A larval development test for the detection of anthelmintic resistance in nematodes of sheep

Taylor, MA

doi:10.1016/s0034-5288(18)31077-4

Cited by 86 publications

(40 citation statements)

References 14 publications

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“…Consequently, fecal egg count reduction tests (FECRT) are commonly used to determine drug efficacy: a 95% reduction in fecal egg count (FEC) is considered efficacious (McKenna, 1994;Wood et al, 1995). Evaluation of anthelmintic efficacy can also be determined in vitro using larval development assays (LDA; Taylor, 1990;Gill et al, 1995). This technique estimates the efficacy of anthelmintics on nematode populations but provides no indication of how well the drug might perform in vivo.…”

Section: Introductionmentioning

confidence: 99%

The Efficacy of Anthelmintic Drugs Against Nematodes Infecting Free-Ranging Eastern Grey Kangaroos, Macropus Giganteus

Cripps

Beveridge

Coulson

2013

Journal of Wildlife Diseases

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ABSTRACT:Effective anthelmintics are valuable tools for biologists conducting manipulative field experiments to examine effects of parasites on wildlife. However, before such experiments are carried out the efficacy of these drugs must be determined. We conducted three field experiments (May 2010-September 2011) on free-ranging eastern grey kangaroos (Macropus giganteus) at a golf course in Victoria, Australia, treating animals with the anthelmintic drugs moxidectin (subcutaneous, 1 mg/kg, 2 mg/kg), ivermectin (subcutaneous, 200 mg/kg), and albendazole (oral, 3.8 mg/kg). After treatment we monitored strongylid fecal egg counts (FECs) over time and assessed anthelmintic efficacy using fecal egg count reduction tests (FECRTs). We also performed a larval development assay (LDA) to evaluate directly the efficacy in the nematode population. Unexpectedly, moxidectin and ivermectin had low efficacy with maximum FEC reductions of 82% and 28%, respectively. However, treatment with albendazole reduced FECs by 100% in all kangaroos and egg counts remained low for up to 3 mo. The results from the LDA supported the FECRTs, with low macrocyclic lactone efficacy and high albendazole efficacy. Macrocyclic lactones, at recommended dose rates, were much less effective against strongylid nematodes in kangaroos than has been reported for domestic herbivores. This may be partly due to pharmacokinetics in the host and partly due to low susceptibility in some of the nematodes infecting eastern grey kangaroos.

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Section: Introductionmentioning

confidence: 99%

The Efficacy of Anthelmintic Drugs Against Nematodes Infecting Free-Ranging Eastern Grey Kangaroos, Macropus Giganteus

Cripps

Beveridge

Coulson

2013

Journal of Wildlife Diseases

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“…AChE is thus proved to be a functional protein, involved in multifaceted activities, which can serve as a suitable candidate for diagnostic purposes. The principal role of AChE is termination of transmission at cholinergic synapses by rapid hydrolysis of the neurotransmitter, acetylcholine [41].…”

Section: Resultsmentioning

confidence: 99%

Effect of Allium sativum on the Motility and Acetylcholinesterase of Haemonchus contortus

2016

IJSR

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Helminths are known to be a major constraint to ruminant's well-being and productive performance. Gastrointestinal helminths are widespread parasitic agents of livestock especially in small ruminants. Helminthiasis plays an important role in the small ruminant production leading to enormous economic losses in areas where extensive grazing is practiced. Haemonchosis is caused by the hematophagous parasite Haemonchus contortus. It is the most important parasites of all the gastrointestinal nematodes that constrain the survival and productivity of sheep and goats owned by rural farmers in the developing countries. In the present investigations anthelmintic effect of Allium sativum on the motility and acetylcholinesterase (AChE) of the nematode Haemonchus contortus were studied in vitro. The worms were exposed to various concentrations of hexane, chloroform, ethyl acetate, ethanol and aqueous extract of Allium sativum and the motility of the parasites were viewed. As ethanol extract was effective, further studies were conducted with various sublethal concentrations 0.005, 0.01, 0.05, 0.1 and 0.5 mg/ml. Quantitative measurement of the motility of the parasites evidently showed the direct impact of the drugs on the parasite. Maximum inhibition in the motility (88.50%) and AChE (90.25%) was remarked in 0.5 mg/ml of AsEE after 8h of exposure. AChE is concerned in muscularly harmonious combination and neurotransmission. The important role of this enzyme can stop cholinergic synaptic communication with immediate hydrolysis of the acetylcholine. Inhibition of AChE in the parasite results in paralysis of musculature and the parasite lose its biochemical holdfast and get expelled from the host. The present study clearly showed that AsEE had killed the parasites by affecting their neurotransmission.

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“…Coles et al (1988) was the first to describe the test where eggs recovered from faeces are incubated for seven days in an aquatic solution of the drug together with culture medium for developing larvae. Lyophilized E. coli (W strain) or Earle's balanced salt solution mixed with yeast extract (Taylor, 1990) was used as a medium. After incubation, the percentage of L1, L2 and L3 larvae is calculated for each drug concentration and for drug-free controls.…”

Section: Methods For Detection Of Anthelminthic Resistancementioning

confidence: 99%

“…Comparison of sensitive and resistant populations of H. contortus, O. circumcincta and T. colubriformis highlights the fact that invasive larvae of benzimidazole-resistant populations possess significantly greater amounts of acetylcholinesterase than larvae of susceptible populations of nematodes (Sutherland & Lee, 1989, 1990, 1993. Sutherland et al (1988) described four biochemical assays for the detection of benzimidazole resistance based on comparisons of non-specific esterases and acetylcholinesterases in resistant and susceptible populations.…”

Section: Methods For Detection Of Anthelminthic Resistancementioning

confidence: 99%

Anthelmintic resistance in parasites of small ruminants: sheep versus goats

et al. 2011

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SummaryAnthelmintic resistance among parasites of sheep and goats has been known to occur for at least four decades. Both species of host have similar genera of nematodes, but the nematodes in goat herds usually develop anthelmintic resistance more rapidly. In vitro tests show higher ED 50 values in goats than in flocks of sheep. Sheep and goats differ in many ways; for example, goats have a higher metabolic rate and require higher dose rates for drugs. The immune system of goats is also different. Additionally, these animals are reared under different management systems, i.e. sheep graze pastures and goats browse bushes, and lambing/kidding periods are different. Most anthelmintics used in goats have not been licensed for this animal species, and correct dose rates have rarely been experimentally determined. Possible explanations for such differences are discussed.

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A larval development test for the detection of anthelmintic resistance in nematodes of sheep

Cited by 86 publications

References 14 publications

The Efficacy of Anthelmintic Drugs Against Nematodes Infecting Free-Ranging Eastern Grey Kangaroos, Macropus Giganteus

The Efficacy of Anthelmintic Drugs Against Nematodes Infecting Free-Ranging Eastern Grey Kangaroos, Macropus Giganteus

Effect of Allium sativum on the Motility and Acetylcholinesterase of Haemonchus contortus

Anthelmintic resistance in parasites of small ruminants: sheep versus goats

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