Parasites In Sheep Research Articles

Spatial patterns of Fasciola hepatica and Calicophoron daubneyi infections in ruminants in Ireland and modelling of C. daubneyi infection

BackgroundFasciola hepatica has always represented a threat to Irish livestock because the Irish climate is highly suitable for the main local intermediate host of the parasite, the snail Galba truncatula. The recent clinical emergence of infections due to Calicophoron daubneyi has raised the question of whether the two parasites, which share a niche during part of their life-cycles, interact in some way. Here, we used geographical information systems (GIS) to analyse the distribution of both parasites in cattle and sheep. We also developed the first predictive model of paramphistomosis in Ireland.ResultsOur results indicated that, in cattle, liver fluke infection is less common than rumen fluke infection and does not exhibit the same seasonal fluctuations. Overall, we found that cattle had a higher likelihood of being infected with rumen fluke than sheep (OR = 3.134, P < 0.01). In addition, infection with one parasite increased the odds of infection with the other in both host species. Rumen fluke in cattle showed the highest spatial density of infection. Environmental variables such as soil drainage, land cover and habitat appeared to be the most important risk factors for C. daubneyi infection, followed by rainfall and vegetation. Overall the risk of infection with this parasite was predicted to be higher in the west of the country.ConclusionsThis study shows differences between the infection rates and spatial patterns of bovine and ovine infections with F. hepatica and C. daubneyi in Ireland. Whether the reasons for this are due to susceptibility, exposure and/or management factors is yet to be determined. Furthermore, the rumen fluke model indicates distinct risk factors and predicted distribution to those of F. hepatica, suggesting potential biological differences between both parasite species.

Chemical Characterization of Opuntia ficus-indica (L.) Mill. Hydroalcoholic Extract and Its Efficiency against Gastrointestinal Nematodes of Sheep.

Opuntia ficus-indica (L.) Mill. is a xerophylous plant that originated in tropical and subtropical America. This plant is popularly known in Brazil as “palma forrageira” (cactus pear) and plays a fundamental role in animal nutrition, mainly in the Northeastern semi-arid region of the country. The plant has several uses since it presents bioactive compounds that confer biological and pharmacological properties. In this context, the cactus pear can also be considered a potential product to combat parasite infections. The objective of this study was to chemically characterize the O. ficus-indica hydroalcoholic extract (OFIEOH) and to determine its efficacy against gastrointestinal parasites using in vitro tests. Initially, the hydroalcoholic extract from cladode peels of O. ficus-indica was produced by maceration for 21 days. For the chemical characterization, colorimetric dosages were performed for carbohydrates, proteins, phenols and condensed tannins. Liquid chromatography coupled to mass spectrometry/electron spray ionization (LC-MS/ESI) was used to characterize the polyphenolic profile of the OFIEOH extract. Fifteen compounds were identified in the OFIEOH extract, such as methyl, glycosylated and aglycone quercetin derivatives and aglycone and glycosylated kaempferol derivatives. Tri-glycosylated methyl quercetin derivatives were the main compounds identified. In vitro egg hatch (EHT) and larval migration tests (LMT) were used in a range of concentrations of OFIEOH from 12.5 to 100 mg/mL for EHT and 12.5 to 200 mg/mL for LMT. In addition, the LMT was used to test ivermectin (IVM) (from 11.4 to 57.1 µM), associated with the inhibitory concentration of 50% (IC50) for OFIEOH. The combination of OFIEOH (12.5 to 200 mg/mL) plus the IC50 of IVM was also tested. The efficacy of OFIEOH alone varied from 19.33 to 90.0% using the EHT. The LMT revealed an efficacy of 5.78 to 77.26% for the extract. Both tests showed a concentration-dependence inhibitory effect. We found a drug-extract antagonistic neutralizing effect when doses of IVM were added to OFIEOH (maximum efficacy of 73.78%), while a positive additive effect was observed when OFIEOH was added to the IC50 of IVM (IC50 of 82.79 for OFIEOH alone against an IC50 of 55.08 of OFIEOH + IVM). The data from this work indicate that OFIEOH alone may be considered as a suitable ecofriendly product to control gastrointestinal parasites of sheep, offering a more holistic approach to improve animal farming and welfare. The drug-extract interaction is also a promising therapeutic alternative, reducing the final dose to the host, with an optimum combination effect.

