Differences within Churra breed sheep in the early immune response to the infection by Teladorsagia circumcincta

This study describes early immunological mechanisms that underlie resistance to Teladorsagia circumcincta infection in adult Churra sheep. After a first experimental infection, 6 animals were classified as resistant (RG) and 6 as susceptible (SG) to T. circumcincta infection based on their cumulative faecal egg count (cFEC) at the end of the infection. RG showed higher IgA levels against somatic antigen of T. circumcincta fourth-larvae stage (L4) in serum at day 3 post-infection (pi) (p < 0.05) and close to significance at day 21 pi (p = 0.06). Moreover, a strong negative correlation between cFEC and specific IgA was only significant in RG at day 3 pi (r = - 0.870; p < 0.05), but absent in SG. At the end of this infection, sheep were treated with moxidectin and infected again 3 weeks later to be slaughtered at day 7 pi. At necropsy, the specific IgA levels in gastric mucosa were similar between groups; the absence differences at day 7 pi could be due to a previous increase in the IgA response, probably around day 3 pi, as described during the first infection. L4 burden, 68% lower in RG than in SG, was influenced by the specific IgA in gastric mucus and the number of γδ T cells. RG group showed a positive correlation between γδ T cells and eosinophils (r = 0.900; p = 0.037); however, this correlation was not found in SG. These results show that these two phenotypes show different early immune response pattern to T. circumcincta infection in Churra sheep.

Genotypic characterisation of monepantel resistance in historical and newly derived field strains of Teladorsagia circumcincta

Recent reports of monepantel (MPTL) resistance in UK field isolates of Teladorsagia circumcincta has highlighted the need for a better understanding of the mechanism of MPTL-resistance in order to preserve its anthelmintic efficacy in this economically important species. Nine discrete populations of T. circumcincta were genotypically characterised; three MPTL-susceptible isolates, three experimentally selected MPTL-resistant strains and three field derived populations. Full-length Tci-mptl-1 gene sequences were generated and comparisons between the MPTL-susceptible isolates, MPTL-resistant strains and one field isolate, showed that different putative MPTL-resistance conferring mutations were present in different resistant isolates. Truncated forms of the Tci-mptl-1 gene were also observed. The genetic variability of individual larvae, within and between populations, was examined using microsatellite analyses at 10 'neutral' loci (presumed to be unaffected by MPTL). Results confirmed that there was little background genetic variation between the populations, global FST <0.038. Polymorphisms present in exons 7 and 8 of Tci-mptl-1 enabled genotyping of individual larvae. A reduction in the number of genotypes was observed in all MPTL-resistant strains compared to the MPTL-susceptible strains that they were derived from, suggesting there was purifying selection at Tci-mptl-1 as a result of MPTL-treatment. The potential link between benzimidazole (BZ)-resistance and MPTL-resistance was examined by screening individual larvae for the presence of three SNPs associated with BZ-resistance in the β-tubulin isotype-1 gene. The majority of larvae were BZ-susceptible homozygotes at positions 167 and 198. Increased heterozygosity at position 200 was observed in the MPTL-resistant strains compared to their respective MPTL-susceptible population. There was no decrease in the occurrence of BZ-resistant genotypes in larvae from each population. These differences, in light of the purifying selection at this locus in all MPTL-resistant isolates, suggests that Tci-mptl-1 confers MPTL-resistance in T. circumcincta, as in Haemonchus contortus, but that different mutations in Tci-mptl-1 can confer resistance in different populations.

A New Species of Bidigiticauda (Nematoda: Strongylida) from the Bat Artibeus Planirostris (Chiroptera: Phyllostomidae) in the Atlantic Forest and a Molecular Phylogeny of the Molineid Bat Parasites

The nematode genus Bidigiticauda has 2 species (Bidigiticauda vivipara and Bidigiticauda embryophilum), which are parasites of bats from the Neotropical region. The present paper describes a new species of Bidigiticauda from a male Artibeus planirostris specimen collected in the Pratigi Environmental Protection Area in Bahia state, Brazil. The new species, Bidigiticauda serrafreirei n. sp., differs from B. embryophilum by having longer spicules, rays 5 and 6 arising from a common trunk and bifurcating in its first third, rays 3 and 4 emerging slightly separated from each other, and dorsal rays reaching the margin of the caudal bursa. The new species also differs from B. vivipara by the dorsal ray bifurcating at the extremity of the trunk. A molecular phylogenetic analysis was conducted to determine the evolutionary affinities of Bidigiticauda serrafreirei n. sp. within the Strongylida, which identified a clade that grouped Bidigiticauda with the other members of the Anoplostrongylinae. However, the molineid subfamilies did not group together, indicating that the family Molineidae is polyphyletic. Further analyses, which include additional taxa and genetic markers, should elucidate the complex relationships within the Molineidae, in particular its subfamilies and the evolution of the traits that define these groups.

Adaptations and phenotypic plasticity in developmental traits of Marshallagia marshalli

Despite the economic, social and ecological importance of the ostertagiine abomasal nematode Marshallagia marshalli, little is known about its life history traits and its adaptations to cope with environmental extremes. Conserved species-specific traits can act as exaptations that may enhance parasite fitness in changing environments. Using a series of experiments, we revealed several unique adaptations of the free-living stages of M. marshalli that differ from other ostertagiines. Eggs were isolated from the feces of bighorn sheep (Ovis canadensis) from the Canadian Rocky Mountains and were cultured at different temperatures and with different media. Hatching occurred primarily as L1s in an advanced stage of development, morphologically very similar to a L2. When cultured at 20 °C, however, 2.86% of eggs hatched as L3, with this phenomenon being significantly more common at higher temperatures, peaking at 30 °C with 28.95% of eggs hatching as L3s. After hatching, free-living larvae of M. marshalli did not feed nor grow as they matured from L1 to infective L3. These life history traits seem to be adaptations to cope with the extreme environmental conditions that Marshallagia faces across its extensive latitudinal distribution in North America and Eurasia. In order to refine the predictions of parasite dynamics under scenarios of a changing climate, basic life history traits and temperature-dependent phenotypic behaviour should be incorporated into models for parasite biology.

Zygocaulus nagoensis n. gen. and n. sp. (Trichostrongyloidea: Dictyocaulidae), a Peculiar Bursate Nematode Collected from an Alien Frog, Polypedates leucomystax, in Nago, Okinawa Island, Japan

A peculiar bursate nematode, Zygocaulus nagoensis n. gen. and n. sp. (Trichostrongyloidea: Dictyocaulidae: Mertensinematinae), was described from an alien frog, Polypedates leucomystax (Anura: Rhacophoridae), collected on Okinawa Island, Japan. It is related to Mertensinema and Borrellostrongylus, the only hitherto known genera of Mertensinematinae, but is readily distinguished from them by having only 2 pairs of lateral rays and simple distal ends of the dorsal ray branches.

Molecular marker sequences of cattle Cooperia species identify Cooperia spatulata as a morphotype of Cooperia punctata

The genus Cooperia includes important parasites of ruminants and currently contains 34 accepted species. However, even for those species infecting livestock, there is a considerable lack of molecular information and many species are only identifiable using subtle morphological traits. The present study aimed to provide molecular data to allow diagnosis of Cooperia species infecting cattle. Partial sequences of two mitochondrial (cytochrome oxidase 2, 12S rRNA gene) and two nuclear genes (isotype 1 β tubulin gene including two introns, internal transcribed spacers (ITS) were obtained from morphologically identified specimens of Cooperia pectinata, Cooperia punctata and Cooperia spatulata as well as from larvae of pure Cooperia oncophora and C. punctata laboratory isolates. Pairwise identity of ITS-2 sequences was very high and it was the only region able to identify a specimen as Cooperia sp. However, the ITS-2 was unreliable for diagnosis at the species level. All other marker sequences could not unequivocally be allocated to the genus Cooperia but allowed clear species identification with the exception of the pair C. punctata/C. spatulata for which no significant differences were found for any marker sequence. Maximum-likelihood phylogenetic analyses of individual genes as well as a multi-locus analysis covering all four sequences confirmed that specimen identified as C. spatulata were randomly distributed throughout the C. punctata cluster and formed no group of their own. In contrast, the other Cooperia species formed clearly separated and statistically supported clusters. These data indicate that C. spatulata is most likely only a morphotype of C. punctata and the name should be considered a synonym. Combinations of nuclear and mitochondrial markers should be used to identify morphotypes or cryptic species to benefit from excellent barcoding properties of the latter but allowing proper phylogenetic analyses and controlling for lineage sorting that might occur for mitochondrial genotypes within a species.

