Pelodera Strongyloides Research Articles

Characterization of a population of Pelodera strongyloides (Nematoda: Rhabditidae) associated with the beetle Lucanus ibericus (Coleoptera: Lucanidae) from Georgia.

During a field survey for entomopathogenic nematodes in Georgia, in the territory of Borjomi-Kharagauli, a nematode population was isolated from the body of single dead beetle of Lucanus ibericus Motschulsky 1845 (Coleoptera: Lucanidae). Based on morphological characters and molecular analyses, the nematode species is identical to Pelodera strongyloides (Schneider, 1860, 1866), being the first record of this species in Georgia. Morphometrics of the Georgian population agree with the original description, and females differ from males by very few characters. The Georgian population of P. strongyloides was molecularly characterized by sequencing the D2 to D3 expansion domains of the 28S rRNA gene and two new molecular markers as the ITS and the mitochondrial COI gene. Phylogenetic analyses revealed that all P. strongyloides sequences grouped together along with all other Pelodera species.

De novo transcriptome assembly of a facultative parasitic nematode Pelodera (syn. Rhabditis) strongyloides

Pelodera strongyloides is a generally free-living gonochoristic facultative nematode. The whole genomic sequence of P. strongyloides remains unknown but 4 small subunit ribosomal RNA (ssrRNA) gene sequences are available. This project launched a de novo transcriptome assembly with 100 bp paired-end RNA-seq reads from normal, starved and wet-plate cultured animals. Trinity assembly tool generated 104,634 transcript contigs with N50 contig being 2195 bp and average contig length at 1103 bp. Transcriptome BLASTX matching results of five nematodes (C. elegans, Strongyloides stercoralis, Necator americanus, Trichuris trichiura, and Pristionchus pacificus) were consistent with their evolutionary relationships. Sixteen genes were identified to be homologous to key elements of the C. elegans RNA interference system, such as Dicer, Argonaute, RNA-dependent RNA polymerase and double strand RNA transport proteins. In starved samples, we observed up-regulation of cuticle related genes and 3 dauer formation genes. Dauer morphology was captured with enlarged phasmid under light microscopy, and dauer and normal larvae counts in clumps had a Pearson's product-moment correlation of 0.805 with P-value = 0.0088. Our results demonstrate that P. strongyloides could be used for studying nematode-related human or pet parasitic diseases. The sequenced assembled transcriptome reported here may be useful to understand the evolution of parasitism in Nematoda.

Pelodera strongyloides as a Cause of Severe Erythematous Dermatitis in 2 Guinea Pigs (Cavia porcellus)

In total, 2 pet guinea pigs (Cavia porcellus) that were 5 years old were presented with pruritus, erythema, alopecia, and crusting of the ventral abdomen. Skin scrapings revealed multiple nematode larvae, identified as Pelodera strongyloides based on morphologic characteristics. Treatment consisted of systemic ivermectin and fenbendazole in addition to topical benzoyl peroxide application. P. strongyloides is a free-living saprophytic nematode, which is ubiquitously present in any decaying organic material, such as soil or feed. The nematode is capable of invading mammalian skin, resulting in pruritic dermatitis. Diagnosis of the nematode induced skin disease is based on history, including husbandry, presence of a ventrally distributed dermatitis, and demonstration of larvae in skin scrapings. Dermal peloderosis cases have been reported in different animal species, including dogs, cattle, horses, sheep, and a laboratory housed guinea pig. This is the first description of P. strongyloides dermatitis in pet guinea pigs. P. strongyloides dermatitis should be considered as a differential diagnosis for alopecic and crusty skin lesions in guinea pigs.

PELODERA STRONGYLOIDESINFECTION IN PACIFIC HARBOR SEALS (PHOCA VITULINA RICHARDII) FROM CALIFORNIA

Skin biopsies were collected from free-ranging harbor seals (Phoca vitulina richardii) from central California (n = 53). Microscopic examination of hematoxylin and eosin-stained tissue sections revealed the presence of tightly coiled nematode larvae within the ostia of numerous hair follicles of four seals. Parasites were characterized by paired lateral alae, platymyarian musculature, and an indistinct, uninucleate digestive tract. Mild chronic superficial dermatitis and perifolliculitis were evident microscopically in association with the intrafollicular parasites. Histomorphologic features of the larvae and their presence within hair follicles are consistent with previous reports of the facultative nematode parasite Pelodera strongyloides. This is the first published report of P. strongyloides infection in any marine mammal. This parasite may be acquired by marine mammals through close contact with soil or decaying organic material and should be considered as a potential differential diagnosis for dermatitis in marine mammals that use terrestrial resting sites.

