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At least 181 records · Page 10Linked to original sources
USGS2005

The severity of Whirling disease among wild trout corresponds to the differences in genetic composition of tubifex tubifex populations in Central Colorado

We analyzed the geographic distribution of Tubifex tubifex from various river drainages in central Colorado by genetic screening with specific mitochondrial 16S ribosomal DNA (mt 16S rDNA) markers. Four distinct mt 16S rDNA lineages are evident. The sites varied with respect to land- and water-use practices. All sites represented habitats presumed capable of supporting oligochaetes. At the locations where whirling disease has had the greatest impact on resident rainbow trout, T. tubifex, representing lineages I and III (genotypes known to be susceptible to Mxyobolus cerebralis), were most commonly found. In contrast, at sites less affected by whirling disease, T. tubifex of lineages V and VI that are more resistant to M. cerebralis infections were more abundant. The predominance of resistant T. tubifex worms (lineages V and VI) at low-impact sites supports the conclusion that when these genotypes are in greater abundance, the potential for more severe effects of whirling disease on wild rainbow trout populations may be diminished. ?? American Society of Parasitologists 2005.

Journal of Parasitology↗
USGS2004

Differential propagation of the metazoan parasite Myxobolus cerebralis by Limnodrilus hoffmeisteri, Ilyodrilus templetoni, and genetically distinct strains of Tubifex tubifex

Whirling disease, caused by the parasite Myxobolus cerebralis, has infected rainbow trout (Oncorhynchus mykiss) and other salmonid fish in the western United States, often with devastating results to native populations but without a discernible spatial pattern. The parasite develops in a complex 2-host system in which the aquatic oligochaete Tubifex tubifex is an obligate host. Because substantial differences in whirling disease severity in different areas of North America did not seem explainable by environmental factors or features of the parasite or its fish host, we sought to determine whether ecological or genetic variation within oligochaete host populations may be responsible. We found large differences in compatibility between the parasite and various laboratory strains of T. tubifex that were established from geographic regions with different whirling disease histories. Moreover, 2 closely related species of tubificids, Limnodrilus hqffmeisteri and Ilyodrilus templetoni, which occur naturally in mixed species assemblages with T. tubifex, were incompatible with M. cerebralis. Virulence of the parasite was directly correlated with the numbers of triactinomyxon spores that developed within each strain of T. tubifex. Thus, the level of virulence was directly related to the compatibility between the host strain and the parasite. Genetic analyses revealed relationships that were in agreement with the level of parasite production. Differences in compatibilities between oligochaetes and M. cerebralis may contribute to the spatial variance in the severity of the disease among salmonid populations. ?? American Society of Parasitologists 2004.

Journal of Parasitology↗
USGS2004

Transmission of Neospora caninum between wild and domestic animals

To determine whether deer can transmit Neospora caninum , brains of naturally infected white-tailed deer ( Odocoileus virginianus ) were fed to 4 dogs; 2 of these dogs shed oocysts. Oocysts from 1 of the dogs were tested by polymerase chain reaction and found to be positive for N. caninum and negative for Hammondia heydorni . The internal transcribed spacer 1 sequence of the new strain (designated NC-deer1) was identical to N. caninum from domestic animals, indicating that N. caninum is transmitted between wild and domestic animals, often enough to prevent divergent evolution of isolated populations of the parasite. NC-deer1 oocysts were administered to a calf that developed a high antibody titer, providing evidence that N. caninum from wildlife can infect cattle. In addition, N. caninum antibody seroprevalence was detected in 64/164 (39%) free-ranging gray wolves ( Canis lupus ), 12/113 (11%) coyotes ( Canis latrans ), 50/193 (26%) white-tailed deer, and 8/61 (13%) moose ( Alces alces ). These data are consistent with a sylvatic transmission cycle of N. caninum between cervids and canids. We speculate that hunting by humans favors the transmission of N. caninum from deer to canids, because deer carcasses are usually eviscerated in the field. Infection of canids in turn increases the risk of transmitting the parasite to domestic livestock.

