Molecular evidence for cryptic species within Cylicostephanus minutus (Nematoda: Strongylidae)

The nucleotide sequences of the first and second internal transcribed spacers of nuclear ribosomal DNA were determined for adults of Cylicostephanus minutus from different geographical origins. The lengths of first and second internal transcribed spacer sequences ranged from 370 to 372bp and 215 to 216bp, respectively. Pairwise sequence comparisons revealed that some individuals of C. minutus had identical first and second internal transcribed spacer sequences, whereas others differed by 3.0% and 7.4% in their first and second transcribed spacers, respectively. Some individuals with sequence differences originated from the same host. The levels of difference within C. minutus were higher than that between the morphologically distinct species, Cylicostephanus goldi and Cylicostephanus longibursatus (0.8% for the first internal transcribed spacer and 3.8% for the second internal transcribed spacer). The data provide support for the proposal that C. minutus represents a complex of at least two species. In order to study the population genetic structure of C. minutus, a PCR-linked single-strand conformation polymorphism technique was also established.     

Inorganic elements in adult Ternidens deminutus (Nematoda: Strongylidae: Oesophagostominae) from humans and baboons

The present paper presents the results of an analysis of the inorganic elements detected in Ternidens deminutus from human and baboon hosts. It reports on the presence of Zn, Fe, P, Ca, Cu, Mg, Mn and K in the worms and notes especially that worms from humans contained a higher percentage of body weight of Zn than those from baboons, a finding in agreement with an earlier EDAX analysis of the pigment granules of this species.     

The morphology and differential diagnosis of parasitic larvae of Triodontophorus (Nematoda, Strongylidae)

356 parasitic larvae of the genus Triodontophorus from Equidae (two Equus hemionus and one E. grevyi) have been investigated. They belong to three phenons, which differ from each other by the shape and dimensions of a stoma, the structure of teeth and other signs. That phenons belong to three different species: T. serratus, T. tenuicollis and T. brevicauda. The differential diagnosis of L4 of that species of Triodontophorus are given.     

Molecular basis of hyperlipidemia in golden hamsters during experimental infection with Ancylostoma ceylanicum (Nematoda:Strongylidae)

An infection of golden hamsters with Ancylostoma ceylanicum, a hookworm parasite, induced profound hyperlipidemia, particularly hypertriglyceridemia, and the effect was directly related to the degree of infection. A significant increase was also noticed in serum cholesterol and phospholipid levels. The appearance of lipoprotein-X, an abnormal low density lipoprotein, was detected in the serum of hookworm-infected animals. The hyperlipidemia was further characterized by an increase in very low density lipoproteins (VLDL) and low density lipoproteins (LDL) with a concomitant decline in high density lipoproteins (HDL). Decreased lipolytic activities, especially triglyceride lipase, in hepatic tissue and induction of lipolytic activities in intestine and adipose tissues indicated mobilization of fats from adipose and jejunum with a defective removal of triglyceride-rich lipoproteins in hepatic tissues. Accumulation of lipids in liver and depletion in adipose tissue supported these results. The derangement may have a significant effect on host parasite interaction and is an important pathophysiological feature occurring during experimental ancylostomiasis.     

Host range of the parasite Strelkovimermis spiculatus (Nematoda: Mermithidae) in Argentina mosquitoes

Strelkovimermis spiculatus ( Poinar and Camino 1986 ) is a nematode parasite of mosquitoes isolated from the Neotropical region. We investigated the host range of this parasite in mosquito populations for a better understanding of the dynamics of temporary breeding sites. Five grassy‐pool habitats filled by rainwater were sampled from the summer 2007 through the fall 2008. Eight mosquito species were collected: Anopheles albitarsis, Culex chidesteri, Culex dolosus, Culex maxi, Aedes albifasciatus, Psorophora ciliata, Psorophora cyanescens, and Psorophora albigenu. Six of these species were parasitized: Cx. chidesteri, Cx. dolosus, Cx. maxi, Ae. albifasciatus, Ps. ciliata, and Ps. cyanescens. The occurrence of this mermithid in natural mosquito populations was increased from the end of winter to the end of the spring. Prevalence ranged from 11% to 100%. High levels of infections were registered only in Ae. albifasciatus larvae, the most abundant mosquito species (95%), followed by Cx. dolosus (2.7%). Strelkovimermis spiculatus completed its development in all infected mosquito larvae. The presence of S. spiculatus in six natural mosquito populations increases the number of susceptible species to 24.     