Expansion of Ashworthius sidemi in red deer and roe deer from the Lower Silesian Wilderness and its impact on infection with other gastrointestinal nematodes

Nematodes Ashworthius sidemi are typical parasites of Asiatic cervids, mostly sika deer (Cervus nippon). Migrating red deer have probably introduced this parasite to the area of Poland from neighbouring countries. The aim of the study was to determine prevalence and intensity of infection of red deer and roe deer from the Lower Silesian Wilderness with A. sidemi after one year from previous studies and to examine the influence of these parasites on other species of gastrointestinal nematodes. 31 abomasa of red deer and 3 abomasa of roe deer from Forest Dictrict of Ruszów have been examined on the presence of parasites. In comparison with previous studies, red deer showed significant, over triple increase of prevalence of A. sidemi and over fivefold increase of mean intensity of infection. Maximum intensity of infection has increased over 24 times. These results indicate on dynamic spread of this new aswortiosis foci. Apart from previously registered parasite species, four new nematodes have been found in examined red deer and roe deer during this year studies. Red deer have been infected with Spiculopteragia assymmetrica, typical for fallow deer and Haemonchus placei - typical for bovine, whereas roe deer have been infected with Trichostrongylus axei and Trichostrongylus capricola, parasites of sheep, goats and bovine. Prevalence of red deer infection with nematodes S. boehmi and Ostertagia leptospicularis was lower than two years ago while prevalence of infection with S. mathevossiani and O. kolchida was higher. Intensity of infection with these nematodes has increased.

Guerrerostrongylus marginalis n. sp. (Trichostrongyloidea: Heligmonellidae) from the Guianan arboreal mouse (Oecomys auyantepui) from French Guiana

Based on the number and arrangement of cuticular ridges and configuration of the dorsal ray, nematode specimens collected from the small intestine of eight Guianan arboreal mice, Oecomys auyantepui (Rodentia: Sigmodontinae), in French Guiana are herein described and characterized. Guerrerostrongylus marginalis n. sp. (Heligmosomoidea: Heligmonellidae) shows a synlophe consisting of more than 40 ridges and a unique bursal arrangement with ray 8 (externo-dorsal) extending to the edge of the bursal margin, and appearing more prominent than the dorsal ray. This bursal arrangement is common in members of Hassalstrongylus Durette-Desset, 1971, but uncommon in the other four species in Guerrerostrongylus Sutton & Durette-Desset, 1991. The placement of the new species in Guerrerostrongylus is based on the number and nature of cuticular ridges and the ray arrangement and symmetry of the caudal bursa. Diagnostic characteristics of Guerrerostrongylus marginalis n. sp. include the length of ray 8 relative to bursal margin, the relative size of the spicules and vestibule, and the number of eggs in the uterus. We propose an amendment to the generic diagnosis of Guerrerostrongylus to modify the characters of the long rays 6 (postero-lateral), rays 8 (externo-dorsal), and dorsal ray as diagnostic, since at least ray 6 appears to be short in two different species in the genus, namely G. ulysi Digiani, Notarnicola & Navone, 2012 and G. marginalis n. sp.

A new species of Torrestrongylus (Trichostrongylidae, Anoplostrongylinae) from Macrotus waterhousii (Chiroptera: Phyllostomidae) in Central Mexico

A new species of nematode, Torrestrongylus tetradorsalis n. sp., is described herein, based on specimens recovered from the small intestine of the leaf-nosed bat, Macrotus waterhousii, from the Biosphere Reserve "Sierra de Huautla" in the state of Morelos, Mexico. The new species is included in Torrestrongylus because it features a bursa of the type 3 - 2, a divided cephalic vesicle with an anterior half in the shape of an umbrella, and a posterior widened half. The new species can be distinguished from the only other congener T. torrei Pérez-Vigueras, 1935 by four key features: first, by the absence of cervical alae in both males and females; second, by the relatively longer second half of the cephalic cap; third, by the configuration of the dorsal ray, that does not have a medial terminal ray, and finally, by the structure of the spicules. This is the second species in the genus, previously known from bats of the families Phyllostomidae and Molossidae in Cuba, and now in Mexico.

Phylogeography analysis and molecular evolution patterns of the nematode parasite Heligmosomum mixtum based on mitochondrial DNA sequences

Mitochondrial DNA was explored to study phylogeography of the nematode parasite Heligmosomum mixtum and elucidate molecular evolution pattern of cytochrome b gene. The size of cyt b gene ranged from 511 bp to 591 bp and the average of GC contents was 28.9%. The overall transition/transversion ratio R was 5.773 indicating that the transitions are more frequent than transversion. The aligned sequences allowed identifying 54 mtDNA haplotypes among the 119 examined individuals. The genetic divergence registered among the populations of H. mixtum was low (0.3% to 1.5%). Neighbor-joining and maximum Likelihood trees evidenced a huge polytomy and unstructured phylogeographic pattern among the studied populations. The demographic analyses tend to evidence a recent and rapid expansion of H. mixtum. Our results imply a positive selection and the genetic hitchhiking effect is unlikely. Parameters performed supported scenario of sweep selection and recent expansion of H.mixtum populations. Both positive selection and demographic histories have jointly contributed to the observed patterns of nucleotide diversity and haplotypes structure. The comparison of the phylogeographical pattern of H. mixtum with the one of its most common rodent host M. glareolus, confirmed a strong incongruence between the two species. These results strongly suggest that the parasite would not be specific to M. glareolus and that it would switch easily from one rodent species to another. The mitochondrial diversity seems to be unstructured with any biogeographic repartition of the variability and that the genetic structure of H. mixtum is probably associated with weak host specificity.

The caudal bursa in the Heligmonellidae (Nematoda: Trichostrongylina). Characterization and hypothesis on its evolution

The different patterns of the caudal bursa of the Heligmonellidae (Nematoda) are redefined, taking into account the grouping of rays 2-6 and the sequence of origin of these rays from their common trunk. The type of symmetry of the caudal bursa is also redefined. The following patterns were observed and characterized: the basic patterns: types 2-3, 2-2-1, 1-3-1 and 1-4 and the intermediary patterns: type 2-3 tending to type 2-2-1, type 2-2-1 tending to type 1-3-1, type 1-3-1 tending to type 1-4 and type 2-2-1 tending to type 1-4. An evolutionary interpretation of the patterns is attempted and seems to follow the direction: 2-3 to 2-2-1 to 1-3-1 to 1-4. Seven atypical patterns are described. The caudal bursae were classified based on their symmetry: subsymmetrical, dissymmetrical and asymmetrical. Independently of the type of symmetry, the two latero-ventral lobes may have the same or different patterns. The type of symmetry, the ratio between the two latero-ventral lobes and a characteristic pattern were utilized to characterize the caudal bursae at the level of the genus and the subfamily. The combination of the right/left ratio and the type of symmetry gives heterogeneous results, with no real association between these characters. The most conspicuous asymmetries and dissymmetries were found among the Nippostrongylinae. The most frequent pattern in the Heligmonellidae is the basic type 2-2-1; types 1-3-1 and 1-4 are less frequent but are characteristic of several genera; type 1-4 is absent from the Heligmonellinae. Whatever the pattern, in the Heligmonellidae rays 4 and 5 are the last to diverge from the common trunk of rays 2-6.

