Gastrointestinal Nematodes Of Sheep Research Articles

First report of multiple anthelmintic resistance in nematodes of sheep in Colombia.

This study aimed to report the presence of parasites resistant to the most used anthelmintic drugs in sheep in Colombia. Four farms (denominated farm 1, 2, 3 and 4) were selected where the animals were not treated with anthelmintics for two months before the trial. Animals with faecal egg count (FEC) above 150 and of different ages were allocated into six groups, each consisting of at least 5 animals. The drugs and dosages used were: ivermectin 1% (0.2 mg/kg), albendazole 25% (5 mg/kg), fenbendazole 10% (5 mg/kg), levamisole 10% (5 mg/kg), and moxidectin 1% (0.2 mg/kg). Anthelmintic efficacy was determined by the FEC reduction test (FECRT) with a second sampling 14 days post-treatment. The efficacy of albendazole and fenbendazole at farm 1 was above 95%, which was different from the others farms. The FECRT indicated the presence of multidrug resistance in the other farms where no tested drugs showed activity higher than 79% (albendazole: 0 to 55%, fenbendazole: 51.4 to 76.6%, ivermectin: 67.3 to 93.1%, levamisole: 0 to 78.1%, and moxidectin: 49.2 to 64.1%).Haemonchus contortus was the predominant (96%) species, followed by a small presence of Trichostrongylus sp. (3%) andCooperia sp. (1%). Therefore, we report for the first time the existence of multiple anthelmintic resistance in gastrointestinal nematodes of sheep in Colombia.

Temporary Immunity of Blackbelly Lambs Reinfected with Trichostrongylus colubriformis

Background: Trichostrongylus colubriformis is one of the most prevalent gastrointestinal nematodes of sheep in warm climates. In this nematode species, anthelmintic resistance (AR) has been reported, which has motivated the search for alternative methods to control it. One practice is to increase the immune response level through the selection of animals with natural resistance, such as Blackbelly sheep. The aim of this study was to investigate the response of IgA and IgG in serum and saliva and the level of cells involved in the acquired resistance in Blackbelly lambs after single artificial reinfection with a resistant strain of Trichostrongylus colubriformis.Materials, Methods & Results: Sixteen weaned lambs grazed for one month in nematode-contaminated grasslands. All the lambs were treated with Albendazole and Levamisole; later, they were stabled for two months. After that, eight lambs were re-infected with 6000 larvae of T. colubriformis and other eight lambs remained naturally infected. In addition, eight nematode-free lambs raised in cages, served as negative control. Blood samples were taken fortnightly to determine packed cell volume (PCV, %), plasmatic protein (g dL-1), as well as absolute and differential leukocytes. The eggs per gram of feces (EPG) were recorded. An indirect ELISA against T. colubriformis Ag was performed to determine the IgG and IgA levels. All data were analyzed by repeated measures. The EPG in the re-infected group increased after 34 days (625 ± 287), while in the naturally infected group it remained close to 200 ± 158 throughout the study. The control lambs did not show any infection. The PCV (29.4 ± 3.4 %), basophils (44 ± 74), lymphocytes (8443 ± 2845) and monocytes (77 ± 91) counts were not affected by infection. The IgA OD against T. colubriformis increased significantly after 15 days post-infection (dpi) in the re-infected lambs (1.69 ± 0.5, 80% with regards to standard). With IgG was not possible to distinguish the effect of infection.Discussion: Highly persistent infection of T. colubriformis was observed for at least four months in the naturally infected group despite having been treated with anthelmintics. It is a significant problem because this species has a high prevalence in the region of study and shows anthelmintic resistance. For such reason, is important to evaluate the ability of the animal to develop an immune response. In other study, a natural reduction in the fecal egg count (FEC) was indicated at 100 dpi in the same species, but in the present work, the FEC could not be reduced until around 120 days when the naturally infected lambs were evaluated. The larger number of neutrophils and leukocytes in both the naturally infected and re-infected groups implies a sustained response for a long time. While the higher counts of eosinophils only in the re-infected group were produced as an immediate response to infection with T. colubriformis. Similarly, with a single infection of T. colubriformis, in Santa Ines sheep the infected lambs showed significantly higher levels of serum IgA than the control group. In this case, differences in IgA activity were observed between the re-infected lambs and the other groups at fifteen dpi, but the basal levels of IgA in the naturally pre-infected lambs were maintained at least five weeks after infection. In conclusion, an increase in the peripheral immune response in lambs re-infected with T. colubriformis resulted from the increase in IgA levels in serum and saliva, and increase in the number of peripheral eosinophils, total leukocytes and neutrophils. Re-infected lambs had a higher level of IgA than naturally infected lambs and control lambs, making possible to promote the immune response with a single re-infection with Trichostrongylus colubriformis.