Experimental evolution of parasite life-history traits in Strongyloides ratti (Nematoda)

Evolutionary ecology predicts that parasite life-history traits, including a parasite's survivorship and fecundity within a host, will evolve in response to selection and that their evolution will be constrained by trade-offs between traits. Here, we test these predictions using a nematode parasite of rats, Strongyloides ratti, as a model. We performed a selection experiment by passage of parasite progeny from either early in an infection ('fast' lines) or late in an infection ('slow' lines). We found that parasite fecundity responded to selection but that parasite survivorship did not. We found a trade-off mediated via conspecific density-dependent constraints; namely, that fast lines exhibit higher density-independent fecundity than slow lines, but fast lines suffered greater reduction in fecundity in the presence of density-dependent constraints than slow lines. We also found that slow lines both stimulate a higher level of IgG1, which is a marker for a Th2-type immune response, and show less of a reduction in fecundity in response to IgG1 levels than for fast lines. Our results confirm the general prediction that parasite life-history traits can evolve in response to selection and indicate that such evolutionary responses may have significant implications for the epidemiology of infectious disease.     

Respiration and carbohydrate energy metabolism of the lung-dwelling parasite Rhabdias bufonis (Nematoda: Rhabdiasoidea)

An investigation of the carbohydrate energy metabolism of Rhabdias bufonis, the lung-dwelling nematode parasite of the African toad, Bufo regularis, indicates that the nematode stores very little glycogen (0.137 +/- 0.003% on a fresh weight basis) but does utilize oxygen in vitro. The intracellular distribution and high levels of activity observed for the enzymes phosphoenolpyruvate carboxykinase, pyruvate kinase, lactate dehydrogenase, malate dehydrogenase, malic enzyme and fumarate reductase suggest two alternative pathways of carbohydrate energy metabolism.     

Some morphological aspects of Cylicocyclus brevicapsulatus (Nematoda: Cyathostominae) parasite of horse

This paper describes some morphological aspects of Cylicocyclus brevicapsulatus (Ihle, 1920) (Nematoda: Cyathostominae) from Equus caballus in Brazil. The worms were studied using an optical microscope (measurements and illustrations) and a scanning electron microscope for a more detailed examination of the external morphology. The buccal capsule is very short, with a very thin wall, and the dorsal gutter is absent. Other morphological aspects are described including measurement of the spicules and gubernaculum.     

Etude morphologique deZenkoxyuris mabokensis (Oxyuridae: Nematoda) parasite deZenkerella insignis (Anomaluridae,Rongeur)

Résumé L'espèce type du genreZenkoxyuris: Z. mabokensis Quentin, 1975, connue seulement par une femelle incomplète, est redécrite à partir d'un matériel nouveau. Le mâle est décrit pour la première fois. Le genreZenkoxyuris comprend deux espèces parasites de Rongeurs Zenkerellinés (Anomaluridés):Z. mabokensis chezZenkerella insignis etZ. quentini Hugot, 1982 chezIdiurus macrotis. Les caractères du genreZenkoxyuris permettent de le rapprocher de l'autre genre parasite d'Anomaluridés:Acanthoxyurus Sandground, 1938 recontré chez les Anomalurinés. Les deux genres forment un petit ensemble particulier parmi les autres Oxyuridae parasites de Rongeurs.

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Summary Morphological study ofZenkoxyuris mabokensis (Oxyuridae: Nematoda), parasite ofZenkerella insignis (Anomaluridae: Rodentia).Zenkoxyuris mabokensis, the type species of the genusZenkoxyuris Quentin, 1975 (known by a single damaged female) is redescribed from new material. The male is described for the first time. The genusZenkoxyuris contains two species parasitic in zenkerellinae rodents (Anomaluridae):Z. mabokensis inZenkererella insignis Matschie andZ. quentini Hugot, 1982 inIdiurus macrotis Miller.Zenkoxyuris parasitic in Zenkerellinae, andAcanthoxyurus Sandground, 1928, pararasitic in Anomalurinae, are closely related. They form a homogeneous evolutionary assemblage amongst the Oxyuridae parasitic in rodents. ac]19830304

