Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Dec;80(24):7732-40.
doi: 10.1128/AEM.02922-14. Epub 2014 Oct 3.

Molecular epidemiology of Cryptosporidium spp. and Giardia spp. in mussels (Mytilus californianus) and California sea lions (Zalophus californianus) from Central California

A D Adell  1 , W A Smith  2 , K Shapiro  3 , A Melli  3 , P A Conrad  4
Affiliations

Molecular epidemiology of Cryptosporidium spp. and Giardia spp. in mussels (Mytilus californianus) and California sea lions (Zalophus californianus) from Central California

A D Adell et al. Appl Environ Microbiol. 2014 Dec.

Abstract

Cryptosporidium and Giardia are of public health importance, with recognized transmission through recreational waters. Therefore, both can contaminate marine waters and shellfish, with potential to infect marine mammals in nearshore ecosystems. A 2-year study was conducted to evaluate the presence of Cryptosporidium and Giardia in mussels located at two distinct coastal areas in California, namely, (i) land runoff plume sites and (ii) locations near sea lion haul-out sites, as well as in feces of California sea lions (CSL) (Zalophus californianus) by the use of direct fluorescent antibody (DFA) detection methods and PCR with sequence analysis. In this study, 961 individual mussel hemolymph samples, 54 aliquots of pooled mussel tissue, and 303 CSL fecal samples were screened. Giardia duodenalis assemblages B and D were detected in hemolymph from mussels collected near two land runoff plume sites (Santa Rosa Creek and Carmel River), and assemblages C and D were detected in hemolymph from mussels collected near a sea lion haul-out site (White Rock). These results suggest that mussels are being contaminated by protozoa carried in terrestrial runoff and/or shed in the feces of CSL. Furthermore, low numbers of oocysts and cysts morphologically similar to Cryptosporidium and Giardia, respectively, were detected in CSL fecal samples, suggesting that CSL could be a source and a host of protozoan parasites in coastal environments. The results of this study showed that Cryptosporidium and Giardia spp. from the feces of terrestrial animals and CSL can contaminate mussels and coastal environments.

PubMed Disclaimer

Figures

FIG 1
FIG 1
Locations of mussel and California sea lion (CSL) fecal sample collection sites along the central California coast, with filled stars representing CSL haul-out sites, filled circles representing land runoff sites, and gray rectangles representing Giardia DNA-positive mussel hemolymph. Map created using Quantum GIS version (QGIS) 1.8-Lisboa open source software (http://qgis.osgeo.org) under a Creative Commons license (http://creativecommons.org/licenses/by-sa/3.0/).
FIG 2
FIG 2
Phylogenetic analysis of Giardia duodenalis sequences detected in hemolymph from mussels based on the nucleotide sequence at the GDH locus and using a neighbor-joining Kimura 2-parameter method. (GenBank reference accession numbers are shown in parentheses.) *, isolates detected in hemolymph from mussels in this study.
FIG 3
FIG 3
Phylogenetic analysis of Giardia duodenalis sequences detected in hemolymph from mussels based on the nucleotide sequence at the beta-giardin locus and using a neighbor-joining Kimura 2-parameter method. (GenBank reference accession numbers are shown in parentheses.) *, isolate detected in hemolymph from mussels in this study.
See this image and copyright information in PMC

References

    1. Haas CN, Rose JB, Gerba CP. 1999. Quantitative microbial risk assessment. John Wiley & Sons, New York, NY.
    1. Acha P, Szyfres B. 2003. Zoonosis y enfermedades transmisibles comunes al hombre y a los hombres animales, p 25–26, 47, 49 In Parasitosis, vol 3 Pan American Health Organization (PAHO), Washington, DC.
    1. Fayer R, Xiao L. 2008. Cryptosporidium and cryptosporidiosis. Taylor & Francis Group, Boca Raton, FL.
    1. Miller MA, Gardner IA, Kreuder C, Paradies DM, Worcester KR, Jessup DA, Dodd E, Harris MD, Ames JA, Packham AE, Conrad PA. 2002. Coastal freshwater runoff is a risk factor for Toxoplasma gondii infection of southern sea otters (Enhydra lutris nereis). Int. J. Parasitol. 32:997–1006. 10.1016/S0020-7519(02)00069-3. - DOI - PubMed
    1. Conrad PA, Miller MA, Kreuder C, James ER, Mazet J, Dabritz H, Jessup DA, Gulland F, Grigg ME. 2005. Transmission of Toxoplasma: clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment. Int. J. Parasitol. 35:1155–1168. 10.1016/j.ijpara.2005.07.002. - DOI - PubMed

Publication types