Mass‐Spectrometric Identification of Anandamide and 2‐Arachidonoylglycerol in Nematodes

The purpose of the study was to see if nematodes (Caenorhabditis elegans, Caenorhabditis briggsae, and Pelodera strongyloides) produce endocannabinoids; i.e., anandamide (AEA) and 2-arachidonoylglycerol (2-AG). In this study, AEA and 2-AG were identified as endogenous products from nematodes by using electrospray-ionization ion-trap MS/MS (ESI-IT-MS) experiments operated in the positive-ionization mode. Endocannabinoids were identified by product ion scan and concentrations were measured by triple quadrupole mass spectrometry in the multiple reaction monitoring mode (MRM). Both AEA and 2-AG were identified in all of the nematode samples, even though these species lack known cannabinoid receptors. Neither AEA nor 2-AG were detected in the fat-3 mutant of C. elegans, which lacks the necessary enzyme to produce arachidonic acid, the fatty acid precursor of these endocannabinoids.

Sarcoptic Mange and Pelodera Dermatitis in an American Black bear (Ursus americanus)

An adult female free-ranging American black bear (Ursus americanus) was presented in poor body condition, with advanced skin disease. Skin changes included hair loss, lichenification, crusting, and focal erosions. Skin scrapings and histopathology identified two distinct parasitic conditions that were contributing to this animal's dermatitis. Large numbers of larvae, nymphs, and adults of Sarcoptes scabiei were present in the superficial epidermis, and nematodes consistent with Pelodera strongyloides were abundant within the hair follicles. This appears to be the first reported case of Pelodera dermatitis in a bear species, adding a new differential agent to the list for dermatitis in bears. The sarcoptic mange and poor body condition of this bear may have been contributing factors to the development of the opportunistic Pelodera infestation.

Parasites of two abundant sympatric rodent species in relation to host phylogeny and ecology

In the present study, two abundant sympatric rodent species (27 Apodemus flavicollis and 33 A. sylvaticus) were studied for their endo- and ectoparasite fauna. The rodents were trapped in Dormagen, a city in North Rhine-Westphalia, Germany. A total of 20 different parasites species were identified, 13 endoparasite (2 Digenea, 5 Cestoda and 7 Nematoda) and 7 ectoparasite (5 Insecta and 2 Arachnida) species. Thirteen parasite species were found inhabiting both rodent species. The predominant endoparasite species in both rodents was the nematode Pelodera strongyloides, followed by the nematode Heligmosomoides polygyrus and a Syphacia species. The flea Ctenophthalmus agyrtes was the dominant ectoparasite in both rodent species. A. flavicollis usually carried 1-7 ecto-/endoparasite species (mean 4.0), whereas A. sylvaticus were mostly infested with 1-9 (mean 4.4). The parasite diversity of A. flavicollis (H' = 0.268, J = 0.097) was marginal lower in comparison to A. sylvaticus (H' = 0.319, J = 0.110). The two rodent species examined show remarkable similarities in the composition of their endo- and ectoparasite fauna being directly related to their similar pattern of living in the investigated area.

