Influence of habitat modification on the community of gastrointestinal helminths of cotton rats.

Dynamics of communities of gastrointestinal helminths of cotton rats (Sigmodon hispidus) were monitored in response to five experimental brush management treatments using herbicide applications with and without prescribed burning on the Cross Timbers Experimental Range in Payne County, Oklahoma (USA). A total of 113 adult cotton rats (68 male and 45 female) was collected from experimental pastures in winter and summer 1986 resulting in the recovery of five species of helminths: Longistriata adunca, Syphacia sigmodontis, Strongyloides sp., Protospirura muris, and Raillietina sp. Prevalences of Raillietina sp. and S. sigmodontis were greater on control than herbicide-treated pastures. Prevalence and abundance of Raillietina sp. and prevalence of S. sigmodontis were significantly lower on annually burned, herbicide-treated pastures compared to unburned herbicide-treated pastures. Triclopyr-treated pastures had greater abundances of L. adunca and lower abundances of Raillietina sp. than those treated with tebuthiuron. Abundances of L. adunca also decreased from winter to summer on annually burned, herbicide-treated pastures while increasing on other pastures. Distribution of all helminths was overdispersed, but distribution of L. adunca showed a significant brush treatment by season interaction as a result of greater overdispersion in summer than winter for cotton rats inhabiting brush-treated pastures. Our results indicate that man-induced habitat modifications can alter host-parasite relationships in the community.     

Systematic position of some nearctic Heligmosomoidea (Nematoda: Trichostrongylina) from the U.S. National Parasite collection and their description

The systematic position of some heligmosomoid nematodes from rodents, deposited in the U.S. National Parasite Collection (USNPC), is revised, mainly through the study of their synlophe, which in all cases was unknown or insufficiently described. The material was registered as different species of Longistriata Schulz, 1926, a genus whose representatives are only parasitic in Holarctic insectivores. Longistriata norvegica Dikmans, 1935, parasitic in Rattus sp. becomes a synonym of Hassalstrongylus aduncus (Chandler, 1932). Specimens registered as Longistriata dalrymplei Dikmans, 1935, from Ondatra zibethicus, are confirmed to belong to Carolinensis (Travassos, 1937). Specimens registered as Longistriata noviberiae Dikmans, 1935, parasitic in Sylvilagus floridanus alacer, were found to belong to Vexillata, and Vexillata noviberiae n. comb. is here proposed. This is the first record of a species of Vexillata in a lagomorph. Other specimens registered as Longistriata norvegica, parasitic in Geomys floridanus austrinus, were also found to be an undescribed species of Vexillata (Hall, 1916), which is named Vexillata chitwoodi n. sp. This is similar to Vexillata chabaudi Yoyotte-Vado, 1972, Vexillata petteri Durette-Desset, 1970, Vexillata scorzai Guerrero, 1984 and Vexillata tejerai Guerrero, 1984, all having the same number of cuticular ridges (4 dorsal, 5 ventral) and the division of the dorsal ray at its apex. The most related species is V. chabaudi, which is differentiated from the new species by rays 4 not curved distally, by thick rays 8, and by a dorsal ray enlarged at the level of the arising of rays 8.     

New species of Oswaldocruzia (Nematoda: Molineoidae), new species of Rhabdias (Nematoda: Rhabdiasidae), and other helminths in Rana cf. forreri (Anura: Ranidae) from Costa Rica

Oswaldocruzia costaricensis n. sp. (Strongylida: Molineidae) from the intestines and Rhabdias savagei n. sp. (Rhabditida: Rhabdiasidae) from the lungs of Rana cf. forreri (Anura: Ranidae) are described and illustrated. Oswaldocruzia costaricensis represents the 77th species assigned to the genus and differs from the other Neotropical species in the genus by possessing a Type II bursa and long cervical alae. Rhabdias savagei represents the 47th species assigned to the genus and differs from other Neotropical species in the genus by possession of 4 lips and a postequatorial vulva. Rana cf. forreri was also found to harbor the trematodes, Haematoloechus parcivitellarius and Megalodiscus temperatus, the nematodes, Aplectana incerta, Aplectana itzocanensis, Cosmocerca podicipinus, Foleyellides striatus, Subulascaris falcaustriformis, and a larva of the nematode Brevimulticaecum sp. Cosmocerca panamaensis is considered to be a synonym of Cosmocerca podicipinus.     

