Gastrointestinal Nematode Parasites Research Articles

Helminth infections and gut microbiota - a feline perspective.

BackgroundInvestigations of the relationships between the gut microbiota and gastrointestinal parasitic nematodes are attracting growing interest by the scientific community, driven by the need to better understand the contribution of parasite-associated changes in the composition of the gut flora to both host malnutrition and immune modulation. These studies have however been carried out mainly in humans and experimental animals, while knowledge of the make-up of the gut commensal flora in presence or absence of infection by parasitic nematodes in domestic animals is limited. In this study, we investigate the qualitative and quantitative impact that infections by a widespread parasite of cats (i.e. Toxocara cati) exert on the gut microbiota of feline hosts.MethodsThe faecal microbiota of cats with patent infection by T. cati (= Tc+), as well as that of negative controls (= Tc-) was examined via high-throughput sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene, followed by bioinformatics and biostatistical analyses of sequence data.ResultsA total of 2,325,366 useable high-quality sequences were generated from the faecal samples analysed in this study and subjected to further bioinformatics analyses, which led to the identification of 128 OTUs and nine bacterial phyla, respectively. The phylum Firmicutes was predominant in all samples analysed (mean of 53.0%), followed by the phyla Proteobacteria (13.8%), Actinobacteria (13.7%) and Bacteroidetes (10.1%). Among others, bacteria of the order Lactobacillales, the family Enterococcaceae and genera Enterococcus and Dorea showed a trend towards increased abundance in Tc+ compared with Tc- samples, while no significant differences in OTU richness and diversity were recorded between Tc+ and Tc- samples (P = 0.485 and P = 0.581, respectively). However, Canonical Correlation and Redundancy Analyses were able to separate samples by infection status (P = 0.030 and P = 0.015, respectively), which suggests a correlation between the latter and the composition of the feline faecal microbiota.ConclusionsIn spite of the relatively small number of samples analysed, subtle differences in the composition of the gut microbiota of Tc+ vs Tc- cats could be identified, some of which in accordance with current data from humans and laboratory animal hosts. Nevertheless, the findings from this study contribute valuable knowledge to the yet little explored area of parasite-microbiota interactions in domestic animals.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1908-4) contains supplementary material, which is available to authorized users.

Structural Basis for Carbohydrate Recognition and Anti-inflammatory Modulation by Gastrointestinal Nematode Parasite Toxascaris leonina Galectin

Toxascaris leonina galectin (Tl-gal) is a galectin-9 homologue protein isolated from an adult worm of the canine gastrointestinal nematode parasite, and Tl-gal-vaccinated challenge can inhibit inflammation in inflammatory bowel disease-induced mice. We determined the first X-ray structures of full-length Tl-gal complexes with carbohydrates (lactose, N-acetyllactosamine, lacto-N-tetraose, sialyllactose, and glucose). Bonds were formed on concave surfaces of both carbohydrate recognition domains (CRDs) in Tl-gal. All binding sites were found in the HXXXR and WGXEER motifs. Charged Arg61/Arg196 and Glu80/Glu215 on the conserved motif of Tl-gal N-terminal CRD and C-terminal CRD are critical amino acids for recognizing carbohydrate binding, and the residues can affect protein folding and structure. The polar amino acids His, Asn, and Trp are also important residues for the interaction with carbohydrates through hydrogen bonding. Hemagglutination activities of Tl-gal were inhibited by interactions with carbohydrates and mutations. We found that the mutation of Tl-gal (E80A/E215A) at the carbohydrate binding region induced protein aggregation and could be caused in many diseases. The short linker region between the N-terminal and C-terminal CRDs of Tl-gal was very stable against proteolysis and maintained its biological activity. This structural information is expected to elucidate the carbohydrate recognition mechanism of Tl-gal and improve our understanding of anti-inflammatory mediators and modulators of immune response.

Structure-Activity Relationship of Condensed Tannins and Synergism with trans-Cinnamaldehyde against Caenorhabditis elegans.