Comparative efficacy and toxic effects of carvacryl acetate and carvacrol on sheep gastrointestinal nematodes and mice

Carvacrol is a compound isolated from some essential oils. It has been reported to possess anthelmintic activity. Acetylation of this monoterpene has been proposed as a potential way to reduce the toxicity and enhance the pharmacological effects of carvacrol. This study aimed to evaluate the effect of carvacryl acetate (CA) using in vitro and in vivo assays with gastrointestinal nematodes of small ruminants. The egg hatching test (EHT), larval development test (LDT) and adult worm motility (AWM) assessment were conducted to evaluate the effect of the acetylated product and pure carvacrol on Haemonchus contortus eggs, larvae and adults. The structural changes induced in adult H. contortus were assessed using scanning electron microscopy (SEM). CA and carvacrol acute toxicity was evaluated in mice. Finally, the efficacy of 250mg/kg CA and 2.5mg/kg monepantel (positive control) were evaluated in 30 sheep naturally infected with gastrointestinal nematodes by the fecal egg count reduction test (FECRT). In vitro tests were analyzed by analysis of variance (ANOVA) followed by comparison with Tukey’s test. The efficacy was calculated by the Boot Street program using the arithmetic average. The number of eggs in feces (epg) of the groups were transformed to log (x+1) and subjected to ANOVA to compare differences among the groups by Tukey’s test. The level of significance was P<0.05. CA and carvacrol inhibited larval hatching by 89.3 and 97.7% at doses of 8.0 and 1.0mg/ml, respectively. At the concentration of 2mg/ml, CA and carvacrol inhibited 100% of larval development. At a concentration of 200μg/ml, CA and carvacrol inhibited the motility of adult worms by 100% and 58.3% at 24h post-exposure, respectively. CA caused cuticle and vulvar flap wrinkling and bubbles to emerge from the tegument. Carvacrol caused more discreet effects on the cuticle and vulvar flap. The LD10 and LD50 of CA were 566.7mg/kg and 1544.5mg/kg, respectively. The LD10 and LD50 of carvacrol were 546.8mg/kg and 919mg/kg, respectively. CA and monepantel reduced the epg of sheep by 65.9 and 96.4%, respectively, at 16 days post-treatment. CA showed in vitro and in vivo anthelmintic activity and was less toxic than carvacrol.

Gastrointestinal Nematodiasis in Small Ruminants and Anthelmintic Resistance: A Review

Out of various diseases affecting sheep, parasitic gastroenteritis caused by gastro-intestinal nematodes, mainly Haemonchus contortus, is very important for the sheep in India and is responsible for high mortality and morbidity (Yadav, 1997). The gastrointestinal nematodes of sheep include H. contortus, Telodorsagia circumcinta, Trichostrongylus axei, Nematodirus spp. and Cooperia spp. The proportions of each of these nematodes in sheep populations vary according to geographic location. H. contortus and T circumcincta represent most of the parasite burdens seen in sheep, with H. contortus being present in highest numbers. Anthelmintic resistance is present in all of these parasites, but the prevalence is highest for H. contortus, making it the most economically important gastrointestinal nematodes of sheep (Fleming et al., 2006).

Anthelmintic activity of Indigofera tinctoria against gastrointestinal nematodes of sheep.

