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At least 163 records · Page 9Linked to original sources
USGS2009

Bothriocephalus acheilognathi and other intestinal helminths of Cyprinella lutrensis in Deep Creek, Kansas

We investigated the intestinal parasites of a wild fish population in a Kansas stream to determine the prevalence and abundance of potentially harmful parasites. In total, 180 red shiners ( Cyprinella lutrensis ) were collected from 6 sites in October-November 2007. Fifteen Asian tapeworms ( Bothriocephalus acheilognathi ) were recovered from 13 fish (prevalence of 7.2%). Prevalence did not differ among sites; however, B. acheilognathi abundance was greatest at the site of a public fishing area. A total of 39 roundworms ( Rhabdochona canadensis ) were recovered from 28 fish (prevalence of 15.6%). Prevalence did not differ among sites, nor did abundance. However, mean abundance tended to be about 50% greater at the site of a public fishing area compared to all other sites. This paper documents the presence of both B. acheilognathi and R. canadensis in Kansas and offers a compilation of the known potential impacts these parasites may have on the native, federally endangered Topeka shiner ( Notropis topeka ).

Journal of Parasitology↗
USGS2010

Stomach nematodes (Mastophorus Muris) in rats (Rattus rattus) are associated with coconut (Cocos nucifera) Habitat at palmyra atoll

Black rats (Rattus rattus) and their stomach nematodes (Mastophorus muris) were historically introduced to islets at Palmyra Atoll in the central Pacific Line Islands. To investigate patterns of parasitism, we trapped rats and quantified nematodes on 13 islets of various sizes and habitat types. Most rats were parasitized (59) with an average of 12 worms per infected rat. Islet size did not greatly influence parasite population biology. Nematodes also did not appear to affect rat condition (weight to skull length). The only strong and consistent factor associated with the mean abundance of nematodes in rats was habitat (dominant cover and locally dominant plant species). Thus, nematodes were much more abundant in rats from sites dominated by coconut trees (Cocos nucifera). Coconut trees may also be an introduced species at Palmyra Atoll. ?? American Society of Parasitologists 2010.

Journal of Parasitology↗
USGS2010

Ecology of the brain trematode Euhaplorchis californiensis and its host, the California Killifish (Fundulus parvipinnis)

We describe the distribution and abundance of the brain-encysting trematode Euhaplorchis californiensis and its second intermediate host, the California killifish ( Fundulus parvipinnis ), in 3 estuaries in southern California and Baja California. We quantified the density of fish and metacercariae at 13–14 sites per estuary and dissected 375 killifish. Density (numbers and biomass) was examined at 3 spatial scales, i.e., small replicate sites, habitats, and entire estuaries. At those same scales, factors that might influence metacercaria prevalence, abundance, and aggregation in host individuals and populations were also examined. Metacercaria prevalence was 94–100% among the estuaries. Most fish were infected with 100s to 1,000s of E. californiensis metacercariae, with mean abundance generally increasing with host size. Although body condition of fish did not vary among sites or estuaries, the abundance of metacercariae varied significantly among sites, habitats, estuaries, and substantially with host size and gender. Metacercariae were modestly aggregated in killifish ( k > 1), with aggregation decreasing in larger hosts. Across the 3 estuaries, the total populations of killifish ranged from 9,000–12,000 individuals/ha and from 7–43 kg/ha. The component populations of E. californiensis metacercariae ranged from 78–200 million individuals/ha and from 0.1–0.3 kg/ha. Biomass of E. californiensis metacercariae constituted 0.5–1.7% of the killifish biomass in the estuaries. Our findings, in conjunction with previously documented effects of E. californiensis , suggest a strong influence of this parasite on the size, distribution, biomass, and abundance of its killifish host.