Parasitic gastrointestinal nematodes (GIN) of livestock are increasingly developing resistance to synthetic nematocidal drugs. Moreover, the use of nematocides can induce ecotoxicity by affecting free-living nematodes. Condensed tannins (CT) are a structurally diverse group of bioactive plant compounds possessing anthelmintic activity against GIN. We investigated the relationship between the chemical structure of contrasting, purified CT and nematocidal effects using Caenorhabditis elegans. We also explored whether the nematocidal activity of CT could synergize with trans-cinnamaldehyde (CIN). A nonsignificant correlation was evident between the ability of CT fractions to inhibit C. elegans motility and the molar proportion of prodelphinidin subunits in purified CT samples. Synergistic inhibition of motility was achieved by combinations of CT and CIN. Galloylation of procyanidins was also a key factor for synergy. To increase the nematocidal effect of CT, plant sources containing CT with specific structural features could be selected and combined with compounds acting in synergy.

Abomasal mucosal immune responses of cattle with limited or continuous exposure to pasture-borne gastrointestinal nematode parasite infection

It has been well documented that cattle raised on pasture are slow in weight gain when compared to those fed with grain. Inflammation in the digestive system commonly caused by pasture-transmitted gastrointestinal (GI) nematode parasites that could negatively impact feed conversion has never been compared in cattle raised with no pasture exposure (NPE, uninfected), limited pasture exposure (LPE, exposure until weaning), or continuous pasture exposure (CPE, life time exposure). In the present study, the abomasal mucosal immune responses and inflammation of LPE and CPE cattle were investigated. Our results indicate that CPE cattle displayed inflamed abomasa with enlarged draining lymph nodes, the presence of Ostertagia ostertagi larvae and higher levels of Ostertagia-specific antibodies in circulation. The level of B cells was elevated in the abomasal mucosa in the presence (nodular) or absence (non-nodular) of Ostertagia-specific pathology, where B cells were 4-fold higher in the nodular mucosa. Foxp3+ CD4T cells were also noticeably elevated in both the abomasal mucosa and blood, but were only slightly higher in non-nodular mucosa than in the nodular mucosa of CPE animals. In contrast, LPE animals presented no enlargement of abomasal draining lymph nodes and exhibited little to no immune cell infiltration in the abomasal mucosa. Further, CPE animals had higher numbers of mucosal mast cells when compared to LPE animals, though mucosal mast cells were high in all animals. Overall, CPE cattle displayed significantly higher levels of inflammation and pathology in their abomasa and may explain in part slowed weight gain relative to LPE animals. The results of this study emphasize the need for GI nematode parasite control in CPE animals and development and application of vaccines which are compatible with the organic cattle production system.

Ivermectin failure in the control of Oxyuris equi in a herd of ponies in France

Drug resistance in equine gastro-intestinal parasitic nematodes has been reported throughout the world. While the focus is usually put on cyathostomins, observations of macrocylic lactone failure against Oxyuris equi have accumulated over the last decade. Here we report the failure of ivermectin in the control of O. equi in an experimental Welsh pony herd.In a first trial, 6 ponies previously drenched with moxidectin and showing patent O. equi infections were administered ivermectin and subsequently monitored for O. equi egg excretion over one month. This trial demonstrated a failure of ivermectin to control O. equi egg excretion as half of ponies demonstrated recurrent egg excretion in the peri-anal region during 21days after treatment.One year later, six female Welsh ponies drenched with moxidectin demonstrated signs of itching and scratching in their peri-anal region with worms being found transiently in fecal materials three weeks later. Ponies were allocated to three treatment groups, i.e. ivermectin, pyrantel embonate and fenbendazole and monitored for egg excretion over five weeks. Fenbendazole and pyrantel embonate broke ivermectin suboptimal efficacy as soon as 8 and 14days respectively after treatment, while egg excretion remained constant throughout the 41-day long trial in the ivermectin-treated ponies.This is the first report of ivermectin failure against O. equi in France. In the absence of critical efficacy test, it remains unclear whether true resistance is at stake or if these observations confound a constitutive suboptimal efficacy of ivermectin against O. equi.

