was detected in hearts and brains using a magnetic capture DNA extraction and real-time PCR assay. Results Antibodies against T. gondii and DNA were detected in 36% and 27% of foxes, respectively. Detection of antibodies was higher in older (64%) compared to younger foxes (22%). More males (36%) than females (31%) were positive for antibodies to T. gondii. Tissue prevalence in foxes from western Nunavik (51%) was higher than in eastern Nunavik (19%). At the Canadian scale, T. gondii exposure was lower in western Inuit regions (13%) compared to eastern Inuit regions (39%), possibly because of regional differences in fox diet and/or environment. Exposure to T. gondii decreased at higher latitude and in foxes having moderate to little fat. Higher mean infection intensity was observed in Arctic foxes compared to red foxes. Fox and human seroprevalence showed similar trends across Inuit regions of Canada, but were less correlated in the eastern sub-Arctic, which may reflect regional differences in human dietary preferences. Conclusions Our study sheds new light on the current status of T. gondii in foxes in northern Canada and shows that foxes serve as a good sentinel species for environmental circulation and, in some regions, human exposure to this parasite in the Arctic. Graphical Abstract

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Section: Discussionmentioning

confidence: 72%

Are foxes (Vulpes spp.) good sentinel species for Toxoplasma gondii in northern Canada?

et al. 2022

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“…Bivalves molluscs and urchins are important filtering organisms of the aquatic environment and the parasite has been detected in 2.1% of 390 clams sampled in Nunavut (Fung et al, 2021). Uncertainty remains around the association between drinking water from municipal or natural sources and seropositivity compared to bottled water, even if a similar trend is observed with the water risk variable.…”

Section: Sensitivity Analysismentioning

confidence: 99%

Epidemiology associated with the exposure to Toxoplasma gondii in Nunavik’s Inuit population using the 2017 Qanuilirpitaa cross‐sectional health survey

Ducrocq

Ndao

Yansouni

et al. 2021

Zoonoses and Public Health

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Foci of high seroprevalence against Toxoplasma gondii are observed in Nunavik, the Inuit land of Northern Quebec (Canada). Considering the rare occurrence of felids in the region, exposure is suspected to be driven by water-and food-borne transmission routes. Hypotheses were that drinking untreated water from natural sources and eating country food mostly raw increased the risk of exposure to the parasite. Data from 1,300 Inuit participants of the 2017 Nunavik Health Survey were included in three weighted robust Poisson regression models. The effect of three types of exposure variables: (1) water treatment (yes/no) and if country food was mostly eaten raw (yes/no); (2) main source of drinking water (bottled/municipal/natural) and frequency of country food consumption (continuous) and (3) drinking water risk (low/ intermediate/high) and frequency of a raw country food consumption (continuous), on the presence of Toxoplasma antibodies were estimated. Models were adjusted for age, sex and ecological region, with multiple sensitivity analyses being performed.Toxoplasma gondii seroprevalences were consistently correlated with age quadratically, sex (prevalence ratio = PR woman/man ranged from 1.18 to 1.22), ecological region (PR HudsonBay/HudsonStrait ranged from 2.18 to 2.41; PR HudsonBay/UngavaBay ranged from 1.52 to 1.59) and consuming bivalve mollusc/urchin (PR varied from 1.02 to 1.21) across all three models. Each increase of two consumptions per month of beluga (PR ranged from 1.01 to 1.03), seal liver (PR ranged from 1.01 to 1.02) and goose (PR ranged from 1.01 to 1.02) were also associated with seropositivity, albeit more clearly in models 2 and 3, while drinking water mainly from natural (PR of 1.47) or municipal (PR = 1.42) sources compared to bottled water, was correlated with seroprevalence, although results were compatible with the null. Our results suggest that both the oocyst-(mollusc/urchin, drinking water) and cyst-borne (walrus, seal liver and goose) transmission pathways could be present in Nunavik.

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“…Indeed, several studies showed that oocysts are very resistant for months and years in the environment, including the marine environment (López Ureña et al, 2022). Oocysts were found in wild and commercial bivalve mollusks (clams, oysters, and mussels) with detection rates varied between 2.1% (Fung et al, 2021) and 6.6% (Ghozzi et al, 2017) in clams from Canada and Tunisia, respectively; from 1.3% (Silva et al, 2020) to 31.0% (Marquis et al, 2019) in oysters from Brazil and United States, respectively; from 1.4% (Shapiro et al, 2015) to 46.3% (Staggs et al, 2015) in different species of mussels from United States (López Ureña et al, 2022). T gondii DNA has been found also in different fish species ranging from 2.9 to 100% (depending on fish species; Marino et al, 2019), in sea otters (54.8%) and cetaceans (30.9%) (Ahmadpour et al, 2022).…”

Section: Discussionmentioning

confidence: 99%

First application of a droplet digital PCR to detect Toxoplasma gondii in mussels

Mancusi,

Proroga,

Giordano

et al. 2023

Front. Microbiol.

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Toxoplasmosis, caused by the protozoan Toxoplasma gondii, is one of the main food-, water- and soil-borne zoonotic disease worldwide. Over the past 20 years many papers were published on the transmission of T. gondii by marine animals, including mollusks, which can concentrate the oocysts and release them. Sporulated oocysts may remain viable and infective for 18 months in seawater. Therefore, raw or undercooked bivalve mollusks pose a risk to humans. This study aimed to apply and validate for the first time a very sensitive digital droplet polymerase chain reaction (ddPCR) protocol to detect and quantify T. gondii DNA in mussels. Four concentration levels: 8000 genomic copies (gc)/μL, 800 gc/μL, 80 gc/μL, 8 gc/μL of a T. gondii reference DNA were tested. DNA was extracted from 80 pools of mussels (Mytilus galloprovincialis). Forty pools were contaminated with T. gondii reference DNA and used as positive controls, while 40 pools were used as negative controls. DdPCR reaction was prepared using a protocol, previously developed by the authors, for detection of T. gondii in meat. Amplification was obtained up 8 gc/μL. All infected replicates resulted positive, as well as no droplets were detected in negative controls. The droplets produced in the reaction ranged from 8,828 to 14,075 (average 12,627 droplets). The sensitivity and specificity of ddPCR were 100% (95%CI = 94.3–99.9). In addition, 100 pools of mussels collected in the Gulf of Naples were used to validate the protocol. Of these 16% were positive (95% CI = 9.7–25.0) for T. gondii. Samples were also tested by real-time PCR and no positive samples were found. Data obtained from ddPCR showed good identification of negative and positive samples with higher specificity and efficiency than real-time PCR. This tool could be very useful for a rapid sensitive detection of low DNA concentrations of T. gondii in mussels, reducing the risk of toxoplasmosis in humans.

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Clams and potential foodborne Toxoplasma gondii in Nunavut, Canada

Cited by 9 publications

References 29 publications

Are foxes (Vulpes spp.) good sentinel species for Toxoplasma gondii in northern Canada?

Are foxes (Vulpes spp.) good sentinel species for Toxoplasma gondii in northern Canada?

Epidemiology associated with the exposure to Toxoplasma gondii in Nunavik’s Inuit population using the 2017 Qanuilirpitaa cross‐sectional health survey

First application of a droplet digital PCR to detect Toxoplasma gondii in mussels

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