Aim:Gastrointestinal (GI) nematodes are considered as a major constraint for successful sheep production. Control of these parasites heavily relies on the use of chemical anthelmintics. Over the past decades, the development of anthelmintic resistance to various groups of anthelmintics and problem of drug residues in animal products has awakened interest in medicinal plants as an alternative source of anthelmintics. Hence, this study was undertaken to evaluate the anthelmintic efficacy of Indigofera tinctoria by scientifically validated in vitro and in vivo tests approved by the World Association for the Advancement of Veterinary Parasitology.Materials and Methods:In vitro assays such as egg hatch assay for ovicidal and larval migration inhibition and larval development assay for larvicidal properties were used to investigate in vitro effect of extracts on strongyle egg and larvae, respectively. Fecal egg count reduction test was conducted in vivo to evaluate the therapeutic efficacy of the extracts administered orally at dose rates of 125, 250, 500 mg/kg to sheep naturally infected with mixed GI nematodes.Results:Ethanolic extract of I. tinctoria demonstrated significant (p<0.01) inhibition on egg hatching at concentrations of 40 mg/ml and 80 mg/ml. In in vivo assay, the ethanolic extract of I. tinctoria reduced the fecal egg count ranging between 30.82% and 47.78% at various doses (125, 250 and 500 mg/kg). Although there was a slight variation, all the hematological parameters were within the normal range reported for sheep. Except for alanine transaminase, the overall mean of all the serum biochemical profile was within the normal range for sheep.Conclusion:Based on the results obtained by in vitro and in vivo assay, the ethanolic extract of I. tinctoria possesses anthelmintic activity and could replace the chemical anthelmintics used presently.

Benzimidazole resistance in the ovine Haemonchus contortus from southern Poland - coproscopical and molecular findings.

Anthelmintic resistance within nematodes has become a very common issue, however, the data about its occurrence in the gastrointestinal nematodes of sheep in Poland are very limited. This study was carried out in order to evaluate the presence of benzimidazole resistance in highly pathogenic Haemonchus contortus by means of parasitological and molecular techniques. The research represents the first Polish attempt to confirm the presence of a mutation at codon 200 of the β-tubulin isotype 1 gene in H. contortus by PCR-RFLP. The occurrence of this mutation indicates the risk of ineffective benzimidazole treatment, nowadays commonly used for parasite control in Poland. The resistant parasites were detected by means of FECRT in a sheep flock (30 individuals) from southern Poland. To confirm the resistance on the molecular level, primers designed according to the sequences available in Genebank were used to detect the mutation. Unfortunately, as the PCR product was shorter than required (403 bp), further analyses are needed. The obtained results may indicate the high variability within the parasite population. Hence, it is essential to adapt the reaction conditions to our geographic strain of the nematode - and further analyses are required. Haemonchus contortus, benzimidazole resistance, PCR, Poland.

Effect of Musa spp. extract on eggs and larvae of gastrointestinal nematodes from infected sheep

Helminthes are listed as one of the main problems facing the development of goat and sheep production. Haemonchus contortus is the specie that causes greatest negative impact in ranching. Resistance to anti-parasitic drugs and demand for residue-free animal-derived food products has elevated the importance of herbal treatments. The aim of this study was to develop an extract of Musa spp. and assess by in vitro testing, the anthelmintic effect on eggs and larvae in the gastrointestinal nematodes in sheep. Stool samples from sheep naturally infected were used to obtain eggs and larvae and was then followed by a test of hatchability and a larval migration inhibition test. In vitro tests on the inhibition of larval hatchability at concentrations of 160 and 180 mg mL-1 of larval extracts and inhibition of migration at concentrations of 800 and 1000 mg mL-1 were observed. The results indicate that the use of banana leaf has an anthelmintic effect and that in vivo studies on the applicability of this technology to the field should be made to further understanding and bring more information to what has already been revealed in this study.

Gastro-intestinal nematodes of sheep and goats in three districts of Kaffa and Bench Maji Zones, Southwest Ethiopia

A cross-sectional study was conducted to estimate the prevalence and to identify the genera of gastrointestinal strongyles infecting sheep goats in Chena and Gimbo (Kaffa Zone) and Semen-Bench (Bench Maji zones) districts, Southwest Ethiopia. A total of 800 faecal samples were collected from sheep (n=492) and goats (n=308), and then examined by floatation technique. Positive faecal samples were pooled and cultured and third stage larvae (L 3 ) were harvested and identified. From 800 examined faecal sample 433 (54.1 %) were positive for gastrointestinal parasites eggs. Among the risk factors considered in this study age, body condition and history of previous deworming showed significant (P < 0.05) association with gastrointestinal parasites prevalence. Strongyle type eggs dominated the spectrum of infections, where by 73.1% sheep and 72.8% goats were positive for strongyles infection. From the pooled faecal sample culture seven nematode genera were identified in all the study districts (Chena, Gimbo and Semen-Bench) and both in sheep and goats. These genera include Bunostomum, Chabertia, Cooperia, Haemonchus, Oesophagostomum, Teladorsagia and Trichostrongylus. Among these Trichostrongylus, Bunostomum, Haemonchus and Cooperia were the dominant genera in all the three districts. This study indicated that gastrointestinal parasites were among the serious health problem both in sheep and goats in Kaffa and Bench Maji zones. Further study is required to identify the prevailing parasite species and assess the seasonal dynamics of the gastrointestinal parasites in the study areas and thereby to design appropriate control methods that enable to overcome the existing problem. Keywords: Coproculture, Bench Maji, Ethiopia, Gastrointestinal parasites, Goats, Kaffa, Prevalence, Sheep