Faecal egg counts and immune markers in a line of Scottish Cashmere goats selected for resistance to gastrointestinal nematode parasite infection

This study aimed to investigate the effect of selection for low faecal egg count (FEC) in Scottish Cashmere goats in comparison to a control line of unselected goats grazing the same pasture. Goats from generations F2 through to F9 were monitored for FEC, bodyweight, peripheral eosinophilia and IgG, IgA and IgE response against Teladorsagia circumcincta from the end of their first grazing season, through winter housing (during which a single artificial challenge dose of 10,000 drug susceptible T. circumcincta was given) and the following full grazing season. The study demonstrated that selected line animals excreted a significantly lower number of parasite eggs (P<0.01) in the majority of generations examined. Liveweight productivity was unaffected by selection. Although selected line animals had greater numbers of circulating eosinophils in many of the generations (four generations of males and six generations of females, P<0.05), there was no direct link between eosinophilia and reduced FEC. Immunoglobulin levels showed no consistent difference between selected and control lines. IgG, IgA and IgE levels were not different between lines over the whole dataset(P>0.05), although the selected line had significantly elevated or reduced levels (P<0.05) for all three within individual generations. There were significant associations between increased IgG and reduced FEC under artificial infection conditions (P=0.02). Increased IgA was also significantly associated with elevated FEC during the second grazing season (P<0.001). The study demonstrates that selection produced a line of goats with consistently reduced FEC compared with control animals, but did not identify a clear relationship between any of the immune markers measured and faecal egg output.

First report of the in vitro nematicidal effects of camel milk

Antipathogenic properties of camel milk have been investigated to substitute for drugs hence overcome drug resistance. The main objective of this present study was to investigate the anthelmintic activity of camel milk in relationship to its chemical composition. In vitro anthelmintic effects of camel milk against Haemonchus contortus from sheep were ascertained by egg hatching and worm motility inhibitions in comparison to milks from cow, ewe and goat as well as a reference drug albendazole. Chemical composition revealed that camel milk has higher contents of protective protein (lactoferrin) and vitamin C than other species’ milk. It showed ovicidal activity at all tested concentrations and completely inhibited egg hatching at a concentration close to 100mg/mL (inhibitory concentration (IC50)=42.39mg/mL). Camel milk revealed in vitro activity against adult parasites in terms of the paralysis and/or death of the worms at different hours post treatment. After 8h of exposure, it induced 100% mortality at the highest tested concentration. There was 82.3% immobility of worms in albendazole 8h post-exposition. No such effects were seen with the other species’ milks. Bioactive compounds such as lactoferrin and vitamin C may be involved in such an effect.To our knowledge, these results depict for the first time that camel milk possesses in vitro anthelmintic properties and further in vitro and in vivo trials against different parasite species and stages are required to make use of this milk for the control of gastrointestinal nematode parasites.

Proteomic Analysis of the Excretory and Secretory Proteins of Haemonchus contortus (HcESP) Binding to Goat PBMCs In Vivo Revealed Stage-Specific Binding Profiles.

Haemonchus contortus is a parasitic gastrointestinal nematode, and its excretory and secretory products (HcESPs) interact extensively with the host cells. In this study, we report the interaction of proteins from HcESPs at different developmental stages to goat peripheral blood mononuclear cells (PBMCs) in vivo using liquid chromatography-tandem mass spectrometry. A total of 407 HcESPs that interacted with goat PBMCs at different time points were identified from a H. contortus protein database using SEQUEST searches. The L4 and L5 stages of H. contortus represented a higher proportion of the identified proteins compared with the early and late adult stages. Both stage-specific interacting proteins and proteins that were common to multiple stages were identified. Forty-seven interacting proteins were shared among all stages. The gene ontology (GO) distributions of the identified goat PBMC-interacting proteins were nearly identical among all developmental stages, with high representation of binding and catalytic activity. Cellular, metabolic and single-organism processes were also annotated as major biological processes, but interestingly, more proteins were annotated as localization processes at the L5 stage than at the L4 and adult stages. Based on the clustering of homologous proteins, we improved the functional annotations of un-annotated proteins identified at different developmental stages. Some unnamed H. contortus ATP-binding cassette proteins, including ADP-ribosylation factor and P-glycoprotein-9, were identified by STRING protein clustering analysis.

Prevalence of parasitic gastrointestinal nematodes of small ruminants at Jalingo abattoir, Taraba state, Nigeria