DEMONSTRATION OF THE ANTHELMINTIC POTENCY OF MARIMASTAT IN THE HELIGMOSOMOIDES POLYGYRUS RODENT MODEL.

In the course of a structure based drug discovery program the known anticancer candidate marimastat was uncovered as a potent inhibitor of an enzyme in nematode cuticle biogenesis. It was shown to kill Caenorhabditis elegans, and the sheep parasites Haemonchus contortus and Teladorsagia circumcinta via an entirely novel nematode-specific pathway, specifically by inhibiting cuticle-remodelling enzymes that the parasites require for the developmentally essential moulting process. This discovery prompted an investigation of the compound's effect on Heligmosomoides polygyrus parasites in a mouse model of helminth infection. Mice were administered the drug via oral gavage daily from day of infection for a period of 2 wk. A second group received the drug via intra-peritoneal implantation of an osmotic minipump for 4 wk. Control groups were administered identical volumes of water by oral gavage in both cases. Counts of H. polygyrus faecal egg and larval load showed that marimastat effected a consistent and significant reduction in egg laying, and a consistent but minor reduction in adult worm load when administered every day, starting on the first day of infection. However, the drug failed to have any significant effect on egg counts or worm burdens when administered to mice with established infections. Therefore, marimastat does not appear to show promise as an anthelmintic in gastrointestinal nematode infections, although other metalloproteases such as batimastat may prove more effective.

Genetic parameters for fecal egg counts and their relationship with body weights in Katahdin lambs.

Reliance on anthelmintic drugs to control internal parasites in sheep is no longer sustainable because of the development of resistance to these drugs in parasite populations. Genetic selection may offer an alternative long-term solution, as differences in parasite resistance exist both within and among sheep breeds. However, selection for parasite resistance may have correlated effects on other production traits. The objectives of this study were to estimate genetic parameters for weaning (WFEC) and postweaning (PWFEC) fecal egg counts (FEC) and assess their relationship with birth (BWT), weaning (WWT), and postweaning (PWWT) BW in Katahdin lambs. The study used WFEC (n = 2,537), PWFEC (n = 3.421), BWT (n = 12,869), WWT (n = 10,961), and PWWT (n = 7,812) from 12,869 lambs measured between 2003 and 2015 in 13 flocks enrolled in the U.S. National Sheep Improvement Program. Animal and sire models were fitted to the data using the ASReml statistical package. Records were corrected for fixed effects of dam age, joint effect of type of birth and rearing, and management group (defined by joint effects of flock, sex, and birth year and season); lamb age in days at each measurement time was fitted as a covariate. Maternal additive and maternal permanent environmental effects were not significant (P > 0.05), but litter effects influenced (P < 0.01) both WFEC and PWFEC. Heritability estimates ranged from 0.18 to 0.26 for WFEC and 0.23 to 0.46 for PWFEC, depending on the model used. Heritability estimates from sire models were higher than estimates from animal models. Direct additive, litter, residual, and phenotypic correlations between WFEC and PWFEC were 0.82, 0.25, 0.15, and 0.29, respectively. Bivariate analyses revealed low to moderate correlations between BW and FEC. Moderate heritabilities for FEC in this study indicated that genetic progress for this trait can be achieved in Katahdin lambs and that selection for low FEC should have little or no effect on BW.

