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.

Characterization of host responder types after a single Cooperia oncophora infection: kinetics of the systemic immune response

After primary infection with 100,000 third stage larvae of the intestinal nematode Cooperia oncophora in 3-month-old calves, a high variability in egg output and worm counts is observed. Based on this variability, infected animals can be divided in different responder types. The three major phenotypes can be classified as high, intermediate and low responder animals. We investigated whether calves classified into different responder types show different immune responses during infection. Peripheral blood eosinophil counts and flow cytometric analysis of different lymphocyte subsets of the blood did not reveal major differences between infected and control animals, nor between responder types. However, the levels of Cooperia-specific immunoglobulin (Ig)G1 and IgA during primary infection were significantly higher in intermediate responders than in low responders. In the intermediate responders, isotype specific responses were negatively correlated with parasitological parameters expressing worm expulsion and influence on worm fecundity. Total serum IgE levels were elevated in most of the infected animals. A quantitative positive relationship between worm counts and total serum IgE levels was observed. Based on the observed correlations, we propose a role for the humoral response against the maintenance of the infection in the gut.

A novel method for the isolation of gastro-intestinal nematode eggs that allows automated analysis of digital images of egg preparations and high throughput screening

A simple and robust method for the isolation of gastro-intestinal nematode eggs from faeces is described that uses both salt- and sugar solutions for flotation. Application of this 'salt-sugar' isolation method to large numbers of faecal samples of adult dairy cows indicates a 3- or 4-fold reduction in the proportion of e.p.g.-negative cows relative to studies that used other techniques for egg isolation. The procedure detects more eggs than the Wisconsin flotation method in replicate samples and in spiked egg-free faeces. The number of recovered eggs in spiked faecal samples is linear over a range of egg concentrations, and the transparent faecal preparations that result from the protocol can be stored as digital images which can be used as input for an efficient automated egg-counting procedure. The increased rate of processing of faeces combined with the large reduction of the percentage of e.p.g.-negative cows allows more accurate analysis of large numbers of adult or resistant animals for studies of nematode parasitism.

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.

Are Teladorsagia circumcincta (Nematoda) morphs equally able to survive under anthelmintic treatment in sheep on pastures?

The nematode Teladorsagia circumcincta is a polymorphic species, morphs T. c. trifurcata and T. c. circumcincta being the most frequent. Among other traits, T. c. trifurcata has lower infectivity than T. c. circumcincta. Anthelmintic treatments that regularly remove populations should favour the more infective T. c. circumcincta. The present investigation was intended to test the respective capabilities of the two morphs to withstand anthelmintic pressure. The nematode strain was susceptible to imidazothiazole and partly resistant to benzimidazole at the onset of experiment. A 2-year grazing season study was undertaken under four levels of anthelmintic pressure [from untreated controls to frequently treated with a poorly efficient benzimidazole (fenbendazole) or an efficient imidazothiazole (levamisole)]. The strain previously maintained in laboratory conditions regained its natural, original proportion of T. c. trifurcata during the first grazing season. The two morphs were equally resistant to fenbendazole; and the proportion of resistant nematodes did not vary between the two morphs. During the second grazing season, the treatments indirectly depleted the proportions of T. c. trifurcata, probably due to the poor infectivity of this morph.

[Libyostrongylus douglassii in ostriches (Struthio camelus ssp.) in the Netherlands: case report and review]

Several types of worms can parasitize ostriches, the most pathogenic of which is the wire worm (Libyostrongylus douglassii). This worm, which occurs in the stomach, can cause severe lesions which can lead to a high mortality, especially among young birds. This article describes mortality due to this parasite on an ostrich farm and discusses relevant literature on L. douglassii.

Effect of benzimidazole under-dosing on the resistant allele frequency in Teladorsagia circumcincta (Nematoda)

This experiment was designed to determine the effects of under-dosing on the frequency of benzimidazole resistant allele in the nematode Teladorsagia circumcincta. Fenbendazole (FBZ) was tested at 1/32, 1/16, 1/8 and 1/4 of the recommended dose for sheep (5 mg/kg body weight). The fraction of the susceptible homozygote (SS), susceptible heterozygote (RS) and resistant homozygote (RR) genotypes were compared among FBZ dose groups to evaluate differences between SS and RS genotype selective advantage. Almost all SS genotype worms were eliminated by 1/4 of the FBZ recommended dose, whereas a significant fraction of the RS genotype worms survived treatment. The selective advantage was 4.5 times higher for the RS genotype. This selective advantage was determined at 1/4 of the manufacturer's recommended dose of FBZ. This value should be taken as an indictor of the selective advantage of RS over the SS genotype when lambs are under-dosed. A computer simulation was used to study the putative spread of anthelmintic resistance over a range of RS selective advantages (2, 4.5 and 10-fold), with two average sizes of individual host worm population (20 or 2000 worms/host) and two initial R allele frequencies (0.1%, or 1%). In all situations, the lowest selective advantage of the RS genotype over the SS genotype was sufficient to promote the spread of resistance in susceptible populations. When the RS genotype had no selective advantage over the SS genotype, genetic drift almost always led to the loss of the R allele, except in the largest populations (average size = 2000 worms).