Phylogenetic relationships of three species within the family Heligmonellidae (Nematoda; Heligmosomoidea) from Japanese rodents and a lagomorph based on the sequences of ribosomal DNA internal transcribed spacers, ITS-1 and ITS-2

Nematodes of the family Heligmonellidae (Heligmosomoidea; Trichostrongylina) reside in the digestive tracts of rodents and lagomorphs. Although this family contains large numbers of genera and species, genetic information on the Heligmonellidae is very limited. We collected and isolated adult worms of three species in Japan that belong to the family Heligmonellidae, namely Heligmonoides speciosus (Konno, 1963) Durette-Desset, 1970 (Hs) from Apodemus argenteus, Orientostrongylus ezoensis Tada, 1975 (Oe) from Rattus norvegicus and Lagostrongylus leporis (Schulz, 1931) (Ll) from Pentalagus furnessi, and sequenced the entire internal transcribed spacer regions, ITS-1 and ITS-2 of ribosomal DNA. ITS-1 of Hs, Oe and Ll was 426, 468 and 449 bp in length, and had a G+C content of about 41, 41 and 37 %, respectively. ITS-2 of Hs, Oe and Ll was 297, 319 and 276 bp in length and had a G+C content of about 38, 40 and 28%, respectively. The data of Hs, Oe and Ll were compared with those of two other known species within the family Heligmonellidae, Calorinensis minutus (Dujardin, 1845) (Cm) and Nippostrogylus brasiliensis (Travassos, 1914) (Nb), and with those of two species of Heligmosomidae (Heligmosomoidea), Heligmosomoides polygyrus bakeri and Ohbayashinema erbaevae. Phylogenetic analysis placed Hs, Oe and Ll in the same clade with Cm and Nb, forming a Heligmonellidae branch in both ITS-1 and ITS-2, separate from the Heligmosomoidea branch. These results demonstrated that the ITS-1 and ITS-2 sequences are useful for differentiating the Heligmonellidae nematode species. This study is the first to describe the ITS-1 and ITS-2 sequences of Hs, Oe and Ll.

Pathological lesions in European bison (Bison bonasus) with infestation by Ashworthius sidemi (Nematoda, Trichostrongylidae)

Asworthius sidemi Schulz, 1933 is a blood sucking gastrointestinal nematode, primarily typical for Asiatic deer. It was found for the first time in Poland in European bison in 1997. To estimate the level of invasion of A. sidemi and histopathological changes connected with the presence of the parasite in the years 2004-2007 parasitological and histopathological examinations of 54 European bison from Białowieza Forest were carried out. Parasitological examination was carried out by the sedimentation method and A. sidemi were diagnosed under a binocular microscope. Samples for histological examination were collected from the abomasum and duodenum walls as well as from regional lymph nodes. Tissue samples were then fixed with 10% buffered formalin, embedded in paraffin, cut in to 5 microm thick sections and stained with hematoxylin and eosin (H&E). Parasitological examinations showed the presence of fourth stage larvae and juvenile forms of A. sidemi. The maximal intensity of invasion rose systematically from 4470 A. sidemi nematodes in 2004/2005 to 44310 in 2006/2007. Histopathological examinations showed infiltrations of inflammatory cells in the walls of abomasa and duodena at various levels of intensity (mainly lymphoid cells and eosinophils), hyperemiae, oedemae and lesions of mucosa and proliferation of lymphatic follicles. In individual cases of dysplasia of epithelial cells, atrophy or hyperplasia of glands and the presence of parasites in the lumen or walls of the abomasum/duodenum were observed. In one case, parasitic nodules were found. In regional lymph nodes proliferation of lymphatic follicles, presence of eosinophils and desolation of reproduction centers were observed. Intensification of histopathological changes was connected to a considerable degree with the developmental stage of A. sidemi as shown by parasitological examination.

[Sheep trichostrongylidosis in Van province]

This study was performed in the Van Municipality Slaughterhouse from January to December 2001. Abomasums and small intestines from a total of 104 sheep were transported to the parasitology laboratory of the Veterinary Faculty of Yüzüncü Yil University for parasitological examination. The abomasums and small intestines of the animals were opened with appropriate technique in the laboratory, and male nematodes were collected from the contents of the abomasums and small intestines using a sampling method, and then these parasites were identified. Gastrointestinal nematodes were encountered in 87.5% out of 104 sheep. Marshallagia marshalli (85%), Teladorsagia circumcincta (75%), Nematodirus oiratianus (75%), N. spathiger (65%), Haemonchus contortus (40%), Tel. occidentalis (36%), Trichostrongylus axei (33%), N. abnormalis (19%) and T. probolurus (19%), Tel. davtiani (15%), Tel. trifurcate (10%), and Camelostrongylus mentulatus (1%) were detected. Among the parasites, the species encountered most often were Tel. circumcincta (45.23%) in abomasums and N.oiratianus (65.73%) in small intestines. The highest rate of parasites in both abomasums and small intestines occurred in August, September and October. It was found that the young animals have a parasite density higher than the adults and the females have parasite density higher than the males.

Trichostrongylina (Nematoda) from Malagasy Muridae. III--description of a new species of Heligmonoides Baylis, 1928 (Heligmonellidae) parasitic in Mus musculus

Heligmonoides variabilis n. sp. (Heligmosomoidea, Nippostrongylinae) a parasite of Mus musculus from Madagascar is related to H. afghanus (Tenora, 1969), H. ikeharai Hasegawa, 1990 and H. josephi (Wertheim & Durette-Desset, 1976), all having the dorsal ray divided anterior to the arising of rays 8. H. ikeharai a parasite of Tokudaia muenninki (Muridae) from Japan is the most closely related species with rays 8 arising at mid-length along the dorsal ray. It is differentiated from the new species by very long spicules (almost half of body length) and by the length of the vestibule (almost one millimeter). A new definition of the genus Heligmonoides Baylis, 1928 is proposed with a dichotomic key of the species. The biogeographic distribution and the host spectrum of the genus are described.

Resistance of trichostrongyles to benzimidazoles in Italy: a first report in a goat farm with multiple and repeated introductions

Anthelmintic resistance is widely distributed in small ruminants throughout the world. The extension of resistance seems lower in southern European countries and has not been reported previously in Italy. In the present study, resistance to benzimidazoles, levamisole and ivermectin was evaluated in a multi-breed goat farm of southern Italy. The farm had a history of repeated goat introductions from other flocks and a moderate regimen of anthelmintic treatments using alternatively the three above-mentioned drugs. Resistance of gastrointestinal strongyles was studied on the basis of faecal egg counts, egg hatch assay and necropsies. Resistance to anthelmintics was evidenced for benzimidazoles only, and Trichostrongylus colubriformis was the only resistant strongyle species. Single drug and single species resistance suggest that resistance is on its beginning and that measures for reducing the spread of resistance are of interest and should be promoted.