Pelodera (syn. Rhabditis) strongyloides as a cause of dermatitis – a report of 11 dogs from Finland

BackgroundPelodera (Rhabditis) strongyloides is a small saprophytic nematode that lives in decaying organic matter. On rare occasions, it can invade the mammalian skin, causing a pruritic, erythematous, alopecic and crusting dermatitis on skin sites that come into contact with the ground. Diagnosis of the disease is based on case history (a dog living outdoors on damp straw bedding) with characteristic skin lesions and on the demonstration of typical larvae in skin scrapings or biopsy. Pelodera (rhabditic) dermatitis cases have been reported mainly from Central European countries and the United States.Case presentationDuring 1975–1999, we verified 11 canine cases of Pelodera dermatitis in Finland. The cases were confirmed by identifying Pelodera larvae in scrapings. Biopsies for histopathology were obtained from three cases, and typical histopathological lesions (epidermal hyperplasia, epidermal and follicular hyperkeratosis, folliculitis and furunculosis with large numbers of nematode larvae of 25–40 μm of diameter within hair follicles) were present. The Pelodera strongyloides dermatitica strain from the first verified case in Finland has been maintained in ordinary blood agar in our laboratory since 1975. Light microscopy (LM) and scanning electron microscopy (SEM) studies were employed to obtain detailed morphological information about the causative agent. The rhabditiform oesophagus at all developmental stages, the morphology of the anterior end of the nematode, copulatory bursa and spicules of the male and the tail of the female were the most important morphological features for identifying P. strongyloides.ConclusionThese cases show that Pelodera dermatitis occurs in Finland, and also farther north than described earlier in the literature. This condition should be considered when a dog living outdoors has typical skin lesions situated at sites in contact with the ground as the main presenting clinical feature. The fastest and easiest way to confirm the diagnosis is to demonstrate typical larvae in skin scrapings. In uncertain cases, skin biopsy and culturing of the worms are recommended as supplementary diagnostic procedures.

Dermatitis in a Dairy Herd Caused by Pelodera strongyloides (Nematoda: Rhabditidae)

A high rate (25%) of infestation of heifers in a dairy cattle herd caused by the saprophytic nematode Pelodera strongyloides is described. Management (crowded) and environmental conditions (moist and filthy) as well as the climate (temperature) apparently favoured the existence and continuation of the nematodes. These infested a large number of heifers by causing dermatitis in skin areas, which were in contact with the contaminated environment. The dermatitis is characterized by a marked thickening of the skin, which became wrinkled and scurfy with alopecia. Pruritus was not observed.

Pelodera strongyloides infestation presenting as pruritic dermatitis

Pelodera strongyloides is a free-living soil nematode of the order Rhabditida. We report an 18-year-old man with P strongyloides skin infestation. In this case, pruritic follicular papulopustules developed on the buttocks, then the right flank. Skin scrapings revealed many live rhabditiform larvae that were cultured adult worms and hatched ova, identified as P strongyloides . The eruption was treated effectively with topical 1% gamma-hexachlorocyclohexane ointment.

Helminth infections inApodemus sylvaticusin southern England: interactive effects of host age, sex and year on the prevalence and abundance of infections

Helminth parasites were studied in the wood mouse, Apodemus sylvaticus, in southern England in September of each of four successive years (1994-1997). Nine species of helminths were recorded: five nematodes (Heligmosomoides polygyrus, Syphacia stroma, Pelodera strongyloides, Trichuris muris, Capillaria murissylvatici), two cestodes (Microsomacanthus crenata, Taenia taeniaeformis) and two trematodes (Corrigia vitta, Brachylaemus recurvum). In total, 134 mice were examined and 91.8% carried at least one species of helminth. The majority of mice carried two to three species (60.5%) and the highest combination was six of the nine species recorded in the study. The patterns of between-year variations in the prevalence and abundance of infection were different for each of the six species for which sufficient quantitative data were available to enable statistical analysis. For H. polygyrus, the most important source of variation arose from between-year differences, host age and the interaction of these factors: abundance increased with host age but in 1995 the age pattern was markedly different from that in the remaining years. The abundance of C. vitta also varied significantly between years but additionally there was a strong independent age effect. For M. crenata, the year x age interaction was significant, indicating that abundance among different age cohorts varied from year to year but there was also a weak significant main effect of age arising from the youngest age cohort carrying no parasites and the oldest age cohort the heaviest infections. For P. strongyloides the only significant factor was between-year variation with 1995 being a year of exceptionally low prevalence and abundance of infection. No significant between-year variation was detected for S. stroma but there was a strong sex effect (males carrying heavier infections) and an age effect (older mice of both sexes carrying heavier infections). The abundance of Trichuris muris varied only in relation to host age, worm burdens growing in intensity with increasing age, but there was also a significant interaction between year and host sex with respect to prevalence. For the remaining three species, the prevalence of infections was too low (< 8.2%) to enable any meaningful interpretation. This analysis emphasizes the need for carefully controlled statistical procedures in aiding the interpretation and the prioritization of the factors affecting worm burdens in wild rodents.