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.

The expression of immunity to Teladorsagia circumcincta in ewes and its relationship to protein nutrition depend on body protein reserves

We hypothesized that expression of immunity to gastrointestinal nematodes and its relationship with dietary metabolizable protein (MP) supply in ewes depended on body protein--but not on body fat reserves. Twin-bearing ewes were trickle infected with Teladorsagia circumcincta. Three mid-pregnancy feeding treatments were used, calculated to maintain body reserves (HH), maintain body protein- and lose body fat reserves (HL), or lose body reserves (LL), and followed by 2 isoenergetic, periparturient feeding treatments, calculated to provide either scarce (LP) or adequate (HP) amounts of MP. At the end of the mid-pregnancy feeding treatment, HL- and LL-ewes had a smaller backfat depth (approximately body fat reserves) than HH-ewes, and LL-ewes had a smaller muscle depth (approximately body protein reserves) and higher faecal egg counts (FEC) than HH- and HL-ewes. Overall, LL-ewes had higher periparturient FEC than HH- and HL-ewes, and LP-ewes had higher periparturient FEC than HP-ewes. However, LL-ewes offered the LP feed had higher periparturient FEC than ewes on any of the other combinations of feeding treatments. Feeding treatments affected plasma pepsinogen but not plasma IgA. The results support the view that body protein- but not body fat reserves may overcome consequences of dietary MP scarcity on periparturient breakdown of immunity to gastrointestinal nematodes.

Persistent efficacy of doramectin and moxidectin against Cooperia oncophora infections in cattle

Duplicate studies in France and Northern Ireland were carried out to determine the persistent efficacy of topical moxidectin and doramectin against natural infections of Cooperia oncophora. In each study, groups of 15 nematode-naïve calves were treated either with topical doramectin or moxidectin, and put out to graze on pasture contaminated with C. oncophora infective larvae. The persistent efficacy for preventing establishment of infection was assessed by the time to faecal egg excretion of C. oncophora eggs. It was found that the moxidectin treatment prevented infection for less than 10 days and the effect of doramectin lasted for 24 days.

Effects of previous suppressive anthelmintic treatments on subsequent nematode infection in fattening cattle in Argentina

The effect of previous suppressive anthelmintic treatments after weaning on parasitological parameters and weight gain of cattle was studied in the Pampeana region of Argentina. The study was carried out at two grazing fattening periods: April 1995/July 1996 and April 1997/July 1998. During both periods, 60 weaned calves that grazed contaminated pastures, were divided into three groups during the first part of the periods: GY1 group was treated every 2 weeks with doramectin while GY2 and GY3 groups remained untreated. During the second part of the periods, from October onwards GY1 and GY2 remained untreated and GY3 was treated every 2 weeks. In this second period two new groups of 20 weaning young calves were added: TG (treated every 2 weeks) and UG (untreated). Egg counts (EPG), larval cultures, pasture larval counts, serum pepsinogen (Pep) and live weight gain (LWG) were recorded monthly. Ostertagia, Cooperia, Trichostrongylus and Haemonchus were the predominant genera. Despite low levels of previous infection during the first part of the period, slight differences of EPG between GY1 (P<0.09) or UG (P<0.05) and GY2 were detected in the second part of the fattening period in 1995/1996. In 1997/1998 moderate infection levels during the first part of the period were observed. During the second part of this period, GY1 and UG showed higher (P<0.001) EPG than GY2, and only GY3 and TG had (P<0.05) lower Pep levels. Also, during the second part of 1997/1998, LWG responses of GY3 were higher (P<0.001) than those of GY1 and GY2. Live weight gain of GY2 exceeded GY1 by 10.7kg (P<0.006). Higher EPG and lower LWG of GY1 suggest that suppressive treatments negatively affected the level of resistance to infection of yearlings, but these effects were influenced by previous levels of nematode infection. The lack of differences between yearling (GY1) and calves (UG) groups suggest that, under the conditions of this study, there was no evidence that resistance to infection and the related parameters are influenced by the age.

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.

Multispecific resistance of trichostrongyles to benzimidazoles in a goat herd in Germany

Anthelmintic resistance of nematodes to benzimidazoles and ivermectin was suspected from field observations in an Angora goat herd in northern Hesse. Larvae of the caprine trichostrongyle isolate were used for artificial infections of helminth-naive sheep. Groups of the lambs were treated with albendazole (3.8 mg/kg p.o.) or ivermectin (0.2 mg/kg s.c.) four weeks after infection or remained untreated as controls and were necropsied one week later. Albendazole reduced the mean faecal egg counts by 82% and the mean worm counts of Haemonchus contortus by 22%, Ostertagia circumcincta by 10% and Trichostrongylus colubriformis by 41% as compared with the controls. Ivermectin was 100% effective. This is the first report from Germany of multispecific resistance to benzimidazoles in a trichostrongyle population of goats.