Treat sheep parasites according to risk

Treat sheep parasites according to risk

Resistance delaying strategies on UK sheep farms: A cost benefit analysis

UK guidelines for the sustainable control of parasites in sheep (SCOPS) were formulated with the primary aim of delaying development of anthelmintic resistance (AR) on UK sheep farms. Promoting their use requires the engagement and commitment of stakeholders. An important driver for behavioural change in sheep farmers is evidence of economic benefits. A recent evaluation of SCOPS guidance in practice demonstrated a significant reduction in anthelmintic use, suggesting economic benefits through a direct reduction in product and labour costs. However, in order to maintain production, a range of alternative control strategies are advised, resulting in additional costs to farmers and so a full cost benefit analysis of best practice management was undertaken. We allocated financial values to the management recommendations described in the SCOPS technical manual. Benefits were calculated using data for production variables and anthelmintic use measured during studies to evaluate the effect of SCOPS recommendations on 16 UK sheep farms and from other published work. As SCOPS control is not prescriptive and a range of different diagnostics are available, best and worst case scenarios were presented, comparing the cheapest methods (e.g. egg counts without larval culture) and management situations (e.g closed flocks not requiring quarantine treatments) with the most laborious and expensive. Simulations were run for farms with a small, medium or large flock (300; 1000; 1900 ewes) as well as comparing scenarios with and without potential production benefits from using effective wormers. Analysis demonstrated a moderate cost for all farms under both scenarios when production benefits were not included. A cost benefit was demonstrated for medium and large farms when production benefits were included and the benefit could be perceived as significant in the case of the large farms for the best case scenario (>£5000 per annum). Despite a significant potential reduction in anthelmintic use by farmers employing SCOPS guidance, the very low price of the older anthelmintic classes meant that the benefit did not always outweigh the additional management/diagnostic costs unless an increase in production was also achieved. This is an important finding. Focussing research on key innovations that will improve the cost effectiveness of diagnostic assays in a diagnostic driven control strategy, as well as designing treatment options that can improve production outcomes, and presenting them in a clear and transparent way, must be high priority goals. Coupling targeted research with improvements in the delivery of messages to the end user is important in the light of increasing global concerns over drug resistance.

Experimental infectivity of Theileria luwenshuni and Theileria uilenbergi in Chinese Kunming mice

Theileria luwenshuni and Theileria uilenbergi are important tick-borne pathogens and cause substantial losses to the sheep industry in China. The improvement in detection techniques has allowed the identification of multi-homing parasitism in Theileria parasites. Herein we evaluated the experimental infectivity of T. luwenshuni and T. uilenbergi in Chinese Kunming mice by screening blood samples of experimentally inoculated mice by microscopic examination (ME) and PCR. T. luwenshuni infected Chinese Kunming mice and 20 mice inoculated with this parasite were positive by ME and PCR. In addition, T. uilenbergi infected mice and 20 mice inoculated with this species were positive by ME and PCR. However, the number of red blood cells and the levels of hemoglobin of 40 infected mice had no obvious changes in the course of infection. Our results demonstrated the multi-homing parasitism of T. luwenshuni and T. uilenbergi, which were believed to be parasites of sheep and goats. This study was the first to demonstrate the infection of T. luwenshuni and T. uilenbergi in Kunming mice.

Immune and other factors modulating host resistance against gastrointestinal nematode parasites in sheep

Infection of small ruminants with gastrointestinal nematode (GIN) parasites is a significant problem with crucial impact on meat and milk production. The strategy of administrating anthelminthic drugs has been implemented for many years and has resulted in the development of resistant strains of parasites. Meanwhile, consumers demand for free of drugs products have led to the adoption of alternative control methods, which involve the selective breeding of animals, which are resistant to parasitism. The development of immunity and therefore, resistance against gastrointestinal parasites is based on the activation of specific host genes. Gene analysis has revealed areas (QTLs), which affect resistance or susceptibility of sheep to gastrointestinal infestations between animals of different breeds and between individuals of the same breed. The role of cytokines and T helper cells has been enhanced as research, strongly, supports the connection of Th2 cells with resistance and Th1 cells with susceptibility against GIN. Latest data implicates T regulatory cells and a specific cell type, Th17, in immune response mechanisms. Specific adhesion molecules (integrins, lectins, cadherins) are produced in the gut lumen in sufficient amounts and appear to boost immunity and reduce clinical signs in sheep. Additionally, the immunoglobulins IgA and IgE have been positively correlated with increased resistance against GIN. In several cases of GIN, where an increased number of eosinophils and mast cells in the intestinal epithelium have been recorded, the animals had a reduced number of parasite eggs in their feces. The genes of the Major Histocompatibility Complex have been referred to as potential resistance or susceptibility markers. Other enzymes, like chitinases, enhance the resilience of animals and protect them effectively. Animal’s nutritional status is another determinant factor of immune capability against GIN in sheep, both systemic, as well as locally. Regarding the effect of reactive oxygen and nitrogen species, some researchers support their direct effect against GIN, resulting in a natural reduction of their number, while others claim the indirect action in the intestinal epithelium by reducing local immunity. Consequently, the detection of genes associated with resistance or susceptibility to gastrointestinal infestations is promising and in line with modern requirements.

