Molecular and bioassay-based detection of Toxoplasma gondii oocyst uptake by mussels (Mytilus galloprovincialis)

Arkush, Kristen D.; Miller, Melissa A.; Leutenegger, Christian M.; Gardner, Ian A.; Packham, Andrea E.; Heckeroth, Anja R.; Tenter, Astrid M.; Barr, Bradd C.; Conrad, Patricia A.

doi:10.1016/s0020-7519(03)00181-4

Cited by 149 publications

(107 citation statements)

References 34 publications

Supporting

Mentioning

102

Contrasting

Order By: Relevance

“…Although filter-feeding bivalves have been shown to remove T. gondii oocysts from contaminated water in laboratory experiments (15,16), our findings do not support the hypothesis that bivalves are the primary source of T. gondii infections in wild sea otters. However, our findings are consistent with a role for filter-feeding bivalves, specifically clams and other soft-sediment infaunal invertebrates, in sea otter infections with S. neurona.…”

Section: Discussioncontrasting

confidence: 91%

“…The life cycle propagating these pathogens in the marine environment has been a fascinating problem because ectotherms, which constitute all but the apex of the marine food web, are unlikely intermediate hosts. Laboratory studies have determined that filter-feeding bivalves can accumulate T. gondii in experimentally-contaminated water (15,16). However, a field study screening Ͼ1,000 sea otter invertebrate prey items (mussels, clams, and sand crabs) detected type X T. gondii in just 1 outplanted sentinel California mussel (17).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system

Johnson

Tinker

Estes

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

124

115

View full text Add to dashboard Cite

The processes promoting disease in wild animal populations are highly complex, yet identifying these processes is critically important for conservation when disease is limiting a population. By combining field studies with epidemiologic tools, we evaluated the relationship between key factors impeding southern sea otter (Enhydra lutris nereis) population growth: disease and resource limitation. This threatened population has struggled to recover despite protection, so we followed radio-tagged sea otters and evaluated infection with 2 disease-causing protozoal pathogens, Toxoplasma gondii and Sarcocystis neurona, to reveal risks that increased the likelihood of pathogen exposure. We identified patterns of pathogen infection that are linked to individual animal behavior, prey choice, and habitat use. We detected a high-risk spatial cluster of S. neurona infections in otters with home ranges in southern Monterey Bay and a coastal segment near San Simeon and Cambria where otters had high levels of infection with T. gondii. We found that otters feeding on abalone, which is the preferred prey in a resource-abundant marine ecosystem, had a very low risk of infection with either pathogen, whereas otters consuming small marine snails were more likely to be infected with T. gondii. Individual dietary specialization in sea otters is an adaptive mechanism for coping with limited food resources along central coastal California. High levels of infection with protozoal pathogens may be an adverse consequence of dietary specialization in this threatened species, with both depleted resources and disease working synergistically to limit recovery.Enhydra lutris nereis ͉ Sarcocystis neurona ͉ Toxoplasma gondii ͉ diet specialization ͉ wildlife disease

show abstract

Section: Discussioncontrasting

confidence: 91%

mentioning

confidence: 99%

Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system

Johnson

Tinker

Estes

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

124

115

View full text Add to dashboard Cite

show abstract

“…Razor clams in Estero Bay were proposed as possible dietary source of S. neurona in the Spring 2004 outbreak . Bivalves can concentrate infective T. gondii oocysts in their tissues (Arkush et al, 2003), and a similar food-borne transmission mechanism of parasites from contaminated water to otters is likely to play a role in S. neurona epidemiology. A recent study indicated that foraging on clams was linked with exposure to S. neurona (Johnson et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…Ingestion of tissue cysts from an intermediate host is not likely to play a major role in disease transmission because sea otters do not typically prey on warm-blooded animals known to be involved in the parasites' life cycles (Estes et al, 2003). Accidental ingestion of oocysts from water or invertebrates that can filter and concentrate them in their tissues has been suggested as a likely route of infection for otters (Arkush et al, 2003). Miller et al (2002a) implicated freshwater runoff as a risk factor for exposure of sea otters to T. gondii.…”

Section: Introductionmentioning

confidence: 99%

Temporal Association Between Land-Based Runoff Events and California Sea Otter (Enhydra Lutris Nereis) Protozoal Mortalities