Illinois, Wisconsin↗
USGS2005

Comparative susceptibility of introduced forest-dwelling mosquitoes in Hawai'i to avian malaria, Plasmodium relictum

To identify potential vectors of avian malaria in Hawaiian native forests, the innate susceptibility of Aedes albopictus, Wyeomyia mitchellii, and Culex quinquefasciatus from 3 geographical sites along an altitudinal gradient was evaluated using local isolates of Plasmodium relictum. Mosquitoes were dissected 5-8 and 9-13 days postinfective blood meal and microscopically examined for oocysts and salivary-gland sporozoites. Sporogony was completed in all 3 species, but prevalence between species varied significantly. Oocysts were detected in 1-2% and sporozoites in 1-7% of Aedes albopictus that fed on infected ducklings. Wyeomyia mitchellii was slightly more susceptible, with 7-19% and 7% infected with oocysts and sporozoites, respectively. In both species, the median oocyst number was 5 or below. This is only the second Wyeomyia species reported to support development of a malarial parasite. Conversely, Culex quinquefasciatus from all 3 sites proved very susceptible. Prevalence of oocysts and sporozoites consistently exceeded 70%, regardless of gametocytemia or origin of the P. relictum isolate. In trials for which a maximum 200 oocysts were recorded, the median number of oocysts ranged from 144 to 200. It was concluded that Culex quinquefasciatus is the primary vector of avian malaria in Hawai'i. ?? American Society of Parasitologists 2005.

Journal of Parasitology↗
USGS2007

A Ribeiroia spp. (Class: Trematoda) - Specific PCR-based diagnostic

Increased reporting of amphibian malformations in North America has been noted with concern in light of reports that amphibian numbers and species are declining worldwide. Ribeiroia ondatrae has been shown to cause a variety of types of malformations in amphibians. However, little is known about the prevalence of R. ondatrae in North America. To aid in conducting field studies of Ribeiroia spp., we have developed a polymerase chain reaction (PCR)-based diagnostic. Herein, we describe the development of an accurate, rapid, simple, and cost-effective diagnostic for detection of Ribeiroia spp. infection in snails (Planorbella trivolvis). Candidate oligonucleotide primers for PCR were designed via DNA sequence analyses of multiple ribosomal internal transcribed spacer-2 regions from Ribeiroia spp. and Echinostoma spp. Comparison of consensus sequences determined from both genera identified areas of sequence potentially unique to Ribeiroia spp. The PCR reliably produced a diagnostic 290-base pair (bp) product in the presence of a wide concentration range of snail or frog DNA. Sensitivity was examined with DNA extracted from single R. ondatrae cercaria. The single-tube PCR could routinely detect less than 1 cercariae equivalent, because DNA isolated from a single cercaria could be diluted at least 1:50 and still yield a positive result via gel electrophoresis. An even more sensitive nested PCR also was developed that routinely detected 100 fg of the 290-bp fragment. The assay did not detect furcocercous cercariae of certain Schistosomatidae, Echinostoma sp., or Sphaeridiotrema globulus nor adults of Clinostomum sp. or Cyathocotyle bushiensis. Field testing of 137 P. trivolvis identified 3 positives with no overt environmental cross-reactivity, and results concurred with microscopic examinations in all cases. ?? American Society of Parasitologists 2007.

Journal of Parasitology↗
USGS2005

An efficient strategy to estimate intensity and prevalence: Sampling metacercariae in fishes

Accurate estimates of population-level parameters of parasites, such as prevalence and mean intensity, require large sample sizes. The processing of such samples becomes an overwhelming task when parasites are abundant, as with trematode metacercariae in fishes. In the present study, a subsampling method reduced processing time while maintaining an accurate estimation of metacercariae prevalence and intensity across 3 trematode species and 2 fish species. By double sampling, we generated regression models to predict total intensity from a combination of subsamples. The key to this approach lies in choosing the best strategy from a large number of potential subsampling routines. We selected the most efficient routine by weighing the costs and benefits of each. This approach, however, could not provide an estimate of parasite abundance when no parasites occurred in the initial subsample. To estimate prevalence accurately, our subsampling algorithm prescribed an additional sampling sequence using a new, optimal regression model. In addition, we optimized the technique to measure three parasite species infecting a single host simultaneously. This efficient subsampling procedure decreased the overall processing time per host by up to 91% while obtaining accurate ( R 2 > 0.8) estimates for both prevalence and intensity.