Determinants of helminth infection in a subterranean rodent, the Cape dune mole-rat ( Bathyergus suillus )

The helminth fauna of the largest bathyergid, the Cape mole-rat ( Bathyergus suillus ) was studied throughout an entire calendar year. The species richness encountered was low, with only 3 species of nematodes ( Longistriata bathyergi , Mammalakis macrospiculum, and Trichostrongylus sp.) and 2 species of cestodes ( Taenia sp. and Rodentolepis sp.). At less than 10%, the prevalence for all helminths species was similarly low and may be a result of the solitary lifestyle and the subterranean habitat exploited by this rodent. Clear seasonal patterns were apparent for the most common nematode ( L. bathyergi ), and prevalence and abundance were highest among non-pregnant females compared to males and pregnant females. Dispersal patterns associated with the mating system of the host could explain this pattern. In contrast, the prevalence of the most common cestode ( Taenia sp.) was neither determined by season nor host sex, suggesting that foraging habits may constantly expose B. suillus to this parasite.     

Strongyloidiasis in cotton rats (Sigmodon hispidus) from central Oklahoma

Thirty-one of 40 cotton rats (Sigmodon hispidus) collected from central Oklahoma were infected with Strongyloides sp. (78% prevalence). Larvae of Strongyloides sp. (rhabditiform or filariform) were not demonstrable in intestinal contents and scrapings. Female nematodes recovered from intestinal contents and scrapings had morphological similarities with Strongyloides sigmodontis. Cotton rats infected with Strongyloides sp. were indistinguishable clinically from non-infected hosts. Infected animals had no significant gross lesions, but the presence of Strongyloides sp. in the intestinal mucosa was associated with villus atrophy and mild to moderate infiltration of the lamina propria by lymphocytes, plasma cells and occasional eosinophils. Other organs or tissues examined were free from lesions induced by Strongyloides sp.     

Helminth community structure of the Mediterranean gull (Ichthyaetus melanocephalus) in Southern Italy

The helminth community of the Mediterranean gull (Ichthyaetus melanocephalus) from the Calabria region in southern Italy was examined. Ten species of helminths, including 2 cestodes (Alcataenia larina and Tetrabothrius cylindraceus), 4 digeneans ( Aporchis massiliensis , Brachylaima fuscatum, Cardiocephaloides longicollis, and Ornithobilharzia canaliculata), and 4 nematodes (Eucoleus contortus, Capillaria sp., Cosmocephalus obvelatus, and Paracuaria adunca), were found. The Mediterranean gull represents new host records for A. larina, A. massiliensis, B. fuscatum, and E. contortus; all species, except C. longicollis and O. canaliculata, constitute new locality records. The gastrointestinal helminth community of I. melanocephalus consisted of 9 species but, at the infracommunity level, species richness, diversity, and total helminth abundance are among the lowest reported from any gull species. Two cestode species accounted for 81% of all helminth specimens found.     