Trichostrongylina (Nematoda) parasitic in Phyllotis sp. (Rodentia: Sigmodontinae) from Argentina, with description of three new species

The Trichostrongylina parasitic in the leaf-eared mouse Phyllotis sp. (Sigmodontinae) from the Province of Catamarca, Argentina are studied. Three new species of Stilestrongylus Freitas, Lent and Almeida, 1937 (Heligmosomoidea: Heligmonellidae: Nippostrongylinae) are described. Stilestrongylus andalgala n. sp. is distinguished from the most closely related species S. moreli Diaw, 1976 parasitic in Auliscomys boliviensis from Bolivia, by the absence of a common trunk of right rays 2 and 3, by left ray 4 shorter than ray 5, and by the shape of the female tail, without a mucron. Stilestrongylus catamarca n. sp. is distinguished from all the other species in the genus by hypertrophied rays 2, larger than rays 3, and from the closely related species Stilestrongylus barusi Durette-Desset, 1971, parasitic in Sigmodontomys alfari from Colombia, by right ray 4 longer than ray 5 and left ray 4 shorter than ray 5, by a larger spicule length/body length ratio (22.6% vs. 7.2%), and by the presence of a mucron on the female tail. Stilestrongylus gracielae n. sp. most closely resembles Stilestrongylus azarai Durette-Desset and Sutton, 1985, parasitic in Akodon azarae and in Graomys griseoflavus, and Stilestrongylus franciscanus Digiani and Durette-Desset, 2003, also parasitic in G. griseoflavus, both from Argentina. These latter differ from the new species by the right lobe of the caudal bursa: in S. azarai rays 4, 5 and 6 arise at same level from their common trunk and in S. franciscanus right rays 4 and 5 diverge at their distal extremity. Lamanema chavezi Becklund, 1963 (Molineoidea: Molineinae), a parasite of South American camelids, is reported in rodents for the second time.

A new species of Sciurodendrium (Nematoda: Heligmonellidae) in Sciurus aureogaster (Rodentia: Sciuridae) from Morelos, Mexico

Sciurodendrium bravohollisae n. sp. (Heligmonellidae) is described as an intestinal parasite of 2 squirrels, Sciurus aureogaster Cuvier, 1829, collected from Los Robles, Municipio de Tlalnepantla, Morelos State, Mexico. The new species differs from all other congeners in possessing a very well-developed and sacciform genital cone. This is the seventh species described for the genus and the first one recorded in Mexico.

Spiculopteragia mathevossianiRuchliadev, 1948 is the minor morph ofSpiculopteragia spiculoptera(Gushanskaya, 1931): molecular evidence

Although Spiculopteragia spiculoptera is primarily a parasite of cervids, it can also but less often contaminate domestic livestock. Little is known about its epidemiology and its pathogenicity in domestic ruminants and other unusual cervid species. Its taxonomic status remains unclear since the hypothesis of morphological polymorphism among males has been proposed. However, accurate taxonomy is fundamental in the identification and survey of potentially pathogenic species of parasites. The second internal transcribed spacer of rDNA (ITS-2) and the mitochondrial (mt) DNA-derived ND4 gene were used to study the polymorphism hypothesis for S. spiculoptera. ND4 evolves more quickly than ITS-2 and is considered to be more discriminant in the characterization of closely related species. DNA sequences of ITS-2 and ND4 were studied in 18 individual males of morphological type spiculoptera and in 3 of morphological type of mathevossiani from Red deer (Cervus elaphus), Roe deer (Capreolus capreolus) and Chamois (Rupicapra rupicapra). Intraindividual ITS-2 variations were detected within and between each morphotype of Spiculopteragia but these differences did not separate the two morphs mathevossiani and spiculoptera. Similarly, although ND4 showed a high level of nucleotide substitution, the morphotypes S. mathevossiani and S. spiculoptera were clustered together. Our genetic data support the dimorphic male hypothesis for the species S. spiculoptera.

Occurrence of Libyostrongylus sp. (Nematoda) in ostriches (Struthio camelus Linnaeus, 1758) from the north region of the state of Rio de Janeiro, Brazil

Domestic production of ostrich in Brazil started in the beginning of the last decade, but its sanitary state has not been reported. Libyostrongylus sp. is an ostrich specific nematode whose parasitism can severely affect the birds. Thus, Libyostrongylus spp. larvae were identified in commercial ostriches in the north region of the state of Rio de Janeiro, Brazil. The EPG was determined and fecal cultivation was performed. The eggs presented typical characteristics of strongylid and were present in five out of six farms. The mean EPG varied from 22 to 2395 and Libyostrongylus spp. prevalence was from 0 to 100%, with adult birds more infected. Two types of infective larvae with tail finishing in a tipped spiny knob were distinguished. The first had a mean length of 848 microm (710-1010) with a long sheath tail of about 66 microm (52-112). The other had a mean length of 826 microm (620-940) with a short, more abruptly ending sheath tail of 32 microm (22-40) and a less rounded cephalic end. The differences between these larvae suggest two Libyostrongylus species.

Prevalence of lungworm infection in sheep and cattle in the Kirikkale province

A slaughterhouse survey was performed for one year in order to determine the prevalence and intensity of lungworm infections in both sheep and cattle in the Kirikkale region. Thirty-four percent of 100 sheep examined were infected with lungworms and the species found in the infected lungs were Cystocaulus ocreatus (50.0%) and Dictyocaulus filaria (23.5%). Mixed infections were detected in 26.5% of the infected lungs. Worm nodules and brood nodules of C. ocreatus were observed in the lungs. The range of worm nodules was 1-116 (mean 19.7) and that of brood nodules, 1-5 (mean 2.8) per lung. D. filaria had a range that increased to a maximum of 45 worms (mean 11.5). Lungworms were observed in 14.0% of sheep fecal specimens. Larvae of C. ocreatus (52.4%) and D. filaria (28.6%) were found during examination of feces. Of the feces containing lungworms, 19% showed the presence of mixed infection. Lungworms were not found in cattle examined by autopsy and coprologic examination. C. ocreatus is the most prevalent lungworm species in Anatolia. D. filaria is another frequently seen lungworm species in Turkey while Dictyocaulus viviparus is very rarely reported in this country. It may be related to different humidity and temperature requirements for the development of free living larvae of the two Dictyocaulus species.

The systematic position of some Ethiopian Nippostrongylinae (Nematoda, Trichostrongylina, Heligmosomoidea) from the National Collection of Animal Helminths, Onderstepoort, South Africa

The taxonomic status of some nippostrongyline nematodes deposited in the National Collection ofAnimal Helminths, Onderstepoort, is revised. Heligmonina boomkeri n. sp. is described from Aethomys chrysophilus from South Africa. The most closely related species by the body measurementsand the pattern of the caudal bursa is Heligmonina bignonensis Diouf, Bâ & Durette-Desset, 1997, a parasite of Mastomys erythroleucus from Senegal. It differs from the new species mainly in thenumber of ventral cuticular ridges at mid-body (four versus five) and the left ala in the male is shorterthan the body diameter. The systematic position of Heligmonina spira (Ortlepp, 1939) and Neoheligmonella capensis (Ortlepp, 1939) is confirmed here through their synlophe, which was not previously studied.

A new species of Vexillata (Nematoda: Trichostrongylina: Ornithostrongylidae) parasite of Heteromys desmarestianus (Rodentia: Heteromyidae) from Costa Rica

In July 1999, 2 heteromyid rodents Heteromys desmarestianus Gray, 1868, were collected from the Area de Conservación Guanacaste, Costa Rica, and examined for parasites. Individuals of a new species of Vexillata (Travassos, 1937) Durette-Desset, 1970, were found from the intestine of hosts. Vexillata brooksi n. sp. differs from all other congeners by the presence of spicules divided at the tip instead of simple spicules. The new species closely resembles Vexillata legallae Denke, 1977, and Vexillata convoluta (Caballero and Cerecero, 1943); however, it can be distinguished from both species by possessing a smaller number of cuticular ridges at the posterior part of the body in males (9 vs. 11 and 12, respectively) and by the absence of a carene at this level.