The trade-off between farmers' autonomy and the control of parasitic gastro-intestinal nematodes of sheep in conventional and organic farms

Farmers value autonomy in the management of their farm. Amongst organic farmers especially, autonomy is thought to contribute to the success of the farm. Wider integrated farming systems however oppose such autonomy by making farm management decisions remotely. One of the greatest threats to the success of meat sheep farms is the presence of parasitic gastrointestinal nematodes. This study questioned whether a greater level of farmer autonomy could be correlated to the better control of the gastrointestinal nematode infections and whether this could be associated with farmer specific health beliefs. Data was collected across 36 meat sheep farms with similar climatic variables but with different beliefs and attitudes to health care in farming. These farms fell within three groups: French organic, French conventional and Algerian conventional farms. Information regarding farmers' health beliefs and their level of autonomy in management was gathered using questionnaires to address autonomy in the following variables: agriculture production, husbandry, feed, therapeutics, commercialization, and farmers' education. The intensity of gastrointestinal nematode infections was also measured on each of these farms using faecal egg counts on composite sheep samples. Statistical and correlation analyses of autonomy variables to gastrointestinal nematode infection intensities were carried out. The results showed farmer autonomy was not associated with better gastrointestinal nematode control in any of the three groups of farms studied. Greater level of autonomy in husbandry and therapeutics specifically were associated with greater levels of infection. Farmers across the 36 farms studied were unanimously concerned about the threat gastrointestinal nematodes present to their flocks. Yet their current knowledge was clearly not sufficient to control infections irrespective of their health beliefs. This paper makes suggestions to facilitate communication with farmers and to improve the integration of gastrointestinal nematode control measures.

In vitro anthelmintic activity of Zanthoxylum simulans essential oil against Haemonchus contortus

The need for new anthelmintic agents with low impact on the environment is becoming urgent. Phytotherapy is an alternative method to control gastrointestinal nematodes in small ruminants. This study aims to determine the composition of Zanthoxylum simulans essential oil (ZSEO) and evaluate the in vitro ovicidal and larvicidal effects of ZSEO on Haemonchus contortus using egg hatch assay, larval development assay (LDA), and larval migration inhibition assay (LMIA). The chemical composition of ZSEO was determined through gas chromatography and mass spectrometry and 94 compounds were identified from the ZSEO. The major constituents of ZSEO were borneol (18.61%), β-elemene (10.87%). ZSEO and borneol both at 40mg/mL inhibited larval hatching by 100%, with LC50 values of 3.98 and 1.50mg/mL, respectively. The LC50 value of β-elemene was not determined because of its insufficient activity. The results of LDA showed that ZSEO, borneol, and β-elemene all at 40mg/mL inhibited larval development by 99.8%, 100%, and 55.4%, respectively, and exhibited dose-dependent responses with LC50 values of 4.02, 1.99, and 32.17mg/mL, respectively. The results of LMIA showed that ZSEO, borneol, and β-elemene all at 40mg/mL inhibited larval migration by 74.3%, 97.0%, and 53.2%, respectively. ZSEO presented ovicidal and larvicidal activities in vitro. Therefore, Zanthoxylum may be an alternative source of anthelmintic agents to control gastrointestinal nematodes in sheep.

Development of novel valerolactam-benzimidazole hybrids anthelmintic derivatives: Diffusion and biotransformation studies in helminth parasites

