The relationship between faecal egg count reduction and the lethal dose 50% in the egg hatch assay and larval development assay

1998 ◽  
Vol 77 (2-3) ◽  
pp. 133-145 ◽  
Author(s):  
N Maingi ◽  
H Bjørn ◽  
A Dangolla
Keyword(s):  
Larval Development ◽  
Lethal Dose ◽  
Egg Hatch ◽  
Faecal Egg Count ◽  
Egg Hatch Assay ◽  
The Relationship

scholarly journals In Vitro Pharmacodynamics of Benzimidazole and Tetrahydropyrimidine Derivatives in European Bison Gastro-Intestinal Nematodes

2017 ◽  
Vol 74 (2) ◽  
pp. 167
Author(s):  
Laura CĂTANĂ ◽  
Aurora URSACHE ◽  
Alexandra PETCU ◽  
Flavia PETREAN ◽  
Raul CĂTANĂ
Keyword(s):  
Larval Development ◽  
Nematode Population ◽  
In Vitro Tests ◽  
European Bison ◽  
Egg Hatch ◽  
Parasitic Resistance ◽  
Faecal Samples ◽  
Egg Hatch Assay ◽  
Inducing Resistance

The present study was aimed to evaluate the efficacy of anthelmintic agents against intestinal nematodes found in European bison. It was performed between October 2016 and May 2017, using Egg Hatch Assay (EHA) and Larval Development Assay (LDA). The parasites were obtained from faecal samples, harvested from bisons in Romania and Sweden. The efficacy of albendazole (ABZ), mebendazole (MBZ) thiabendazole (TBZ) and pyrantel (PYR) was tested. In EHA, the maximum efficacy was observed in MBZ (EC50 = - 0.227 μg/ml), and then TBZ (EC50 = - 0.2228). ABZ had a weaker result, EC50 being 0.326 μg/ml. All tested benzimidazoles registered hatching percentages below 50%, reflecting the lack of parasitic resistance. MIC obtained in the LDA tests were 0.2144 μg/ml for TBZ, 0.2792 μg/ml for PYR, 0.5429 μg/ml for MBZ, while ABZ came last (MIC = 0.8187 μg/ml). The in vitro tests proved the antiparasitic molecules efficacy against bisons nematode population and a limited risk of inducing resistance phenomena.

Anthelmintic evaluation of Cucurbita pepo againstgastrointestinal nematodes of sheep

2017 ◽  
Author(s):  
Ambalathaduvar Meenakshisundaram ◽  
Tirunelveli Jayagopal Harikrishnan ◽  
Thavasi Anna
Keyword(s):  
Larval Development ◽  
Anthelmintic Activity ◽  
Gastrointestinal Nematodes ◽  
Migration Inhibition ◽  
Egg Hatch ◽  
Larval Migration ◽  
Faecal Egg Count ◽  
Ethanolic Extracts

The study was aimed at to investigate the anthelmintic efficacy of aqueous and ethanolic extracts of Cucurbita pepo against gastrointestinal nematodes of sheep by scientifically validated in vitro and in vivo tests. In vitro anthelmintic activity was determined by egg hatch assay, larval migration inhibition assay and larval development assay against eggs and larvae of mixed gastrointestinal nematodes of sheep. The extracts which were found to be effective in in vitro assays were further evaluated by in vivo faecal egg count reduction test against mixed species of sheep gastrointestinal nematodes with 3 different doses (125, 250 and 500 mg kg-1). Haematological and serum parameters were estimated before and after treatment to determine the impact of plant extracts on health of the animal. Aqueous extract of C. pepo demonstrated significant inhibition of egg hatch at 40 and 80 mg/ml. The ED50 value of egg hatch inhibition was 3.51mg/ml. In larval migration inhibition assay, both aqueous and ethanolic extracts of C. pepo demonstrated inhibition of larval migration and the LM50 was 1.75 and 0.32 mg/ml respectively. However, in larval development assay, both aqueous and ethanolic extracts showed only marginal inhibition of larval development at all concentrations tested. In faecal egg count reduction test (FECRT), aqueous extracts of C. pepo at 500 mg/kg caused significant reduction in eggs per gram (96.61 per cent) the reduction being higher than the result obtained with albendazole, the positive control (93.25 per cent). There was a significant difference in EPG reduction between sheep treated with albendazole and C. pepo. Haematological and serum parameters were not affected in both the treated and untreated sheep indicating that the extracts did not cause toxic effects. Based on the results obtained in this study, the aqueous extract of C. pepo possesses anthelmintic activity and could offer an alternative source for the control of gastrointestinal nematodes of sheep.

