An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality

M. A. Miller, M. E. Grigg, Christine K Johnson, E. R. James, A. C. Melli, P. R. Crosbie, D. A. Jessup, J. C. Boothroyd, D. Brownstein, Patricia A Conrad

Research output: Contribution to journalArticle

127 Citations (Scopus)

Abstract

Toxoplasma gondii-associated meningoencephalitis is a significant disease of California sea otters (Enhydra lutris nereis), responsible for 16% of total mortality in fresh, beachcast carcasses. Toxoplasma gondii isolates were obtained from 35 California otters necropsied between 1998 and 2002. Based on multi-locus PCR-restriction fragment length polymorphism and DNA sequencing at conserved genes (18S rDNA, ITS-1) and polymorphic genes (B1, SAG1, SAG3 and GRA6), two distinct genotypes were identified: type II and a novel genotype, here called type x, that possessed distinct alleles at three of the four polymorphic loci sequenced. The majority (60%) of sea otter T. gondii infections were of genotype x, with the remaining 40% being of genotype II. No type I or III genotypes were identified. Epidemiological methods were used to examine the relationship between isolated T. gondii genotype(s) and spatial and demographic risk factors, such as otter stranding location and sex, as well as specific outcomes related to pathogenicity, such as severity of brain inflammation on histopathology and T. gondii-associated mortality. Differences were identified with respect to T. gondii genotype and sea otter sex and stranding location along the California coast. Localised spatial clustering was detected for both type II (centred within Monterey Bay) and x (centred near Morro Bay)-infected otters. The Morro Bay cluster of type x-infected otters overlaps previously reported high-risk areas for sea otter infection and mortality due to T. gondii. Nine of the 12 otters that had T. gondii-associated meningoencephalitis as a primary cause of death were infected with type x parasites.

Original languageEnglish (US)
Pages (from-to)275-284
Number of pages10
JournalInternational Journal for Parasitology
Volume34
Issue number3
DOIs
StatePublished - Mar 9 2004
Externally publishedYes

Fingerprint

Otters
Toxoplasma
Genotype
Mortality
Meningoencephalitis
Epidemiologic Methods
Toxoplasmosis
Encephalitis
Ribosomal DNA
DNA Sequence Analysis
Restriction Fragment Length Polymorphisms
Genes
Cluster Analysis
Virulence
Cause of Death
Parasites

Keywords

  • B1
  • Enhydra lutris
  • GRA6
  • SAG
  • Sea otter
  • Toxoplasma gondii
  • Type x

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases

Cite this

An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality. / Miller, M. A.; Grigg, M. E.; Johnson, Christine K; James, E. R.; Melli, A. C.; Crosbie, P. R.; Jessup, D. A.; Boothroyd, J. C.; Brownstein, D.; Conrad, Patricia A.

In: International Journal for Parasitology, Vol. 34, No. 3, 09.03.2004, p. 275-284.

Research output: Contribution to journalArticle

Miller, M. A. ; Grigg, M. E. ; Johnson, Christine K ; James, E. R. ; Melli, A. C. ; Crosbie, P. R. ; Jessup, D. A. ; Boothroyd, J. C. ; Brownstein, D. ; Conrad, Patricia A. / An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality. In: International Journal for Parasitology. 2004 ; Vol. 34, No. 3. pp. 275-284.
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abstract = "Toxoplasma gondii-associated meningoencephalitis is a significant disease of California sea otters (Enhydra lutris nereis), responsible for 16{\%} of total mortality in fresh, beachcast carcasses. Toxoplasma gondii isolates were obtained from 35 California otters necropsied between 1998 and 2002. Based on multi-locus PCR-restriction fragment length polymorphism and DNA sequencing at conserved genes (18S rDNA, ITS-1) and polymorphic genes (B1, SAG1, SAG3 and GRA6), two distinct genotypes were identified: type II and a novel genotype, here called type x, that possessed distinct alleles at three of the four polymorphic loci sequenced. The majority (60{\%}) of sea otter T. gondii infections were of genotype x, with the remaining 40{\%} being of genotype II. No type I or III genotypes were identified. Epidemiological methods were used to examine the relationship between isolated T. gondii genotype(s) and spatial and demographic risk factors, such as otter stranding location and sex, as well as specific outcomes related to pathogenicity, such as severity of brain inflammation on histopathology and T. gondii-associated mortality. Differences were identified with respect to T. gondii genotype and sea otter sex and stranding location along the California coast. Localised spatial clustering was detected for both type II (centred within Monterey Bay) and x (centred near Morro Bay)-infected otters. The Morro Bay cluster of type x-infected otters overlaps previously reported high-risk areas for sea otter infection and mortality due to T. gondii. Nine of the 12 otters that had T. gondii-associated meningoencephalitis as a primary cause of death were infected with type x parasites.",
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AU - James, E. R.

AU - Melli, A. C.

AU - Crosbie, P. R.

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AU - Conrad, Patricia A

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