Helminth fauna of the yellow-legged gull Larus cachinnans in Galicia, north-west Spain

Thirty-six helminth species were found in 324 gulls examined during June 1994 to February 1996 from different localities of Galicia: 25 trematodes (Brachylaima sp., Brachylecithum microtesticulatum, Cardiocephaloides longicollis, Cryptocotyle lingua, Cryptocotyle concavum, Diplostomum spathaceum, Echinostephilla virgula, Galactosomum phalacrocoracis, Gigantobilharzia acotylea, Gymnophallus deliciosus, Gynaecotyla longiintestinata, Himasthla elongata, Himasthla quissetensis, Knipowitschiatrema nicolai, Levinseniella (Levinseniella) propinqua, Maritrema gratiosum, Maritrema linguilla, Microphallus primas, Microphallus similis, Ornithobilharzia canaliculata, Parorchis acanthus, Phagicola minuta, Psilostomum brevicolle, Renicola sp. and Stephanoprora denticulata), four cestodes (Alcataenia micracantha, Microsomacanthus ductilis, Tetrabothrius (Oriana) erostris and Wardium cirrosa), six nematodes (Anisakis simplex, Contracaecum rudolphii, Cosmocephalus obvelatus), Eucoleus contortus, Paracuaria adunca and Tetrameres (Tetrameres) skrjabini) and one acanthocephalan (Arhythmorhynchus longicollis). Tetrabothrius erostris was the most prevalent species (79.6%), followed by C. obvelatus (47.8%), C. lingua (37.4%), G deliciosus (30.9%), G. longiintestinata (22.8%), P. adunca (21.9%), B. microtesticulatum (17.6%), E. contortus (14.5%) and M. similis (9.3%). Microphallus similis was the dominant species, with a Berger-Parker index (BP) of 0.32, followed by T. erostris (BP=0.10). All species presented an aggregated dispersion except G. acotylea and G. phalacrocoracis, which showed a random dispersion. Species that seem to have the greatest predilection for specific sites along the intestine are: C. longicollis and A. micracantha (first third), Brachylaima sp., M. similis and G. longiintestinata (last third) and A. longicollis (second half). Eight species are known to be pathogenic to commercially important fish or molluscan species and several are pathogenic to humans.     

Helminths parasitizing larval fish from Pantanal, Brazil

Fish larvae of 'corvinas' (Pachyurus bonariensis and Plagioscion ternetzi) from Sinhá Mariana Lagoon, Mato Grosso State, were collected from March 2000 to March 2004, in order to determine the parasitic fauna of fishes. Larvae from the two species were parasitized by the same endoparasites: Contracaecum sp. Type 2 (larvae) (Nematoda: Anisakidae) in the mesentery and Neoechinorhynchus (Neoechinorhynchus) paraguayensis (Acanthocephala: Neoechinorhynchidae) in the stomach and the terminal portion of the intestine. Statistical analysis showed that there was a significant positive correlation between the standard length of hosts and the abundance of acanthocephalans and nematodes, and that the prevalence of nematodes presented a significant positive correlation with the standard length of the two species of hosts, indicating the presence of a cumulative process of infection. The present study constitutes the first record of nematodes and acanthocephalans parasitizing larval fish, as well as the first record of endoparasites in fish larvae in Brazil. In addition, it lists a new locality and two species of hosts for Contracaecum sp. Type 2 (larva) and N. (N.) paraguayensis.     

The Distribution of Tardigrades Upwind and Downwindof a Missouri Coal-Burning Power Plant

Significant differences occurred in the density of tardigrades, rotifers, and nematodes and the diversity of tardigrades between collecting sites located upwind and downwind from a coal-burning power plant in Missouri. The oak tree species and lichen genera also varied in the two areas. Tardigrade and rotifer densities were greater in upwind sites, whereas nematode density was higher in downwind samples. One tardigrade species (Ramazzottius sp.) was found only at the upwind sites, and one species (Echiniscus sp.) was only in the downwind samples. In contrast, three species (Macrobiotus sp., Minibiotus sp., and Milnesium tardigradum) were found both upwind and downwind but in different densities in the two areas. The study presents baseline data for long-term monitoring of the effects of environmental factors on nematode and rotifer densities as well as tardigrade density and diversity.     

