scholarly journals Combination of immunostimulants with moxidectin in the treatment of animals experimentally infected with Haemonchus contortus

2021 ◽  
Vol 42 (2) ◽  
pp. 707-720
Author(s):  
Luiza Pires Portella ◽  
◽  
Fagner D'ambroso Fernandes ◽  
Luís Antônio Sangioni ◽  
Fernanda Ramos ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Experimental Infection ◽  
Haemonchus Contortus ◽  
Infected Sheep ◽  
Subtropical Region ◽  
Anthelmintic Drug ◽  
Parasitic Resistance ◽  
Efficacy Of Treatment

Considering the importance of Haemonchus contortus infection in herds along with parasitic resistance, the goal of this study was to evaluate the influence of the administration of adjuvants alone or in combination with anthelmintics for the treatment of H. contortus, in experimentally infected sheep. Thirty sheep of the Texel breed of both genders, raised in a herd located in the subtropical region of Brazil, were used in this experiment. Experimental infection with H. contortus was performed in sheep, and the infected sheep were then separated into groups for the administration of antiparasitic and immunostimulant drugs. The results obtained from the excretion of eggs per gram of feces and the count of parasites during necropsy affirm that the use of adjuvants in combination with anthelmintics is associated with higher efficacy of treatment, lower rate of reinfection, and retardation in the development of anthelmintic drug resistance by H. contortus. Based on these results, we can conclude that the combination of anthelmintics and immunostimulants may favor potential anthelmintic treatments for H. contortus.

Voluntary intake of a medicated feed block by grazing sheep is increased by gastrointestinal nematode infection

2012 ◽  
Vol 52 (12) ◽  
pp. 1136
Author(s):  
F. J. Fishpool ◽  
L. P. Kahn ◽  
D. J. Tucker ◽  
J. V. Nolan ◽  
R. A. Leng
Keyword(s):  
Haemonchus Contortus ◽  
Gastrointestinal Nematode ◽  
Gastrointestinal Nematodes ◽  
Infected Sheep ◽  
Self Medication ◽  
Blood Samples ◽  
Voluntary Intake ◽  
Grazing Sheep ◽  
Long Acting ◽  
To Receive

The aim of this study was to determine the rate, variability and repeatability of intake by grazing sheep of a medicated feed block (MFB) containing fenbendazole and investigate if infection with gastrointestinal nematodes altered consumption patterns of the MFB in the same grazing mob. In Experiment 1, 30 Merino wethers were given access to an MFB for two separate 1-week periods, with blood sampling at Days 2, 4 and 6 of each period to determine MFB intake. In Experiment 2, the wethers were selected based on previous MFB intake and allocated to receive an oral dose of 10 000 Trichostrongylus colubriformis and 3000 Haemonchus contortus (anthelmintic susceptible) or a long acting anthelmintic. After 5 weeks, sheep were given access to an MFB (1.5 mg fenbendazole/g) and eight blood samples were taken over 2 weeks to determine intake. In Experiment 1, individual MFB intake in Week 1 and Week 2 was positively correlated (P = 0.002, R2 = 0.287). Mean individual MFB intake in Experiment 1 and Experiment 2 was positively correlated (P = 0.008, R2 = 0.047). In Experiment 2, more infected wethers (95%) consumed the MFB than did uninfected wethers (79%) (P < 0.001) and infected wethers ate significantly more MFB over the first 4 days (P = 0.041) of access. All infected sheep consumed sufficient MFB to receive a therapeutic dose and worm egg counts in infected sheep declined from 2165 epg to 120 epg in the first week of access to MFB. The decline in differences in MFB intake between infected and uninfected sheep corresponded to the decline in worm egg count, suggesting the existence of self-medication with parasitism accounting for intake differences.

Effects of single or trickle Haemonchus contortus experimental infection on digestibility and host responses of naïve Creole kids reared indoor

2013 ◽  
Vol 191 (3-4) ◽  
pp. 284-292 ◽  
Author(s):  
J.C. Bambou ◽  
W. Cei ◽  
S. Camous ◽  
H. Archimède ◽  
A. Decherf ◽  
...  
Keyword(s):  
Experimental Infection ◽  
Haemonchus Contortus ◽  
Host Responses

scholarly journals Comparison of two in vitro methods for the detection of ivermectin resistance in Haemonchus contortus in sheep

2016 ◽  
Vol 53 (2) ◽  
pp. 120-125 ◽  
Author(s):  
M. Urda Dolinská ◽  
A. Königová ◽  
M. Babják ◽  
M. Várady
Keyword(s):  
Drug Resistance ◽  
Haemonchus Contortus ◽  
Anthelmintic Resistance ◽  
Economic Losses ◽  
Parasitic Nematodes ◽  
Migration Inhibition ◽  
In Vitro Methods ◽  
Parasitic Helminths