Journal of Parasitology↗
USGS2004

A rapid method for counting nucleated erythrocytes on stained blood smears by digital image analysis

Measures of parasitemia by intraerythrocytic hematozoan parasites are normally expressed as the number of infected erythrocytes per n erythrocytes and are notoriously tedious and time consuming to measure. We describe a protocol for generating rapid counts of nucleated erythrocytes from digital micrographs of thin blood smears that can be used to estimate intensity of hematozoan infections in nonmammalian vertebrate hosts. This method takes advantage of the bold contrast and relatively uniform size and morphology of erythrocyte nuclei on Giemsa-stained blood smears and uses ImageJ, a java-based image analysis program developed at the U.S. National Institutes of Health and available on the internet, to recognize and count these nuclei. This technique makes feasible rapid and accurate counts of total erythrocytes in large numbers of microscope fields, which can be used in the calculation of peripheral parasitemias in low-intensity infections.

Journal of Parasitology↗
USGS2010

Thermal constraints to the sporogonic development and altitudinal distribution of avian malaria Plasmodium relictum in Hawai'i

More than half of the Hawaiian honeycreepers (Drepanidinae) known from historical records are now extinct. Introduced mosquito-borne disease, in particular the avian malaria Plasmodium relictum , has been incriminated as a leading cause of extinction during the 20th century and a major limiting factor in the recovery of remaining species populations. Today, most native Hawaiian bird species reach their highest densities and diversity in high elevation (>1,800 m above sea level) forests. We determined the thermal requirements for sporogonic development of P. relictum in the natural vector, Culex quinquefasciatus , and assessed the current distribution of native bird species in light of this information. Sporogonic development was completed at constant laboratory and mean field temperatures between 30 and 17 C, but development, prevalence, and intensity decreased significantly below 21 C. Using a degree-day (DD) model, we estimated a minimum threshold temperature of 12.97 C and a thermal requirement of 86.2 DD as necessary to complete development. Predicted (adiabatic lapse-rate) and observed summer threshold isotherm (13 C) correspond to the elevation of high forest refuges on the islands of Maui and Hawai'i. Our data support the hypothesis that avian malaria currently restricts the altitudinal distribution of Hawaiian honeycreeper populations and provide an ecological explanation for the absence of disease at high elevation.

Hawaii↗
USGS2010

Release of infectious cells from epidermal ulcers in Ichthyophonus sp.–infected Pacific Herring (Clupea pallasii): Evidence for multiple mechanisms of transmission

A common clinical sign of ichthyophoniasis in herring and trout is “sandpaper” skin, a roughening of the epidermis characterized by the appearance of small papules, followed by ulceration and sloughing of the epithelium; early investigators hypothesized that these ulcers might be a means of transmitting the parasite, Ichthyophonus sp ., without the necessity of ingesting an infected host. We examined the cells associated with the epidermal lesions and confirmed that they were viable Ichthyophonus sp. cells that were readily released from the skin into the mucous layer and ultimately into the aquatic environment. The released cells were infectious when injected into the body cavity of specific-pathogen-free herring. Our hypothesis is that different mechanisms of transmission occur in carnivorous and planktivorous hosts: Planktonic feeders become infected by ingestion of ulcer-derived cells, while carnivores become infected by ingestion of whole infected fish.

Journal of Parasitology↗
USGS2009

Acceptance of the 2009 Henry Baldwin Ward Medal: The accidental parasitologist

Members of the Society, President Conn, colleagues, friends, and particularly students, the Ward Medal recipient, from Clarke Read onward, traditionally recounts how their career was shaped. A decade ago, in a crumbling Kona hotel, the ASP's own tattooed lady, Janine Caira, opened her Ward Medal address with: “To all future Ward Medalists, many of whom I trust are sitting in the audience out there today, I say: savor the moment! You have no idea how much easier it is to be sitting out there where you are than standing up here where I am” ( Caira 1998 ). I certainly didn't imagine that Janine was delivering her advice to me and it is presumptuous to imagine my story is a template for shaping a career. As the title of my talk indicates, it was an accident.

