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thioredoxins of a parasitic nematode: comparison of the 16- and 12-kda thioredoxins from haemonchus contortus.thioredoxins are a family of small proteins conserved through evolution, which are essential for the maintenance of cellular homeostasis. the "classic" thioredoxin, identified in most species, is a 12-kda protein with a cys-pro-gly-cys (cpgc) active site. however, in nematodes a larger protein, 16 kda, with a cys-pro-pro-cys (cppc) active site was identified. we report that in the parasitic nematode haemonchus contortus, both the 12-kda (hctrx1) and the 16-kda (hctrx3) species are expressed thro ...200818410747
anthelmintic efficacy of achillea millifolium against gastrointestinal nematodes of sheep: in vitro and in vivo studies.achillea millifolium linn., commonly called 'pehl-ghasa', is used by farmers in traditional animal health care as a vermifuge. the objective of this study was to evaluate the anthelmintic efficacy of crude aqueous extracts and crude ethanolic extracts of entire a. millifolium against the gastrointestinal nematodes of sheep. the worm motility inhibition assay was used for in vitro studies and faecal egg count reduction assay was used for in vivo studies. in vitro studies revealed significant anth ...200818419857
development and survival of haemonchus contortus infective larvae derived from sheep faeces under sub-tropical conditions in the potohar region of pakistan.assessment on the development and survival of haemonchus contortus larvae was made to evaluate the influence of microclimatic variables viz., relative humidity (%), temperature (degreesc), rainfall (mm) and intensity of sunlight (hrs). pasture plots in a subtropical area, pakistan were contaminated with h. contortus eggs at the start of every month. the plots were sampled on fortnightly basis after contamination for three consecutive months. the overall pattern indicated the most favorable condi ...200818422250
haemonchus contortus calreticulin binds to c-reactive protein of its host, a novel survival strategy of the parasite.calreticulin (calr), a ca(2+) binding multifunctional protein, is secreted by the parasitic nematode haemonchus contortus. we have earlier observed binding of this protein to a 24-kda polypeptide (p24) present in an enriched preparation of prothrombin. in the present study, the identity of p24 was established as a c-reactive protein (crp) by several criteria. calr binding to crp is an elegant strategy devised by the parasite to survive in the host. the secreted calr may achieve this either by li ...200818422872
gastrointestinal nematode challenge induces some conserved gene expression changes in the gut mucosa of genetically resistant sheep.sheep have a varying ability to resist infection with gastrointestinal nematodes. this ability is due in part to genetic differences that exist between individuals. in order to define these differences we have used real-time pcr to quantify gene expression responses in the gut mucosal surface of genetically resistant and susceptible sheep, following a nematode challenge. expression profiles were determined in response to two different nematode species, haemonchus contortus and trichostrongylus c ...200817826780
gender-enriched transcripts in haemonchus contortus--predicted functions and genetic interactions based on comparative analyses with caenorhabditis elegans.in the present study, a bioinformatic-microarray approach was employed for the analysis of selected expressed sequence tags (ests) from haemonchus contortus, a key parasitic nematode of small ruminants. following a bioinformatic analysis of est data using a semiautomated pipeline, 1885 representative ests (rests) were selected, to which oligonucleotides (three per est) were designed and spotted on to a microarray. this microarray was hybridized with cyanine-dye labelled crna probes synthesized f ...200817707841
microsatellite analysis reveals marked genetic differentiation between haemonchus contortus laboratory isolates and provides a rapid system of genetic fingerprinting.many of the haemonchus contortus isolates currently used for experimental work were originally derived from different regions of the world and are commonly exchanged between laboratories. in most cases, these are largely genetically uncharacterised other than the analyses conducted on specific genes of interest. we have used a panel of eight microsatellite markers to genetically characterise five different commonly used h. contortus isolates including mhco3 (ise), the isolate chosen for full gen ...200817727857
gender-enriched transcription of activation associated secreted proteins in ostertagia ostertagi.activation associated secreted proteins (asp) are members of a nematode-specific protein family belonging to the scp/tpx-1/ag5/pr-1/sc7 family. three different types of molecules have been identified in this family: two-domain asps and single-domain asps showing homology to either the c-terminal or n-terminal domain of the two-domain asp. the function of these proteins is still unclear, but a role in transition to parasitism and a role as allergen are often suggested. here we report that the abo ...200817961575
chemical and biological stability of artemisinin in bovine rumen fluid and its kinetics in goats (capra hircus).there is a pressing need to develop alternative, natural anthelmintics to control widespread drug-resistant gastrointestinal nematodes in ruminants, such as haemonchus contortus. artemisinin and its semi-synthetic derivatives are widely used against drug-resistant plasmodium falciparum, but their role in veterinary medicine is only emerging. artemisinin may be useful in controlling gastrointestinal parasites including haemonchus. however, no ruminant studies involving artemisinin have been repor ...200820059827
[gastrointestinal nematode parasitism in ewes and lambs raised in são carlos, são paulo].gastrointestinal nematode infections were evaluated in santa inês crossbreed sheep (santa inês predominance) in a rotational grazing system and in lambs kept indoors, born from the breeding of these females with purebred santa ines, dorper and suffolk males. fecal egg counts (fec), fecal cultures, packed cell volume (pcv) and weights were evaluated during two years. climate data were registered. only animals that presented fec higher than 4,000 and/or pcv lower than 21% were drenched with anthel ...200820059831
in vitro effect of condensed tannin extract from acacia (acacia mearnsii) on gastrointestinal nematodes of sheep.the aim of this study was to determine the inhibitory effects of condensed tannin extract from acacia on the feeding of first-stage larvae (l1) of haemonchus contortus, trichostrongylus vitrinus and teladorsagia circumcincta. the experiment was developed such that the inhibition of feeding for each of the nematode species could be evaluated. l1 recovered from fecal samples from a donor with monospecific infection was incubated in several dilutions of acacia extract (ae). the ld50 was determined ...200820059834
targeted treatment strategies for sustainable worm control in small ruminants.sustainable worm control strategies are based largely on ensuring that a source of worms not exposed to anthelmintics ("in refugia") remains after treatments are given, so that resistant worms do not become a dominant part of the total population. in environments with seasonally poor survival of worm larvae on pasture, this may require withholding treatments from a proportion of animals when the whole group would normally be treated. the "targeted treatment" approach involves using anthelmintics ...200818414373
prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern ethiopia.a 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (gi) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern ethiopia. during may 2003 to april 2005, viscera including liver, lungs and gi tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of haramaya, harar, dire dawa and jijiga in eastern ethiopia. all animals were raised in the farming areas ...200717969715
trichostrongylus colubriformis and haemonchus contortus infections in light bodyweight merino lambs.objective; to show that low bodyweight is a predisposing cause of high trichostrongylus colubriformis and haemonchus contortus burdens and egg counts in merino lambs.200717970846
performance and nematode infection of ewe lambs on intensive rotational grazing with two different cultivars of panicum maximum.the daily live weight gain (dlwg), faecal nematode egg counts (fec), and packed cell volume (pcv) of suffolk, ile de france and santa inês ewe lambs were evaluated fortnightly for 56 days in the dry season (winter) and 64 days in the rainy season (summer) of 2001-2002. the animals were distributed in two similar groups, one located on aruana and the other on tanzania grass (panicum maximum), in rotational grazing system at the instituto de zootecnia, in nova odessa city (sp), brazil. in the dry ...200717847820
moisture requirements for the free-living development of haemonchus contortus: quantitative and temporal effects under conditions of low evaporation.the key influence of moisture availability on development of the free-living stages of haemonchus contortus is well-documented, although quantitative relationships between moisture variables and development are poorly defined. a factorial experiment (3x2x2) was conducted in programmable incubators to determine the effects of amount and distribution of simulated rainfall on h. contortus development at low evaporation rates (approximately 2 mm/day) under temperatures typical of summers on the nort ...200717920198
the requirement for early exposure of haemonchus contortus larvae to bacillus thuringiensis for effective inhibition of larval development.the potential for a nematocidal bacillus thuringiensis (bt) to target the free-living larval stages of haemonchus contortus was examined using in vitro larval development and migration assays. bt toxicity in larval development assays decreased as the time period between egg hatch and initial exposure to the bt was increased; a time lag of 48 h resulted in a 350-fold increase in the ic(50) (from 2.6 ng/ml to 910 ng/ml). the effects on larval migration largely paralleled the effects on larval deve ...200717951006
comparison of three different preservatives for morphological and real-time pcr analyses of haemonchus contortus eggs.despite the development of several recent pcr assays for the egg stages of various trichostrongyles, there have been no protocols described for preserving field samples for pcr without refrigeration. in this study, lugol's iodine (li), sodium azide (sa), and neutral buffered formalin (nbf) were evaluated using haemonchus contortus eggs to determine their potential as a preservative for trichostrongyle egg samples to be processed with real-time pcr. when egg recovery, embryo development, and egg ...200717289268
relationships between sterol/phospholipid composition and xenobiotic transport in nematodes.therapeutic failure limits prophylaxis of nematode diseases and has been mainly attributed to mutations in cellular targets of anthelmintics. besides these specific mechanisms, alterations of drug transport also occur in parasites resistant to anthelmintics and depend on both the presence of membrane pumps such as p-glycoprotein (pgp) and on the lipid composition of membranes. we recently showed in the nematode haemonchus contortus, using eggs as a model, that the total cholesterol (tc) concentr ...200717294217
a novel approach for combining the use of in vitro and in vivo data to measure and detect emerging moxidectin resistance in gastrointestinal nematodes of goats.ivermectin and moxidectin are closely related avermectin/milbemycin anthelmintics and available data suggest that side resistance occurs with these two drugs. however, moxidectin remains effective against many species of ivermectin-resistant worms due to its higher potency. the larval development assay (lda) is routinely used to diagnose ivermectin resistance in haemonchus contortus but laboratory diagnosis of moxidectin resistance is hampered by the lack of any validated in vitro tests. the obj ...200717307184
anthelmintic activity of aporphine alkaloids from cissampelos capensis.two known aporphine alkaloids, (s)-dicentrine (1) and (s)-neolitsine (2), have been isolated from the meoh extract of the aerial parts of cissampelos capensis (menispermaceae). the structures of these compounds were elucidated by nmr and ms analysis and comparison to literature data. these compounds were isolated by bioassay-guided fractionation using the haemonchus contortus larval development assay. compounds 1 and 2 exhibited ec90 values (concentration at which 90% loss of larval motility is ...200717309014
individual administration of three tanniferous forage plants to lambs artificially infected with haemonchus contortus and cooperia curticei.we investigated direct anthelmintic effects associated with the feeding of fresh tanniferous forages against established populations of haemonchus contortus and cooperia curticei in lambs. twenty-four parasite naive lambs were inoculated with a single dose of infective larvae of these two parasites 27 days prior to the start of the feeding experiment. lambs were individually fed with either chicory (cichorium intybus), birdsfoot trefoil (lotus corniculatus), sainfoin (onobrychis viciifolia) or a ...200717336459
the kinetics of exsheathment of infective nematode larvae is disturbed in the presence of a tannin-rich plant extract (sainfoin) both in vitro and in vivo.the mode of action of bioactive plants on gastrointestinal nematodes remains obscure. previous in vitro studies showed that exsheathment was significantly disturbed after contact with tannin-rich extracts. however, the role of important factors (extract concentration, parasite species) has not been assessed and no information is available on the occurrence in vivo. these questions represent the objectives of this study. the model incorporated the parasites haemonchus contortus and trichostrongyl ...200717346358
trapping efficacy of duddingtonia flagrans against haemonchus contortus at temperatures existing at lambing in australia.the aim of this study was to determine the trapping efficacy of duddingtonia flagrans against haemonchus contortus at the temperature ranges experienced around lambing in the major sheep producing regions of australia. faeces were collected from merino wethers, maintained in an animal house and which had received either d. flagrans chlamydospores for a 6-day period (df) or not (nil). faeces were incubated at one of four daily temperature regimens which were composed of hourly steps to provide 6- ...200717349746
scutiaquinones a and b, perylenequinones from the roots of scutia myrtina with anthelmintic activity.haemonchus contortus is a worm that causes serious infections in livestock. two new perylenequinones, scutiaquinone a (1) and scutiaquinone b (2), have been isolated from a methanol extract of the roots of scutia myrtina by bioassay-guided fractionation, using an assay that kills this parasite in vitro. the structures of compounds 1 and 2 were elucidated by analysis of their 1d- and 2d-nmr and ms spectra. the isolation, structure, and anthelmintic activities of compounds 1 and 2 are reported.200717378532