A cross-sectional study was conducted from December, 2014 to May, 2015 on 914 animals (345 sheep and 569 goats) at Jalingo abattoir, Taraba State, Nigeria based on faecal examination. The objective of the study was to determine the prevalence rate of parasitic gastrointestinal nematodes in slaughtered small ruminants according to thespecies, age and sex of the animals. A total of 914 faecal samples were examined by Simple Floatation Test Tube Technique, 390 (42.7%) were infested with parasitic gastrointestinal nematodes. The species of nematodes were Haemonchus, Osophagustomum, Strongyloids, Ostertagia and Trichostrongyle. Out of the 345 sheep and 569 goats examined during the period, 144 (41.7%) and 246 (43.2%) were infected with parasitic gastrointestinal nematodes respectively. There was no statistical significance (P&gt;0.05) on the prevalence of the infection between the species. Out of the 306 and 371 adult sheep and goats examined, 136 (44.4%) and 175 (47.2%) were infected respectively. Among the sheep and goats examined, the adult was found to be more infected than the young. However, infection rates among the young animals of both species was statistical significant (P&lt;0.05). According to the sex, out of the 120 rams and 375 bucks examined, 44 (36.7%) and 164 (43.7%) were infected respectively. Out of the 225 ewes and194 does that were examined, 100 (44.4%) and 82 (42.3%) were infected respectively. There was no statistical significance (P&gt;0.05) among male and female animals. These results show that parasitic gastrointestinal nematode was prevalent in both sheep and goats at Jalingo abattoir and all the parasite eggs detected were strongyle type. Hence, further laboratory examination is recommended to identify parasite species in order to design appropriate control measures.Keywords: Gastrointestinal nematodes, Jalingo Abattoir, Prevalence, Small ruminants, Taraba State

Anthelmintic effects of forage chicory (Cichorium intybus) against gastrointestinal nematode parasites in experimentally infected cattle.

Two experiments studied the effects of dietary chicory against gastrointestinal nematodes in cattle. In Experiment (Exp.) 1, stabled calves were fed chicory silage (CHI1; n = 9) or ryegrass/clover hay (CTL1; n = 6) with balanced protein/energy intakes between groups. After 16 days, all calves received 10 000 Ostertagia ostertagi and 66 000 Cooperia oncophora third-stage larvae (L3) [day (D) 0 post-infection (p.i.)]. In Exp. 2, calves were assigned to pure chicory (CHI2; n=10) or ryegrass/clover (CTL2; n = 10) pastures. After 7 days, animals received 20 000 O. ostertagi L3/calf (D0 p.i.) and were moved regularly preventing pasture-borne infections. Due to poor regrowth of the chicory pasture, CHI2 was supplemented with chicory silage. At D40 p.i. (Exp. 1) and D35 p.i. (Exp. 2) calves were slaughtered for worm recovery. In Exp.1, fecal egg counts (FEC) were similar between groups. However, O. ostertagi counts were significantly reduced in CHI1 by 60% (geometric mean; P < 0·01), whereas C. oncophora burdens were unaffected (P = 0·12). In Exp. 2, FEC were markedly lowered in CHI2 from D22 p.i onwards (P < 0·01). Ostertagia ostertagi adult burdens were significantly reduced in CHI2 by 66% (P < 0·001). Sesquiterpene lactones were identified only in chicory (fresh/silage). Chicory shows promise as an anti-Ostertagia feed for cattle and further studies should investigate its on-farm use.

In vitro and in vivo anthelmintic activities of Iris kashmiriana Linn.

In search of a natural antiparasitic, in vitro and in vivo anthelmintic activities of methanol and aqueous extracts of Iris kashmiriana Linn. rhizome were tested against gastrointestinal nematodes of sheep. A worm motility inhibition assay was used for in vitro study and a faecal egg count reduction assay was used for in vivo study. Crude aqueous extracts of I. kashmiriana exhibited greater anthelmintic activity against Haemonchus contortus than crude methanolic extract (P<0.05). The aqueous extracts of I. kashmiriana resulted in a mean worm motility inhibition of 85.0%, while methanolic extracts resulted in a mean worm motility inhibition of 100.0%. The in vivo anthelmintic activity of aqueous and methanolic extracts of I. kashmiriana in sheep naturally infected with mixed gastrointestinal nematodes species demonstrated a maximum (70.27%) egg count reduction in sheep treated with aqueous extracts at 2gkg−1 body weight on day 15 after treatment, closely followed by methanolic extracts at 1gkg−1 body weight on day 15 after treatment (33.17% egg count reduction) while as lethal concentration (LC50) values of aqueous and methanolic extracts of I. kashmiriana on adult worms of gastrointestinal nematodes of sheep H. contortus are 18.50mg/ml and 16.66mg/ml respectively. Thus aqueous extracts exhibited greater anthelmintic activity under both in vitro and in vivo conditions; this could be due to the presence of water soluble active ingredients in I. kashmiriana. From the present study it can be suggested that I. kashmiriana rhizome exhibited significant anthelmintic activity against gastrointestinal nematodes of sheep and has the potential to contribute to the control of gastrointestinal nematode parasites of small ruminants.

