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

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

Research output: Contribution to journalArticle

101 Citations (Scopus)

Abstract

Toxoplasma gondii is associated with morbidity and mortality in a variety of marine mammals, including fatal meningoencephalitis in the southern sea otter (Enhydra lutris nereis). The source(s) of T. gondii infection and routes of transmission in the marine environment are unknown. We hypothesise that filter-feeding marine bivalve shellfish serve as paratenic hosts by assimilation and concentration of infective T. gondii oocysts and their subsequent predation by southern sea otters is a source of infection for these animals. We developed a TaqMan PCR assay for detection of T. gondii ssrRNA and evaluated its usefulness for the detection of T. gondii in experimentally exposed mussels (Mytilus galloprovincialis) under laboratory conditions. Toxoplasma gondii-specific ssrRNA was detected in mussels as long as 21 days post-exposure to T. gondii oocysts. Parasite ssrRNA was most often detected in digestive gland homogenate (31 of 35, i.e. 89%) compared with haemolymph or gill homogenates. Parasite infectivity was confirmed using a mouse bioassay. Infections were detected in mice inoculated with any one of the mussel sample preparations (haemolymph, gill, or digestive gland), but only digestive gland samples remained bioassay-positive for at least 3 days post-exposure. For each time point, the total proportion of mice inoculated with each of the different tissues from T. gondii-exposed mussels was similar to the proportion of exposed mussels from the same treatment groups that were positive via TaqMan PCR. The TaqMan PCR assay described here is now being tested in field sampling of free-living invertebrate prey species from high-risk coastal locations where T. gondii infections are prevalent in southern sea otters.

Original languageEnglish (US)
Pages (from-to)1087-1097
Number of pages11
JournalInternational Journal for Parasitology
Volume33
Issue number10
DOIs
StatePublished - Sep 2003

Fingerprint

Mytilus
Oocysts
Bivalvia
Toxoplasma
Biological Assay
Otters
Hemolymph
Polymerase Chain Reaction
Parasites
Shellfish
Meningoencephalitis
Infectious Disease Transmission
Toxoplasmosis
Invertebrates
Infection
Mammals
Morbidity
Mortality

Keywords

  • Bioassay
  • Bivalve shellfish
  • Marine environment
  • Oocyst
  • TaqMan PCR
  • Toxoplasma gondii

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases

Cite this

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; Packham, Andrea E.; Heckeroth, Anja R.; Tenter, Astrid M.; Barr, Bradd C.; Conrad, Patricia A.

In: International Journal for Parasitology, Vol. 33, No. 10, 09.2003, p. 1087-1097.

Research output: Contribution to journalArticle

Arkush, Kristen D. ; Miller, Melissa A. ; Leutenegger, Christian M. ; Gardner, Ian ; Packham, Andrea E. ; Heckeroth, Anja R. ; Tenter, Astrid M. ; Barr, Bradd C. ; Conrad, Patricia A. / Molecular and bioassay-based detection of Toxoplasma gondii oocyst uptake by mussels (Mytilus galloprovincialis). In: International Journal for Parasitology. 2003 ; Vol. 33, No. 10. pp. 1087-1097.
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AU - Packham, Andrea E.

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