Pseudostertagia bullosa (Nematoda: Trichostrongyloidea) in artiodactyl hosts from North America: redescription and comments on systematics

A relationship for Pseudostertagia bullosa within the trichostrongyloids has been enigmatic or unresolved. Studies of the synlophe in males and females of P. bullosa revealed a tapering system anterior to the deirids and a pattern of parallel ridges extending to near the caudal extremity in both lateral and median fields. Structurally, the synlophe differs considerably from that seen among the Cooperiinae and exhibits homoplasy with respect to ridge systems among some Ostertagiinae. Other structural characters due to symplesiomorphy, homoplasy or because they represent autapomorphies do not serve to reveal the putative relationships for P. bullosa with other trichostrongyloids. Although somewhat equivocal, the 2-2-1 pattern of the bursa and position of rays 2 and 3 suggest an association with the Cooperinae, as postulated by Durette-Desset and others. Pseudostertagia bullosa appears to be a species that has survived in the pronghorn, Antilocapra americana, a relictual pecoran artiodactyl that occurs in xeric regions of western North America; pronghorn are the sole remnant of the late Tertiary radiation for Antilocapridae across North America. Pseudostertagia bullosa may occur in mixed infections with a number of ostertagiines in the abomasa of mule deer (Odocoileus hemionus) and domestic sheep (Ovis aries) in regions of sympatry for pronghorn and these artiodactyl hosts.

Graphidioides subterraneusn. sp. (Nematoda: Trichostrongyloidea) from the South American subterranean rodentCtenomys talarumThomas, 1898 (Rodentia: Octodontidae)

A new nematode species, Graphidioides subterraneus n. sp., found in the stomach of C. talarum from Argentina is described. The new species more closely resembles G. mazzai Lent & Freitas, 1935, parasite of Galea leucoblephara from Argentina, and G. kravetzi Sutton & Durette-Desset, 1995, parasite of Holochilus brasiliensis from Uruguay. It can be distinguished by shorter spicules, by the shape of the gubernaculum, by shorter uterine branches, and by a different number of ridges of the synlophe all along the body.

Additional molecular evidence to support a sister taxon relationship between Heligmosomoidea and Molineoidea nematodes (Trichostrongylina)

Sequences of the first and second internal transcribed spacers of the ribosomal DNA were used to infer the evolutionary relationships of 19 species of parasitic nematode belonging to three superfamilies, Trichostrongyloidea, Molineoidea and Heligmosomoidea, within the sub-order Trichostrongylina. Analyses using maximum parsimony, maximum likelihood and neighbor-joining methods revealed strong statistical support for monophyly of each superfamily as defined on morphological criteria. Furthermore, in most analyses, there was also strong support for a sister taxon relationship between the Molineoidea and Heligmosomoidea, which supports the findings of a previous study based on partial LSU rDNA sequence data.

[Morphology of some tricostrongilinae (Strongylida) from the National Helminth Collection, Institute of Biology, UNAM, Mexico]

The present study analyses the taxonomic status of eleven species of trichostrongylins that parasitize rodents and lagomorphs deposited in the Colección Nacional de Helmintos, Instituto de Biología. UNAM. Mexico. This analysis is based on the morphology of the synlophe, characteristic that had not been studied for most of these nematode species and at present, it has a very important taxonomic value. As a result of this study, the identity of five species is ratified (Trichostrongylus calcaratus, Obeliscoides cuniculi, Carolinensis huehuetlana. Stilestrongylus peromysci and Nippostrongylus brasiliensis), the transference suggested previously for two more (Vexillata convoluta and Vexillata vexillata) is confirmed, Trichostrongylus chiapensis is synonymized with Boehmiella willsoni, and finally Lamothiella romerolagi is re-determined as Teporingonema cerropeladoensis and Stilestrongylus atlatilpinensis as Stilestrongylus hidalguensis.

Two new species of Nippostrongylinae (Nematoda: Trichostrongylina: Heligmonellidae) from the grey leaf-eared mouse Graomys griseoflavus (Sigmodontinae) in Argentina

Two new species of Nippostrongylinae, Hassalstrongylus puntanus n. sp., and Stilestrongylus franciscanus n. sp. are described from the intestine of the grey leaf-eared mouse Graomys griseoflavus (Waterhouse, 1837) (Sigmodontinae) from the Province of San Luis, Argentina. Hassalstrongylus puntanus n. sp. is distinguished from the most closely related species H. dollfusi (Díaz-Ungría, 1963), a parasite of Mus musculus from Venezuela by longer rays 2, shorter rays 4, proximal half of the dorsal ray non-enlarged and a non-retractile female tail. Stilestrongylus franciscanus n. sp. is distinguished from the most closely related species S. flavescens Sutton & Durette-Desset, 1991, a parasite of Oryzomys flavescens from Argentina, by rays 2 and 3 diverging separately from common trunk of rays 2 to 6, and by right ray 3 arising from this trunk more distally than ray 6. Stilestrongylus azarai Durette-Desset & Sutton, 1985, a parasite of Akodon azarae from Buenos Aires, Argentina, was also found parasitizing G. griseoflavus, representing new host and locality records. Some additional morphological data for this species are also provided.

A new genus of Nippostrongylinae (Nematoda: Heligmonellidae) from the water rat Scapteromys aquaticus (Sigmodontinae) in Argentina

A new genus of Nippostrongylinae, Malvinema n. gen., with 3 coparasitic species M. frederici n. sp., M. carolinae n. sp., and M. victoriae n. sp. from the intestine of the water rat, Scapteromys aquaticus Thomas (Rodentia: Muridae), from the northeast of Buenos Aires Province, Argentina, is proposed in this study. The new genus shows similarities to 2 Neotropical Nippostrongylinae: Carolinensis (Travassos, 1937) by some characters of the synlophe and Stilestrongylus Freitas, Lent and Almeida, 1937, by the pattern of the caudal bursa. It is characterized by a synlophe with triple or quadruple gradient of size of the ridges, lateromedian, decreasing from the largest left and right ridges. The gradient situated in the right ventral quadrant is always present. The caudal bursa shows a pattern of type 1-4. Malvinema frederici possesses a synlophe with 17 ridges and an axis of orientation inclined at 45 degrees from the sagittal axis; M. carolinae possesses a synlophe with 22-24 ridges and an axis of orientation almost merged with the sagittal axis. Both species have a caudal bursa with the right lobe enlarged transversally. Malvinema victoriae possesses a synlophe with 22-24 ridges, an axis of orientation inclined at 45 degrees from the sagittal axis, and a caudal bursa with the right lobe enlarged vertically.

Expansion of the Asiatic parasite Ashworthius sidemi (Nematoda, Trichostrongylidae) in wild ruminants in Polish territory

The abomasa of 40 wild ruminants (18 red deer, 9 roe deer, 13 European bison) shot in the Bieszczady Mountains and another 8 European bison shot in Bialowieza Primeval Forest, were examined for worms. Ashworthius sidemi was found in all of the animals from the Bieszczady Mountains, and the intensity of infection was usually massive. In Bialowieza Forest few specimens of A. sidemi were noted among three bison. Wild ruminants were infected by A. sidemi from June to September. The nematodes originating from this infection only attained sexual maturity in June of the following year, and from September the process of expelling the parasites of that generation began. From June to autumn, two generations of nematodes, one consisting of mature individuals from the previous year and the other of the current year comprising fourth stage larvae as well as juveniles, occur in these hosts. In the winter and spring periods until June, only one generation of the parasite, arrested fourth-stage larvae and juveniles, occurs in the hosts.