     

Abbreviata terrapenis (Nematoda: Physalopteridae): an accidental parasite of the banded rock rattlesnake (Crotalus lepidus klauberi)

The nematode, Abbreviata terrapenis (Physalopteridae) was found in 16 (6%) of 267 banded rock rattlesnakes (Crotalus lepidus klauberi) from Arizona and New Mexico. Abbreviata terrapenis in C. lepidus represents an accidental parasite in that "infection" was acquired by the ingestion of lizard prey. Feeding captive snakes on wild-caught lizards poses a risk of introducing nematodes to the snakes.     

Fine structure of adult Litomosoides carinii (Nematoda: Filarioidea)

The fine structure of the body wall and the intestine of male and female Litomosoides carinii was studied in sections through the middle and posterior regions of the worms. In the sublateral cells of the female hypodermis the organelles are arranged in regular layers. The zone with the basal labyrinth is the most prominent layer. The intestinal epithelium of the female worm varies considerably in thickness. The cytoplasm of these cells contains many large droplets. The lateral hypodermal chords of the male worm are very narrow bands. The muscle cells of the male worm are of the circomyarian type, without an afibrillar portion. The intestinal lumen of the male worm is very narrow, and the epithelial cells contain very large droplets. In both sexes the hypodermis contains bacteria. Larger glycogen deposits were absent in the hypodermal chords and in the muscle cells of the midbody regions.     

Linking community assembly and structure across scales in a wild mouse parasite community

Understanding what processes drive community structure is fundamental to ecology. Many wild animals are simultaneously infected by multiple parasite species, so host–parasite communities can be valuable tools for investigating connections between community structures at multiple scales, as each host can be considered a replicate parasite community. Like free‐living communities, within‐host–parasite communities are hierarchical; ecological interactions between hosts and parasites can occur at multiple scales (e.g., host community, host population, parasite community within the host), therefore, both extrinsic and intrinsic processes can determine parasite community structure. We combine analyses of community structure and assembly at both the host population and individual scales using extensive datasets on wild wood mice (Apodemus sylvaticus) and their parasite community. An analysis of parasite community nestedness at the host population scale provided predictions about the order of infection at the individual scale, which were then tested using parasite community assembly data from individual hosts from the same populations. Nestedness analyses revealed parasite communities were significantly more structured than random. However, observed nestedness did not differ from null models in which parasite species abundance was kept constant. We did not find consistency between observed community structure at the host population scale and within‐host order of infection. Multi‐state Markov models of parasite community assembly showed that a host's likelihood of infection with one parasite did not consistently follow previous infection by a different parasite species, suggesting there is not a deterministic order of infection among the species we investigated in wild wood mice. Our results demonstrate that patterns at one scale (i.e., host population) do not reliably predict processes at another scale (i.e., individual host), and that neutral or stochastic processes may be driving the patterns of nestedness observed in these communities. We suggest that experimental approaches that manipulate parasite communities are needed to better link processes at multiple ecological scales.     

Broad infectivity of Leidynema appendiculatum (Nematoda: Oxyurida: Thelastomatidae) parasite of the smokybrown cockroach Periplaneta fuliginosa (Blattodea: Blattidae)

Host specificity of parasites is important for the understanding of evolutionary strategies of parasitism that would be a basis of predictions of the disease expansion when parasitized hosts invade new environments. The nematode order Oxyurida is an interesting parasite group for studying the evolution of parasitism as it includes parasites of both invertebrates and vertebrates. In our survey, we found that the smokybrown cockroach Periplaneta fuliginosa was primarily infected with only one nematode species Leidynema appendiculatum. In two cases, L. appendiculatum was isolated from two additional cockroach species Pycnoscelus surinamensis, sold in Japan as a reptile food, and Blatta lateralis, captured in the field and cultured in the laboratory. Inoculation of L. appendiculatum into three additional cockroach species P. japonica, Blattella nipponica, and P. surinamensis also resulted in parasitism. Infection prevalence was high, and timing of postembryonic development from hatched nematode larva to mature adult in these hosts was identical with that in P. fuliginosa. While ecological interactions strongly determine the host range, such broad infectivity is still possible in this parasitic nematode.