Incidence of gastrointestinal helminth parasites in goats and their therapeutic management

As per faecal examination the incidence of gastrointestinal helminth parasite infection in goats was 80 per cent. The percentage of infections was highest in monsoon season followed by winter and summer season. Susceptibility to the infection was highest in older age groups (>24 months age) followed by adult goat (12.1-24 months age) and kid (1-12 months age). The infection percentage in female is slightly high as compared to the male goats due to maintenance and production stress. Majority of the goats were suffering from mix infection of Haemonchus species, Trichostrongylus species, Stongyloidesspecies, Oesophagostomumspp., amphistomes and Fasciola spp. with some cases of Trichuris spp., Bunostomum spp. and Moniezia spp. Ivermectin and Clorsulon was found to be most effective for the treatment of gastrointestinal nematode parasites as compared to Closantel and Fenbendazole.

Selenoprotein Expression in Macrophages Is Critical for Optimal Clearance of Parasitic Helminth Nippostrongylus brasiliensis

The plasticity of macrophages is evident in helminthic parasite infections, providing protection from inflammation. Previously we demonstrated that the micronutrient selenium induces a phenotypic switch in macrophage activation from a classically activated (pro-inflammatory; M1/CAM) toward an alternatively activated (anti-inflammatory; M2/AAM) phenotype, where cyclooxygenase (COX)-dependent cyclopentenone prostaglandin J2 (15d-PGJ2) plays a key role. Here, we hypothesize that dietary selenium modulates macrophage polarization toward an AAM phenotype to assist in the increasing clearance of adult Nippostrongylus brasiliensis, a gastrointestinal nematode parasite. Mice on a selenium-adequate (0.08 ppm) diet significantly augmented intestinal AAM presence while decreasing adult worms and fecal egg production when compared with infection of mice on selenium-deficient (<0.01 ppm) diet. Further increase in dietary selenium to supraphysiological levels (0.4 ppm) had very little or no impact on worm expulsion. Normal adult worm clearance and enhanced AAM marker expression were observed in the selenium-supplemented Trsp(fl/fl)Cre(WT) mice that express selenoproteins driven by tRNA(Sec) (Trsp), whereas N. brasiliensis-infected Trsp(fl/fl)Cre(LysM) selenium-supplemented mice showed a decreased clearance, with lowered intestinal expression of several AAM markers. Inhibition of the COX pathway with indomethacin resulted in delayed worm expulsion in selenium-adequate mice. This was rescued with 15d-PGJ2, which partially recapitulated the effect of selenium supplementation on fecal egg output in addition to increasing markers of AAMs in the small intestine. Antagonism of PPARγ blocked the effect of selenium. These results suggest that optimal expression of selenoproteins and selenium-dependent production of COX-derived endogenous prostanoids, such as Δ(12)-PGJ2 and 15d-PGJ2, may regulate AAM activation to enhance anti-helminthic parasite responses.

Prevalence of common gastro-intestinal nematode infections in commercial goat farms in Central Uganda

Gastro-intestinal nematode (GIN) infections are the leading cause of production losses in commercial goat farms worldwide. This study determined the level of gastro-intestinal nematodes (GIN) infection and identified the common GIN parasites in commercial goat production in Central Uganda. Faecal egg counts and morphological larval identification in coprocultures were used to estimate the burden of common GIN of goats in Central Uganda. Egg shedding was detected in 43% of the goats. Worm burdens were highest (498 -713 epg) in goats 3-5 and 8-9 months old. Goats of 6-8 and older than 9 months showed relatively lower egg counts (254- 491epg). Haemonchus (56%), Oesophagostomum (33%) and strongyloides species (11%) were the only nematode species identified on coprocultures.Key words: Gastro-intestinal nematode, Haemonchus species, Oesophagostomum, worms

Curiouser and Curiouser: The Macrocyclic Lactone, Abamectin, Is also a Potent Inhibitor of Pyrantel/Tribendimidine Nicotinic Acetylcholine Receptors of Gastro-Intestinal Worms