Shapiro¹,

Miller²,

Mazet³

2012

Journal of Wildlife Diseases

View full text Add to dashboard Cite

ABSTRACT:Toxoplasma gondii and Sarcocystis neurona have caused significant morbidity and mortality in threatened Southern sea otters (Enhydra lutris nereis) along the central California coast. Because only terrestrial animals are known to serve as definitive hosts for T. gondii and S. neurona, infections in otters suggest a land to sea flow of these protozoan pathogens. To better characterize the role of overland runoff in delivery of terrestrially derived fecal pathogens to the near shore, we assessed the temporal association between indicators of runoff and the timing of sea otter deaths due to T. gondii and S. neurona. Sea otter stranding records 1998-2004, from Monterey and Estero bays were reviewed and cases identified for which T. gondii or S. neurona were determined to be a primary or contributing cause of death. Precipitation and stream flow data from both study sites were used as indicators of land-based runoff. Logistic regression was applied to determine if a temporal association could be detected between protozoal mortalities and runoff indicators that occur in the 2 mo preceding mortality events. A significant association was found between S. neurona otter deaths at Estero Bay and increased stream flow that occurred 30-60 days prior to mortality events. At this site, the cause of otter mortality following increased river flows was 12 times more likely to be S. neurona infection compared with nonprotozoal causes of death. There were no significant associations between the timing of T. gondii otter deaths and indicators of overland runoff. Our results indicate that the association between overland runoff and otter mortalities is affected by geography as well as parasite type, and highlight the complex mechanisms that influence transmission of terrestrially derived pathogens to marine wildlife. Policy and management practices that aim to mitigate discharges of contaminated overland runoff can aid conservation efforts by reducing pathogen pollution of coastal waters, which impacts the health of threatened marine wildlife and humans.

show abstract

“…These oocysts are able to reach coastal seawaters and several studies have demonstrated the presence of T. gondii in marine mammal species including pinnipeds, cetaceans, sirenians, sea otters (Enhydra lutris) and polar bears (Ursus maritimus) (Cole et al, 2000;Dubey, 2010;Mathews et al, 2012;Oksanen et al, 2009). Different transmission routes such as coastal run-off and mechanical vectors have been hypothesized, but the exact mode of transmission remains unknown (Arkush et al, 2003;Lindsay et al, 2001;Massie et al, 2010). Immunosuppressive factors, such as polychlorbiphenyls and Morbillivirus infection could make marine mammals more susceptible to disease induced by T. gondii infection (Mazzariol et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Toxoplasma gondii in stranded marine mammals from the North Sea and Eastern Atlantic Ocean: Findings and diagnostic difficulties

Velde

Devleesschauwer

Leopold³

et al. 2016

Veterinary Parasitology

View full text Add to dashboard Cite

a b s t r a c tThe occurrence of the zoonotic protozoan parasite Toxoplasma gondii in marine mammals remains a poorly understood phenomenon. In this study, samples from 589 marine mammal species and 34 European otters (Lutra lutra), stranded on the coasts of Scotland, Belgium, France, The Netherlands and Germany, were tested for the presence of T. gondii. Brain samples were analysed by polymerase chain reaction (PCR) for detection of parasite DNA. Blood and muscle fluid samples were tested for specific antibodies using a modified agglutination test (MAT), a commercial multi-species enzyme-linked immunosorbent assay (ELISA) and an immunofluorescence assay (IFA). Out of 193 animals tested by PCR, only two harbour porpoise (Phocoena phocoena) cerebrum samples, obtained from animals stranded on the Dutch coast, tested positive. The serological results showed a wide variation depending on the test used. Using a cut-off value of 1/40 dilution in MAT, 141 out of 292 animals (41%) were positive. Using IFA, 30 out of 244 tested samples (12%) were positive at a 1/50 dilution. The commercial ELISA yielded 7% positives with a cut-off of the sample-to-positive (S/P) ratio ≥ 50; and 12% when the cut-off was set at S/P ratio ≥ 20. The high number of positives in MAT may be an overestimation due to the high degree of haemolysis of the samples and/or the presence of lipids. The ELISA results could be an underestimation due to the use of a multispecies conjugate. Our results confirm the presence of T. gondii in marine mammals in The Netherlands and show exposure to the parasite in both the North Sea and the Eastern Atlantic Ocean. We also highlight the limitations of the tests used to diagnose T. gondii in stranded marine mammals.

show abstract

Molecular and bioassay-based detection of Toxoplasma gondii oocyst uptake by mussels (Mytilus galloprovincialis)

Cited by 149 publications

References 34 publications

Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system

Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system

Temporal Association Between Land-Based Runoff Events and California Sea Otter (Enhydra Lutris Nereis) Protozoal Mortalities

Toxoplasma gondii in stranded marine mammals from the North Sea and Eastern Atlantic Ocean: Findings and diagnostic difficulties

Contact Info

Product

Resources

About