Antibody response after treatment in cattle infected with Psoroptes ovis

Lonneux, J. F.; Nguyen, T.Q.; Delhez, M; Losson, Bertrand

doi:10.1016/s0034-5288(97)90158-2

Cited by 10 publications

(9 citation statements)

References 16 publications

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“…When ML products were introduced in the market, injectable ML products were highly effective against P. ovis. A single administration of the recommended (commercialised) dose of an injectable ML product was sufficient to kill the mites and obtain clinical cure [24][25][26][27][28]. In practice, a second injection is recommended to get the desired efficacy [7,25].…”

Section: Discussionmentioning

confidence: 99%

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

et al. 2020

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Background: Psoroptic mange is an important disease in Belgian Blue cattle. Treatment failure of macrocyclic lactones against Psoroptes ovis has been reported, but clear evidence of in vivo resistance is lacking. This study assessed the efficacy of macrocyclic lactone products on 16 beef farms in Belgium and the Netherlands in vivo and in vitro. Methods:On each farm a group of animals (n = 7-14) with psoroptic mange was treated with two subcutaneous injections of a macrocyclic lactone product with 7-10 days interval (15 farms) or a single injection with a long-acting macrocyclic lactone (1 farm). In vivo efficacy was assessed by the reduction in mite counts, clinical index (proportion of the body surface affected by lesions), the proportion of the animals with negative mite counts after the first treatment round and the number of treatment rounds needed to obtain zero mites counts in all animals. A mite population was categorized as sensitive when the mite count reduction after the first treatment round > 95% and the lower limit of the uncertainty interval > 90%. Resistance was detected when both parameters were below their threshold and suspected when one parameter was too low. In vitro knockdown and mortality were evaluated in a contact test. Results:The proportion of the animals with negative mite counts after the first treatment round varied from 0 to 80%. All farms needed two or more treatments rounds to obtain zero mite counts on all animals. Clinical index only started to reduce after the second treatment round. Mite populations from three farms were categorized as sensitive, one as suspected resistant and 12 as resistant. No correlation was found between in vitro lethal dose 50 and knockdown dose 50 values and in vivo efficacy parameters. Conclusions:Unambiguous treatment failure was detected on 12 out of 16 farms, confirming the presence of macrocyclic lactone resistance on Belgian Blue beef farms. In vitro parameters could not discriminate the farms based on their in vivo sensitivity. The mean reduction in mite counts and the lower limit of the confidence interval are proposed as parameters to identify acaricide resistance.

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Section: Discussionmentioning

confidence: 99%

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

et al. 2020

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show abstract

Section: Discussionmentioning

confidence: 99%

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

Mol

Wilde

Casaert

et al. 2020

Preprint

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Background Psoroptic mange is an important disease in Belgian Blue cattle. Treatment failure of macrocyclic lactones against Psoroptes ovis has been reported, but clear evidence of in vivo resistance is lacking. This study assessed the efficacy of macrocyclic lactone products on 16 beef farms in Belgium and the Netherlands in vivo and in vitro . Methods On each farm a group of animals ( n = 7–14) with psoroptic mange was treated with two subcutaneous injections of a macrocyclic lactone product with 7–10 days interval (15 farms) or a single injection with a long-acting macrocyclic lactone (1 farm). In vivo efficacy was assessed by the reduction in mite counts, clinical index (proportion of the body surface affected by lesions), the proportion of the animals with negative mite counts after the first treatment round and the number of treatment rounds needed to obtain zero mites counts in all animals. A mite population was categorized as sensitive when the mite count reduction after the first treatment round > 95% and the lower limit of the uncertainty interval > 90%. Resistance was detected when both parameters were below their threshold and suspected when one parameter was too low. In vitro knockdown and mortality were evaluated in a contact test. Results The proportion of the animals with negative mite counts after the first treatment round varied from 0 to 80%. All farms needed two or more treatments rounds to obtain zero mite counts on all animals. Clinical index only started to reduce after the second treatment round. Mite populations from three farms were categorized as sensitive, one as suspected resistant and 12 as resistant. No correlation was found between in vitro lethal dose 50 and knockdown dose 50 values and in vivo efficacy parameters. Conclusions Unambiguous treatment failure was detected on 12 out of 16 farms, confirming the presence of macrocyclic lactone resistance on Belgian Blue beef farms. In vitro parameters could not discriminate the farms based on their in vivo sensitivity. The mean reduction in mite counts and the lower limit of the confidence interval are proposed as parameters to identify acaricide resistance.

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“…When ML were introduced in the market, injectable ML were highly effective against P. ovis. A single treatment with injectable ML was sufficient to kill the mites and obtain clinical cure [26,27]. Other authors later advised a second injection to get the desired efficacy [8,14,28].…”

Section: Discussionmentioning

confidence: 99%

“…A single treatment with injectable ML was sufficient to kill the mites and obtain clinical cure [26,27]. Other authors later advised a second injection to get the desired efficacy [8,14,28]. Moreover, a biological model of Sarcoptes infection dynamics suggests that eradication of scabies with acaricides without ovicidal activity is only possible if two treatments are given [29].…”

Section: Discussionmentioning

confidence: 99%

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

Mol

Wilde

Casaert

et al. 2019

Preprint

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BackgroundPsoroptic mange is an important disease in beef cattle, and Belgian Blue cattle are particularly susceptible. Treatment failure of macrocyclic lactones against Psoroptes ovis has been reported, but clear evidence of in vivo resistance is still lacking. This study was conducted to investigate ML efficacy in 16 beef farms in Belgium and The Netherlands in vivo and in vitro. MethodsOn each farm a group of animals (n= 7-14) with clinical psoroptic mange was treated with two subcutaneous injections of a macrocyclic lactone with 7-10 days interval (15 farms) or a single injection with a long-acting macrocyclic lactone (1 farm). In vivo efficacy was assessed by the reduction in mite counts and clinical index (part of the body affected by lesions), the cure rate after the first treatment round and the number of treatment rounds needed to cure all animals. In vitro knock-down and mortality was evaluated in a contact test. ResultsCure rates after the first treatment round varied from 0-80%. All farms needed two or more rounds of treatments to obtain full efficacy. Clinical index had a high variation and only started to reduce after the second treatment round. Only three farms were categorized as susceptible with a mean mite count reduction>95% and a lower limit of the uncertainty interval>90%. One farm had a mean reduction>95%, but its lower limit of the confidence interval was <90%. All other farms had mean reductions<95% and lower limits of their uncertainty intervals<90%. No correlation was found between in vitro lethal dose 50 and knock-down dose 50 values and any parameter of in vivo efficacy. ConclusionUnambiguous treatment failure was detected on 12/16 beef farms, confirming the presence of macrocyclic lactone resistance in Belgian Blue beef farms. In vitro parameters could not discriminate the farms based on their in vivo susceptibility. The mean reduction in mite counts and the lower limit of the confidence interval stood out as most useful parameter to identify acaricide resistance.

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Antibody response after treatment in cattle infected with Psoroptes ovis

Cited by 10 publications

References 16 publications

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

Resistance against macrocyclic lactones in Psoroptes ovis in cattle

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