Preliminary study on small ruminant GIT helminthiasis in select arid and semi-arid pastoral and agro-pastoral areas of Afar region, Ethiopia

A cross-sectional study was conducted to determine the prevalence and identification of GIT parasites of sheep and goats in two selected districts of Afar from December 2014 to February 2016. Totally 590 faecal samples were collected from small ruminants (332 goat and 258 sheep) managed in pastoral and agro-pastoral production. Out of the total examined small ruminant 87.8% (518) were found to harbor one or more genera of helminth parasites. The result of the study revealed that 92.2% (306) of the goats and 82.2% (212) of the sheep were found positive for GIT parasites. Helminth parasites identified in small ruminant of the study area were Strongyles, Fasciola, Strongyloides, Paramphistomum, Trichuris, Ascaris and Monezia. The risk of infection with GIT helminth parasites in goats were 4.009 times higher than sheep (OR=4.009, p=0.011). Age and sex related difference was not observed in the prevalence of helminth parasites in sheep and goats. Significantly (OR=0.119, p=0.000) higher prevalence of overall helminth parasites in poor body condition sheep and goats than good body condition was observed. Likewise significant variation in overall parasite prevalence was observed between the study districts (OR=0.169, p=0.000). In this study, species of the animals, origin, and body condition score are important risk factors associated with gastrointestinal parasites in the study area. In the study area nutrition is generally poor, low productivity in small ruminants is likely to be aggravated by a high prevalence of polyparasitism.

Modeling of the annual cycle of Melophagus ovinus (L.) in two sheep flocks of Patagonia, Argentina

The ked Melophagus ovinus (L.), one of the most common obligate external parasites in sheep, is a recurrent problem in temperate sheep production areas worldwide. Modeling of its annual dynamics, which is lacking, can contribute to delineate integrated management strategies. We sampled ked density along a one-year period in two sheep farms of Northwest Patagonia, Argentina. In one farm with semi-intensive sheep management, we sampled 20 lambs and 10 adult Corriedale-cross sheep naturally parasitized prior to our study. In a second farm with extensive management, we sampled 10 Merino lambs, which we artificially infested in early autumn. We fitted bell-shaped curves to describe the annual ked population dynamics in each animal group and used global fitting to compare the models. In the two-cohort flock, the peak ked density in lambs was almost two-fold higher (Nmax = 186 vs. 86) and occurred 1.5 months earlier (early August) than that in adult sheep; time span parameter was equal in both curves (SD ≈ 64 days). In the artificially parasitized lambs, the ked population showed a ca. five-month lag period, after which density increased sharply to a peak of Nmax = 155, reached well into spring (late October); the span of the model was SD = 38 days. Based on the ked annual cycles modeled and considering the traditional sheep management practices, we suggest monitoring flocks at least twice a year: at pre-mating in mid-autumn and at the annual shearing in spring (pre-lambing shearing or traditional shearing). Ked detection and treatment at pre-mating can prevent keds from entering the exponential phase and the consequent sanitary and economic impacts. In case keds are detected, treatment after pre-lambing shearing may prevent infestation of newborn lambs. Monitoring at traditional shearing is also an opportunity for ked detection, although it could be hard since ked populations will be in a phase of advanced decline in both adult and young sheep. Future works that statistically model the annual population dynamics of keds, under well-defined conditions, may allow meta-analyses of the behavior of this widely distributed plague, especially under the accelerating climate and agricultural changes worldwide.