悉生培养微缩体系食细菌线虫提高土壤激素含量的机制

研究土壤食细菌线虫与细菌的相互作用及其生态功能是土壤生态学的核心内容之一。食细菌线虫取食细菌可以促进土壤中氮素的矿化,提高氮素养分的供给,改善土壤的营养条件,从而促进植物的生长发育。土壤食细菌线虫促进植物根系生长的"养分作用机制"已得到确认,而"激素作用机制"还存在争议。从供试土壤中筛选获得一株高效产IAA细菌和两种不同cp值的食细菌线虫,通过设置简化的悉生培养系统,对这两种土著食细菌线虫与土著产IAA细菌之间的相互作用,及其对土壤中IAA含量变化的影响进行研究。结果表明:两种食细菌线虫的取食均能促进细菌数量和活性的增强,食细菌线虫与产IAA细菌相互作用也能显著增加土壤中IAA的含量;这些促进作用受到接种食细菌线虫的种类以及培养时间的影响:在培养第10天和第20天时,接种cp值为1的中杆属食细菌线虫显著增加了产IAA细菌的数量;在培养第10天和第30天时,相比较接种cp值为2的头叶属食细菌线虫,接种中杆属食细菌线虫显著提高了土壤中IAA的含量。     

The helminth fauna of the shrew genus Sorex (Insectivora: Soricidae) in the Kandalksha nature reserve

The helminth fauna of shrews (Sores araneus, S. caecutiens, S. minutus, S. minutissimus) from the Karelian coast and islands of the Kandalaksha nature reserve was studied. 18 helminth species belonging to 3 taxonomic groups, Trematoda (3), Cestoda (8), and Nematoda (7) were found. The main body of the helminth fauna of shrews is represented by the nematodes species Longistriata codrus, L. didas, and the cestode species Ditestolepis diaphana. Inhabiting of shrews in the insular localities leads to the decrease of the species diversity and the abundance of their helminths. The distribution ranges of the shrew parasites have been outlined more accurately.     

Metazoan parasites of sticklebacks on Sable Island, Northwest Atlantic Ocean: biogeographic considerations

Three species of sticklebacks ( Apeltes quadracus, Gasterosteus aculeatus , and Pungitius pungitius ( n = 236) were collected from five ponds on Sable Island. The nematodes Pseudoterranova decipiens, Contracaecum sp., Paracuaria adunca , and Cosmucephalus obvelatus , and the cestode Diphyllobothrium ditremum parasitized three-spined sticklebacks ( G. aculeatus ) and four-spined sticklebacks ( A. quadracus ) inhabiting four brackish water ponds. All the parasites except P. decipiens infected nine-spined sticklebacks ( P. pungitius ) from a freshwater pond. In addition, the cestode Schistocephalus pungitii , the copepod Thersitina gasterostei , and the monogenean Gyrodactylus canadensis occurred in nine-spined sticklebacks from the freshwater pond. The two cestodes, the copepod, and the sealworm, P. decipiens , were the most common parasites encountered. The remaining helminths were relatively rare. Most of the parasite species were larval forms which use gulls or seals as definitive hosts. These parasites probably colonized Sable Island with their definitive hosts, whereas only two species ( T. gasterostei and G. canadensis ) successfully colonized the island ponds with their fish hosts. The low parasite species richness encountered is attributed to the impoverished nature of the host fauna of Sable island, and the difficulty of colonization as a result of the island's isolation with respect to the mainland.     