In the search for new anthelmintics able to overcome the resistance problem against all available drugs in livestock, the synthesis of novel valerolactam-benzimidazole hybrid compounds was reported. This allowed us to obtain these in vitro and in vivo bioactive compounds using Nippostrongylus brasiliensis rat model by integrating physiology-based assays and ex vivo diffusion studies. In order to further study those novel hybrid molecules, Haemonchus contortus (a sheep gastrointestinal nematode of interest) and Mesocestoides vogae tetrathyridia (a useful system to study the efficacy of anthelmintic drugs against cestoda) were used as parasite models to compare the ex vivo patterns of diffusion and biotransformation of benzimidazoles and their valerolactam-benzimidazole hybrid derivatives. On average, a nine-fold higher intraparasitic concentration of compounds was found in M. vogae compared with H.contortus, with similarities regarding the order of entry of compounds, highlighting febendazole (FEB) and its hybrid compound 10, while valerolactam compound 2 practically did not penetrate the parasites. Interestingly, sulphoxidation drug metabolism was observed and measured, revealing percentages of oxidation of 8.2% and 14.5% for albendazole (ABZ) and febendazole respectively in M. vogae, while this effect was more relevant in H. contortus parasite. More importantly, significant differences were observed between anthelmintic-susceptible adult parasites (Hc S) and those from sheep farms (Hc U). In fact, the percentages of oxidation of FEB and the hybrid compound 8 were higher in Hc U (25.5%, 54.1%, respectively) than in Hc S (8.8%, 38.2%). Interestingly, sulphoxidation of hybrid compound 10 was neither observed in M. vogae nor in H. contortus parasites, suggesting that increased drug metabolism (oxidation reactions) could not be used by these parasites as a defense mechanism against this novel drug.

Comparison of efficacy of albendazole and a association among abamectin and levamizole in sheep

Sheep rearing in Brazil has shown growth in the market. Together with the increase of production of these animals, there is the increase of the damage caused by the presence of gastrointestinal nematodes in these animals and increasing cases of resistance to anthelmintic drugs. This study aimed to evaluate and compare the anthelmintic efficacy of an association between antihelminthic drugs, abamectin and levamisole, and a topical formulation per os of albendazole to the control of gastrointestinal nematodes in sheep. Thus, sheep feces samples were harvested of a property in which the animals were separated into groups and it was proceeded to the treatment of animals, which were divided into three groups, namely C1, control, T1, a association between abamectin levamisole, and T2 and in which there was made the use of albendazole. It was found that only the T1 formulation showed satisfactory efficacy. Still, the groups T1 and T2 showed an average of eggs per gram of feces different C1 group (p <0.01). It was observed that there was no difference in mean helminth genera between these two groups. The association of a commercial formulation of abamectin and levamisole applied via percutaneous was effective for the control of nematodes present in sheep of assessed property.

Establishment rate of sheep gastrointestinal nematodes in farmed red deer (Cervus elaphus)

To investigate the establishment of sheep gastrointestinal nematodes (GIN) in red deer, five red deer and five sheep aged 5–6 months were challenged with a mixed burden of sheep GIN at a rate of 327L3/kg bodyweight. The LSmean (SE) establishment rates (%) for Haemonchus contortus, Teladorsagia circumcincta, Cooperia curticei, Trichostrongylus spp. and Oesophagostomum+Chabertia spp. were 18.6 (0.03), 35.5 (0.04), 30.7 (0.04), 74.9 (0.05), 19.9 (0.06), respectively in sheep and 10.5 (0.03), 1.0 (0.04), 0.1 (0.04), 1.0 (0.05), 4.8 (0.06) respectively, in deer. Establishment rates were significantly different (p<0.05) between hosts for all genera. No Trichostrongylus colubriformis or Trichostrongylus vitrinus were seen in any deer but were present in all sheep. Trichostrongylus axei were seen in both hosts but there were relatively more which established in sheep than in deer (p<0.01). No Chabertia ovina were seen in any deer but were present in four of five sheep in low numbers. The only species of Oesophagostomum seen in either host was Oesophagostomum venulosum. These results suggest that the sheep GIN most likely to infect red deer grazing the same pastures are H. contortus, T. axei and O. venulosum.

Emergence of Resistance Against Benzimidazole Group of Drugs in Gastrointestinal Nematodes of Sheep in Mathura

A study was carried out from July 2010 to March 2011 with an objective to evaluate the efficacy of three anthelmintics of benzimidazole group (albandazole, fenbendazole and oxfendazole) in one organized Madhurikund sheep farm and three unorganized sheep farms of Balajipuram, Aurangabad and Damodarpura villages of Mathura district of Uttar Pradesh. Gastrointestinal nematode (GIN) in all sheep farms were found resistant to fenbendazole with FECR 75.1–88.5%, while albandazole resistance was suspected in three farms with FECR 86.6–92.5% Oxfendazole was found susceptible to GIN in all selected sheep farms with FECR 96.80–98.64%. Larval culture examination revealed the predominance of Haemonchus spp. followed by Trichostrongylus spp., Oesophagostomum spp., and Strongyloides spp. As only a few broad spectrum anthelmintics are available, regular monitoring for their efficacy is important to delay emergence of resistance. The information from this study generated important data for timely management of benzimidazole resistance in parasites.