haemonchus contortus: in vitro and in vivo anthelmintic activity of aqueous and hydro-alcoholic extracts of hedera helix.in vitro anthelmintic activity of crude extracts of the ripe fruits of hedera helix was investigated on eggs and adult nematode parasites haemonchus contortus. aqueous extract of h. helix was also evaluated for in vivo anthelmintic activity at dose of 1.13 and 2.25 g/kg in sheep artificially infected with h. contortus. ed(50) for egg hatch inhibition was 0.12 and 0.17 mg/ml for aqueous and hydro-alcoholic extracts, respectively. there was no statistically significant difference in the activity o ...200717382320
three surface antigens dominate the mucosal antibody response to gastrointestinal l3-stage strongylid nematodes in field immune sheep.although gastrointestinal nematode parasites are a major human and veterinary health problem, little is known about how the host is sometimes able to mount an effective immune rejection response. in previous work, we identified a carbohydrate larval surface antigen (carla) as the target of mucosal antibodies that can elicit rejection of trichostrongylus colubriformis l3s in sheep. here we characterise the natural mucosal antibody responses to l3s from three major strongylid gastrointestinal para ...200717383657
effect of pelleting on efficacy of sericea lespedeza hay as a natural dewormer in goats.resistance of gastrointestinal nematodes (gin) to anthelmintic treatment has increased pressure to find alternative, non-chemical control methods. feeding hay of the high condensed tannin (ct) forage sericea lespedeza [sl; lespedeza cuneata (dum-cours.) g. don.] to sheep and goats has reduced gin fecal egg count (fec) and worm numbers in the abomasum and small intestines. this effect has been reported with both unground (long) and ground hay. pelleting of ground hay increases ease of storage, tr ...200717383822
in vitro and in vivo characterization of p-amino-phenethyl-m-trifluoromethylphenyl piperazine (papp), a novel serotonergic agonist with anthelmintic activity against haemonchus contortus, teladorsagia circumcincta and trichostrongylus colubriformis.the neurotransmitter serotonin (5-hydroxy tryptamine or 5ht) regulates key physiological processes in nematodes such as locomotion and feeding. papp (p-amino-phenethyl-m-trifluoromethylphenyl piperazine) is a known agonist of the 5-ht(1hc) receptor of the barber pole worm, haemonchus contortus. in this study, papp was highly active against l3-stage larvae of h. contortus and trichostrongylus colubriformis in an in vitro larval migration assay, with ec50 values of 9.36 and 11.8 microm, respective ...200717383823
the effects of amount, timing and distribution of simulated rainfall on the development of haemonchus contortus to the infective larval stage.three studies were undertaken to determine the effects of amount, timing and distribution of simulated rainfall on the developmental success of haemonchus contortus. faeces containing h. contortus eggs were deposited onto pasture plots under a rainfall-activated retractable roof which eliminated incident rainfall. in october (spring) 2004 and january (summer) 2005, the effects of amount (6, 12, 18 or 24 mm) and timing (1, 4, 8 or 15 days post-faecal deposition) of a single simulated rainfall eve ...200717398009
combining the effects of supplementary feeding and copper oxide needles for the control of gastrointestinal nematodes in browsing goats.the aim was to assess the benefits obtained from combining supplementary feeding and copper needles (cowp), compared to the use of both approaches independently, for the control of gastrointestinal nematode (gin) infections in browsing kids. forty-four nematode free criollo kids were exposed to natural parasite infection. the kids were divided into six experimental groups: not treated, supplemented (nt-s), not treated, not supplemented (nt-ns), moxidectin treated, supplemented (m-s), moxidectin ...200717400391
trends and challenges in the effective and sustainable control of haemonchus contortus infection in sheep. review.haemonchosis, with its very wide distribution, has become a very important production constraint in sheep farms in tropical, subtropical and temperate regions worldwide. various intrinsic and extrinsic factors determine the survival of haemonchus contortus and hence the development of the disease in the animal. in general, control of gastrointestinal nematode infestation in sheep relies heavily on anthelmintic treatments. however, the indiscriminate use of these drugs has led to the widespread e ...200717432053
control of gastrointestinal nematodes with copper oxide wire particles in a flock of lactating polypay ewes and offspring in iowa, usa.copper oxide wire particles (cowp) have been used to reduce infection of haemonchus contortus in hair breed lambs in southeastern usa without signs of copper toxicity. however, copper sensitivity among breeds and regions varies. the objective was to determine the effectiveness and safety of cowp in lactating polypay ewes and their offspring grazing alfalfa/bluegrass pasture in a rotational grazing system. mature polypay ewes were administered 0, 0.5, 1, or 2 g (n=8 or 9/dose) cowp approximately ...200717433548
expression and purification of an active cysteine protease of haemonchus contortus using caenorhabditis elegans.many proteolytic enzymes of parasitic nematodes have been identified as possible targets of control. testing these as vaccine or drug targets is often difficult due to the problems of expressing proteases in a correctly folded, active form in standard expression systems. in an effort to overcome these difficulties we have tested caenorhabditis elegans as an expression system for a haemonchus contortus cathepsin l cysteine protease, hc-cpl-1. recombinant hc-cpl-1 with a polyhistidine tag added to ...200717451718
synthesis and anthelmintic activity of cyclohexadepsipeptides with cyclohexylmethyl side chains.cyclohexadepsipeptides (chdps) with cyclohexylmethyl side chains represent novel enniatins with in vivo activity against the parasitic nematode haemonchus contortus rudolphi in sheep. it was found that the replacement of benzylic by cyclohexylmethyl side chains on the enniatin skeleton can increase anthelmintic efficacy. here we report on a simple total synthesis of the precursors for this type of chdps and an efficient chemical transformation of the benzylic into the corresponding cyclohexylmet ...200717475487
accuracy of the famacha system for on-farm use by sheep and goat producers in the southeastern united states.famacha is a practical on-farm system designed to provide small ruminant producers a tool for improving their management of haemonchus contortus infections. although this system has become very popular and widely accepted by small ruminant producers in many regions of the southern united states, there is very limited data reported on the effectiveness of the famacha system when performed by farmers. the objective of this study was to evaluate the accuracy of the famacha system for on-farm use by ...200717482368