Helminth communities of Nectomys squamipes naturally infected by the exotic trematode Schistosoma mansoni in southeastern Brazil

The water rat Nectomys squamipes is endemic in Brazil and found naturally infected with Schistosoma mansoni. Helminth communities, their prevalences, intensity of infection and abundance in N. squamipes in an endemic area of schistosomiasis in the state of Rio de Janeiro, Brazil were studied. Four species of nematodes (Physaloptera bispiculata, Syphacia venteli, Hassalstrongylus epsilon and Litomosoides chagasfilhoi) were recovered in 85.3%, two trematodes (Schistosoma mansoni and Echinostoma paraensei) in 38.8% and one cestode species (Raillietina sp.) in 1.7% of rats examined. Rats were infected with up to five helminth species each, and these were highly aggregated in distribution. For H. epsilon and S. venteli, intensities and abundances were higher in adult male and subadult female hosts, respectively. Hassaltrongylus epsilon, P. bispiculata, S. venteli and S. mansoni were classified as dominant species, L. chagasfilhoi and E. paraensei as co-dominant and Raillietina sp. as subordinated. No significant correlation was found in the intensity of infecton between each pair of helminth species. Schistosoma mansoni was not related to any other helminth species according to their infection rates, althougth S. mansoni was well established in the natural helminth comunity of the water rat.     

A Trichodorus (Triplonchida: Trichodoridae) Nematode from Thrips (Thysanoptera: Panchaetothripinae)

A thrips insect Caliothrips sp. (Thysanoptera: Panchaetothripinae) from persimmon fruit (Ebenaceae: Diospyros sp.) from an unknown origin, possibly Asia, was intercepted in a passenger bag in November 2012 at the Peace Arch Border Crossing from Canada to Blaine, WA, by a USDA-APHIS-PPQ port inspector. Nematodes were attached to the abdomen of the female insect and sent to us in saline. Seven nematodes (five females, two males) were measured and these and others were processed for permanent slides. An adult female and a female juvenile were prepared for PCR. Morphologically these nematodes belonged to the Trichodorus sparsus group, and the 28S rDNA D2-D3 sequence showed greatest similarity to Trichodorus paragiennensis (94%) and T. giennensis (93%), with greatest morphological similarity to the latter species. Among other morphological differences, the innermost uterus width is wider than in related species. Trichodorus spp. are normally found in soil, so this is the first population seen in the atypical habitat of an insect. Morphological and molecular characteristics of Trichodorus sp. are presented, but a putative new species name is not currently advisable because of relatively poor condition of specimens. Ecological associations are also discussed.     

Evaluation of broad-spectrum anthelmintic activity in a novel assay against Haemonchus contortus, Trichostrongylus colubriformis and T. sigmodontis in the gerbil Meriones unguiculatus

The gerbil Meriones unguiculatus, infected with three species of nematodes, each located in a separate part of the gastrointestinal tract, provided a reliable laboratory assay for the evaluation of broad-spectrum anthelmintic activity. Gerbils harbouring 6-day-old infections of Haemonchus contortus, Trichostrongylus colubriformis and T. sigmodontis were given selected broad-spectrum anthelmintics by gavage. Three benzimidazoles, thiabendazole, oxfendazole and albendazole, a tetrahydropyrimidine, morantel, an imidazothiazole, levamisole hydrochloride, a macrocyclic lactone, ivermectin and an experimental natural product, paraherquamide, were active against all three nematodes at various dosages. Trichostrongylus colubriformis was most sensitive to levamisole hydrochloride, morantel, thiabendazole and paraherquamide whereas ivermectin, oxfendazole and albendazole were more effective against H. contortus. All compounds were active against the caecal nematode T. sigmodontis although it was less sensitive than T. colubriformis. Haemonchus contortus was more sensitive than T. sigmodontis to all anthelmintics tested except thiabendazole.     