scholarly journals Benzimidazoles Pharmacodynamics in Equine Strongyles

2016 ◽  
Vol 73 (2) ◽  
pp. 360
Author(s):  
Laura Catana ◽  
Csongor Olah ◽  
Raul Catana ◽  
Mihai Cernea
Keyword(s):  
Larval Development ◽  
Treatment Protocol ◽  
Average Intensity ◽  
Egg Hatch ◽  
Maximum Value ◽  
Limited Effectiveness ◽  
Faecal Egg Count ◽  
Comparative Risk

Our research aimed to assess the effectiveness of four benzimidazoles: albendazole, fenbendazole, mebendazole and thiabendazole against equine strongyles. The tests were performed between March 2015 and May 2016, on samples collected from 20 horses and 8 donkeys living in Harghita County. In vivo, Faecal Egg Count Reduction Test (FECRT) was used to evaluate fenbendazole pharmacodynamics. In vitro, Egg hatch assay (EHA) and Larval development assay (LDA) were used to evaluate the effectiveness of albendazole, fenbendazole, mebendazole and thiabendazole. The predominance of small strongyle species was observed, mostly Cyathostomum type A. In the horse group, before treatment, the average intensity was 1595.5 EPG, the maximum value being 4000, and extensivity 55%. Tested again at 14 days after treatment, all samples were negative. In the donkey group, before treatment, the total number was 6550 EPG, intensity of 935.7 and extensivity of 87.5%. 14 days after treatment, the average intensity was 150 and the extensivity 50%. In the horse group, EHA proved the efficacy of fenbendazole (0.0192%), albendazole (0.3740%) and thiabendazole (11.62%) and a major risk of inducing adaptive phenomena for mebendazole (Y parameter 1009.92). In the donkey group, all benzimidazoles had limited effectiveness: thiabendazole (73.93%), mebendazole (87.51%), fenbendazole (94.05%), albendazole (111.67%). All benzimidazoles inhibited larval development. For all tested benzimidazoles, the resistance induction predictive comparative risk analysis highlighted the benefit of their use, provided that the treatment protocol allows sufficient contact time.

scholarly journals Detection of benzimidazole resistance in gastrointestinal nematode parasites of sheep in the Czech Republic

2009 ◽  
Vol 54 (No. 10) ◽  
pp. 467-472 ◽  
Author(s):  
E. Vernerova ◽  
R. Vondrova ◽  
H. Kisova ◽  
V. Svobodova ◽  
A. Hera
Keyword(s):  
Czech Republic ◽  
Larval Development ◽  
Infection Intensity ◽  
Gastrointestinal Nematode ◽  
Egg Hatch ◽  
The Czech Republic ◽  
Nematode Parasites ◽  
Benzimidazole Resistance ◽  
Faecal Egg Count ◽  
Larval Development Test

During 2004–2007 the efficacy of benzimidazole type drugs was studied on 14 sheep farms in the Czech Republic. The study was based on the evaluation of faecal egg count reduction test (FECRT), egg hatch test (EHT), and larval development test (LDT). The prevalence of benzimidazole resistance on farms ranged from 25% to 98%; however, the infection intensity was typically low to moderate on most of the farms. Based of FECRT, resistance was identified on three farms. Resistance was suspected on one of the farms after repeated examination performed the following year.

scholarly journals ANALYSIS OF RELATIONSHIPS BETWEEN THE CAPACITY OF CHEMICALS TO THE CUMULATION AND THE STRUCTURE OF THEIR MOLECULES

2019 ◽  
Vol 96 (10) ◽  
pp. 970-974
Author(s):  
Nina V. Kharchevnikova ◽  
Z. I. Zholdakova ◽  
V. I. Zhurko ◽  
D. Yu. Fedortsova ◽  
V. G. Blinova
Keyword(s):  
Lethal Dose ◽  
Practical Interest ◽  
Training Dataset ◽  
Jsm Method ◽  
Hazard Class ◽  
Structural Class ◽  
Chemical Hazard ◽  
Leave One Out ◽  
The Relationship