haemonchus contortus: characterization of the baculovirus expressed form of aminopeptidase h11.recombinant form of haemonchus contortus aminopeptidase h11, an intestinal membrane glycoprotein considered to be in its native form the most promising vaccine candidate, was produced in insect cells, characterised and tested in pilot vaccination-challenge trial on sheep. the sequence of the cloned gene, obtained by rt pcr isolated from adult worms, showed 97% identity to the highly immunogenic h11 clone, described by graham et al., (database accession number aj249941.1). a 1305 bp fragment of h ...200717482594
a rapid colorimetric assay for the quantitation of the viability of free-living larvae of nematodes in vitro.with increasing drug resistance in gastrointestinal parasites, identification of new anthelmintics is essential. the non-parasitic nematode caenorhabditis elegans is used extensively as a model to identify drug targets and potential novel anthelmintics because it can be readily cultured in vitro. traditionally, the assessment of worm viability has relied on labour-intensive developmental and behavioral assays. the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide-formazan (mtt-formaz ...200717492469
vaccination of goats with recombinant galectin antigen induces partial protection against haemonchus contortus infection.the efficacy of vaccination against haemonchus contortus infection with two recombinant proteins, rhco-gal-m and rhco-gal-f, was studied in 9-10-month-old goats. vaccination with 100 microg protein reduced faecal egg output and worm burdens by 37.25% and 41.1%, respectively. corresponding reductions with 200 microg protein were 48.03% and 46.19%. vaccinated groups had significantly higher igg levels than the negative and positive controls. significant negative correlations were detected between ...200717518950
haemonchosis and teladorsagiosis in a scottish sheep flock putatively associated with the overwintering of hypobiotic fourth stage larvae.the cause of ill thrift and deaths was investigated in a group of 40 scottish lowground ewes, which had been treated with levamisole and then turned onto clean grazing after lambing, 6-8 weeks previously. concurrent haemonchosis and teladorsagiosis were diagnosed, putatively associated with the spring maturation of large numbers of hypobiotic larvae. ill thrift due to parasitic gastroenteritis consequently occurred in the lambs which had been turned onto the 'clean' grazing with their dams, desp ...200717531390
use of copper oxide wire particles to control gastrointestinal nematodes in goats.the objectives of these experiments were to determine the optimal dose of copper oxide wire particles (cowp) necessary to reduce gastrointestinal nematode (gin) infection in young and mature goats naturally infected with haemonchus contortus or a mixed infection and to determine whether the effectiveness could be enhanced through feeding management. two experiments were conducted during cooler months in georgia, and 4 experiments were conducted during warmer spring or summer months in arkansas. ...200717565056
morphological characterization of haemonchus contortus in goats (capra hircus) and sheep (ovis aries) in penang, malaysia.the large stomach worm, haemonchus contortus is an important pathogen of goats (capra hircus) and sheep (ovis aries). this paper describes characteristics of surface cuticular ridges (synlophe) of h. contortus adults from the two hosts. there were more ridges in h. contortus from goats compared to that from sheep. total body length, vulvar morphology, spicule length and cervical papillae had been considered as markers of physical adaptation and were studied and described.200717568374
abomasal nematodes of the red deer cervus elaphus in north-eastern italy.the composition of the abomasal helminth fauna and parasite diversity were studied in 298 red deer collected during 1997-2000 from three different sectors (bolzano, trento and sondrio provinces) of the stelvio national park, one of the main protected areas of north-eastern italy. the association between parasite burdens and geographical areas of the hosts was assessed using the negative binomial regression. a variety of abomasal helminths, both host specific and generalist, was found in all sect ...200717594740
identification of levamisole resistance markers in the parasitic nematode haemonchus contortus using a cdna-aflp approach.cdna-aflp (cdna-amplified fragment length polymorphism)-based strategy has been used to identify levamisole (lev) resistance markers in the nematode haemonchus contortus. transcript profiles of adult nematodes from two lev-resistant and two susceptible isolates were compared. among the 17 280 transcript-derived fragments (tdfs) amplified, 26 presented a polymorphic pattern between resistant and susceptible nematodes: 11 tdfs were present in both resistant isolates and absent from both susceptibl ...200717608970
nematode ligand-gated chloride channels: an appraisal of their involvement in macrocyclic lactone resistance and prospects for developing molecular markers.summaryligand-gated chloride channels, including the glutamate-(glucl) and gaba-gated channels, are the targets of the macrocyclic lactone (ml) family of anthelmintics. changes in the sequence and expression of these channels can cause resistance to the ml in laboratory models, such as caenorhabditis elegans and drosophila melanogaster. mutations in multiple glucl subunit genes are required for high-level ml resistance in c. elegans, and this can be influenced by additional mutations in gap junc ...200717608971
abc transporters and beta-tubulin in macrocyclic lactone resistance: prospects for marker development.macrocyclic lactones (mls) are highly lipophilic anthelmintics which are known to bind to and open ligand-gated ion channels. however, these anthelmintics, and particularly the avermectin members of the ml class of endectocides, are potent substrates for abc transporters and these transporters may regulate drug concentration in both the host and the parasite. there is accumulating evidence that ivermectin (ivm), and to a lesser extent moxidectin (mox), selects for certain alleles of p-glycoprote ...200717608972
anthelmintic activity of croton zehntneri and lippia sidoides essential oils.because of the development of anthelmintic resistant populations, the search for new drugs is essential to maintain the productivity of small ruminants. the aim of this study was to evaluate the anthelmintic activity of croton zehntneri and lippia sidoides essential oils and their major constituents, anethole and thymol. the effects of these oils and their constituents were determined by in vitro assays with the eggs and larvae of the sheep gastrointestinal nematode haemonchus contortus. the two ...200717629623
anthelmintic macrolactams from nonomuraea turkmeniaca ma7364.two new macrolactams, 6-desmethyl-n-methylfluvirucin a1 (1) and n-methylfluvirucin a1 (2), have been isolated from the acetone extract of nonomuraea turkmeniaca ma7364. these compounds were isolated by bioassay-guided fractionation as part of our search for new anthelmintics. the structures of these compounds were elucidated by comparison of their nmr and ms data to those of previously reported fluvirucins and confirmed by 2d nmr. compound 1 exhibited in vitro activity (ec(90) 15 +/- 5 microg/ml ...200717636954
the second glutamic acid in the c-terminal crd affects the carbohydrate-binding properties of recombinant galectins of haemonchus contortus.the effects of the second glutamic acid (e) in the c-terminal crds on the hemagglutination and lactose-binding characteristics of the recombinant galectins of nematode haemonchus contortus were observed using two isoforms of recombinant galectins as models, and the sugar-binding abilities of the n-terminal and c-terminal crds of the galectins were also compared. the second e in the crd, wgneer, of hco-gal-m was mutated to glycine acid (g) and resulted in a recombinant galectin (mg mutate) with a ...200717643820