Journal of Parasitology↗
USGS2011

Sphaeridiotrema globulus and Sphaeridiotrema pseudoglobulus (Digenea): Species differentiation based on mtDNA (Barcode) and partial LSUrDNA sequences

Flukes belonging to Sphaeridiotrema are important parasites of waterfowl, and 2 morphologically similar species Sphaeridiotrema globulus and Sphaeridiotrema pseudoglobulus , have been implicated in waterfowl mortality in North America. Cytochrome oxidase I (barcode region) and partial LSU-rDNA sequences from specimens of S. globulus and S. pseudoglobulus , obtained from naturally and experimentally infected hosts from New Jersey and Quebec, respectively, confirmed that these species were distinct. Barcode sequences of the 2 species differed at 92 of 590 nucleotide positions (15.6%) and the translated sequences differed by 13 amino acid residues. Partial LSU-rDNA sequences differed at 29 of 1,208 nucleotide positions (2.4%). Additional barcode sequences from specimens collected from waterfowl in Wisconsin and Minnesota and morphometric data obtained from specimens acquired along the north shore of Lake Superior revealed the presence of S. pseudoglobulus in these areas. Although morphometric data suggested the presence of S. globulus in the Lake Superior sample, it was not found among the specimens sequenced from Wisconsin or Minnesota.

Minnesota, Wisconsin↗
USGS2012

Infection by Haemoproteus parasites in four species of frigatebirds and the description of a new species of Haemoproteus (Haemosporida: Haemoproteidae)

Among seabirds, the fregatids stand out with a high prevalence of blood parasites. Four of 5 species in this family have been found to be infected with Haemoproteus ; however, complete species descriptions with molecular phylogeny are lacking. Seventy-five samples from 4 species of frigatebirds, i.e., Fregata andrewsi , Fregata minor , Fregata magnificens , and Fregata aquila , were screened for infections caused by species of Haemoproteus . Four different parasite haplotypes were found infecting frigatebirds based on the sequencing of a fragment of the cytochrome b gene. Two haplotypes belong to the subgenus Parahaemoproteus , and the other 2 correspond to haplotypes within the subgenus Haemoproteus . The more prevalent and cosmopolitan Parahaemoproteus haplotype (FregPHae1) was phylogenetically grouped with other Haemoproteus parasites infecting non-passerine birds, but it could not be detected from the single sample from F. aquila . The other Parahaemoproteus haplotype (FregPHae2) was not phylogenetically clustered with parasites infecting non-passerine birds, and it was sequenced from a single (1 each) F. andrewsi and F. minor . Blood smears from F. andrewsi infected only by FregPHae1 haplotype showed sufficient gametocytes to allow description of a new species, Haemoproteus valkiūnasi sp. nov. In contrast to Haemoproteus iwa , the only previously known blood parasite infecting frigatebirds and described from F. minor from Galapagos Islands, parasites from F. andrewsi (1) are shorter with no contact of gametocyte with host cell membrane, (2) have fewer pigment granules, and (3) have wider microgametocytes, with a smaller host nuclear displacement. In contrast, patent single infections corresponding to the cosmopolitan haplotype of the subgenus Haemoproteus (FregHae1) were also found in samples from 1 F. andrewsi , 1 F. minor , and 1 F. aquila . In all these cases, the number of microgametocytes was very low, resembling H. iwa , which lacks microgametocytes in the original description. Macrogametocytes of haplotype FregHae1 in F. andrewsi differ significantly from all the characteristics measured from H. valkiūnasi . In addition, it also differs from all characteristics of H. iwa despite being genetically identical in the analyzed fragment.

Journal of Parasitology↗
USGS2012

Parasites of fishes in the Colorado River and selected tributaries in Grand Canyon, Arizona.