Journal of Parasitology↗
USGS2005

Epizootiology of spirorchid infection in green turtles (Chelonia mydas) in Hawaii

We describe the epizootiology of spirorchiid trematode infections in Hawaiian green turtles (Chelonia mydas) by quantifying tissue egg burdens in turtles submitted for necropsy and by assessing antibody response to crude adult worm and egg antigens among a variety of age groups. Hapalotrema sp. and Laeredius sp. predominated in turtles infected with spirorchiids. Tissue egg burdens decreased with increasing size and increased with deteriorating body condition of turtles. No relationship was found between tissue egg burdens and sex or fibropapillomatosis status. Tissue egg burdens increased in turtles from southeast to northwest in the main Hawaiian Islands (Hawaii to Kauai). Hatchling and captive-reared turtles had significantly lower levels of antibodies against crude worm and egg antigens. Based on tissue egg burdens and antibody status, we hypothesize that immature turtles become infected with spirorchiids shortly after recruiting into coastal foraging pastures from the pelagic environment, that infection levels decrease with age, and that spirorchiids detrimentally affect the body condition of sea turtles independent of tumor burden. The low intensity of infection in turtles with the endemic trematode Carettacola hawaiiensis suggests either that turtles are less susceptible to infection with this parasite or that the parasite is outcompeted by species of Hapalotrema and Laeredius. Given that the 2 latter species are found in the Pacific and other oceans, they are not likely endemic and were probably introduced into Hawaii through an undetermined route.

Hawai'i↗
USGS2005

Prevalence of agglutinating antibodies to Toxoplasma gondii and Sarcocystis neurona in beavers (Castor canadensis) from Massachusetts

The present study examined the seroprevalence of Toxoplasma gondii and Sarcocystls neurona in a population of beavers (Castor canadensis) from Massachusetts. Sixty-two blood samples were collected during the field seasons over 3 consecutive years from different animals. Blood was collected onto filter paper and shipped to the Department of Biomedical Sciences, Virginia Tech, Blacksburg, Virginia, for parasite testing. The samples were tested at dilutions of 1:25, 1:50, and 1:100 against each parasite antigen by modified agglutination tests to determine whether antibodies to either parasite were present in the blood. Six of 62 samples (10%) were positive for T. gondii, with 2 samples having titers of 1:25 and 4 having titers of 1:50. Four of 62 samples (6%) were positive for S. neurona, with 2 samples having titers of 1:25 and 2 having titers of 1:50. ?? American Society of Pathologists 2005.

Journal of Parasitology↗
USGS2006

Molecular phylogeny of Babesia poelea from brown boobies ( Sula leucogaster ) from Johnston Atoll, Central Pacific

The phylogenetic relationship of avian Babesia with other piroplasms remains unclear, mainly because of a lack of objective criteria such as molecular phylogenetics. In this study, our objective was to sequence the entire 18S, ITS-1, 5.8S, and ITS-2 regions of the rRNA gene and partial ß-tubulin gene of B. poelea , first described from brown boobies ( Sula leucogaster ) from the central Pacific, and compare them to those of other piroplasms. Phylogenetic analyses of the entire 18S rRNA gene sequence revealed that B. poelea belonged to the clade of piroplasms previously detected in humans, domestic dogs, and wild ungulates in the western United States. The entire ITS-1, 5.8S, ITS-2, and partial ß-tubulin gene sequence shared conserved regions with previously described Babesia and Theileria species. The intron of the ß-tubulin gene was 45 bp. This is the first molecular characterization of an avian piroplasm.

Johnston Atoll National Wildlife Refuge↗
USGS2007

Evidence of experimental postcyclic transmission of Bothriocephalus acheilognathi in bonytail chub (Gila elegans)

We examined the role that predation of infected conspecific fish and postcyclic transmission might play in the life cycle of the Asian fish tapeworm, Bothriocephalus acheilognathi (Cestoda: Pseudophyllidea) Yamaguti, 1934. Young-of-the-year (YOY) bonytail chub ( Gila elegans ) were exposed to copepods infected with B. acheilognathi and subsequently fed to subadult bonytail chub. Within 1 wk after consumption of the YOY chub, subadults were necropsied and found infected with gravid and nongravid tapeworms. This study provides evidence that postcyclic transfer of B. acheilognathi can occur. Postcyclic transmission may be an important life history trait of B. acheilognathi that merits consideration when studying the impact and distribution of this invasive and potentially pathogenic tapeworm.