Preliminary study on Small Ruminant GIT Helminthiasis in Select Arid and Semi-arid Pastoral and Agro-pastoral Areas of Afar Region, Ethiopia

A cross-sectional study was conducted to determine the prevalence and identification of GIT parasites of sheep and goats in two selected districts of Afar from December 2014 to February 2016. Totally 590 faecal samples were collected from small ruminants (332 goat and 258 sheep) managed in pastoral and agro-pastoral production. Out of the total examined small ruminant 87.8% (518) were found to harbor one or more genera of helminth parasites. The result of the study revealed that 92.2% (306) of the goats and 82.2% (212) of the sheep were found positive for GIT parasites. Helminth parasites identified in small ruminant of the study area were Strongyles, Fasciola, Strongyloides, Paramphistomum, Trichuris, Ascaris and Monezia. The risk of infection with GIT helminth parasites in goats were 4.009 times higher than sheep (OR=4.009, p=0.011). Age and sex related difference was not observed in the prevalence of helminth parasites in sheep and goats. Significantly (OR=0.119, p=0.000) higher prevalence of overall helminth parasites in poor body condition sheep and goats than good body condition was observed. Likewise significant variation in overall parasite prevalence was observed between the study districts (OR=0.169, p=0.000). In this study, species of the animals, origin, and body condition score are important risk factors associated with gastrointestinal parasites in the study area. In the study area nutrition is generally poor, low productivity in small ruminants is likely to be aggravated by a high prevalence of polyparasitism.

Evaluating the longevity of surgically extracted Xenopus laevis oocytes for the study of nematode ligand-gated ion channels.

Xenopus laevis oocytes have been extensively used as a heterologous expression system for the study of ion channels. While used successfully worldwide as tool for expressing and characterizing ion channels from a wide range of species, the limited longevity of oocytes once removed from the animal can pose significant challenges. In this study, we evaluate a simple and useful method that extends the longevity of Xenopus oocytes after removal from the animal and quantitatively assessed the reliability of the electrophysiological date obtained. The receptor used for this study was the UNC-49 receptor originally isolated from the sheep parasite, Haemonchus contortus. Overall, we found that immediate storage of the ovary in supplemented ND96 storage buffer at 4°C could extend their use for up to 17days with almost 80% providing reliable electrophysiological data. This means that a single extraction can provide at least 3weeks of experiments. In addition, we examined 24-day-old oocytes (week 4) extracted from a single frog and also obtained reliable data using the same approach. However, 50% of these oocytes were usable for full dose-response experiments. Overall, we did find that this method has the potential to significantly extend the use of single oocyte extractions for two-electrode voltage clamp electrophysiology.

Molecular expression and characterization of GCP7 gene of Haemonchus contortus

Haemonchus contortus is a highly pathogenic and most economically important parasite of sheep and goats worldwide. The cysteine proteases from H. contortus are prime targets for vaccine development. In the present communication we report the molecular expression and characterization of cathepsin B-like cysteine protease, GCP7 gene of H. contortus to study its efficiency as target protein for immunoprophylaxis against haemonchosis in sheep and goats. The complete ORF of GCP7 gene, devoid of the signal sequence, was amplified by RT-PCR from mRNA isolated from H. contortus and was cloned initially into pTZ57R/T cloning vector and then sub-cloned in the pET32a(+) expression vector to produce GCP7 antigen. The nucleotide and deduced amino acid sequence of the GCP7 was aligned against the related sequences of H. contortus available in public domain for in silico analysis by DNA STAR and MEGA version 4.0 softwares. The nucleotide sequence revealed that the GCP7 gene of H.contortus (Indian isolate) encodes 324 amino acids (devoid of signal sequence) and its nucleotide sequence had 95.9% to 99.4% sequence homology with that of U.S.A. and previously published Indian isolates. A high level expression of recombinant (r) GCP7 protein was observed in the molecular range (Mr) of 55 kDa. The rGCP7 protein was confirmed by its specific immunoreactivity against known reference positive sheep sera.

Association between Epidemiology and Haematophagous Behaviour of Haemonchus contortus and Ostertagia ostertagi Infecting Sheep of Kashmir Valley, India

Haemonchus contortus and Ostertagia ostertagi are predominantly sheep parasites and majority of the pathological effects they cause are due to their bloodfeeding behaviour. This study was carried out to ascertain the prevalence of these two parasites in sheep of Kashmir Valley, India and to determine effect on haematological parameters of sheep. H. contortus was more prevalent than O. ostertagi ; the infection was found to be higher in summer, lower age groups and males. As far as the effect on haematology is concerned, haemoglobin concentration, packed cell volume and red blood cell count showed significant decrease and white blood cell count showed significant increase in case of infected sheep.