As part of the endangered humpback chub (HBC; Gila cypha) Adaptive Management Program, a parasite survey was conducted from 28 June to 17 July 2006 in 8 tributaries and 7 adjacent sections of the main stem of the Colorado River, U.S.A. In total, 717 fish were caught, including 24 HBC. Field necropsies yielded 19 parasite species, 5 of which (Achtheres sp., Kathlaniidae gen. sp., Caryophyllaidae gen. sp., Myxidium sp., and Octomacrum sp.) are new records for Grand Canyon, Arizona, U.S.A. Spearman's correlation coefficient analyses showed no correlations between parasite burden and fork length for various combinations of fish and parasite species. Regression analyses suggest that no parasite species had a strong effect on fish length. The most diverse parasite community (n=14) was at river kilometer (Rkm) 230, near the confluence of Kanab Creek. The most diverse parasite infracommunity (n=12) was found in the non-native channel catfish (CCF; Ictaluris punctatus). Overall parasite prevalence was highest in CCF (85%) followed by that in HBC (58%). The parasite fauna of humpback chub was mainly composed of Bothriocephalus acheilognathi and Ornithodiplostomum sp. metacercariae.

Arizona↗
USGS2011

Diagnostic methodology is critical for accurately determining the prevalence of ichthyophonus infections in wild fish populations

Several different techniques have been employed to detect and identify Ichthyophonus spp. in infected fish hosts; these include macroscopic observation, microscopic examination of tissue squashes, histological evaluation, in vitro culture, and molecular techniques. Examination of the peer-reviewed literature revealed that when more than 1 diagnostic method is used, they often result in significantly different results; for example, when in vitro culture was used to identify infected trout in an experimentally exposed population, 98.7% of infected trout were detected, but when standard histology was used to confirm known infected tissues from wild salmon, it detected ~50% of low-intensity infections and ~85% of high-intensity infections. Other studies on different species reported similar differences. When we examined a possible mechanism to explain the disparity between different diagnostic techniques, we observed non-random distribution of the parasite in 3-dimensionally visualized tissue sections from infected hosts, thus providing a possible explanation for the different sensitivities of commonly used diagnostic techniques. Based on experimental evidence and a review of the peer-reviewed literature, we have concluded that in vitro culture is currently the most accurate diagnostic technique for determining infection prevalence of Ichthyophonus, particularly when the exposure history of the population is not known.

Journal of Parasitology↗
USGS2012

Description of two new gill myxozoans from smallmouth (Micropterus dolomieu) and largemouth bass (Micropterus salmoides)

Two previously undescribed species of myxozoan parasites were observed in the gills of bass inhabiting the Potomac and James River basins. They are described using morphological characteristics and small-subunit (SSU) rDNA gene sequences. Both were taxonomically identified as new species of Myxobolus; Myxobolus branchiarum n. sp. was found exclusively in smallmouth bass, and Myxobolus micropterii n. sp. was found in largemouth and smallmouth bass. Small, spherical, white plasmodia of M. branchiarum from smallmouth bass were observed grossly in the gills; these plasmodia had an average length of 320.3 µm and width of 246.1 µm. The development of the plasmodia is intralamellar in the secondary lamellae of the gills. Mature spores were pyriform in shape with a length of 12.8 ± 1.4 (8.1–15.1) µm and width of 6.9 ± 1.1 (4.0–9.0) µm. Analysis of SSU rDNA identified M. branchiarum in a sister-group to 3 species of Henneguya, although morphologically caudal appendages were absent. Myxobolus micropterii observed in the gills of largemouth and smallmouth bass had larger, ovoid, cream-colored plasmodia with an average length of 568.1 µm and width of 148.1 µm. The cysts developed at the distal end of the gill filament within the primary lamellae. The mature spores were ovoid in shape with a length of 10.8 ± 0.7 (9.2–12.2) µm and width of 10.6 ± 0.6 (9.0–11.8) µm. SSU rDNA analysis placed M. micropterii in a sister group with Henneguya lobosa and Myxobolus oliveirai. The highest prevalence of M. branchiarum was observed in the gills of bass collected from the Cowpasture River (50.9%). Prevalence was 44.6% in bass from the Potomac River and only 4.3% in bass collected from the Shenandoah River. A seasonal study of M. branchiarum, which included both infected and uninfected smallmouth bass, determined that a significantly higher intensity was observed in the spring than in the summer (P < 0.001) or fall (P = 0.004). In an analysis excluding uninfected bass, a higher intensity was observed in the spring than in the summer (P = 0.001) or fall (P = 0.008). Prevalence and seasonal differences were not determined for M. micropterii.