Ashworthius Patriciapilittae n. sp. (Trichostrongyloidea: Haemonchinae), an abomasal nematode in Odocoileus virginianus from Costa Rica, and a new record for species of the genus in the Western Hemisphere

A species of Ashworthius is reported for the first time in the Western Hemisphere, and A. patriciapilittae n. sp. is described on the basis of specimens in white-tailed deer Odocoileus virginianus from Costa Rica. Among 8 known species, A. patriciapilittae is morphologically similar to A. tuyenquangi in red muntjac Muntjacas muntjak from northern Vietnam. The synlophe in A. patriciapilittae is composed of 26 ridges in the cervical zone and is continuous to the caudal extremity in males and females. Males are characterized by a complex dorsal ray and narrow trifurcate spicules (351-356 microm long) lacking an "eyelet." with dissimilar ventral and dorsal processes; the gubernaculum is 45-48% of the spicule length. Females have a prominent linguiform flap at the vulva and large eggs (108-142 microm long). The presence of A. patriciapilittae in Costa Rica is examined in the context of competing hypotheses for cospeciation or contemporary host-switching in cervids: either A. patriciapilittae is a component of an endemic Central and South American fauna that has diversified through coevolution of Ashworthius and cervid hosts or it has been introduced. Among haemonchines in the Western Hemisphere, specimens of A. patriciapilittae may be confused with 3 species of Haemonchus, including H. contortus, H. placei, and H. similis, that occur in both domestic and wild ruminants. Discovery of A. patriciapilittae emphasizes the continued need for survey and inventory to define the structure and distribution of parasite faunas in wild and domestic ruminants from the Nearctic and Neotropical regions.

Quantitative analysis of ITS2 sequences in trichostrongyle parasites

Real-time PCR assays were developed to identify and quantify common gastrointestinal nematodes of ruminants. The assays were based on genus-specific primer and probe combinations derived from the second internal transcribed spacer (ITS2) ribosomal DNA transcription unit of Haemonchus contortus, Ostertagia leptospicularis, Trichostrongylus colubriformis and Cooperia curticei. The TaqMan probes for the first two species were labelled with 6-carboxyfluorescein and those for the latter two with VIC and all were synthesised as dihydrocyclopyrroloindole minor groove binder conjugates. Cloned ITS2 DNA or genomic DNA isolated from first stage larvae, derived from overnight cultures, were used as template. The real-time PCRs reproducibly allowed the identification of at least 100 copies of cloned ITS2 DNA or one hundredth part of a single larval genomic DNA equivalent. The assays proved to be genus-specific since the addition of DNA from heterologous trichostrongyle genera did not change the cycle threshold values obtained with only homologous DNA. Furthermore, the use of genomic DNA of several other ruminant nematode parasite genera gave negative results. In duplex experiments, 6-carboxyfluorescein-labelled H. contortus or O. leptospicularis probes were used together with the VIC-labelled T. colubriformis and C. curticei probes, respectively, confirming the specificity and sensitivity of the probes found in the simplex experiments. The primer and probe combinations gave comparable results when applied with core reagents from different suppliers and with both the M x 4000 and the ABI 7700 instruments. This technique provides means for a rapid, reliable and quantitative detection and differentiation of the most important parasitic nematodes of sheep and cattle.

The integration of grazing management and summer treatments for the control of trichostrongylid infections in Merino weaners

OBJECTIVE

To compare two strategies for the preparation of pastures that have reduced trichostrongylid infections during winter and spring for Merino weaners.

DESIGN

A replicated field experiment was conducted over two successive years. A 'standard' strategy, comprising set-stocked wethers given anthelmintic treatments in late October and early February, was compared with a 'new' one in which intensive grazing for 1 month after each treatment and destocking for 1 or 2 months was integrated with the anthelmintic treatments. Paddocks prepared according to these strategies were set-stocked at 15 Merino weaners/ha from April to October inclusively.

RESULTS

Contamination of pastures prepared according to the new strategy was substantially reduced compared to those of the standard strategy. Worm counts showed that on new strategy paddocks the numbers of trichostrongylid larvae, except Nematodirus spp, were reduced by 50 to 95% compared to standard strategy paddocks. Worm egg counts from the set-stocked weaners were reduced by about 50% on new strategy paddocks from April to October. Weaners grazing the new strategy paddocks grew significantly more clean wool (254 g, P = 0.01) and were significantly heavier in October (3.2 kg, P = 0.01) than weaners in the standard strategy paddocks. The improved production was attributable partially to better pasture growth early in winter and partially to reduced parasitism.

CONCLUSION

The new strategy is a simple, practical and widely applicable example of the integration of grazing management with strategically timed anthelmintic treatments to reliably reduce trichostrongylid infections in weaners grazing during winter and spring.

Trichostrongylina (Nematoda) from Malagasy muridae. II--Description of two new species of Heligmonina (Heligmonellidae) in Nesomys rufus and Eliurus tanala

Two new species of Heligmonellidae from Madagascar are described, Heligmonina madagascariensis n. sp. in Nesomys rufus and Heligmonina tanala n. sp. in Eliurus tanala. Both species belong to the Heligmonina species with a pattern of type 1-3-1 for the right lobe of the caudal bursa and 1-4 for the left lobe. In H. madagascariensis, H. dupuisi (Desset, 1964) and H. praomyos Baylis, 1928, left ray 6 arises before ray 3 from the common trunk to rays 3 to 6 while in H. tanala and the other species, it arises at the same level. H. madagascariensis is differentiated from H. dupuisi and H. praomyos by the symmetry of the branches of the dorsal ray. H. tanala is differentiated from H. malacomys Sakka & Durette-Desset, 1988, the closely related species by a different pattern of the cuticular ridges at mid-body, by the sharpness of the tips of the spicules and by the ratio of the length of the spicules on the length of the body (6.9, 8.8% versus 25-27.8%). Heligmonina chippauxi (Desset, 1964) a parasite of Oenomys hypoxanthus from the Republic of Central Africa is considered a valid species.

Allintoshius bioccai n. sp. (Nematoda), a parasite of the bat Eptesicus furinalis from Paraguay, and new data on A. parallintoshius (Araujo, 1940)

A new species of parasitic nematode (Nematoda: Trichostrongylina, Heligmosomoidea) Allintoshius bioccai n. sp., found in the small intestine of the vespertilionid bat Eptesicus furinalis from Paraguay, is described. The new species can be differentiated from A. urumiac (Freitas and Mendonça, 1960) by the absence of vulvar spines in females, and from A. nudicaudus (Freitas and Mendonça, 1963) by the shape of the spicules and the dorsal ray of the copulatory bursa. New data on the morphology and distribution of Allintoshius parallintoshius (Araujo, 1940) are also reported. E. furinalis, Myotis albescens and M. riparius are recorded as new hosts for this species. A key for the identification of the species belonging to the genus Allintoshius is also given.

Identical ITS-1 and ITS-2 sequences suggest Spiculopteragia asymmetrica and Spiculopteragia quadrispiculata (Nematoda: Trichostrongylidae) constitute morphologically distinct variants of a single species

Sequences of ITS-1 and ITS-2 rDNA for adult males of Spiculopteragia asymmetrica and Spiculopteragia quadrispiculata in red deer (Cervus elaphus) were determined. They were found to be identical, suggesting that S. asymmetrica and S. quadrispiculata represent a single species and do not refute the concept of dimorphic species in the Spiculopteragia.

Trichostrongylina (Nematoda) from Malagasy Muridae. I--Description of two new species of Heligmonellidae in Nesomys spp

Two new species of Heligmonellidae, Heligmonina wrightae n.sp. (Nippostrongylinae) and Nesomystrongylus fissicauda n.gen., n. sp. (Brevistriatinae) are described from Madagascar in Nesomys rufus and N. audeberti (Muridae). In Nesomys audeberti, the species are coparasites. Heligmonina wrightae is differentiated from all the other species of the genus, except H. malacomysi Sakka & Durette-Desset, 1988, by the ratio of the length of the spicules on the length of the body (25-27.8% versus 9.5-7%). It differs from H. malacomysi by the pattern of the caudal bursa and by the angle of the axis of orientation of the cuticular ridges on the sagittal axis. Nesomystrongylus fissicauda is related to the genus Fissicauda Durette-Desset & Krishnasamy, 1976, by the absence of the carene, by the ridges discontinuous on all the sides of the body and by the deeply divided dorsal ray. It differs from this genus by a different structure of the ridges, by the pattern of the caudal bursa, (very tiny rays 2 and strongly developed rays 3, rays 8 arising from common trunk of rays 2 to 6) and by the presence of a caudal tip in the female.