New Mexico↗
USGS2007

Ectoparasites in an urban population of big brown bats (Eptesicus fuscus) in Colorado

Ectoparasites of an urban population of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado, were investigated during summers 2002, 2003, and 2004. Eleven species of ectoparasites were found (the macronyssid mite Steatonyssus occidentalis, the wing mite Spinturnix bakeri, the myobiid mites Acanthophthirius caudata and Pteracarus aculeus, the chirodiscid mite Alabidocarpus eptesicus, the demodicid mite Demodex sp., the chigger Leptotrombidium myotis, the soft tick Carios kelleyi, the batfly Basilia forcipata, the batbug Cimex pilosellus, and the flea Myodopsylla borealis). Five species were analyzed by prevalence and intensity (C. pilosellus, M. borealis, L. myotis, S. bakeri, and S. occidentalis) based on 2,161 counts of 1,702 marked individual bats over the 3 summer study periods. We investigated 4 factors potentially influencing prevalence and intensity: age class of the host, reproductive status of adult female hosts, roosts in which the hosts were found, and abiotic conditions during the year sampled. The macronyssid mite, S. occidentalis, was the most prevalent and abundant ectoparasite. Adult big brown bats had more ectoparasites than volant juveniles for most of the species analyzed. In a sample of known age bats at 1 large colony, bats of 4 yr of age or greater had higher ectoparasite loads of S. occidentalis and S. bakeri when compared with younger bats. Lactating female bats had the highest prevalence and intensities of most ectoparasites. Annual differences in ectoparasite prevalence and intensity were related to temperature and humidity, which can affect the nidicolous species of ectoparasites. Residents of 2 buildings sprayed insecticides in response to Cimex sp., and this appeared to reduce ectoparasitism of S. occidentalis and C. pilosellus present at these buildings. Intensity of S. occidentalis had no influence on annual survival of big brown bats. ?? American Society of Parasitologists 2007.

Journal of Parasitology↗
USGS2002

Blood parasites of American crows (Corvus brachyrhynchos) and fish crows (Corvus ossifragus) in Florida, U.S.A.

Blood films from 46 fish crows ( Corvus ossifragus Wilson) and 42 American crows ( Corvus brachyrhynchos Brehm) from Florida, U.S.A., were examined for blood parasites. Haemoproteus picae Coatney and Roudabush, Haemoproteus danilewskii Kruse, Trypanosoma avium (Danilewsky), and microfilariae of an unidentified filarioid were identified from both species of crows. An unidentified species of Haemoproteus and Trypanosoma ontarioensis Woo and Bartlett were observed in American crow blood films. Fish crow blood films contained Plasmodium relictum Celli and Sanfelice. Prior to this study, T. avium and P. relictum had not been reported from fish crows.

Florida↗
USGS2002

What are parasitologists doing in the United States Geological Survey?

The United States Geological Survey (USGS) was formed in 1879 as the nation's primary natural science and information agency. The mission of the agency is to provide scientific information to a??describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.a?? Prior to 1996, the USGS comprised 3 divisions or disciplines: geology, mapping, and water. Historically, the agency was most noted for cartographic products that were used widely by both government and private sector. With the inclusion of the National Biological Service into the USGS in 1996 as the Biological Resource Discipline (BRD), a living resources dimension was added to the earth sciences character of the USGS. With the addition of BRD, the bureau is able now to contribute both the physical and biological sciences to address the nation's resource management problems.

Comparative Parasitology↗
USGS2002

Parasites of the slimy sculpin, Cottus cognatus Richardson, 1836, from Lake Huron, U.S.A

One hundred slimy sculpins, Cottus cognatus (Cottidae), collected from Six Fathom Bank Lake Trout Refuge in Lake Huron in June 1995 were examined for parasites. A total of 17 parasite species (3 Digenea, 2 Monogenea, 3 Cestoda, 3 Nematoda, 2 Acanthocephala, 2 Ciliophora, 1 Microspora, and 1 Myxosporea) were found to infect sculpins. Tetracotyle sp. had the highest prevalence, mean intensity, and mean abundance, followed by Diplostomum sp. The most common gastrointestinal helminth species was Echinorhynchus salmonis . Epistylis sp. occurred on the gills of 79 sculpins. The mean parasite species richness ± SD and mean helminth abundance ± SD were 5.4 ± 1.6 and 242.6 ± 264.5, respectively. The mean Brillouin's diversity and evenness values were 0.5773 ± 0.1915 and 0.5248 ± 0.1892, respectively. Although the helminth community of slimy sculpins is dominated by larval trematodes that mature in piscivorous birds, it is believed that few slimy sculpins are eaten by birds at this location.