attempts to detect synergy between vaccination and anthelmintic against a drug resistant isolate of haemonchus contortus.an experiment was conducted to determine whether any synergistic activity could be detected between an experimental vaccine and anthelmintic treatment against a drug resistant strain of haemonchus contortus, i.e. would the combined effect of both interventions be greater than the sum of either alone. two groups of 14 worm-free sheep were immunised twice, either with haemonchus galactose containing glycoprotein complex (h-gal-gp) in quila as adjuvant or with adjuvant alone. all were challenged wi ...200717643823
immune response to haemonchus contortus infection in susceptible (inra 401) and resistant (barbados black belly) breeds of lambs.the immune responses to haemonchus contortus were compared in studies in resistant barbados black belly (bbb) and susceptible inra 401 (inra) breeds of lambs. the cytokine patterns indicated a th2-biased response in both breeds. a more persistent and elevated th2 cytokine mrna transcription and blood eosinophilia were noted in the bbb lambs. however, at days 4 and 30 post-infection, abomasal recruitment of eosinophils and mast cells were similar between the two breeds. following primary infectio ...200717650183
in vitro pre-exposure of haemonchus contortus l3 to blood eosinophils reduces their establishment potential in sheep.different authors have reported that eosinophils are capable of immobilising infective larvae of different species of nematodes in vitro. however, classifying larvae as mobile or immobile is so subjective that it does not always mean all apparently immobile larvae are dead or those that are mobile are capable of surviving further immune responses if administered to their natural hosts. the objective of this experimental study was therefore to substantiate the role of eosinophils in the killing o ...200717682295
the effect of dietary protein supplementation on the pathophysiology of haemonchus contortus infection in west african dwarf goats.the effect of dietary protein on the pathophysiology of haemonchus contortus infection in reproducing first pregnancy west african dwarf (wad) goats was studied. eighteen 10-12-month-old pubertal female wad goats divided into two equal groups were used and confined separately. one group was maintained on high-protein diet (hpd) while the other was maintained on low-protein diet (lpd) from day 1 of pregnancy up to week 6 post-partum. each animal was infected with 600 infective larvae of h. contor ...200717689870
in vitro detection of benzimidazole resistance in haemonchus contortus: egg hatch test versus larval development test.the present study was designed to compare the egg hatch test (eht) and the larval development test (ldt) as in vitro tools for detection of benzimidazole (bz) resistance in haemonchus contortus, a nematode parasite of small ruminants. comparisons were made during a course of infection and changes in both eht and ldt were monitored to measure the correlation between resistance and susceptibility in different parasite stages (eggs and larvae). in addition, mixed doses of known numbers of susceptib ...200717697753
[prolactin as a modulator of antiparasitic immunity].prolactin (prl) is a polypeptide hormone of the pituitary origin, that expresses over 300 separate biological activities, including its involvement in the regulation of immune functions. the hormone's immune capacities are related, among others, to comitogenic activity, prevention of immune cell apoptosis, stimulation of interleukins and antibodies production. prolactin acts as a potent positive modulator of immunity to some protozoan parasites. it is well established that the hormone stimulates ...200718441871
multivariate spatially-structured variability of ovine helminth infections.a cross-sectional survey was carried out on 2004-2005 in the campania region, southern italy, to study the multivariate geographical distribution of four different sheep helminths, i.e. fasciola hepatica (liver fluke), calicophoron (paramphistomum) daubneyi (rumen fluke), dicrocoelium dendriticum (lancet fluke), and the gastrointestinal strongyle haemonchus contortus. a series of multivariate bayesian hierarchical models based on square root transformation of faecal egg counts were performed. th ...200718686259
anthelmintic activity of chenopodium album (l) and caesalpinia crista (l) against trichostrongylid nematodes of sheep.the present study was carried out to determine the anthelmintic activity of caesalpinia crista (l.) (fabaceae) seed kernel and chenopodium album (l.) (chenopodiaceae) whole plant in order to justify their traditional use in veterinary medicine.200717826017
epidemiology and seasonal dynamics of gastrointestinal nematode infections of sheep in a semi-arid region of eastern ethiopia.a study on the epidemiology and seasonal dynamics of gastrointestinal nematode infections of sheep was carried out in a semi-arid region of eastern ethiopia for 2.5 years (may 2003 to september 2005). the experimental flock comprised a total of 60 black head ogaden sheep, consisting of four equal groups of young male and female and old male and female sheep. these grazed on communal pastures together with a larger university flock, as well as with animals owned by neighbouring small-holder farme ...200716965858
anthelmintic action of eprinomectin in lactating anglo-nubian goats in brazil.eprinomectin is the only avermectin approved for use to control gastrointestinal nematodes in lactating cows. some studies in the usa and europe have also demonstrated that this drug is highly effective in small ruminants. the aim of the present work was to evaluate the anthelmintic efficacy of pour-on eprinomectin in anglo-nubian goats at the end of lactation. twenty-four goats were used, naturally infected with gastrointestinal nematodes, and divided into two groups: control and treated with e ...200717031697
effects of condensed tannin from acacia mearnsii on sheep infected naturally with gastrointestinal helminthes.the effect of tannins on endoparasite control in hair sheep was investigated using 20 entire lambs of the santa inês breed. at the beginning of the experiment these animals were 6-months old and weighed 22.5kg+/-4.7. the treatments used were (10 animals each): gt (animals receiving 18g of acácia negra containing 18% of condensed tannin/animal/week) and gc (animals not receiving tannin). the experiment lasted 84 days, with animals kept on an andropogon gayanus pasture. faeces were collected weekl ...200717067741
evaluation of a recombinant excretory secretory haemonchus contortus protein for use in a diagnostic enzyme-linked immunosorbent assay.the nematode haemonchus contortus (h. contortus) is one of the most pathogenic and economically important parasites of sheep. a 24 kda protein is one of the important components in h. contortus excretory/secretory (es), which was shown to have important biological function. in our research, the cdna of its open reading frame (es24) was obtained and analyzed. then the es24 was sub-cloned into pet-30a expression vector. the recombinant vector that codes hexahistidyl peptide fusion protein (his-es2 ...200717069805
