Anthelmintic resistance in nematode parasites of sheep: learning from the Australian experience

Waller, P.J.; Dash, K.M.; Barger, I.A.; Jambre, LF Le; Plant, J. W.

doi:10.1136/vr.136.16.411

Cited by 90 publications

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“…This latter problem is by far the most important because frequent mass chemotherapy with the currently available anthelmintics has generated an environment favouring selection for resistant parasites. Resistance is now virtually global among GI nematodes of livestock (Waller, 1986 ;Gill & Lacey, 1998 ;Jackson & Coop, 2000), and there are some indications of resistance among GI nematodes of humans (Coles, 1995 ;de Clercq et al 1997 ;Reynoldson et al 1997). Resistance has already developed to the three drug classes in current use (the benzimidazoles, the imidazothiazoles/ tetrahydropyrimidines and the macrocyclic lactones), despite each class having a different mode of action (Coles, 1998 ;Martin & Robertson, 2000).…”

Section: Introductionmentioning

confidence: 99%

Assessment of the anthelmintic effect of natural plant cysteine proteinases against the gastrointestinal nematode,Heligmosomoides polygyrus,in vitro

et al. 2004

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. We examined the mechanism of action and compared the anthelmintic efficacy of cysteine proteinases from papaya, pineapple, fig, kiwi fruit and Egyptian milkweed in vitro using the rodent gastrointestinal nematode Heligmosomoides polygyrus. Within a 2 h incubation period, all the cysteine proteinases, with the exception of the kiwi fruit extract, caused marked damage to the cuticle of H. polygyrus adult male and female worms, reflected in the loss of surface cuticular layers. Efficacy was comparable for both sexes of worms, was dependent on the presence of cysteine and was completely inhibited by the cysteine proteinase inhibitor, E-64. LD 50 values indicated that the purified proteinases were more efficacious than the proteinases in the crude latex, with purified ficin, papain, chymopapain, Egyptian milkweed latex extract and pineapple fruit extract, containing fruit bromelain, having the most potent effect. The mechanism of action of these plant enzymes (i.e. an attack on the protective cuticle of the worm) suggests that resistance would be slow to develop in the field. The efficacy and mode of action make plant cysteine proteinases potential candidates for a novel class of anthelmintics urgently required for the treatment of humans and domestic livestock.

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Section: Introductionmentioning

confidence: 99%

Assessment of the anthelmintic effect of natural plant cysteine proteinases against the gastrointestinal nematode,Heligmosomoides polygyrus,in vitro

et al. 2004

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“…The traditional, and most widely implemented, control measure for GI nematodes is mass chemotherapy at regular times throughout the year, a treatment regimen that encourages the development of anthelmintic resistance (Waller, 1986 ;Coles, 1995 ;Condor & Campbell, 1995 ;Jackson & Coop, 2000). One approach that might reduce the onset and spread of resistance would be to replace mass chemotherapy with selective chemotherapy, focussing treatment only on those animals that require drenching because of worm burdens that threaten production traits if left untreated (Smith, 1990).…”

Section: Introductionmentioning

confidence: 99%

Copro-antigen capture ELISA for the detection ofTeladorsagia(Ostertagia)circumcinctain sheep: improvement of specificity by heat treatment