Prevalence of drug-resistant gastrointestinal nematodes in an organized sheep farm

Aim: The present study was aimed to determine the resistance against albendazole, fenbendazole, levamisole and closantel in gastrointestinal (GI) nematodes of sheep. Introduction: Anthelmintics are used traditionally as an integral part of helminthic control strategies for grazing livestock to prevent production losses from parasitic infections. The continuous and indiscriminate use of the same anthelmintics over years together as the sole means of control are now failing due to the emergence of resistance strains of helminths. Resistance to the commonly used anthelmintics in GI nematodes of sheep has become an increasingly widespread problem throughout the world. Materials and Methods: Fifty-five naturally infected Madras Red lambs of 6-12 months of age were selected and distributed randomly into five treatment groups of 11 animals each. Four groups were treated orally with albendazole (5 mg/kg), fenbendazole (7 mg/kg), levamisole (7.5 mg/kg) and closantel (10 mg/kg) respectively, whereas the fifth group served as untreated control. Fecal samples were collected per rectum of each lamb just prior to treatment (pre-treatment) and on 7, 14, 21 and 28 days post-treatment. The anthelmintic resistance was evaluated by in vivo fecal egg count reduction test (FECRT), post-treatment larval culture and in vitro egg hatch assay. Results: In the FECRT, albendazole reduced the faecal egg count by 86.50%, 84.81%, 85.28% and 84.47% respectively for 4 weeks after treatment. Fecal egg count reduction using fenbendazole was 92.64, 93.04, 90.80 and 90.06% respectively for 4 weeks after treatment. The percent efficacy for levamisole and closantel was more than 95%. The post-treatment larval culture contained only Haemonchus contortus. In the in vitro egg hatch assay, the ED50 value for benzimidazole was 0.299 μg albendazole/ml and levamisole showed an ED50 value of 0.283 μg/ml. Conclusion: Our study confirmed the resistance of H. contortus to benzimidazole in sheep.

Synergic interaction of aromatic compounds thymol and carvacrol against nematode Haemonchus contortus resistant strain

The aim of this work was to evaluate the aromatic compounds thymol and carvacrol and its synergic anthelmintic interactions against sheep gastrointestinal nematode Haemonchus contortus multi resistant strain. Anthelmintic resistance has been a hindrance in animal production causing economic losses and because of the repetitive use of those ineffective chemicals; it is usual to found contamination on meat, milk and environment. New sources of anthelmintic compounds have been investigated. Plant extracts and natural compounds have demonstrated as promising candidates. Eggs were collected from feces of sheep infected with H. contortus according to Bizimenyera et al. [1] technique. A hundred eggs were exposed to solutions of thymol, carvacrol and half and half thymol and carvacrol diluted in water and solvent Tween 80 in concentrations ranging from 2.08 mg/mL to 0.007 mg/mL (decreasing three fold concentrations) with six replicates using a 24 well plate to perform tests. Eggs were incubated for 24h at 27 ° C and the count of eggs hatched was done using an inverted microscope. Data were analyzed by SAS Probit to estimate LC50 with independent variables (dose) transformed by natural logarithm (log dose). The LC50 (fiducial limits) in mg/mL of thymol was 0.13 (0.12 – 0.14), carvacrol was 0.11 (0.10 – 0.12) and the synergic interaction of carvacrol + thymol was 0.037 (0.034 – 0.041). Gas chromatography/mass spectrometry was performed for carvacrol and thymol and 100% and 98% were the similarity with authentic molecules, respectively.

Anthelmintic resistance in sheep gastrointestinal nematodes in Slovakia detected by in-vitro methods.