a combined bioinformatics and chemoinformatics approach for the development of new antiparasitic drugs.a modern concept for the development of novel antiparasitic drugs is the combination of bioinformatics and chemoinformatics approaches. this covers, for example, the identification of target proteins serving as molecular points of attack for parasiticides--the idea is that, owing to some essential role, inhibition of a target protein should eradicate the parasite. to prevent toxicity problems for vertebrate host organisms, it is advantageous that these proteins show significant differences from ...200717070005
avermectin-resistance in gastrointestinal nematodes of boer goats and dorper sheep in switzerland.anthelmintic resistance in gastrointestinal nematodes among small ruminants is widespread in south africa and dorper sheep and boer goats have been imported into switzerland from this country on a number of occasions. therefore, this study aimed to investigate the occurrence of avermectin (avm) resistant gastrointestinal nematodes (gin) in these breeds in switzerland. a total of 24 boer goat farms and 12 dorper sheep farms participated in the study. according to the faecal egg count reduction te ...200717088023
extending from pars in caenorhabditis elegans to homologues in haemonchus contortus and other parasitic nematodes.signal transduction molecules play key roles in the regulation of developmental processes, such as morphogenesis, organogenesis and cell differentiation in all organisms. they are organized into 'pathways' that represent a coordinated network of cell-surface receptors and intracellular molecules, being involved in sensing environmental stimuli and transducing signals to regulate or modulate cellular processes, such as gene expression and cytoskeletal dynamics. a particularly important group of m ...200717107637
doramectin and albendazole resistance in sheep in the netherlands.a faecal egg count reduction test was conducted on a sheep farm with suspected avermectin resistance. five groups of 10 sheep were formed. group 1 was the untreated control group. groups 2-5 were treated according to weight with the recommended dose of, respectively, levamisole, doramectin, moxidectin or albendazole. resistance was found in the sheep treated with doramectin (15% efficacy) and albendazole (87% efficacy). levamisole and moxidectin were 100 and 99% effective, respectively. larval i ...200717113232
in vitro and in vivo anthelmintic activity of crude extracts of coriandrum sativum against haemonchus contortus.in vitro anthelmintic activities of crude aqueous and hydro-alcoholic extracts of the seeds of coriandrum sativum (apiaceae) were investigated on the egg and adult nematode parasite haemonchus contortus. the aqueous extract of coriandrum sativum was also investigated for in vivo anthelmintic activity in sheep infected with haemonchus contortus. both extract types of coriandrum sativum inhibited hatching of eggs completely at a concentration less than 0.5 mg/ml. ed(50) of aqueous extract of coria ...200717113738
direct and indirect anthelmintic effects of condensed tannins in sheep.anthelmintic activity of condensed tannins (ct) was evaluated both in vitro and in vivo. in vitro tests included egg hatch test and paralysis/mortality assay on adult haemonchus contortus. in vivo anthelmintic effect was determined by faecal egg count reduction test in lambs. to this end, 18 lambs were divided into three groups (low tannin, high tannin and control). the lambs of low and high tannin groups were fed diets containing 2 and 3% ct while the control group was fed on diets without ct. ...200717097807
phenotyping and genotyping of haemonchus contortus isolates reveals a new putative candidate mutation for benzimidazole resistance in nematodes.in order to monitor and eventually control the spread of drug-resistant haemonchus contortus, knowledge of the molecular mechanisms underlying resistance is essential. here we phenotypically and genotypically characterize three multidrug-resistant h. contortus field isolates from australia and south africa. all were significantly less susceptible to thiabendazole than a sensitive reference strain in an in vitro egg-hatch assay. the sensitivity was further reduced in a surviving population after ...200717101226
recombinant galectins of male and female haemonchus contortus do not hemagglutinate erythrocytes of their natural host.recombinant galectins of female and male adult worms of haemonchus contortus were expressed in escherichia coli and their hemagglutinating activities to human and different animal erythrocytes were analyzed. the results showed that female and male galectins could be highly expressed in e. coli using a temperature-sensitive plasmid, with the recombinant protein being mainly appeared in inclusion bodies. hemagglutinating activity assays showed that both of the galectins hemagglutinated human a, b, ...200717125929
detection and measurement of benzimidazole resistance alleles in haemonchus contortus using real-time pcr with locked nucleic acid taqman probes.benzimidazole resistance is a common problem in parasitic nematodes of ruminants and early detection is vital if its spread is to be monitored and controlled. real time pcr offers a fast and reliable method for rapid detection and measurement of resistance allele frequencies. in haemonchus contortus a single nucleotide polymorphism at codon 200 of the beta-tubulin gene (ttc to tac), causing a phenylalanine to tyrosine amino acid substitution, has been shown to be involved in many cases of resist ...200717129676
discovery of (z)-2-phenyl-3-(1h-pyrrol-2-yl)acrylonitrile derivatives active against haemonchus contortus and ctenocephalides felis (cat flea).a series of 2-phenyl-3-(1h-pyrrol-2-yl)acrylonitrile derivatives were synthesized and evaluated for in vitro activity against the endoparasite haemonchus contortus and the ectoparasite ctenocephalides felis. some compounds had significant in vitro activity against these parasites.200717150358
real-time pcr for quantifying haemonchus contortus eggs and potential limiting factors.the purpose of this study was to evaluate the practicality of using real-time pcr for quantifying feces-derived trichostrongyle eggs. haemonchus contortus eggs were used to evaluate fecal contaminants, time after egg embryonation, and the presence of competing and non-competing dnas as factors that might interfere with generating reproducible results during simplex and multiplex quantitative real-time pcr (qpcr). real-time pcr results showed linear quantifiable amplification with dna from five t ...200717206500
co-delivery of plasmid-encoded cytokines modulates the immune response to a dna vaccine delivered by in vivo electroporation.in this study, in vivo electroporation of a dna vaccine adjuvanted with plasmids encoding different cytokines was investigated in large animals. sheep were injected intramuscularly with a dna vaccine encoding an antigen of haemonchus contortus (pnpa) and plasmids encoding different cytokines followed by in vivo electroporation. plasmids (pci) carrying the genes of different cytokines including ovine il-4(pci-il4), il-10(pci-il10), gm-csf(pci-gmcsf), and mcp-1alpha(pci-mcp1alpha), and pci-il4+pci ...200717224210
assessment of caenorhabditis elegans as a model in haemonchus contortus vaccine research. 200717234278
