scholarly journals Case Study: An assessment of anthelmintic resistance through in vivo fecal egg count reduction test and in vitro egg hatch test on small ruminant farms in the southcentral United States

2017 ◽  
Vol 33 (5) ◽  
pp. 627-633
Author(s):  
Y. Tsukahara ◽  
Z. Wang ◽  
T.A. Gipson ◽  
S.P. Hart ◽  
L.J. Dawson ◽  
...  
2007 ◽  
Vol 76 (1) ◽  
pp. 79-85 ◽  
Author(s):  
M. Saeed ◽  
Z. Iqbal ◽  
A. Jabbar

This study was carried out to screen goat farms for anthelmintic resistance (AR) against oxfendazole (OXF) and to determine contributory factors for its development. For this purpose, Beetal goat farms (n = 18) were randomly selected, with natural mixed gastrointestinal nematodosis infection. In vivo (faecal egg count reduction test) and in vitro (egg hatch assay) tests were used to ascertain the presence of AR while a scorecard was used to determine the role of possible contributory factors for oxfendazole resistance. For in vivo test, the experimental animals were divided into two groups of 10 animals each; one group received OXF treatment, while the other served as control. Pre- and post-treatment coproculture was performed to identify the species and genera of nematodes. Egg hatch assay (EHA) was used to confirm the results of FECRT. Fecal egg count reduction test (FECRT) revealed the development of resistance on six farms and post-treatment larval cultures indicated Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, Teladorsagia circumcincta and Oesophagostomum spp. as dominant species with resistance. Furthermore, EHA confirmed the results of FECRT. Among the presumptive factors for AR, the highest composite score was for rotation of anthelmintics followed by treatment frequency, dose rate and nature of medication. The scorecard for the development of AR, used in this study, may be helpful for the assessment of contributory factors of AR.


Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1063
Author(s):  
Fabio Castagna ◽  
Domenico Britti ◽  
Manuela Oliverio ◽  
Antonio Bosco ◽  
Sonia Bonacci ◽  
...  

The worldwide increased difficulty to counteract gastrointestinal nematode (GIN) infection in sheep, due to progressing anthelmintic resistance, has led to the evaluation of other alternative helminth control options, mainly from plants. The anthelmintic efficacy of an aqueous Punica granatum macerate was evaluated in sheep naturally infected by GIN in southern Italy. The macerate was chemically characterized by chromatographic analysis coupled with high-resolution mass spectrometry (LC/HRMS) and an aliquot was concentrated to obtain a dry extract. A part was characterized, the remaining washed with methanol to obtain an insoluble residue and methanol phase. In the methanol fraction, the quantitatively predominant gallic acid was purified to obtain the pure molecule. The three fractions thus obtained were used for in vitro studies (i.e., egg hatch test) to verify anthelmintic efficacy. For this purpose, fecal samples were collected from sheep naturally infected by GINs. Fractions were diluted in H2O/DMSO 0.5% at 1.00, 0.5, 0.25, 0.125, 0.05, and 0.005 mg/mL concentrations. Thiabendazole (0.25 and 0.5 mg/mL) and deionized water were used as positive and negative controls, respectively. Egg hatch test results indicated that all fractions caused a significant (p < 0.05) egg hatch inhibition within 48 h of exposure highlighting a high (>82%) efficacy in vitro at all tested doses. Maximal egg hatching inhibition effect was exhibited by the methanol fraction (99.3% and 89.3% at 1 and 0.005 mg/mL concentrations), followed by the insoluble residue and gallic acid (94.7% and 85.3% and 94.0% and 82.7% at 1 and 0.005 mg/mL, respectively). The current study validated the anthelmintic potential of traditional P. granatum macerate against GIN infection in sheep, thus highlighting the role of gallic acid as principal component and justifying a need to undertake further in vivo studies on these ethno-veterinary remedies.