Helminth infections in Apodemus sylvaticus in southern England: interactive effects of host age, sex and year on the prevalence and abundance of infections

Helminth parasites were studied in the wood mouse, Apodemus sylvaticus, in southern England in September of each of four successive years (1994–1997). Nine species of helminths were recorded: five nematodes (Heligmosomoides polygyrus, Syphacia stroma, Pelodera strongyloides, Trichuris muris, Capillaria murissylvatici), two cestodes (Microsomacanthus crenata, Taenia taeniaeformis) and two trematodes (Corrigia vitta, Brachylaemus recurvum). In total, 134 mice were examined and 91.8% carried at least one species of helminth. The majority of mice carried two to three species (60.5%) and the highest combination was six of the nine species recorded in the study. The patterns of between-year variations in the prevalence and abundance of infection were different for each of the six species for which sufficient quantitative data were available to enable statistical analysis. For H. polygyrus, the most important source of variation arose from between-year differences, host age and the interaction of these factors: abundance increased with host age but in 1995 the age pattern was markedly different from that in the remaining years. The abundance of C. vitta also varied significantly between years but additionally there was a strong independent age effect. For M. crenata, the year × age interaction was significant, indicating that abundance among different age cohorts varied from year to year but there was also a weak significant main effect of age arising from the youngest age cohort carrying no parasites and the oldest age cohort the heaviest infections. For P. strongyloides the only significant factor was between-year variation with 1995 being a year of exceptionally low prevalence and abundance of infection. No significant between-year variation was detected for S. stroma but there was a strong sex effect (males carrying heavier infections) and an age effect (older mice of both sexes carrying heavier infections). The abundance of Trichuris muris varied only in relation to host age, worm burdens growing in intensity with increasing age, but there was also a significant interaction between year and host sex with respect to prevalence. For the remaining three species, the prevalence of infections was too low (&lt; 8.2%) to enable any meaningful interpretation. This analysis emphasizes the need for carefully controlled statistical procedures in aiding the interpretation and the prioritization of the factors affecting worm burdens in wild rodents.

First record of the larval parasitic nematode Rhabditis orbitalis from Japanese wood mice (Apodemus spp.)

Parasitic larvae of Rhabditis orbitalis (formerly confused with Pelodera strongyloides) were found in the conjunctival sacs of the eyes of Apodemus argenteus and A. speciosus from Japanese islands.

Association between Pelodera strongyloides (Nematoda: Rhabditidae) and wood mice, Apodemus sylvaticus.

Pelodera strongyloides larvae were found in the conjunctival sacs of Apodemus sylvaticus and Clethrionomys glareolus and in hair follicles of A. sylvaticus. Those in the eyes were 3rd-stage larvae while most of those in the dermis were early 4th stages. There was no evidence of pathology and sections of the skin showed that the nematodes of freshly killed mice and moulted once to the adult stage in 1-2 days at 15 degrees C. The stimulus to resume development appeared to be a reduction in temperature rather than presence of bacterial food or reduction in osmotic pressure. Countless generations ensued on nutrient agar provided the nematodes were periodically sub-cultured onto fresh agar. Nematodes from the eyes died in culture. Dauerlarvae of P. strongyloides were produced in exhausted cultures. They resumed development on fresh agar but not in distilled water. About half could be induced to exsheath by a temperature similar to that of mouse skin. A. sylvaticus probably accumulates nematode larvae in the dermis during its life and the nematodes resume development when the host dies.

Development of Pelodera strongyloides (Schneider, 1860) Schneider, 1866 (Nematoda: Rhabditidae) in culture.