Journal of Parasitology↗
USGS2012

The role of spatial and temporal heterogeneity and competition in structuring trematode communities in the great pond snail, Lymnaea stagnalis (L.)

We assessed how spatial and temporal heterogeneity and competition structure larval trematode communities in the pulmonate snail Lymnaea stagnalis . To postulate a dominance hierarchy, mark-release-recapture was used to monitor replacements of trematode species within snails over time. In addition, we sampled the trematode community in snails in different ponds in 3 consecutive years. A total of 7,623 snails (10,382 capture events) was sampled in 7 fishponds in the Jindřichův Hradec and Třeboň areas in South Bohemia (Czech Republic) from August 2006 to October 2008. Overall, 39% of snails were infected by a community of 14 trematode species; 7% of snails were infected with more than 1 trematode species (constituting 16 double- and 4 triple-species combinations). Results of the null-model analyses suggested that spatial heterogeneity in recruitment among ponds isolated trematode species from each other, whereas seasonal pulses in recruitment increased species interactions in some ponds. Competitive exclusion among trematodes led to a rarity of multiple infections compared to null-model expectations. Competitive relationships among trematode species were hypothesized as a dominance hierarchy based on direct evidence of replacement and invasion and on indirect evidence. Seven top dominant species with putatively similar competitive abilities (6 rediae and 1 sporocyst species) reduced the prevalence of the other trematode species developing in sporocysts only.

Journal of Parasitology↗
USGS2003

Microparasite assemblages of conspecific shrew populations in Southern California

The microparasite component communities of 2 species of shrews, Notiosorex crawfordi and Sorex ornatus, were investigated for the first time in 2 isolated and 3 continuous landscapes in southern California. With microscopical examination, a total of 6 parasite species was found in N. crawfordi and 8 species in S. ornatus. The highest number (5) of parasite species was detected in the lungs. The corrected estimate of parasite species richness did not significantly correlate with the host abundance in either shrew species. Altitude, and also latitude in N. crawfordi, appeared to be significantly positively associated with the parasite species richness, but this could be due to a false association because of the rare occurrence of some of the parasites or the small altitude range (or both). No other landscape variable analyzed (location, size of the study site, disturbance) was significantly associated with the parasite species richness of the shrews. The parasite assemblages of the 2 shrew species were similar despite the fact that N. crawfordi has a lower metabolic rate than S. ornatus.

Journal of Parasitology↗
USGS2013

New species of Parapharyngodon (Nematoda: Pharyngodonidae) in Rhinella marina (Anura: Bufonidae) from Grenada, West Indies

Parapharyngodon grenadaensis n. sp. (Nematoda: Pharyngodonidae) from the large intestine of the cane toad, Rhinella marina, is described and illustrated. Parapharyngodon grenadaensis n. sp. is the 48th species assigned to the genus and the 16th species from the Neotropical region. It differs from other species in the genus by possessing 4 pairs of caudal papillae, an echinate anterior cloacal lip, and a blunt spicule of 67&ndash;104 &mu;m. This is only the second report of R. marina harboring a species of Parapharyngodon.