Author(s):  
Mihai CERNEA ◽  
Roxana FILIP ◽  
Raul CĂTANĂ ◽  
Laura CĂTANĂ

Our research aimed to evaluate the efficacy of anthelmintic treatments in sheep, as well as the resistance occurrence risk for the most commonly used substances. Anthelmintic medication efficacy was evaluated on 30 animals from a private farm, located in Sânmihaiu Almaşului, Sălaj County. In vivo studies were performed by using Fecal Egg Count Reduction Test (FECRT) and testing an albendazole-based (ABZ) product. In vitro, we used Egg Hatch Assay (EHA) and Larval Development Assay (LDA) for albendazole (ABZ), mebendazole (MBZ), fenbendazole (FBZ), thiabendazole (TBZ) and ivermectin (IVM) (only for LDA). FECRT showed that intestinal nematodes developed resistance phenomena against the ABZ-based product, with an extensivity of 80% at seven days post therapy, an egg reduction percentage of 41.89% at seven days post-therapy and 43.9% at 14 days post-therapy. The in vitro EHA highlighted a superior efficacy of TBZ (egg hatch percentage at reference concentration being 51.21) compared to ABZ (71.89%), MBZ (84.46%) and FBZ (79.22%), with a minimum risk of anthelmintic resistance. The LDA test revealed the superior efficacy of FBZ (MIC 0.59 mcg/ml) and IVM (MIC 0.078 mcg/ml), with a minimal risk of inducing parasitic resistance. All in vivo and in vitro tests revealed a limited ABZ efficacy, recommending avoiding the therapy with this substance.


Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 62
Author(s):  
Michal Babják ◽  
Alžbeta Königová ◽  
Michaela Urda Dolinská ◽  
Tomas Kupčinskas ◽  
Jaroslav Vadlejch ◽  
...  

Considerable research has been directed towards optimising in vitro tests that can diagnose resistance in pre-parasitic stages of parasites. The objective of this study was to compare the in vivo faecal egg count reduction test (FECRT), the in vitro egg hatch test (EHT), and the molecular determination of the frequency of a codon 200 allele of β-tubulin isotype 1 associated with benzimidazole resistance in larval stages of Haemonchus contortus obtained from infected goats. Animals were infected with composite infective doses representing 10, 20, 30, 40, 60, and 80% resistant alleles. Faecal samples for the EHT were collected on 28, 33, and 35 days post-infection. The results of the in vivo FECRT indicated that albendazole treatment reduced infections consisting of composite doses of 10, 20, 30, 40, 60, and 80% larvae of the resistant isolate by 91.3, 78.0, 63.3, 48.4, 36.5, and 41.4%, respectively. The drug concentration at which 50% of the eggs were prevented from developing hatching larvae (ED50) in the in vitro EHT varied from 0.09 ± 0.01 to 15.63 ± 12.10 μg/mL thiabendazole. The results of the in vitro EHT indicated that the test could estimate in vivo resistance well. The EHT could thus accurately estimate the in vivo efficacy of the drug and percentage of the resistance allele in the population using hatching parameters in delineation doses. This finding was also supported by comparing the FECRT data to the hatching percentages in the EHT on 30 goat farms in Slovakia with natural mixed infections of gastrointestinal parasites.


Author(s):  
Yousmel Alemán Gainza ◽  
Isabella Barbosa dos Santos ◽  
Amanda Figueiredo ◽  
Leonardo Aparecido Lima dos Santos ◽  
Sérgio Novita Esteves ◽  
...  

Abstract This study evaluated the resistance status of Haemonchus contortus from sheep flocks in the state of São Paulo, Brazil, through comparison between the fecal egg count reduction test (FECRT) and the larval development test (LDT). For the FECRT, 35 sheep were selected in each of five flocks and divided into groups treated with: benzimidazole, levamisole, ivermectin, monepantel and control. Feces were collected for EPG and fecal cultures. The LDT was performed using thiabendazole (TBZ), levamisole (LEV), ivermectin aglycone (IVM-A) and Zolvix (ZLV). Resistance to all drugs was detected using FECRT in 100% of the flocks, except in relation to ZLV (40% resistant and 20% suspected of resistance). LDT indicated resistance to TBZ and IVM-A in all flocks, to LEV in 80% of flocks and to ZLV in 10%. Total agreement was obtained between the two tests for TBZ and IVM (k = 1.0), while for LEV (k = 0.8) and ZLV (k = 0.9), substantial and almost perfect agreement were obtained, respectively. The concordance between the tests was significant, thus showing that it is possible to use the outcome of the LDT to predict the FECRT, and hence validating the former as a fast diagnostic test for use by sheep farmers in Brazil.