SummaryGastrointestinal parasitic nematodes in sheep cause severe economic losses. Anthelmintics are the most commonly used drugs for prophylaxis and therapy against parasitic helminths. The problem of drug resistance has developed for all commercially available anthelmintics in several genera and classes of helminths. In vitro and in vivo tests are used to detect anthelmintic resistance. Two in vitro methods (larval migration inhibition test and micromotility test) for the detection of ivermectin (IVM) resistance were compared using IVM-resistant and IVM-susceptible isolates of Haemonchus contortus. The degree of resistance for each test was expressed as a resistance factor (RF). The micromotility test was more sensitive for quantitatively measuring the degree of resistance between susceptible and resistant isolates. The RFs for this test for IVM and eprinomectin ranged from 1.00 to 108.05 and from 3.87 to 32.32, respectively.

Anthelmintic drug resistance in the UK

1989 ◽  
Vol 125 (7) ◽  
pp. 143-147 ◽  
Author(s):  
M. Taylor ◽  
K. Hunt
Keyword(s):  
Drug Resistance ◽  
Anthelmintic Drug ◽  
The Uk

scholarly journals UDP-Glycosyltransferases and Albendazole Metabolism in the Juvenile Stages of Haemonchus contortus

2020 ◽  
Vol 11 ◽  
Author(s):  
Pavlína Kellerová ◽  
Martina Navrátilová ◽  
Linh Thuy Nguyen ◽  
Diana Dimunová ◽  
Lucie Raisová Stuchlíková ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Resistant Strain ◽  
Haemonchus Contortus ◽  
Resistance Mechanism ◽  
Constitutive Expression ◽  
Primary Metabolite ◽  
Resistance Development ◽  
Enhanced Solubility ◽  
Juvenile Stages ◽  
Resistant Strains

The nematode Haemonchus contortus, a gastrointestinal parasite of ruminants, can severely burden livestock production. Although anthelmintics are the mainstay in the treatment of haemonchosis, their efficacy diminishes due to drug-resistance development in H. contortus. An increased anthelmintics inactivation via biotransformation belongs to a significant drug-resistance mechanism in H. contortus. UDP-glycosyltransferases (UGTs) participate in the metabolic inactivation of anthelmintics and other xenobiotic substrates through their conjugation with activated sugar, which drives the elimination of the xenobiotics due to enhanced solubility. The UGTs family, in terms of the biotransformation of commonly used anthelmintics, has been well described in adults as a target stage. In contrast, the free-living juvenile stages of H. contortus have attracted less attention. The expression of UGTs considerably varies throughout the life cycle of the juvenile nematodes, suggesting their different roles. Furthermore, the constitutive expression in a susceptible strain with two resistant strains shows several resistance-related changes in UGTs expression, and the exposure of juvenile stages of H. contortus to albendazole (ABZ) and ABZ-sulfoxide (ABZSO; in sublethal concentrations) leads to the increased expression of several UGTs. The anthelmintic drug ABZ and its primary metabolite ABZSO biotransformation, tested in the juvenile stages, shows significant differences between susceptible and resistant strain. Moreover, higher amounts of glycosidated metabolites of ABZ are formed in the resistant strain. Our results show similarly, as in adults, the UGTs and glycosidations significant for resistance-related differences in ABZ biotransformation and warrant further investigation in their individual functions.

scholarly journals Image recognition based on deep learning in Haemonchus contortus motility assays

2021 ◽  
Author(s):  
Martin Žofka ◽  
Linh Thuy Nguyen ◽  
Eva Mašátová ◽  
Petra Matoušková
Keyword(s):  
Drug Resistance ◽  
Deep Learning ◽  
Haemonchus Contortus ◽  
Model Organism ◽  
Absolute Error ◽  
Wide Field ◽  
Forecast Precision ◽  
Wide Field Of View ◽  
Poor Efficacy

Poor efficacy of some anthelmintics and rising concerns about the widespread drug resistance have highlighted the need for new drug discovery. The parasitic nematode Haemonchus contortus is an important model organism widely used for studies of drug resistance and drug screening with the current gold standard being the motility assay. We applied a deep learning approach Mask R-CNN for analysing motility videos and compared it to other commonly used algorithms with different levels of complexity, namely Wiggle Index and Wide Field-of-View Nematode Tracking Platform. Mask R-CNN consistently outperformed the other algorithms in terms of the forecast precision across the videos containing varying rates of motile worms with a mean absolute error of 5.6%. Using Mask R-CNN for motility assays confirmed the common problem of algorithms that use Non-Maximum Suppression in detecting overlapping objects, which negatively impacted the overall precision. The use of intersect over union (IoU) as a measure of the classification of motile / non-motile instances had an overall accuracy of 89%. In comparison to the existing methods evaluated here, Mask R-CNN performed better and we can anticipate that this method will broaden the number of possible approaches to video analysis of worm motility. IoU has shown promise as a good metric for evaluating motility of individual worms.

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