BackgroundThe intensive use of anthelmintics for the control of helminthic infections has resulted in the development of anthelmintic resistance, which has become a major practical problem in many countries. A variety of tests are available to monitor anthelmintic resistance but most of them are expensive, laborious and time consuming and therefore unpractical for large field surveys. The main aim of this survey was thus to detect the occurrence of benzimidazole (BZ) and macrocyclic lactone resistance on sheep farms in Slovakia by using novel and modified in vitro methods that are inexpensive, easy to use and quick and therefore practical for large surveys.ResultsBZ-resistant gastrointestinal nematodes were found on all 27 farms. Two farms (7.4%) had high levels of resistance (>40% of hatching), and 22 farms had low levels (<20% of hatching) of resistant nematodes. IVM-resistant populations were found on 14 of 49 sheep farms. The prevalence of BZ and IVM resistance has slightly increased on Slovak sheep farms during the last two decades.ConclusionsBoth the BZ and IVM surveys indicated that resistance against anthelmintics was present on Slovak sheep farms. Resistance against the BZ class of anthelmintics had been stable for two decades, but a slight increase on IVM resistance was confirmed. Farmers must thus observe the preventive measures to avoid a faster onset of IVM resistance, otherwise the presence of resistant parasites and ineffective treatment may harm the economy of their farms.

Monepantel: the most studied new anthelmintic drug of recent years.

Monepantel (MOP), a new anthelmintic drug from a group of amino-acetonitrile derivatives, has been intensively studied during last years. Many authors examined this new drug from different perspectives, e.g. efficacy against different species and stages of parasites, mode of action, metabolism, pharmacokinetics, toxicity, resistance, ecotoxicity, etc. MOP is an anthelmintic for livestock (currently only sheep and goats), with molecular mode of action which is different to all other anthelmintics. MOP has a broad-spectrum of activity against gastrointestinal nematodes of sheep, including adults and L4 larvae of the most important species. The key feature of MOP is its full effectiveness against strains of nematodes resistant to benzimidazoles, levamisole, macrocyclic lactones and closantel. After oral administration, MOP is quickly absorbed into the bloodstream and quickly metabolized to MOP sulfone that has a similar efficacy as the parent molecule. Several other MOP metabolites formed in ovine hepatocytes were described. MOP and its metabolites are considered to be non-toxic to environment and its components, such as soil microflora, aquatic organisms, dung organisms, vegetation, etc. The aim of the presented review was not to collect all reported data but to bring an overview of various approaches in the study of MOP and to evaluate their principal results.

In vitro and in vivo anthelmintic activity of Murraya koenigii against gastro-intestinal nematodes of sheep.

The present study have been conducted to evaluate the anthelmintic activity of crude aqueous and crude methanolic leaf extracts of Murraya koenigii. Infection of ruminants with gastro-intestinal (GI) parasite has become a worldwide problem. The parasite causes economic losses in a variety of ways. Previously sheep producers relied heavily on anti-parasitic drugs to control gastro-intestinal parasites of the flocks. But due to misuse of these drugs the parasites become resistant to drugs. Thus created interest in studying medicinal plants as an alternative source of controlling the GI parasites. Adult motility assay (AMA) and egg hatch assay (EHA) have been done for in vitro study, and faecal egg count reduction (FECR) assay have been done for in vivo study. The in vitro study revealed anthelmintic effects of M. koenigii on Haemonchus contortus as evident from their paralytic condition and/or death at eight hour post exposure in different concentrations (12.5, 25, 50mg/ml) of aqueous and methanolic extracts which exhibit to be dose-dependent. Aqueous and methanolic extracts of M. koenigii were found to have low percent inhibitory effect on egg hatching. It may be concluded that M. koenigii showed significant anthelmintic activity.

Anthelmintic, antimicrobial, antioxidant and cytotoxic activity of Caltha palustris var. alba Kashmir, India

The methanolic extract obtained from the root portion of Caltha palustris var. alba was evaluated for its anthelmintic efficacy against gastrointestinal nematodes of sheep under both in vitro and in vivo conditions using worm motility inhibition (WMI) assay and fecal egg count reduction (FECR) assay, respectively. The extract was subjected to antimicrobial activity using agar-well diffusion method against different bacterial strains. In addition the extract was evaluated for cytotoxic and antioxidant activity against cultured THP-1(Leukemia), A-549 (Lung), HCT-15 (Colon), Cervix (HeLa) and PC-3(Prostrate) cell lines by SRB and DPPH radical scavenging assays.The extract used resulted in mean %WMI of 94.44%, as observed when the worms were put in lukewarm buffer for 30 min after exposure to different treatments. The mean mortality index of the sample was 0.95. The lethal concentration (LC50) was 0.11 mg·mL−1. Cell lines were exposed to concentration of 100 μg·mL−1 of extract for 48 h, which reduced the viability of these cell lines. The same plant extract also showed 55.58% DPPH radical scavenging activity.