Author(s):  
Daniel L. Villeneuve ◽  
Brett R. Blackwell ◽  
Jenna E. Cavallin ◽  
Wan‐Yun Cheng ◽  
David J. Feifarek ◽  
...  

2018 ◽  
Vol 46 (1) ◽  
pp. 14 ◽  
Author(s):  
Weibson Paz Pinheiro André ◽  
Wesley Lyeverton Correia Ribeiro ◽  
Lorena Mayana Beserra de Oliveira ◽  
Iara Tersia Freitas Macedo ◽  
Fernanda Cristina Macedo Rondon ◽  
...  

Background: Gastrointestinal nematodes are one of the major health and economic problem of sheep and goats in the world. The control of these nematodes is carried out conventionally with synthetic anthelminths, which favored the selection of gastrointestinal nematode (GIN) populations multiresistant to anthelmintics. The emergence of anthelmintic resistance has stimulated the search for new alternatives to control small ruminant GIN, standing out the use of plants and their bioactives compounds, such as essential oils (EO). The objective of this review was to present the main characteristics and anthelmintic activity of EO, their isolated compounds and drug delivery systems in the control of GIN.Review: Essential oils are a complex blend of bioactive compounds with volatile, lipophilic, usually odoriferous and liquid substances. EO are composed of terpenes, terpenoids, aromatic and aliphatic constituents. EO has various pharmacological activities of interest in preventive veterinary medicine such as antibacterials, antifungals, anticoccicids, insecticides and anthelmintics. In vitro and in vivo tests are used to validate the anthelmintic activity of EO on GIN. In vitro tests are low cost screening tests that allow the evaluation of the anthelmintic activity of a large amount of bioactive compounds on eggs, first (L1) and third stage larvae (L3), and adult nematodes. The antiparasitic effect of EO is related to its main compound or to the interaction of the compounds. These bioactive compounds penetrate the cuticle of the nematodes by transcuticular diffusion, altering the mechanisms of locomotion, besides causing cuticular lesions. Following in vitro evaluation, the acute and sub-chronic toxicity test should be performed to assess the toxicity of the bioactive compounds and to define the dose to be used in in vivo tests. In vivo tests are more reliable because the anthelmintic effectiveness of bioactive compounds is evaluated after the metabolization process. The metabolization process of the bioactive compounds can generate metabolites that exhibit or not anthelmintic effectiveness. The in vivo tests assessing the anthelmintic effectiveness of bioactive compounds in sheep and goats are the fecal egg count reduction test and the controlled test.  OE promoted reduction of egg elimination in faeces which may be related to cuticular and reproductive alterations in GIN, and reduction of parasite burden in in vivo tests. Due to the promising results obtained with OE in the in vivo tests, interest has been aroused in using nanotechnology as an alternative to increase the bioavailability of OE and consequently, potentializing its anthelmintic effect, reducing the dose and  toxicity of the biocompounds. In addition to nanotechnology, the isolation and chemical modification of compounds isolated from OE have been employed to obtain new molecules with anthelmintic action and understand the mechanism of action of EO on the small ruminant GIN.Conclusion: The use of EO and their compound bioactive in the control of resistant populations of GIN is a promising alternative. The adoption of strategies in which natural products can replace synthetic anthelmintics, such as in dry periods and use synthetic anthelmintics in the rainy season when the population in refugia in the pasture is high, thus reducing the dissemination of GIN resistant populations. As perspective, the evaluation of pharmacokinetics and pharmacodynamics of these natural products should be performed so that one defines treatment protocols that optimize the anthelmintic effect.


2021 ◽  
Vol 40 (4) ◽  
pp. 287-295
Author(s):  
I.K. Idika ◽  
V.J. Ebuk ◽  
E.I. Okoro ◽  
T.A. Nzeakor ◽  
N.M. Uzonnah ◽  
...  

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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