Nematode parasites may be controlled with drugs, but their regular application has given rise to concerns about the development of resistance. Drug combinations may be more effective than single drugs and delay the onset of resistance. A combination of the nicotinic antagonist, derquantel, and the macrocyclic lactone, abamectin, has been found to have synergistic anthelmintic effects against gastro-intestinal nematode parasites. We have observed in previous contraction and electrophysiological experiments that derquantel is a potent selective antagonist of nematode parasite muscle nicotinic receptors; and that abamectin is an inhibitor of the same nicotinic receptors. To explore these inhibitory effects further, we expressed muscle nicotinic receptors of the nodular worm, Oesophagostomum dentatum (Ode-UNC-29:Ode-UNC-63:Ode-UNC-38), in Xenopus oocytes under voltage-clamp and tested effects of abamectin on pyrantel and acetylcholine responses. The receptors were antagonized by 0.03 μM abamectin in a non-competitive manner (reduced Rmax, no change in EC50). This antagonism increased when abamectin was increased to 0.1 μM. However, when we increased the concentration of abamectin further to 0.3 μM, 1 μM or 10 μM, we found that the antagonism decreased and was less than with 0.1 μM abamectin. The bi-phasic effects of abamectin suggest that abamectin acts at two allosteric sites: one high affinity negative allosteric (NAM) site causing antagonism, and another lower affinity positive allosteric (PAM) site causing a reduction in antagonism. We also tested the effects of 0.1 μM derquantel alone and in combination with 0.3 μM abamectin. We found that derquantel on these receptors, like abamectin, acted as a non-competitive antagonist, and that the combination of derquantel and abamectin produced greater inhibition. These observations confirm the antagonistic effects of abamectin on nematode nicotinic receptors in addition to GluCl effects, and illustrate more complex effects of macrocyclic lactones that may be exploited in combinations with other anthelmintics.

Use of fluorescent lectin binding to distinguish eggs of gastrointestinal nematode parasites of sheep

The binding of a panel of 19 lectins to carbohydrates on the eggs of economically important nematode parasites of sheep has been assessed as the basis of a rapid test to distinguish parasite eggs, at least at the genus level. A total of six lectins can be used to identify eggs of six nematode parasites: peanut agglutinin (PNA) for Haemonchus contortus; Lens culinaris agglutinin (LCA) for Teladorsagia sp; Aleuria aurantia agglutinin (AAL) for Trichostrongylus sp; Psophocarpus tetragonolobus‑II (PTLII) for Nematodirus sp; Lotus tetragonolobus lectin (LTL) for Cooperia sp and wheat germ agglutinin (WGA) for Chabertia ovina. For WGA, LCA and LTL, weak binding was also observed to H. contortus and Teladorsagia sp, Trichostrongylus sp and C. ovina eggs, respectively. Nematode eggs in two faecal samples were identically identified by both lectin binding and PCR, except for PCR identification of the eggs of Nematodirus sp, as these did not lyse. Lectins bound best to H. contortus eggs extracted from fresh faecal samples or after storage at room temperature or 4°C for up to 24h, but eggs stored at −20°C or −80°C did not bind PNA.

Risk Factors Associated with the Occurrence of Gastrointestinal Helminths among Indigenous Donkeys (Equus asinus) in Northeastern Nigeria.

Aim. This survey study was conducted from April 2014 through March 2015 in Bauchi, Yobe, and Gombe states, northeastern Nigeria, to explore the risk factors associated with the occurrence of gastrointestinal helminthosis among indigenous donkeys (Equus asinus). Materials and Methods. A total of six hundred fresh faecal samples were randomly collected from indigenous donkeys of varying age, sex, and settlements. Simple flotation and sedimentation techniques were used for the detection of helminths eggs. Results. Three gastrointestinal nematode parasites were encountered including Strongyle, Parascaris equorum, and Oxyuris equi. An overall prevalence of 98.3% was obtained, of which 78.3%, 40.3%, and 17.5% were, respectively, from Strongyle, Parascaris equorum, and Oxyuris equi. Age, sex, and season were not statistically associated with the risk of helminth infection as were the different study areas (p > 0.05). However, body condition score, settlement, anthelminthic medication history, and management practices were significantly associated with the risk of gastrointestinal helminthosis. Statistically high prevalence of helminthic infections was observed in donkeys, with poor (thin) body condition, from rural settlements, that were not dewormed and raised under poor management systems (p < 0.001). Conclusion. It is concluded from the study that gastrointestinal helminths particularly Strongyle were endemic among the indigenous donkeys in northeastern Nigeria. Further control and preventive measures were discussed.