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.

The influence of relative resistance and urea-supplementation on deliberate infection with Teladorsagia circumcincta during winter

The consequences for lambs of infection over the winter with Teladorsagia circumcincta were quantified by deliberate, trickle infection of selected animals at 7 months of age. Infected and control uninfected animals were each allocated into four groups, relatively resistant animals on a normal diet, relatively resistant animals on an isocaloric diet supplemented with urea, and relatively susceptible animals on the same two diets. Resistance and susceptibility was assessed by faecal egg counts following natural infection during the summer preceding the deliberate infection. During the deliberate infection egg counts remained low and most parasites recovered at necropsy were inhibited larvae. Nonetheless, infection reduced weight gain, decreased albumin and fructosamine concentrations and provoked a noticeable pepsinogen and eosinophil response. As most larvae were inhibited these responses may have been largely a consequence of immuno-inflammatory responses in the host rather than the direct action of parasites themselves. Relatively resistant animals on the supplemented diet allowed fewer larvae to establish and had higher fructosamine concentrations, higher albumin concentrations and decreased pepsinogen responses. Therefore, a combination of relatively resistant sheep and nutritional supplementation appears most efficient at controlling infection.

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.

Cross-sectional serological survey on gastrointestinal and lung nematode infections in first and second-year replacement stock in the netherlands: relation with management practices and use of anthelmintics

A cross-sectional survey was carried out on 86 farms randomly distributed in The Netherlands. After housing following the first and the second grazing season (FGS and SGS) serum samples were collected to determine IgG levels against Cooperia oncophora and Dictyocaulus viviparus, and the pepsinogen content. A questionnaire was used to inquire on grazing management practices and the use of anthelmintic drugs. On 80.7 and 60.2% of the farms FGS and SGS animals, respectively, were treated at least once with an anthelmintic drug. The percentage for the SGS animals indicates that the use of anthelmintic drugs in those animals has increased enormously over the last 10-15 years. Generally, parasitic nematode control in the FGS is good on most farms, but it can be characterised as being overprotective. There is a tendency that if anthelmintic drugs are used in the FGS they also are used more often in the SGS. On 12 farms (14%), no anthelmintic drugs were given in the FGS and the SGS. These farms did not differ from the others with respect to management practices in any obvious way. The serological results were in general very low, indicating low levels of exposure to gastrointestinal nematode infection in both FGS and SGS animals. This was not surprising in view of the good to high level of nematode control practices reported by the farmers. Although not statistically significant, a consistent result was that serological results for the SGS animals were more often positive or on average higher on those farms where FGS parasite control tended to be excessive. For D. viviparus, a prevalence rate of 41% positive farms was found. Following comparison with previous data, it is speculated that lungworm (sero-)prevalence in replacement stock may be declining as a result of continuing high levels of parasite control in replacement stock. It is concluded that the results confirm previous surveys, lending support to the conclusion that parasitic nematode control on Dutch dairy farms, certainly in FGS calves, is good but tends to be overprotective.

Nematode parasites of sheep: a survey of epidemiological parameters and their application in a simple model

We review the literature on parameter values relevant to the epidemiology of strongyle nematode infections of domestic sheep. Information is subdivided by parasite genus, country of origin and climate type. While field observations have been made in a large number of countries, the bulk of studies under controlled conditions have been conducted in Australia, New Zealand and the UK. For these countries, experiments and parameters are interpreted in terms of a previously published model of nematode dynamics, and are used to calculate the basic reproduction number. Average values range from less than 6 for Haemonchus contortus in New Zealand and a winter rainfall region of Australia, to more than 16 for Ostertagia circumcincta in New Zealand and the UK. Additional considerations of the effects of climate and the annual replacement of host stock show that for conditions favourable for parasite transmission this is a robust indicator of parasite epidemiology. When climate variation and annual replacement are added to the model, it is shown to reasonably describe the qualitative behaviour of an experimental data set, indicating it to be a useful tool for further investigation of some of the underlying assumptions of sheep-nematode dynamics.

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.

Identification by polymerase chain reaction (PCR) of Marshallagia marshalli and Ostertagia gruehneri from Svalbard reindeer

A polymerase chain reaction (PCR) assay to identify two common abomasal nematodes Marshallagia marshalli and Ostertagia gruehneri of Svalbard reindeer was developed. Species-specific PCR primers were designed from internal transcribed spacer (ITS)-2 sequences of rDNA and validated using morphologically identified adult male and female nematodes. Using the species-specific primers, a 110 bp fragment was amplified from M. marshalli and its minor morph Marshallagia occidentalis and a 149 bp fragment was amplified from Ostertagia gruehneri and its minor morph Ostertagia arctica. No PCR products were amplified from the third rare species, Teladorsagia circumcincta, or DNA from the reindeer host. The assay provides a useful tool to estimate species composition for both sexes in this nematode community.