Study of types of some species of "Filaria" (Nematoda) parasites of small mammals described by Von Linstow and Molin

Parasitic nematodes from the Berlin (ZMB) and Vienna (NMW) Museum collections referred to the genus Filaria Mueller, 1787 by von Linstow or Molin were studied. Three samples were in good condition and the specimens redescribed. Litomosa hepatica (von Linstow, 1897) n. comb., sample ZMB Vermes Entozoa 3368, from the megachiropteran Pteropus neohibernicus, Bismarck Archipelago, resembles L. maki Tibayrenc, Bain & Ramanchandran, 1979, from Pteropus vampyrus, in Malaysia, but the buccal capsule differs. Both species display particular morphological characters which differ from species of Litomosa parasitic in microchiropterans. The remaining material originates from Brazil. The spicule morphology of Litomosoides circularis (von Linstow, 1899) Chandler, 1931, sample ZMB Vermes Entozoa 1059 from Hesperomys spec. (= Holochilus brasiliensis), Porto Alegre, confirms that it belongs to the sigmodontis group; the microfilaria presents characters of the genus Litomosoides, e.g. body attenuated at both extremities and salient cephalic hook. Taxonomic discussions by others confirm that species of Litomosoides belonging to the sigmodontis group and described subsequently are distinct from L. circularis. Litomosoides serpicula (Molin, 1858) Guerrero, Martin, Gardner & Bain, 2002, is redescribed, sample NMW 6323 from the bat Phyllostoma spiculatum (= Sturnira lilium), Ypanema. It is very close to L. brasiliensis Almeida, 1936, type host Moytis sp., but distinguished by a single ring in the buccal capsule, rather than two, supporting previous conclusions that the taxon L. brasiliensis, as generally regarded, may represent a complex of species. Samples NMW 6322 and NMW 6324, from other bats and also identified by Molin (1858) as Filaria serpicula, contain unidentifiable fragments of Litomosoides incertae sedis. Filaria hyalina von Linstow, 1890, sample ZMB Vermes Entozoa Q 3905 from Sorer vulgaris (= Sorex araneus), is incertae sedis because it contains two unidentifiable posterior parts of male, which might be an acuarid, Stammerinema sp. Filaria vesperuginis von Linstow, 1885, sample ZMB Vermes Entozoa Q 3929, from the bat Vesperugo serotinus (= Eptesicus serotinus), contains encysted nematode larvae and is a nomen dubium.     

Eimeria species (Eucoccidida: Eimeriidae) found in the cotton rat Sigmodon hispidus in Costa Rica]

Cotton rats (Sigmodon hispidus) were collected from Ojo de Agua, Alajuela (N = 74) and Ca?as, Guanacaste (N = 29). Feces had 31 E. sigmodontis, nine E. tuskegeensis, eight E. roperi, three E. webbae and two Eimeria sp. This is the first report of these coccidian parasites for Costa Rica.     

Endemic infections of Parastrongylus (=Angiostrongylus) costaricensis in two species of nonhuman primates, raccoons, and an opossum from Miami, Florida

Parastrongylus (=Angiostrongylus) costaricensis was first reported in the United States from cotton rats, Sigmodon hispidus, in Texas in 1979. Here, we report the findings of P. costaricensis in a siamang (Hylobates syndactylus) from the Miami MetroZoo, in 2 Ma's night monkeys (Aotus nancymaae) from the DuMond Conservancy located at Monkey Jungle in Miami, in 4 raccoons (Procyon lotor) trapped near the MetroZoo, and in an opossum (Didelphis virginiana) trapped at the MetroZoo. These records are the first records of P. costaricensis from all 4 species of hosts. All of the primates were zoo-born, and the raccoons and opossum were native, indicating that this parasite is now endemic at these 2 sites.     

Helminth parasites of unisexual and bisexual whiptail lizards (Teiidae) in North America. I. The Colorado checkered whiptail (Cnemidophorus tesselatus)

Eleven of 27 (41%) parthenogenetic Colorado checkered whiptails (Cnemidophorus tesselatus) from four counties of western and southwestern Texas were infected with one or more helminths. These included a linstowiid cestode (Oochoristica sp.), a larval spirurid nematode (Physaloptera sp.) and two species of oxyurid nematodes (Parathelandros texanus and Pharyngodon warneri). This note, the first in a series of reports on helminths of Cnemidophorus spp., represents the first record of parasites from C. tesselatus.