duration of anthelmintic effect of three formulations of ivermectin (oral, injectable and pour-on) against multiple anthelmintic-resistant haemonchus contortus in sheep.we report the results of investigations that were conducted in a sheep flock in uttaranchal, india where repeated failure of anthelmintic medication was noted. the study revealed that haemonchus contortus in sheep had developed resistance to benzimidazoles (fenbendazole, mebendazole and albendazole), imidazothiazole (levamisole) and salicylanide (rafoxanide), while it was fully susceptible to avermectins (ivermectin). further, the suppression of nematode egg output in faeces of sheep naturally i ...200717237985
haemonchus contortus intestine: a prominent source of mucosal antigens.we sought to identify antigens from haemonchus contortus, an abomasal nematode of small ruminants, that stimulate local (abomasal lymph node, aln) cd4+ t lymphocyte responses during a primary infection. results led to a focus on antigens from the parasite intestine. the h. contortus intestine proved to be a major source of antigens that stimulated aln cd4+, cd25+ t lymphocyte responses during infections in lambs. when stimulated by intestinal antigens, aln lymphocytes from these lambs expressed ...200717266741
vaccines against blood-feeding nematodes of humans and livestock.this paper summarises the progress towards vaccine development against the major blood-feeding nematodes of man and livestock, the hookworms and haemonchus contortus, respectively. the impact of the diseases and the drivers for vaccine development are summarized as well as the anticipated impact of the host immune response on vaccine design. the performance requirements are discussed and progress towards these objectives using defined larval and adult antigens, many of these being shared between ...200617274849
helminth parasites of gemsbok (oryx gazella) in the klein karoo.the number and species of helminth parasites from three gemsbok (oryx gazella) were recorded, and their faecal nematode egg counts and the level of pasture contamination determined. six nematode genera were recovered and four species identified, of which trichostrongylus rugatus was the most prevalent. other nematode species recovered were cooperia sp., agriostomum sp., haemonchus contortus, nematodirus spathiger and ostertagia ostertagi. none of the worms were present in all animals studied, an ...200617283732
selective and on-demand drenching of lambs: impact on parasite populations and performance of lambs.to determine whether drenching regimes for lambs by which a proportion (10%) of the heaviest animals was selectively left untreated, or animals are only drenched 'on demand' when faecal nematode egg counts (fec) exceeded a threshold level, would result in measurable increases in parasite larval challenge in the autumn and/or decreases in the performance of lambs.200617151729
abomasal nematode community in an alpine chamois (rupicapra r. rupicapra) population before and after a die-off.abomasa of 185 chamois shot during 5 consecutive hunting seasons were collected as part of a health monitoring program in an alpine area of italy and examined for nematodes. the data were obtained during both the preceding period and that following a severe die-off caused by a pneumonia outbreak. prevalence, mean abundance, mean intensity, and thul importance index were consistently high, in particular for haemonchus contortus, having a low host specificity and high pathogenic potential. species ...200617152929
anhydrobiosis increases survival of trichostrongyle nematodes.this study demonstrates that infective-stage larvae of 2 trichostrongyle ruminant gastrointestinal nematodes, haemonchus contortus and trichostrongylus colubriformis, can enter into anhydrobiotic states when completely desiccated. larvae of control trichostrongyle species, heligmosomoides polygyrus and nippostrongylus brasiliensis, that infect mice were unable to survive desiccation or to enter into anhydrobiosis. ruminant larvae were able to survive up to 7 desiccation/rehydration cycles, and, ...200617152941
use of bacillus thuringiensis toxin as an alternative method of control against haemonchus contortus.the biocide activity of bacillus thuringiensis (b. thuringiensis) ib-16 strain was evaluated against the blood-feeding nematode haemonchus contortus (h. contortus) in vitro and in vivo assays. twenty experimental jirds (meriones unguiculatus) and 32 sheep were infected with h. contortus by oral route. fourteen days post infection 10 jirds were treated with 0.2 mg per ml of ib-16 soluble toxin by intraperitoneal (i.p.) route and 8 sheep were treated with 0.5 mg of toxin per kg of body weight by i ...200617135537
[a new control method for haemonchus contortus: famacha].famacha is a method that has been developed against haemonchus contortus which causes anemia in sheep and goats especially in tropical and subtropical areas. the basic principle of the method is the detection of the color changes in the mucous membrane of the eye that is caused by anemia. according to the famacha anemia guide, (fag), the mucous membranes of the eyes of animals are inspected for color differences at two or three week intervals. the criteria are used for treating the animals. thus ...200617106855
evaluation of broad-spectrum anthelmintic activity in a novel assay against haemonchus contortus, trichostrongylus colubriformis and t. sigmodontis in the gerbil meriones unguiculatus.the gerbil meriones unguiculatus, infected with three species of nematodes, each located in a separate part of the gastrointestinal tract, provided a reliable laboratory assay for the evaluation of broad-spectrum anthelmintic activity. gerbils harbouring 6-day-old infections of haemonchus contortus, trichostrongylus colubriformis and t. sigmodontis were given selected broad-spectrum anthelmintics by gavage. three benzimidazoles, thiabendazole, oxfendazole and albendazole, a tetrahydropyrimidine, ...200617125549
effect of sainfoin (onobrychis viciifolia) silage and hay on established populations of haemonchus contortus and cooperia curticei in lambs.the objective of the study was to examine the effect of dried and ensiled sainfoin (onobrychis viciifolia) on established populations of haemonchus contortus (abomasum) and cooperia curticei (small intestine) in lambs under controlled conditions. twenty-four parasite naïve lambs were inoculated with a single dose of infective larvae of these parasites 28 days prior to the start of the feeding experiment. twenty-four days post-infection, 4 days prior to the start of the feeding experiment, animal ...200616934938
global patterns reveal strong population structure in haemonchus contortus, a nematode parasite of domesticated ruminants.we have examined the global population genetic structure of haemonchus contortus. the genetic variability was studied using both amplified fragment length polymorphism (aflp) and nad4 sequences of the mitochondrial genome. to examine the performance and information content of the two different marker systems, comparative assessment of population genetic diversity was undertaken in 19 isolates of h. contortus, a parasitic nematode of small ruminants. a total of 150 individual adult worms represen ...200616950266
gastrointestinal nematodes of small ruminants: life cycle, anthelmintics, and diagnosis.strongylid gastrointestinal nematodes are an important cause of disease and economic loss in small ruminants. these parasites are particularly important in the eastern united states where the bloodsucking parasite haemonchus contortus is the predominant species. sheep and goats are infected with gastrointestinal nematodes while grazing and the biology of the infective larvae on the pastures is important in planning effective control programs. fecal egg counts can be used to monitor control progr ...200617071351