New molecular evidence that Teladorsagia circumcincta (Nematoda: Trichostrongylidea) is a species complex

In the polymorphic Teladorsagia circumcincta (morphs circumcincta and trifurcata), a sheep and goat line (SGL) and a goat line (GL) have been previously described on the basis of the malate dehydrogenase allozyme polymorphism (MDH-2) and of the morphology of the dorsal ray. The GL were never found alone in 1 host, so the status of species was not given to these 2 lines. To investigate further whether there are other genetic markers that will delineate them, we collected T. circumcincta worms from goat and sheep at 8 farms in Touraine (west-central France). The worms were identified individually as being SGL or GL on the basis of MDH-2 polymorphism. This distinctiveness was corroborated by sequences of the beta-tubulin isotype I gene, the second internal transcribed spacer (ITS2) of their rDNA, and the nicotinamide dehydrogenase (ND4) gene of their mDNA. The extent of the divergence in the 3 additional genetic markers was such that SGL and GL may be considered as 2 species. A third putative species was found in the SGL line based exclusively on the ND4 gene. These findings suggest that T. circumcincta is a species complex and that further investigation is required on a wider geographic scale.

New Pudicinae (Trichostrongylina, Heligmosomoidea) coparasites of Proechimys longicaudatus (Caviomorpha) from Bolivia. I--Description of Pudica ginsburgi n. sp. and Heligmostrongylus chiarae n. sp

Two new Pudicinae (Trichostrongylina, Heligmosomoidea, Heligmonellidae) coparasites of Proechimys longicaudatus (Caviomorph rodent) from Bolivia are described: Pudica ginsburgi n. sp. is differentiated from all the other species of the genus by the great length of the spicules and of the vestibule and by a different ratio of the length of the spicules on the length of the body. Heligmostrongylus chiarae n. sp. has very developed rays 4, strongly divergent from rays 5 as occurs in three other species, H. almeidai (Durette-Desset & Tcheprakoff, 1969), a parasite of Trichomys apereoides (= Cercomys cunicularius) from Brazil, H. squamastrongylus (Travassos, 1937), a parasite of Proechimys oris from Brazil and H. proechimysi Durette-Desset, 1970, a parasite of Proechimys semispinosus from Columbia. The specimens from Bolivia are differentiated from the three species by the division of the dorsal ray (anterior half versus posterior half) and by a different ratio of the length of the spicules on the length of the body.

Vexillata liomyos n. sp. (Nemata: Ornithostrongylidae) from Liomys pictus (Rodentia: Heteromyidae) from Mexico, with comments on the synlophe of Vexillata armandae

Individuals of a new species of Vexillata were collected from the small intestines of Liomys pictus from the Estaci6n de Biología Chamela, in Jalisco State, Mexico. The new species shows an array of characters that allow us to recognize it as a member of Vexillata; however, it can be distinguished from other species of the genus in that males possess an asymmetrical caudal bursa, females possess a characteristic cuticular inflation at the level of the ovijector, and both sexes possess a synlophe with 9 ridges at the midbody. Additional detail of the synlophe of Vexillata armandae Gardner et al., 1994 from Chaetodipus hispidus in New Mexico shows that both sexes have 12 cuticular ridges just posterior to the cephalic inflation, and in the posterior region of the body, females have 9 ridges of equal size while males possess 11 equal-sized ridges. In both sexes, the carene disappears at the posterior end of the body.

Phylogeny of the Trichostrongylina (Nematoda) inferred from 28S rDNA sequences

We produced a molecular phylogeny of species within the order Strongylida (bursate nematodes) using the D1 and D2 domains of 28S rDNA, with 23 new sequences for each domain. A first analysis using Caenorhabditis elegans as an outgroup produced a tree with low resolution in which three taxa (Dictyocaulus filaria, Dictyocaulus noerneri, and Metastrongylus pudendotectus) showed highly divergent sequences. In a second analysis, these three species and C. elegans were removed and an Ancylostomatina, Bunostomum trigonocephalum, was chosen (on the basis of previous morphological analyses) as the outgroup for an analysis of the phylogenetic relationships between and within the Strongylina (strongyles) and Trichostrongylina (trichostrongyles). A very robust tree was obtained. The Trichostrongylina were monophyletic, but the Strongylina were paraphyletic, though this requires confirmation. Within the Trichostrongylina, the three superfamilies defined from morphological characters are confirmed, with the Trichostrongyloidea sister group to a clade including the Molineoidea and Heligmosomoidea. Within the Trichostrongyloidea, the Cooperiidae, Trichostrongylidae, and Haemonchidae were polytomous, the Haemonchinae were monophyletic, but the Ostertagiinae were paraphyletic. The sister-group relationships between Molineoidea and Heligmosomoidea were unsuspected from previous morphological analysis. No unequivocal morphological synapomorphy could be found for the grouping Molineoidea + Heligmosomoidea, but none was found which contradicted it.

Evolutionary relationships of trichostrongyloid nematodes (Strongylida) inferred from ribosomal DNA sequence data

The evolutionary relationships of 21 species of trichostrongyloid nematodes were determined by use of sequence data of the second internal transcribed spacer of the ribosomal DNA aligned according to secondary structure information. Irrespective of the method of analysis used, the topologies of the phylogenetic trees derived from the molecular data differed with respect to all four hypotheses proposed previously for the evolutionary relationships of the different subfamilies within the Trichostrongylidae based on morphological data. Thus, the molecular data set did not resolve the conflict between the four previous proposals for the subfamilial relationships. Nonetheless, all trees derived from the molecular data showed strong support for the exclusion of the genera Filarinema and Amidostomum from the clade containing the species within the family Trichostrongylidae. This represents a major difference from the most recent proposal of the systematics of the Trichostrongyloidea in which these two genera were included within the Trichostrongylidae. Therefore, the molecular data support an earlier systematic framework in which Filarinema and Amidostomum were considered to be sister groups of the Trichostrongyloidea.

Molineus torulosus (Nematoda, Trichostrongylina, Molineoidea) a parasite of Neotropical primates: new morphological and histological data

Molineus torulosus (Molin, 1861) parasite of Cebus spp. from South America is redescribed in Cebus apella and C. olivecaeus (new host) from French Guyana with emphasis on the synlophe. During the maturation process, the larvae dwelt in the cysts carved alongside the external part of the small intestine. The turn-out of the mature worms and the laid eggs depended on the tissular organisation of cyst walls as the inflammatory process waned and fibrosis progressed to seal the cystic lumen. Adult worms entwine themselves in the cysts, live there permanently as their presence has never been evidenced in the intestinal lumen. They copulated, laid eggs, degenerated and died once entrapped by the fibrotic process. Laid eggs released in the intestinal lumen through a narrow channel ensured the continuation of the developmental cycle. However, erratic migration was possible via the vascular channels surrounding the cysts.