Site-Directed Mutagenesis Study Revealed Three Important Residues in Hc-DAF-22, a Key Enzyme Regulating Diapause of Haemonchus contortus.

Haemonchus contortus (H. contortus) is one of the most important parasites of small ruminants, especially goats and sheep. The complex life cycle of this nematode is a main obstacle for the control and prevention of haemonchosis. So far, a special form of arrested development called diapause different from the dauer stage in Caenorhabditis elegans (C. elegans) has been found in many parasitic nematodes. In our previous study, we have characterized a novel gene Hc-daf-22 from H. contortus sharing high homology with Ce-daf-22 and functional analysis showed this gene has similar biological function with Ce-daf-22. In this study, Hc-daf-22 mutants were constructed using site-directed mutagenesis, and carried out rescue experiments, RNA interference (RNAi) experiments and in vitro enzyme activity analysis with the mutants to further explore the precise function site of Hc-DAF-22. The results showed that Hc-daf-22 mutants could be expressed in the rescued ok693 worms and the expression positions were mainly in the intestine which was identical with that of Hc-daf-22 rescued worms. Through lipid staining we found that Hc-daf-22 could rescue daf-22 mutant (ok693) from the fatty acid metabolism deficiency while Hc-daf-22 mutants failed. Brood size and body length analyses in rescue experiment along with body length and life span analyses in RNAi experiment elucidated that Hc-daf-22 resembled Ce-daf-22 in effecting the development and capacity of C. elegans and mutants impaired the function of Hc-daf-22. Together with the protease activity assay, this research revealed three important active resides 84C/299H/349H in Hc-DAF-22 by site-directed mutagenesis.

RESISTÊNCIA À VERMINOSE E SUPLEMENTAÇÃO PROTEICA NO PERIPARTO: EFEITO NO PARASITISMO E NO DESEMPENHO REPRODUTIVO DE OVELHAS DO GRUPAMENTO RACIAL PANTANEIRO

Resumo Os objetivos do trabalho foram avaliar o efeito do grau de resistência à verminose e da suplementação proteica nos índices reprodutivos e no parasitismo em ovelhas do grupamento racial Pantaneiro. As ovelhas foram classificadas pelo número de ovos de nematodas por grama de fezes (OPG) como resistentes (RR), sensíveis (SS) e intermediárias (RS), e submetidas (SUPL) ou não (NSUPL) à suplementação durante o terço final da gestação e na lactação. Em dois ciclos reprodutivos, a cada 28 dias, as ovelhas foram pesadas e tratadas com anti-helmínticos quando o OPG apresentava-se ≥ 4000. O peso das ovelhas não foi influenciado pelo grau de resistência aos nematódeos e a suplementação teve efeito no peso somente no período em que foi ofertada. As taxas de natalidade e de desmame não foram influenciadas pelo grau de resistência e pela suplementação. A taxa de mortalidade de crias foi menor no grupo SUPL. A taxa de mortalidade de ovelhas foi três vezes mais elevada no grupo SS em relação ao grupo RR e o peso das crias foi menor no grupo SS em relação aos grupos RR e RS. Os três grupos mostraram picos no OPG durante o terço final da gestação, mas as médias foram sempre menores no grupo RR que, no geral, necessitaram 2,5 vezes menos tratamentos anti-helmínticos que as SS. A suplementação não apresentou correlação com o OPG e com o número de tratamentos anti-helmínticos. A classificação de ovelhas pelo OPG em resistentes aos nematodas proporcionou menor número de tratamentos anti-helmínticos, menor taxa de mortalidade de ovelhas e peso maior das crias ao nascimento.

The complete mitochondrial genome of the parasitic sheep ked Melophagus ovinus (Diptera: Hippoboscidae)

The complete mitochondrial genome (15,573 bp) of an understudied sheep parasite Melophagus ovinus was sequenced and characterized. Its organization and characteristics, including the size, structure, gene order, start/stop codon usage and gene overlaps, are largely typical for Diptera. It exhibits very high A + T bias (81%). Posterior probability values in the inferred phylogenetic dendrogram were very high, but Oestroidea and Muscoidea superfamilies were both paraphyletic. The sequence was nested within the Oestridae clade, thus also rendering the family paraphyletic. A larger number of Hippoboscoidea mitogenomes will have to be available to achieve a better phylogenetic resolution.

