Evaluation of an Indirect Fluorescent Antibody Test (Ifat) for Demonstration of Antibodies to Toxoplasma Gondii in the Sea Otter (Enhydra Lutris)

Miller, Melissa A.; Gardner, Ian A.; Packham, Andrea E.; Mazet, Jonna A. K.; Hanni, Krista; Jessup, David A.; Estes, J.A.; Jameson, R.; Dodd, Erin; Barr, Bradd C.; Lowenstine, Linda J.; Gulland, Frances M. D.; Conrad, Patricia A.

doi:10.1645/0022-3395(2002)088[0594:eoaifa]2.0.co;2

Cited by 80 publications

(51 citation statements)

References 20 publications

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“…The diagnostic assay used here detects infection with persistent tissue cyst stages (22), but not clinical disease, and all otters were apparently healthy at capture. We detected T. gondii infection in 48% of otters (56/118) and S. neurona infection in 33% of otters (39/118).…”

Section: Overview Of Datasetsmentioning

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.

123

117

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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

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Section: Overview Of Datasetsmentioning

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.

123

117

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“…Serum was drawn off and tested using an indirect fluorescent antibody test (IFAT). This test has been standardized by serial dilution and a cutoff of  1:320 has been determined to be optimal detection of Toxoplasma gondii infection in southern sea otters of known infection status (Miller et al 2002b). …”

Section: Serum Collection and Analysismentioning

confidence: 99%

The High Cost of Motherhood: End-Lactation Syndrome in Southern Sea Otters (Enhydra Lutris Nereis) on the Central California Coast, Usa

Chinn

Miller

Tinker

et al. 2016

Journal of Wildlife Diseases

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“…After drying, 30 l of the fluorescein isothiocyanate labelled conjugate was applied in a 1/25 dilution in PBS with Evans Blue as counter dye. The following conjugates were used: anti-bovine IgG to test cetacean sera (Jaber et al, 2003), anti-ferret IgG to test otter sera (Miller et al, 2002) and anti-dog IgG to test seal sera (Carlson-Bremer et al, 2015). Table 5 lists the conjugates used per tested animal species.…”

Section: Immunofluorescent Assay (Ifa)mentioning

confidence: 99%

“…Finding appropriate specific conjugates for all the tested species of sea mammals is not only challenging (as for most of them they are not commercially available), it is also rather expensive and impractical. Therefore, for the IFA we relied on previously published cross-reactivity between species (Miller et al, 2002;Nollens et al, 2008) (Table 5). Another way to approach this problem is using a multispecies conjugate consisting of protein G, which non-specifically binds to the Fc portion of IgG antibodies.…”

Section: Animal Nomentioning

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

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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.

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Evaluation of an Indirect Fluorescent Antibody Test (Ifat) for Demonstration of Antibodies to Toxoplasma Gondii in the Sea Otter (Enhydra Lutris)

Cited by 80 publications

References 20 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

The High Cost of Motherhood: End-Lactation Syndrome in Southern Sea Otters (Enhydra Lutris Nereis) on the Central California Coast, Usa

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

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