2004

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk A copro-antigen capture ELISA for the detection of Teladorsagia circumcincta infection in sheep was developed and evaluated. Experiments with faeces from worm-free sheep, that had been spiked with known concentrations of excretory-secretory (E-S) antigen indicated that a positive signal was generated with 180 ng of E-S/ml. A nested design, based on 8 infected and 8 worm-free sheep, was employed to assess the stages during sample preparation contributing to variation in signal from the assay. This showed that 87% of the variance in the optical density readings (ODs) was directly explained by infection status. Variation between individual sheep within infection groups, and between samples at various stages in the assay, collectively accounted for the remaining variance. Initial evaluation of specificity using faeces from animals carrying a range of monospecific infections indicated cross-reactivity with Haemonchus contortus and Nematodirus spathiger. However, by treating the supernatant from faeces for 20 min at 100 xC, the cross-reactive signal was eliminated whilst the specific signal was largely preserved. Heat treatment of faeces from 12 non-infected sheep, 12 sheep with T. circumcincta and 6 with H. contortus resulted in sensitivity being increased from 66 . 7 to 85 . 7 %, and specificity from 62 . 5 to 87 . 5%. OD values showed a significant positive relationship with adult worm burdens, although at low infection intensities there was some overlap between infected and worm-free animals. We discuss the application of CC-ELISAs in facilitating selective chemotherapy of sheep, as a means of avoiding the development of anthelmintic resistance in pastoral regions where sheep are farmed on a large scale.

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“…Several programmes to reduce the pressure of selection for anthelmintic resistant worms were previously explored in sheep in Australia and in New Zealand. They were usually based on practices which tend to reduce the role of factors known to favour the emergence/development of resistance in worm populations, that is reducing the frequency of treatments; avoiding underdosing; alternating anthelmintic families and recommending, when possible, the use of narrow spectrum drugs [15,16,76]. On the other hand, one of the main solutions to preserve the current drugs is to stop using them without discrimination and to promote a more selective use, by targeting the most infected animals within a flock.…”

Section: The Possible Solutionsmentioning

confidence: 99%

Control of gastrointestinal parasitism with nematodes in dairy goats by treating the host category at risk

Hoste¹,

Chartier

Frileux

2002

Vet. Res.

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-Infections of the gastrointestinal tract with parasitic nematodes remain one of the main limiting factors in grazing dairy goats. The usual mode of control of these parasitic diseases has up to now been based on the repeated use of anthelmintics. However, the prevalence rates of anthelmintic resistances, in particular to benzimidazoles, are now particularly high in the French dairy goat production. This situation makes it mandatory to reconsider the usual mode of control of these nematodes and to look for short term, alternative solutions which combine the control of gastrointestinal infections and management of anthelmintic resistances. One of the possible options is to leave a part of the flock without treatment during the grazing season in order to maintain alleles of susceptibility to anthelmintics within the worm populations. Previous epidemiological observations identifying the categories of host populations at risk are presented which provide the rationale for targeted applications of treatments. The results of assays on experimental flocks and from farm surveys examining the advantages and drawbacks of selective treatments are presented. The value of these results in combination with other alternative solutions of control are discussed in order to use minimum treatments with maximum benefits. dairy goat / anthelmintic / selective treatment / anthelmintic resistance / parasitic nematode Résumé -Maîtrise des strongyloses gastro intestinales chez les chèvres laitières par l'application de traitements ciblés. Les infestations par les nématodes du tractus gastro intestinal demeurent un des principaux facteurs limitant à l'élevage des chèvres laitières au pâturage. Le mode usuel de maîtrise de ce parasitisme reposait jusqu'à présent sur un usage répété de molécules anthelminthiques. Cependant, la prévalence des lignées résistantes aux anthelminthiques, en particulier aux benzimidazoles, en éle-vage caprin laitier en France, est désormais très élevée. Ce constat oblige à rechercher rapidement des 531

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Anthelmintic resistance in nematode parasites of sheep: learning from the Australian experience

Cited by 90 publications

References 0 publications

Assessment of the anthelmintic effect of natural plant cysteine proteinases against the gastrointestinal nematode,Heligmosomoides polygyrus,in vitro

Assessment of the anthelmintic effect of natural plant cysteine proteinases against the gastrointestinal nematode,Heligmosomoides polygyrus,in vitro

Copro-antigen capture ELISA for the detection ofTeladorsagia(Ostertagia)circumcinctain sheep: improvement of specificity by heat treatment

Control of gastrointestinal parasitism with nematodes in dairy goats by treating the host category at risk

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