Effect of biochemical profiles and reproductive performance during internal parasites in Goat and Sheep

Gastrointestinal parasitic infected ewes and does were kept almost parasite free for about 3 months using Albendazole alone or supplemented with mineral mixture. The Hb (g/dl) level ranged from 8.83±0.08 to 8.96±0.03 in ewes and does was 8.78±0.02 to 8.95±0.24 before treatment. The level of Hb increased significantly (P less than 0.01) in both the treatment groups after treatment on day 20.The Serum level of Ca, P, Cu and Zn in ewes and does increased significantly after treatment on day 20 in both the treatment groups as comparison to control group. Although they did not vary significantly among themselves except the level of Cu which was significantly (P less than 0.01) higher in group II than the group I in ewes and does. The level of Zn was higher in group I than group II in does. The minimum interval from treatment to onset of estrus were recorded in group II , 41 days in ewes and 43 days in does which was followed by group I 44 days in ewes and 46 days in does and control group 55 days in ewes and 52 days in does. The average required number of services per conception in does were 1.33, 1.00 and 2.00 for I, II and control groups, respectively. The corresponding values in ewes were 1.67, 1.17 and 2.17, respectively. The pregnancy rates in the three groups were 66.66, 83.33 and 33.33%, respectively in case of does. The corresponding values in ewes were 50.00, 66.66 and 33.36%, respectively.

Genomic introgression mapping of field-derived multiple-anthelmintic resistance in Teladorsagia circumcincta.

Preventive chemotherapy has long been practiced against nematode parasites of livestock, leading to widespread drug resistance, and is increasingly being adopted for eradication of human parasitic nematodes even though it is similarly likely to lead to drug resistance. Given that the genetic architecture of resistance is poorly understood for any nematode, we have analyzed multidrug resistant Teladorsagia circumcincta, a major parasite of sheep, as a model for analysis of resistance selection. We introgressed a field-derived multiresistant genotype into a partially inbred susceptible genetic background (through repeated backcrossing and drug selection) and performed genome-wide scans in the backcross progeny and drug-selected F2 populations to identify the major genes responsible for the multidrug resistance. We identified variation linking candidate resistance genes to each drug class. Putative mechanisms included target site polymorphism, changes in likely regulatory regions and copy number variation in efflux transporters. This work elucidates the genetic architecture of multiple anthelmintic resistance in a parasitic nematode for the first time and establishes a framework for future studies of anthelmintic resistance in nematode parasites of humans.

Efficacy of glutathione-S-transferase purified antigen of the gastro-intestinal nematode Haemonchus contortus in diagnosis of sheep haemonchosis.

Haemonchus contortus is one of the most pathogenic and economically important parasites of sheep. Different H. contortus antigens; crude somatic antigen (CSA), excretory/secretory antigen (ESA), crude larval antigen (CLA), glutathione-S-transferase antigen (GST) and recombinant protein (rhcp 26/23) were prepared and characterized using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blot. The antigens were immunologically evaluated through indirect enzyme linked immunosorbent assay (ELISA) for diagnosis of haemonchosis in experimentally and naturally infected sheep. Analysis of the resultant bands of SDS-PAGE demonstrated that 13, 6, 11, 2 and 1 protein bands from CSA, ESA, CLA, GST and rhcp 26/23, respectively and analysis of the resultant bands of western blot showed that 13, 6, 4 and 1 reactive bands detected from CSA, ESA, CLA and GST, respectively. The results of ELISA of different antigens revealed that sero-prevelance of CSA, ESA, CLA, GST and rhcp 26/23 were 78.51, 82.34, 85.319, 45.319 and 90.8% respectively, sensitivity were 100, 90, 100, 96.66 and 90%, respectively and specificity were 0, 70, 10, 70 and 6.66%, respectively with diagnostic potency were 50, 80, 55, 83.33 and 48.33%, respectively. Statistical analysis using Chi square test found that GST is the best one that can be used. The cross reactivity of GST antigen, crude Fasciola antigen and crude Moniezia antigen tested versus their homologous hyper immune sera at different dilutions using ELISA. The current study reported that GST antigen could be considered as a promising antigen for diagnosis of haemonchosis.