Comparative Parasitology↗
USGS2017

Distribution of Placobdella hollensis (Whitman, 1892) (Hirudinida: Glossiphoniidae)

Confusion regarding the identification of Placobdella hollensis ( Whitman, 1892 ) (Hirudinida: Glossiphoniidae) has led to an unclear understanding of the distribution of the species. Two specimens of P. hollensis were collected from Merchants Millpond State Park, Gates County, North Carolina, U.S.A., representing a new geographic distribution record. Specimens were confirmed as P. hollensis by morphological and molecular study. Specimens of P. hollensis from North Carolina, had accessory eyes, 2 thin paramedial dark lines, and 3 pairs of pre-anal papillae. Molecular comparison of cytochrome c oxidase subunit I sequence data revealed a 99.0 to 99.7% similarity to specimens of P. hollensis collected from its type locality (Barnstable County, Massachusetts, U.S.A.). From confirmed specimens of P. hollensis , this report supports the assertion that P. hollensis has an Atlantic coastal distribution.

Comparative Parasitology↗
USGS2003

Parasites of burbot, Lota lota , from Lake Huron, Michigan, U.S.A., with a checklist of the North American parasites of burbot

Forty-five adult burbot, Lota lota , collected in July 1998 from Six Fathom Bank (Six Fathom Bank Lake Trout Refuge) and Yankee Reef in Lake Huron, Michigan, U.S.A., were examined for parasites. A total of 10 parasite species infected burbot. Diplostomum sp., Eubothrium rugosum , Haplonema hamulatum , Echinorhynchus salmonis , and Trichodina sp. infected 60% or more of the burbot examined from each location. Diplostomum sp. had the highest mean intensity, and E. salmonis had the highest mean abundance in burbot from Six Fathom Bank. Echinorhynchus salmonis had the highest mean intensity and mean abundance in burbot from Yankee Reef. Diplostomum sp., H. hamulatun , and E. salmonis in burbot from Yankee Reef had significantly higher mean intensities and mean abundances than those in fish from Six Fathom Bank. The lengths and weights of burbot from Yankee Reef were significantly greater than those of fish from Six Fathom Bank. A checklist of parasites of burbot from published records in North America is presented.

Journal of Comparative Parasitology↗
USGS2004

Intestinal helminths in mourning doves (Zenaida macroura) from Arizona, Pennsylvania, South Carolina, and Tennessee, U.S.A.

We examined 115 hunter-killed mourning doves ( Zenaida macroura ) from 4 states (Arizona, Pennsylvania, South Carolina, and Tennessee, U.S.A.) in 1998 and 1999 to investigate geographical variation in the prevalence and intensity of intestinal helminth infections. Four intestinal helminth species were identified: Killigrewia delafondi , Ornithostrongylus crami , Ascaridia columbae , and Capillaria obsignata . The number of worms (all helminth species combined) per infected bird ranged from 1 to 166 (mean ± SE = 12.7 ± 7.45, median = 2.0). Filarids, Aproctella stoddardi , were found in 2 birds but were probably adhering to the outside of the intestine. Overall, 18% of the doves were infected with 1 or more species of helminths. The percentage of doves infected with at least 1 helminth species varied from 4% in Arizona to 27% in South Carolina. Mixed infections occurred in only 3 individuals (14% of infected birds). We found no significant differences in prevalence of infection among any of the 4 helminths by host age or sex, and prevalences were too low to test for differences among states. The intensity of O. crami was higher in males than in females but did not differ significantly among states. Intensities of the other 3 helminths did not differ by sex or state, and we found no differences in helminth intensity by age. Intestinal length was significantly greater in infected than in uninfected birds.

Arizona, Pennsylvania, South Carolina, Tennessee↗
USGS2004

Parasites of the African clawed frog, Xenopus laevis , in southern California, U.S.A

A total of 230 feral African clawed frogs, Xenopus laevis , from 3 localities in southern California were examined for parasites. The following species were found: 3 species of Protozoa, Nyctotherus sp., Balantidium xenopodis , Protoopalina xenopodus ; 2 species of Monogenea, Protopolystoma xenopodis , Gyrdicotylus gallieni ; 1 species of Digenea, Clinostomum sp. (as metacercariae); 1 species of Cestoda, Cephalochlamys namaquensis ; 2 species of Nematoda, Contracaecum sp. (as larvae), Eustrongylides sp. (as larvae); and 1 species of Acanthocephala, Acanthocephalus sp. (as cystacanth). Of these, the protozoans P. xenopodus and B. xenopodis , both monogeneans, and the cestode have an African origin. Contracaecum sp., Eustrongylides sp., and Acanthocephalus sp. have not been previously reported from X. laevis .

Comparative Parasitology↗