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Results for “Veterinary Parasitology”

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7 recordsLinked to original sources
USGS2004

Zoonotic protozoa in the marine environment: a threat to aquatic mammals and public health

This collection of abstracts provides an account of four presentations at the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP) (held in New Orleans, LA, USA from 10–14 August 2003) in a symposium session on zoonotic protozoan parasites found in the marine environment and chaired by Ronald Fayer and David Lindsay. The focus was on three genera of parasites of veterinary and public health concern - Toxoplasma , Giardia , and Cryptosporidium with emphasis on their epidemiology in the marine environment.

Veterinary Parasitology↗
USGS2007

Effects of supplemental feeding on gastrointestinal parasite infection in Rocky Mountain Elk (Cervus elaphus): Preliminary observations

The effects of management practices on the spread and impact of parasites and infectious diseases in wildlife and domestic animals are of increasing concern worldwide, particularly in cases where management of wild species can influence disease spill-over into domestic animals. In the Greater Yellowstone Ecosystem, USA, winter supplemental feeding of Rocky Mountain elk ( Cervus elaphus ) may enhance parasite and disease transmission by aggregating elk on feedgrounds. In this study, we tested the effect of supplemental feeding on gastrointestinal parasite infection in elk by comparing fecal egg/oocyst counts of fed and unfed elk. We collected fecal samples from fed and unfed elk at feedground and control sites from January to April 2006, and screened all samples for parasites. Six different parasite types were identified, and 48.7% of samples were infected with at least one parasite. Gastrointenstinal (GI) nematodes (Nematoda: Strongylida), Trichuris spp., and coccidia were the most common parasites observed. For all three of these parasites, fecal egg/oocyst counts increased from January to April. Supplementally fed elk had significantly higher GI nematode egg counts than unfed elk in January and February, but significantly lower counts in April. These patterns suggest that supplemental feeding may both increase exposure and decrease susceptibility of elk to GI nematodes, resulting in differences in temporal patterns of egg shedding between fed and unfed elk.

Wyoming↗
USGS2008

Genetic diversity among sea otter isolates of Toxoplasma gondii

Sea otters ( Enhydra lutris ) have been reported to become infected with Toxoplasma gondii and at times succumb to clinical disease. Here, we determined genotypes of 39 T. gondii isolates from 37 sea otters in two geographically distant locations (25 from California and 12 from Washington). Six genotypes were identified using 10 PCR-RFLP genetic markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico, and by DNA sequencing of loci SAG1 and GRA6 in 13 isolates. Of these 39 isolates, 13 (33%) were clonal Type II which can be further divided into two groups at the locus Apico. Two of the 39 isolates had Type II alleles at all loci except a Type I allele at locus L358. One isolate had Type II alleles at all loci except the Type I alleles at loci L358 and Apico. One isolate had Type III alleles at all loci except Type II alleles at SAG2 and Apico. Two sea otter isolates had a mixed infection. Twenty-one (54%) isolates had an unique allele at SAG1 locus. Further genotyping or DNA sequence analysis for 18 of these 21 isolates at loci SAG1 and GRA6 revealed that there were two different genotypes, including the previously identified Type X (four isolates) and a new genotype named Type A (14 isolates). The results from this study suggest that the sea otter isolates are genetically diverse.

California, Washington↗
USGS2011

Sarcocystis neurona retinochoroiditis in a sea otter ( Enhydra lutris kenyoni )

Sarcocystis neurona is an important cause of fatal disease in sea otters in the USA. Encephalitis is the predominant lesion and parasites are confined to the central nervous system and muscles. Here we report retinochoroiditis in a sea otter ( Enhydra lutris kenyoni ) found dead on Copalis Beach, WA, USA. Salient lesions were confined to the brain and eye. Multifocal nonsuppurative meningoencephalitis was present in the cerebrum and cerebellum associated with S. neurona schizonts. The retina of one eye had a focus of inflammation that contained numerous S. neurona schizonts and merozoites. The focus extended from the retinal pigment epithelium inward through all layers of the retina, but inflammation was most concentrated at the inner surface of the tapetum and the outer retina. The inner and outer nuclear layers of the retina were disorganized and irregular at the site of inflammation. There was severe congestion and mild hemorrhage in the choroid, and mild hemorrhage into the vitreous body. Immunohistochemistry with S. neurona -specific polyclonal rabbit antibodies stained schizonts and merozoites. To our knowledge this is the first report of S. neurona -associated retinochoroiditis in any naturally infected animal.