Regulation of type 2 diabetes by helminth-induced Th2 immune response.

Helminth-induced type 2 cytokines increase the number of regulatory T cells and alternatively activated macrophages, resulting in modulation of the host–immune system. Studies on these parasite-induced immunoregulatory mechanisms might contribute to the development of new therapies for inflammatory diseases, including type 2 diabetes (T2D). Previous studies have suggested that progression of obesity-associated metabolic abnormalities is under pathophysiological control of CD4+ T cells. Glucose absorption through the intestinal epithelium reduced after infection in a STAT-6-dependent manner. In this study, we investigated whether infection with the gastrointestinal nematode parasite Heligmosomoides polygyrus (Hp) can modulate T2D-associated pathology in a mouse model (KK-Ay/TaJcl). KK-Ay/TaJcl mice were inoculated with infective third-stage Hp larvae and studied at Day 8 following infection. Uninfected KK-Ay/TaJcl mice showed high blood glucose levels even 120 min after administration of glucose by IP injection. However, it was significantly improved in the infected group. HOMA-IR, fat accumulation and FAS gene expression in the liver were significantly decreased by Hp infection. GLUT2 gene expression in this group was significantly lower than that in the uninfected diabetic mice, which might be related to the decrease in glucose absorption in the parasite-infected intestine. In conclusion, helminth-induced type 2 immune responses might contribute to T2D disease control.

Anthelmintic resistance in gastrointestinal nematodes of dairy cattle in the Macalister Irrigation District of Victoria.

To report anthelmintic resistance in gastrointestinal nematode parasites of cattle on commercial dairy farms in the Macalister Irrigation District of Gippsland, Victoria. Faecal egg count reduction tests (FECRTs) were used to assess anthelmintic resistance on 20 Macalister Irrigation District dairy farms between May 2013 and June 2014. All three currently available anthelmintic classes for cattle nematodes in Australia were tested. Faecal samples were collected 10-14 days post-treatment for individual faecal egg counts (FEC) and larval differentiation. The arithmetic mean FEC for each treatment group was compared with an untreated control post-treatment. Resistance was defined as <95% reduction in FEC, with a lower 95% confidence interval <90% when the mean FEC of the control group, differentiated by genus, was greater than 25 eggs/g. Anthelmintic resistance was present on all 20 dairy farms involved in this study. Resistance to doramectin in at least one species was detected on 15/20 (70%) farms, fenbendazole on 16/20 (80%) farms and levamisole on 5/20 (25%) farms. On three farms, resistance by Ostertagia ostertagi to all three anthelmintic classes was detected. This is the first report of anthelmintic-resistant O. ostertagi on Australian dairy farms. Resistance to all three available anthelmintic classes is of concern, given the high pathogenicity of this species. The study highlights the need for veterinarians and dairy farmers to be aware of the risks posed by anthelmintic resistance.

Fecal antibody levels as a noninvasive method for measuring immunity to gastrointestinal nematodes in ecological studies.

Among-individual variation in antibody-associated immunity to gastrointestinal nematode parasites (GIN) is known be associated with life-history traits and vital rates in wild vertebrate systems. To date, measurement of levels of antibodies against GIN antigens in natural populations has exclusively been based on invasive blood sampling techniques. Previous work in laboratory rodents and ruminant livestock suggests that antibody measures from feces may provide a viable noninvasive approach. We measured total and anti-GIN antibodies of different isotypes (immunoglobulin (Ig) G, IgA and IgE) from paired samples of plasma and feces from free-living Soay sheep of different ages and sexes. We tested the correlations among these measures as well as their associations with body mass and Strongyle nematode fecal egg counts (FEC). Significant positive correlations were present among plasma and fecal anti-GIN antibody levels for IgG and IgA. Generally, correlations between total antibody levels in plasma and feces were weaker and not significant. No significant relationships were found between any antibody measures and body mass; however, fecal anti-GIN antibody levels were significantly negatively correlated with FEC. Our data clearly demonstrate the feasibility of measuring anti-GIN antibodies from fecal samples collected in natural populations. Although associations of fecal antibody levels with their plasma counterparts and FEC were relatively weak, the presence of significant correlations in the predicted direction in a relatively small and heterogeneous sample suggests fecal antibody measures could be a useful, noninvasive addition to current eco-immunological studies.