Dauerlarvae of Pelodera strongyloides, recovered from two species of lemmings, Dicrostonyx groenlandicus (Traill) and Lemmus trimucronatus (Richardson) trapped at Eskimo Point, N.W.T, were cultured on agar medium with E. coli. Development from egg to adult stage was followed. Eggs hatched between 22 and 26 hours at 22 degrees C. The first moult occurred 24 to 28 hours after the eggs hatched, the second at 40 to 48 hours, the third at 60 to 64 hours and the fourth at 84 to 88 hours at 22 degrees C. Adults lived approximately 5 to 6 days and females oviposited for 2 to 3 days during this time. All stages were measured and described. The effect of temperature on development was examined. Dauerlarvae survived freezing temperatures, short periods of desiccation and prolonged periods without food.

Dauerlarvae of Pelodera strongyloides (Schneider, 1860) (Nematoda: Rhabditidae) in the conjunctival sacs of lemmings

Dauerlarvae of Pelodera strongyloides (Schneider, 1860) Schneider, 1866 were found for the first time in the conjunctival sacs of Dicrostonyx groenlandicus (Traill) and Lemmus trimucronatus (Richardson). Prevalence of dauerlarvae was significantly higher in D. groenlandicus than in L. trimucronatus. The larvae were cultured and populations of P. strongyloides were obtained. Dauerlarvae obtained from the cultures were transmitted to various rodents in the laboratory. Larvae remained in the conjunctival sac for a maximum of 5 days. They had no apparent effect on rodents and were not morphologically different from those reared on agar.

Development of Caenorhabditis briggsae and Hymenolepis nana in Interchanged Media

Chemically defined media supplemented with proteinaceous growth factors have been developed independently for axenic culture of Caenorhabditis briggsae and Hymenolepis nana. The chemical compositions of the media and characteristics of the growth factors are compared. Either growth factor was found to be an effective supplement for each organism. The chemically defined portions of the media can be interchanged if suitable adjustments are made in the salts and buffers. It therefore appears possible to develop a single basal medium for both types of organism, and to use the convenience of the C. briggsae bioassay for further isolation and the characterization of growth factors for helminths. Media have been developed independently to meet the culture requirements of free-living and of parasitic helminths. These media consist of chemically defined components supplemented with partially characterized proteinaceous materials. The chemically defined medium designed for culture of Caenorhabditis briggsae has been used with or without minor modifications for the continuous culture of several species of free-living nematodes (Hansen and Cryan, 1966), in culture of Pelodera strongyloides (Yarwood and Hansen, 1968), and for the insect parasite Neoaplectana carpocapsae (Hansen et al., 1968) and the plant parasite Aphelenchoides sp. (Myers, 1968). It seemed possible that it could be used for an even wider range of species. It was, for example, used as a supporting medium for Haemonchus contortus for production of antigen (Silverman, Alger, and Hansen, 1966). The chemically defined medium designed for culture of Hymenolepis nana has been used for two other species of Hymenolepis, and for Spirometra mansonoides, Trichinella spiralis (Bemtzen, 1966), and Mesocestoides corti (Voge and Coulombe, 1966; Hart, 1968). The objective of this work was to arrive at a chemically defined medium which would be suitable for the culture of both parasitic and free-living organisms. For the comparisons described in this paper the species used were those for which the respective media were designed, i.e., C. briggsae and H. nana. It might be possible to use the simpler assay Received for publication 10 January 1969. system with a free-living organism to assess the effectiveness of supplements used in the more complex parasitic system. MATERIALS AND METHODS The methods used for cultivation of C. briggsae and H. nana under axenic conditions have been described in detail (Dougherty et al., 1959; Berntzen, 1966). For assay with C. briggsae, 3 newly hatched larvae were inoclulated into duplicate aliquots of 0.25 ml of medium, incubated at 20 C under air, and the Fi time, required for new larvae to appear was determined (Lower, Hansen, and Yarwood, 1966). For H. nana, evaluation of media was carried out under experimental conditions designed to achieve optimum comparison with control medium in each test. Portions of 4, 10, or 100 ml of medium were used. These were gently agitated by aspiration or rotation to facilitate gas exchange. Some experiments were carried out with continuous flow or periodic flow of medium (Berntzen, 1965, 1966). The gaseous environment was 5 or 10% carbon dioxide, and 5, 10, or 15% oxygen in nitrogen; the ratio 10:5:85 was used in most experiments. Axenized cysticercoids were inoculated, 2 per ml of medium. Response was determined by their increase in length and accompanying degree of differentiation of the proglottids and formation of ova. The time of appearance of the internal structures in the proglottids was determined as previously described (Berntzen, 1966). Worms in some culture media showed comparable organ formation even though they did not achieve the same length. Therefore, relative length was used to compare the media of differing composition shown in Table III. In all these cultures developed eggs were observed. The 2 chemically defined media used in this study were C. briggsae Maintenance Medium, designated as CbMM (Buecher et al., 1966) and medium 115, designated as M-115 (Berntzen and Mueller, 1964). Their components are listed in Table I.