Relationship between helminth species diversity, intensity of infection and breeding management in dairy goats

Helminth infection, species diversity (proportion of each species in the community), species number, intensity of infection and anthelmintic resistance were investigated in 16 dairy-goat farms of south-western France. The aim of the study was to estimate which breeding management factors may affect diversity and intensity of infection. Anthelmintic resistance was investigated because this factor may modify composition of nematode communities. Farm history and breeding management were recorded by means of a questionnaire. Natural and experimental infections were compared to determine which strategy was the best to estimate diversity index and number of species from nematode community of a whole herd. A total of 17 species of helminths, among which 14 nematodes, one cestode (Moniezia spp.) and two trematodes (Paramphistomum daubneyi and Dicrocoelium lanceolatum) were recovered in the 26 necropsied culled goats. One culled goat worm burden represented conveniently species number but not species diversity (Shannon index) of parasite community harboured in the whole herd. Experimental sheep infection with larvae from pooled faeces of 15 goats was the best strategy to estimate species diversity in farms. Diversity could be predicted from the number of farms from which goats originated at constitution of the herd, the duration of goat winter withdrawal from pastures, and intensity of infection. Anthelmintic resistance was correlated with the number of farms of origin, area of permanent pastures and intensity of infection. The strategy adopted for the herd constitution was a critical step as species diversity and risk of anthelmintic resistance increased with the number of farms of origin. Intensity of infection was negatively correlated with species diversity. This suggested that more diverse communities were better controlled by the host, in agreement with the widespread statement that diversity would beget stability.

Gastric Ollulanus tricuspis infection identified in captive cheetahs (Acinonyx jubatus) with chronic vomiting

Gastritis, vomition and weight loss are common in captive cheetahs (Acinonyx jubatus). Gastric spiral bacteria (Helicobacter spp.) and the very small, viviparous nematode Ollulanus tricuspis, a stomach worm of cats, are believed to be important causes. Three sibling cheetahs at Wellington Zoo, New Zealand, developed chronic vomiting, diarrhoea and debility. Their parents were both South African-born. Response to antibacterial treatment was poor. Endoscopic examinations revealed chronic lymphoplasmacytic gastritis and Ollulanus infection. Treatment with oxfendazole and pyrantel embonate resulted in clinical improvement; however, 1 cheetah, which died 7 months later as a result of a ruptured liver due to hepatic amyloidosis, still had Ollulanus worms present in her stomach. Ollulanus tricuspis is a significant cause of gastritis and vomiting in captive cheetahs, lions and tigers, as well as wild cougars and tigers. The parasite has not yet been found in sub-Saharan Africa. Because of the unusual characteristics of this parasite, the literature on its life history and techniques for diagnosis is reviewed.

Phylogenetic relationships among species of Stilestrongylus Freitas, Lent and Almeida, 1937 (Trichostrongyloidea: Heligmonellidae: Nippostrongylinae), parasites of myomorph rodents (Rodentia: Muridae) in the Neotropics

The phylogenetic relationships of 14 species of Stilestrongylus were analyzed using the comparative morphology of 21 characters. We obtained 2 shortest trees of 50 steps, with a consistency index of 0.540 and 25 apomorphic character states. Ingroup monophyly was supported on these trees by 2 and 3 synapomorphies, respectively, and the ingroup was defined by the following characters: greater number of ventral ridges relative to the number of ridges dorsally, asymmetric bursa, and externodorsal rays differing in size. Sister-group relationships among Stilestrongylus and the other genera designated as outgroups are relatively consistent with those postulated by Durette-Desset's in a classification of the Nippostrongylinae. The ancestor of the species groups comprising Hassalstrongylus, Guerrerostrongylus, and Stilestrongylus originated and diversified in murids in the Neotropical region. Species of Hassalstrongylus occur in rodents between southeastern North America and the eastern part of South America (Brazil and Argentina), whereas species of Guerrerostrongylus and Stilestrongylus diversified exclusively in rodents in the Neotropics.

Synlophe patterns of the Haemonchinae of ruminants (Nematoda: Trichostrongyloidea)

The pattern of longitudinal ridges (synlophe) on the external cuticular surface of trichostrongylid nematodes has been shown to be of value for distinguishing species and determining relationships among higher taxa. In the process of studying Mecistocirrus digitatus, the large stomach worm of bovids of Asia that has been imported and established in the Americas, we observed remarkably similar synlophe patterns to those described for 3 species of Haemonchus and to those we examined in a species of Ashworthius. In all 3 genera, the synlophe is absent from the posterior part of the body. Only in Haemonchus does the synlophe extend beyond midbody. In both M. digitatus and Ashworthius sidemi, the synlophe extends posteriorly only about 1/4 of body length. In all 3 genera, the synlophe consists of about 30 ridges in the region of the esophagus with variation among species in specific areas, including additional pairs of subventral and subdorsal ridges and different lengths of sublateral ridges. This information is useful for identifying species and determining relationships among these large stomach worm parasites of cattle, sheep, goats, and farmed and wild cervids.

Status and origin of Haemonchinae (Nematoda: Trichostrongylidae) in deer: a survey conducted in France from 1985 to 1998

During our investigations on helminthofauna in roe deer (Capreolus capreolus) and red deer (Cervus elaphus) in France (1985-1998) we isolated nematodes not only of the genus Haemonchus Cobb, 1898 but also of the genus Ashworthius Le Roux 1930, both of which belong to the same subfamily of Haemonchinae. The prevalence of Ashworthius was 22% (65/294) in roe deer and 40% (10/25) in red deer. H. contortus was not found in red deer, whereas its prevalence was only 3% (9/294) in roe deer. These data contrast with those observed in other European countries. The presence of A. sidemi in red and roe deers in France suggests a case of parasitism imported via sika deer. A hypothesis of their spread is proposed.

Reassignment of Lamanema from Nematodirinae to Molineinae (Nematoda: Trichostronglyloidea)

The monospecific Lamanema historically has been assigned to the Nematodirinae within the Molineidae. Inconsistencies in morphological characters, within a phylogenetic context for Nematodirinae, led to a re-evaluation of the putative relationships and taxonomic placement of Lamanema. Among 7 putative synapomorphies for Nematodirinae, Lamanema possesses only 1, large eggs. Large eggs, sporadically present in phylogenetically disparate taxa of trichostrongyles, are equivocal with respect to placement of Lamanema; it is considered that possession of this single homoplasious character alone is insufficient justification to retain the genus in Nematodirinae. Affinities with the Trichostrongylidae (Cooperiinae or Haemonchinae) have also been proposed; however, Lamanema possess neither of 2 synapomorphies that diagnose monophyly of the family. Lamanema is retained in the Molineidae and transferred to the Molineinae as it possesses all characters of the family as currently defined. The origin of Lamanema represents a secondary colonization of ruminants by molineids and provides no context for elucidating the history of the Nematodirinae and Nematodirus.

Relationships of Nematodirus species and Nematodirus battus isolates (Nematoda: Trichostrongyloidea) based on nuclear ribosomal DNA sequences

Nuclear ribosomal sequence data from the internal transcribed spacers (ITS-1 and ITS-2), 5.8S subunit, and regions of the 18S and 28S genes were used to investigate sequence diversity among geographic samples of Nematodirus battus, and to infer phylogenetic relationships among Nematodirus species. Phylogenetic analysis of these data yielded strong support for relationships among species, depicting Nematodirus helvetianus and Nematodirus spathiger as sister-taxa and a clade of these 2 species and Nematodirus filicollis. This tree is consistent with caprine bovids as ancestral hosts, with a subsequent host shift to Bovinae in N. helvetianus. Eleven of 14 N. battus sequences were unique, with 19 variable sites among sequences representing 5 geographic samples. The lowest number of variable nucleotide sites was observed in samples representing apparently recent introductions to the United States and Canada, which is consistent with a population bottleneck concomitant with translocation. Comparison of directly sequenced polymerase chain reaction products and clones revealed evidence for intraindividual variation at some of the sequence sites, and this pattern of variation and that within geographic samples indicates incomplete rDNA repeat homogenization within species. This pattern of variation is not conducive for inferring phylogenetic relationships among sequences representing N. battus or addressing the putative history of introduction.