Washington↗
USGS2018

An update on Toxoplasma gondii infections in northern sea otters (Enhydra lutris kenyoni) from Washington State, USA

Toxoplasmosis in marine mammals is epidemiologically and clinically important. Toxoplasma gondii antibodies (by modified agglutination test, cut-off ≥1:25) were detected in serum of 65 of 70 (92.9%) northern sea otters ( Enhydra lutris kenyoni ) from Washington State, USA. Brains and/or muscles of 44 sea otters were bioassayed in mice (INF-γ knock-out [KO], Swiss Webster outbred [SW]) and viable T. gondii was isolated from 22 of 44 (50%); T. gondii strains were lethal to KO mice but not SW mice. These T. gondii isolates were further propagated in cell culture. Multi-locus PCR-RFLP genotyping of cell culture-derived tachyzoites revealed four different genotypes among 22 isolates including ToxoDB PCR-RFLP genotype #5 (14 isolates), #1 (three isolates), #3 (four isolates), and #167 (one isolate). PCR-DNA sequencing based genotyping using polymorphic gene GRA6 revealed one of four different alleles. Among the 14 RFLP genotype #5 strains, 10 have GRA6 sequences that match with the Type A, one match with the Type X, two strains did not generate sequence data, and one strain had double peaks at known polymorphic sites indicating a mixed infection. The seven strains belong to genotypes #1 and #3, all have identical sequences to T. gondii Type II reference isolate ME49. Genotype #167 strain has identical sequence to Type I reference strain. In summary, we observed high seroprevalence, and high rate of isolation of T. gondii from northern sea otters and predominant genotype #5 that has been previously reported a dominant and widespread strain among terrestrial wildlife in North America. GRA6 sequence analysis of the genotype #5 isolates indicated the dominance of Type A lineage in sea otters in Washington State.

Washington↗
USGS2003

Toxoplasma gondii, Neospora caninum, Sarcocystis neurona, and Sarcocystis canis-like infections in marine mammals

Toxoplasma gondii, Neospora caninum, Sarcocystis neurona, and S. canis are related protozoans that can cause mortality in many species of domestic and wild animals. Recently, T. gondii and S. neurona were recognized to cause encephalitis in marine mammals. As yet, there is no report of natural exposure of N. caninum in marine mammals. In the present study, antibodies to T. gondii and N. caninum were assayed in sera of several species of marine mammals. For T. gondii, sera were diluted 1:25, 1:50, and 1:500 and assayed in the T. gondii modified agglutination test (MAT). Antibodies (MAT a?Y1:25) to T. gondii were found in 89 of 115 (77%) dead, and 18 of 30 (60%) apparently healthy sea otters (Enhydra lutris), 51 of 311 (16%) Pacific harbor seals (Phoca vitulina), 19 of 45 (42%) sea lions (Zalophus californianus), 5 of 32 (16%) ringed seals (Phoca hispida), 4 of 8 (50%) bearded seals (Erignathus barbatus), 1 of 9 (11.1%) spotted seals (Phoca largha), 138 of 141 (98%) Atlantic bottlenose dolphins (Tursiops truncatus), and 3 of 53 (6%) walruses (Odobenus rosmarus). For N. caninum, sera were diluted 1:40, 1:80, 1:160, and 1:320 and examined with the Neospora agglutination test (NAT) using mouse-derived tachyzoites. NAT antibodies were found in 3 of 53 (6%) walruses, 28 of 145 (19%) sea otters, 11 of 311 (3.5%) harbor seals, 1 of 27 (3.7%) sea lions, 4 of 32 (12.5%) ringed seals, 1 of 8 (12.5%) bearded seals, and 43 of 47 (91%) bottlenose dolphins. To our knowledge, this is the first report of N. caninum antibodies in any marine mammal, and the first report of T. gondii antibodies in walruses and in ringed, bearded, spotted, and ribbon seals. Current information on T. gondii-like and Sarcocystis-like infections in marine mammals is reviewed. New cases of clinical S. canis and T. gondii infections are also reported in sea lions, and T. gondii infection in an Antillean manatee (Trichechus manatus manatus).

Alaska, California, Washington↗
USGS2008

Modest genetic differentiation among North American populations of Sarcocystic neurona may reflect expansion in its geographic range

Sarcocystis neurona is an important cause of neurological disease in horses (equine protozoal myeloencephalitis, EPM) and sea otters in the United States. In addition, EPM-like disease has been diagnosed in several other land and marine mammals. Opossums are its only definitive hosts. Little genetic diversity among isolates of S. neurona from different hosts has been reported. Here, we used 11 microsatellites to characterize S. neurona DNA isolated from natural infections in 22 sea otters (Enhydra lutris) from California and Washington and in 11 raccoons (Procyon lotor) and 1 striped skunk (Mephitis mephitis) from Wisconsin. By jointly analyzing these 34 isolates with 26 isolates previously reported, we determined that geographic barriers may limit S. neurona dispersal and that only a limited subset of possible parasite genotypes may have been introduced to recently established opossum populations. Moreover, our study confirms that diverse intermediate hosts share a common infection source, the opossum (Didelphis virginiana).

California, Washington↗