The relationships between the capacity of chemicals to cumulate a toxic effect (functional cumulation) and the structure of their molecules were investigated. In the process of substantiation of safe levels (MAC) of substances in water this capacity is characterized by the cumulation hazard class (later in the text - hazard class). This class is stated to be depend on the value of the relationship between the mean lethal dose of the acute experiment and the threshold dose of the chronic experiment. The experimental study of a huge amount of new chemicals in the chronic experiments is a very difficult task, thus the study of the possibility to predict the hazard class of a chemical is of great scientific and practical interest. By using a logical combinatorial method JSM, named in honor of an English logic J.S. Mill, the structural groups in molecules, determining the appurtenance of these chemicals to a hazard class were identified and the possibility of the prediction of the hazard class of a chemical belonging to a definite structural array, containing such structural group were investigated. The training dataset (583 compounds) was automatically derived from the database WATERTOX, containing the data on acute and chronic toxicity for about 2000 substances. The results suggest the JSM method to be limitedly applicable for the determination of a hazard class of an untested chemical using this heterogeneous training dataset because we were unable to unambiguously derive the list of chemicals belonging to the class of moderately hazard substances. The chemical in some cases was predicted to belong to one or other of the neighboring classes. However taking in mind this uncertainty, the accuracy of the method evaluated, when using the “leave-one-out” method was 78%. Nevertheless the JSM method enables us to find structural subgroups “responsible” for the functional cumulation. The relation of the hazard class of a chemical belonging to a definite structural class with its structure and the possibility of the prediction of an untested chemical hazard class are demonstrated. The prognosis of the hazard classes for chemicals belonging to several structural sets including the anthraquinone derivatives, phthalimides, perfluorated aliphatic compounds, chlorosubstituted phenols, phenylureas is performed.

scholarly journals In vitro Efficacy of Albendazole against Strongyle eggs recovered from Trade Goats slaughtered at the Nsukka Abattoir: A Preliminary Survey of Resistance to Albendazole

2021 ◽  
Vol 40 (4) ◽  
pp. 287-295
Author(s):  
I.K. Idika ◽  
V.J. Ebuk ◽  
E.I. Okoro ◽  
T.A. Nzeakor ◽  
N.M. Uzonnah ◽  
...  
Keyword(s):  
Faecal Sample ◽  
Anthelmintic Resistance ◽  
Egg Hatch ◽  
Lc50 Value ◽  
Nematode Parasites ◽  
Faecal Culture ◽  
World Association ◽  
Egg Hatch Assay ◽  
Set Up

The efficacy of Albendazole against trichostrongyle nematode parasites in goats presented for slaughter at the Nsukka municipal  abattoir was evaluated using the In vitro Egg hatch assay (EHA) model. The abattoir was visited once every week for 4 consecutive months during which a total of 240 goats were sampled. Fecal samples were collected per rectum from a minimum of 15 goats on each day of the visit. Egg Hatch Assay was performed on strongyle eggs recovered from pooled faecal sample on each day of sampling with a 2.5% W/V Albendazole. Faecal culture was also set up from the pooled faecal sample on each sampling day to recover and identify the nematode parasites present in the goats. Among the 240 goats sampled, the prevalence of trichostrongylosis as observed by the presence of strongyle eggs was 94.6% (227/240). Faecal culture and larval identification revealed 69.8% of the strongyles as  Haemonchus contortus, while 25.5 and 4.8% were Trichostrongylus colubriformis and Oesophagostomum species respectively. In the EHA, Albendazole had mean LC50 value of 0.16 µg/ml which is slightly in excess of the discriminating dose of 0.1µg/ml as prescribed by the World Association for the Advancement of Veterinary Parasitology (WAAVP) as an indication of anthelmintic resistance. There is therefore an urgent need to screen the nematode parasite population in the Nigeria for the presence Albendazole resistance genes. Key words: GI nematode; egg hatch assay; goat; Albendazole; Resistance; Nigeria

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