Journal of Parasitology↗
USGS2013

Evidence for an amoeba-like infectious stage of ichthyophonus sp. and description of a circulating blood stage: a probable mechanism for dispersal within the fish host

Small amoeboid cells, believed to be the infectious stage of Ichthyophonus sp., were observed in the bolus (stomach contents) and tunica propria (stomach wall) of Pacific staghorn sculpins and rainbow trout shortly after they ingested Ichthyophonus sp.–infected tissues. By 24–48 hr post-exposure (PE) the parasite morphed from the classically reported multinucleate thick walled schizonts to 2 distinct cell types, i.e., a larger multinucleate amoeboid cell surrounded by a narrow translucent zone and a smaller spherical cell surrounded by a “halo” and resembling a small schizont. Both cell types also appeared in the tunica propria, indicating that they had recently penetrated the columnar epithelium of the stomach. No Ichthyophonus sp. pseudo-hyphae (“germination tubes”) were observed in the bolus or penetrating the stomach wall. Simultaneously, Ichthyophonus sp. was isolated in vitro from aortic blood, which was consistently positive from 6 to 144 hr PE, then only intermittently for the next 4 wk. Small PAS-positive cells observed in blood cultures grew into colonies consisting of non-septate tubules (pseudo-hyphae) terminating in multinucleated knob-like apices similar to those seen in organ explant cultures. Organ explants were culture positive every day; however, typical Ichthyophonus sp. schizonts were not observed histologically until 20–25 days PE. From 20 to 60 days PE, schizont diameter increased from ≤25 μm to ≥82 μm. Based on the data presented herein, we are confident that we have resolved the life cycle of Ichthyophonus sp. within the piscivorous host.

Journal of Parasitology↗
USGS2004

Occurrence of Ergasilus megaceros Wilson, 1916, in the sea lamprey and other fishes from North America

Ergasilus megaceros (Copepoda: Ergasilidae) was recovered from the nasal fossae (lamellae) of the olfactory sac in 1 (1.8%) of 56 sea lampreys, Petromyzon marinus Linne, 1758, collected in May 2002 from the Cheboygan River, Michigan. Although the sea lamprey is a new host record for E. megaceros , this fish species may not be a preferred host because of its low prevalence. Ergasilus megaceros is the second ergasilid species reported from the sea lamprey in North America. This is the third report of an ergasilid species infecting the nasal fossae of fishes in North America, with E. rhinos being the only other species reported from this site.

Journal of Parasitology↗
USGS2004

Flow cytometric analysis of lectin binding to in vitro-cultured Perkinsus marinus surface carbohydrates

Parasite surface glycoconjugates are frequently involved in cellular recognition and colonization of the host. This study reports on the identification of Perkinsus marinus surface carbohydrates by flow cytometric analyses of fluorescein isothiocyanate-conjugated lectin binding. Lectin-binding specificity was confirmed by sugar inhibition and Kolmogorov-Smirnov statistics. Clear, measurable fluorescence peaks were discriminated, and no parasite autofluorescence was observed. Parasites (GTLA-5 and Perkinsus-1 strains) harvested during log and stationary phases of growth in a protein-free medium reacted strongly with concanavalin A and wheat germ agglutinin, which bind to glucose-mannose and N-acetyl-D-glucosamine (GlcNAc) moieties, respectively. Both P. marinus strains bound with lower intensity to Maclura pomifera agglutinin, Bauhinia purpurea agglutinin, soybean agglutinin (N-acetyl-D-galactosamine-specific lectins), peanut agglutinin (PNA) (terminal galactose specific), and Griffonia simplicifolia II (GlcNAc specific). Only background fluorescence levels were detected with Ulex europaeus agglutinin I (L-fucose specific) and Limulus polyphemus agglutinin (sialic acid specific). The lectin-binding profiles were similar for the 2 strains except for a greater relative binding intensity of PNA for Perkinsus-1 and an overall greater lectin-binding capacity of Perkinsus-1 compared with GTLA-5. Growth stage comparisons revealed increased lectin-binding intensities during stationary phase compared with log phase of growth. This is the first report of the identification of surface glycoconjugates on a Perkinsus spp. by flow cytometry and the first to demonstrate that differential surface sugar expression is growth phase and strain dependent. ?? American Society of Parasitologists 2004.

Journal of Parasitology↗