Axenic Culture of Pelodera strongyloides Schneider

The dioecious nematode Pelodera strongyloides has been established in axenic culture. It has been maintained by serial subculture in films of nutrient media on agar and by continuous culture in media on glass fibers. Cultures cannot be maintained in deep media in test tubes, the adults being unable to mate without a suitable physical substrate. In axenic culture the optimal incubation temperature was 23 to 25 C; reproduction ceased at 33 C, and only dauer larvae survived 37 C. Axenic culture of Pelodera strongyloides Schneider, 1866 (Dougherty, 1953) in liquid medium was undertaken with the purpose of establishing cultures at 37 C, so that nutritional requirements at this temperature could be investigated. The possibility of culturing this nematode at 37 C was suggested by its xenic environment, bovine skin pustules (Levine et al., 1950). MATERIALS AND METHODS Pelodera strongyloides was obtained as a culture with mixed flora on blood agar from Dr. Norman Levine who had isolated it from bovine dermatitis. Culture media used were those developed for nutritional studies of Caenorhabditis briggsae: A. A basal medium of soy peptone and yeast extract, each at 3 g/100 ml, supplemented with heated liver extract at 20% by volume (Cryan et al., 1963), referred to hereafter as liver-peptone-yeast medium. B. A chemically basal medium supplemented with growth factor at 250 gug/ml and containing 8.2% Ficoll (Buecher et al., 1966), referred to hereafter as defined medium. C. A chemically basal medium supplemented with heated liver extract at 20% by volume. In initial tests, as indicated below, lower levels of supplement were used, i.e., 10% heated liver extract or 100 gug/ml growth factor. The media were used in 0.25-mi aliquots in 10by 75-mm test tubes, as a film on nutrient agar (Difco) slants in 16by 150-mm test tubes, or as a film on glass fibers in continuous culture vessels (Hansen and Cryan, 1966). Cultures were also carried on nutrient agar slants holding pieces of sterile rabbit kidney (Stoll, 1959). Transfers of individual eggs, larvae or adults were made by micropipette in a sterile chamber with the aid of a dissecting microscope. Axenization was initially carried out with a preparation of 10,000-unit penicillin and 1% streptomycin. AntiReceived for publication 11 October 1967. * Supported by NIH Grant AI 07359, formerly Al 00926. biotics were not added to culture media used subsequently. As a step toward axenization, a monoxenic culture with Escherichia coli was established. Loop transfers were made from the original xenic culture to nutrient agar slants preincubated for 2 hr with a film of inoculum from a broth culture of E. coli. After 12 days at room temperature, these cultures were transferred by loop to sterile nutrient agar slants and subcultured again 3 days later. Scrapings from the second subculture at 5 days were placed in antibiotic mixture in a BPI dish; adults and eggs were then removed to a second dish of antibiotics. The next day eggs and newly hatched larvae were removed to 0.066 Mi potassium phosphate buffer, pH 7, allowed to settle, and transferred by pipette to a nutrient agar slant inoculated with E. coli and preincubated at 37 C for 30 min. The culture was kept in a room where the temperature ranged 15.5 to 18 C. New larvae appeared on the 8th day. At 3 weeks a broth culture inoculated from this slant and streaked on agar showed no growth other than E. coli. This monoxenic culture has been maintained for 2 years by loop transfers at 3to 4-week intervals. It provided the source of worms for successful axenization.