rnai in haemonchus contortus: a potential method for target validation.rna interference (rnai) is a method for the functional analysis of specific genes, and is particularly well developed in the free-living nematode caenorhabditis elegans. there have been several attempts to apply this method to parasitic nematodes. in a recent study undertaken in haemonchus contortus, geldhof and colleagues concluded that, although a mechanism for rnai existed, the methods developed for rnai in c. elegans had variable efficacy in this parasitic nematode. the potential benefits of ...200616971180
endomesoderm specification in caenorhabditis elegans and other nematodes.the endomesoderm gene regulatory network (grn) of c. elegans is a rich resource for studying the properties of cell-fate-specification pathways. this grn contains both cell-autonomous and cell non-autonomous mechanisms, includes network motifs found in other grns, and ties maternal factors to terminal differentiation genes through a regulatory cascade. in most cases, upstream regulators and their direct downstream targets are known. with the availability of resources to study close and distant r ...200616998834
[experiences with the famacha-eye-colour-chart for identifying sheep and goats for targeted anthelmintic treatment].the bloodsuckling abomasal parasite haemonchus contortus is the most pathogenic worm in sheep and goats. high prevalences of anthelmintic-resistant isolates make h. contortus difficult to control. detecting the most anaemic animals could support a targeted selective treatment approach. leaving the rest of the flock untreated would generate a refuge for anthelmintic-sensitive parasites. south-african researchers tried the famacha-eye-colour-chart for anaemic sheep and goats with good success. fie ...200617007472
ivermectin selection on beta-tubulin: evidence in onchocerca volvulus and haemonchus contortus.ivermectin resistance is common in trichostrongylid nematodes of livestock, such as haemonchus contortus. this anthelmintic is the only drug approved for mass administration to control onchocerciasis caused by the nematode parasite, onchocerca volvulus. in parts of west africa up to 18 rounds of ivermectin treatment have been administered to communities and there are reports of poor parasitological responses to treatment. understanding ivermectin resistance and ivermectin selection is an importa ...200617007942
feasibility of genus-specific real-time pcr for the differentiation of larvae from gastrointestinal nematodes of naturally infected sheep.results of real-time pcr analysis of coproculture third stage larvae (l3) using genus specific taqman minor groove binder probes were compared with the results of morphological differentiation of l3 after coprocultured and direct morphological worm differentiation from gastrointestinal samples of eight sheep with naturally acquired nematodes infections. faecal egg counts prior to postmortem confirmed infections with trichostrongyles with a geometric mean count of 4828 eggs per gram for all sheep ...200617009713
ecology of the free-living stages of major trichostrongylid parasites of sheep.significant developments over recent decades make it timely to review the ecology of the major gastrointestinal nematode (gin) species of sheep. these include the relentless development and spread of anthelmintic resistance in all of the major sheep production regions of the world, and the consequent drive towards integrated parasite management (ipm) systems incorporating non-chemotherapeutic strategies such as grazing management. the success of such programs is dependent on a detailed understan ...200617011129
isolation and insecticidal/anthelmintic activity of xanthonol, a novel bis-xanthone, from a non-sporulating fungal species.xanthonol, a novel dimeric xanthone, was isolated from a fermentation broth of a non-sporulating fungal species using sephadex lh20 followed by hplc and the structure elucidated by spectral analysis. xanthonol exhibited insecticidal and anthelmintic activities against larvae of lucilia sericata, aedes aegypti, and haemonchus contortus with ld90 of 33, 8, and 50 microg/ml, respectively.200616883778
understanding anthelmintic resistance: the need for genomics and genetics.anthelmintic resistance is a major problem for the control of many parasitic nematode species and has become a major constraint to livestock production in many parts of the world. in spite of its increasing importance, there is still a poor understanding of the molecular and genetic basis of resistance. it is unclear which mutations contribute most to the resistance phenotype and how resistance alleles arise, are selected and spread in parasite populations. the main strategy used to identify mut ...200616889782
evaluation of multiple low doses of copper oxide wire particles compared with levamisole for control of haemonchus contortus in lambs.high levels of anthelmintic resistance in gastrointestinal nematodes (gin) of small ruminants have created the need for alternative approaches to parasite control. copper oxide wire particles (cowp; 2g) have proven effective in decreasing gin infection in lambs. however, the risk of copper toxicity has limited the usefulness of this approach. recently, smaller doses (0.5 and 1g) have proven effective in gin control, reducing the risk of toxicity. the objective of this study was to examine the ef ...200616574324
immunological aspects of nematode parasite control in sheep.gastrointestinal nematode parasitism is arguably the most serious constraint affecting sheep production worldwide. economic losses are caused by decreased production, the costs of prophylaxis and treatment, and the death of the infected animals. the nematode of particular concern is haemonchus contortus, which can cause severe blood loss resulting in anemia, anorexia, depression, loss of condition, and eventual death. the control of nematode parasites traditionally relies on anthelmintic treatme ...200616582083
anthelmintic activity of leucaena leucocephala seed extract on haemonchus contortus-infective larvae. 200616603554
segregation of natural and experimental gastrointestinal nematode infection in f2 progeny of susceptible suffolk and resistant gulf coast native sheep and its usefulness in assessment of genetic variation.gastrointestinal nematode parasitism is a concern to small ruminants worldwide. productivity has been compromised because such nematodes, particularly haemonchus contortus, have developed resistance to available anthelmintics. some sheep breeds and lines within breeds are relatively resistant to infection, a trait that may be useful for developing control strategies. suffolk sheep, which are susceptible to infection, were crossed with gulf coast native sheep, which are more resistant to infectio ...200616621290
ovicidal and larvicidal activity of melia azedarach extracts on haemonchus contortus.haemonchus contortus is responsible for severe economic losses in sheep and goat breeding in the northeast of brazil. however, the effectiveness of control is compromised due to anthelmintic resistance and misuse. in the search for natural anthelmintics, melia azedarach l., a plant indigenous to india but now distributed throughout brazil, was selected due to the reported anthelmintic properties of its seeds. the aim of this study was to evaluate the anthelmintic activity of the seed and leaf ex ...200616621294
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