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An exploratory study to assess the activity of the acarine growth inhibitor, fluazuron, against Sarcoptes scabei infestation in pigs.

Pasay C, Rothwell J, Mounsey K, Kelly A, Hutchinson B, Miezler A, McCarthy J - Parasit Vectors (2012)

Bottom Line: In-vitro, biochemical and molecular studies have demonstrated that human mites are becoming increasingly resistant to both acaricides.Clinical scores, skin scrapings for mite counts and blood sampling for pharmacokinetic analysis were undertaken.No adverse effects were observed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Clinical Tropical Medicine Laboratory, Queensland Institute of Medical Research, Herston, Australia. Cielo.Pasay@qimr.edu.au

ABSTRACT

Background: The most common treatments for scabies in human and veterinary settings are topical 5% permethrin or systemic treatment with ivermectin. However, these treatments have very little activity against arthropod eggs, and therefore repeated treatment is frequently required. In-vitro, biochemical and molecular studies have demonstrated that human mites are becoming increasingly resistant to both acaricides. To identify alternate acaricides, we undertook a pilot study of the in vivo activity of the benzoylphenyl urea inhibitor of chitin synthesis, fluazuron, in pigs with sarcoptic mange.

Findings: Pigs (n = 5) were infested with S. scabei var suis, and randomised to treatment at the start of peak infestation with fluazuron at a dose of 10 mg/kg/day per os for 7 days (n = 3) or no treatment (n = 2). Clinical scores, skin scrapings for mite counts and blood sampling for pharmacokinetic analysis were undertaken. Fluazuron was well absorbed in treated pigs with measureable blood levels up to 4 weeks post treatment. No adverse effects were observed. Modest acaricidal activity of the compound was observed, with a reduction in severity of skin lesions in treated pigs, as well as a reduction in number of scabies mite's early life stages.

Conclusions: The moderate efficacy of fluazuron against scabies mites indicates a lead to the development of alternate treatments for scabies, such as combination therapies that maybe applicable for human use in the future.

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Related in: MedlinePlus

Fold-change in mite counts in trial pigs in (A) Juveniles and (B) All life stages.
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Figure 2: Fold-change in mite counts in trial pigs in (A) Juveniles and (B) All life stages.

Mentions: From 2 weeks post treatment, a decline in overall mite counts especially in early life stages was observed in two fluazuron treated pigs (Tx6360 and Tx6362). This reduction is expressed as a fold change of < 1 compared to the baseline mite counts (set at 1) (Figure 2A and 2B). Tx6367 pig which had the lowest level of blood fluazuron showed the slowest reduction in juvenile stage mite counts with changes observed only on the 7th week post treatment. Of note, the baseline mite burden of this pig was heavy and the oral dosage (10 mg/kg) used may not have been sufficient to kill all mites present in the crusted skin. In comparison, the untreated pigs had an increase (> 1 fold change) in mite counts compared to baseline from 2 weeks onwards.


An exploratory study to assess the activity of the acarine growth inhibitor, fluazuron, against Sarcoptes scabei infestation in pigs.

Pasay C, Rothwell J, Mounsey K, Kelly A, Hutchinson B, Miezler A, McCarthy J - Parasit Vectors (2012)

Fold-change in mite counts in trial pigs in (A) Juveniles and (B) All life stages.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298804&req=5

Figure 2: Fold-change in mite counts in trial pigs in (A) Juveniles and (B) All life stages.
Mentions: From 2 weeks post treatment, a decline in overall mite counts especially in early life stages was observed in two fluazuron treated pigs (Tx6360 and Tx6362). This reduction is expressed as a fold change of < 1 compared to the baseline mite counts (set at 1) (Figure 2A and 2B). Tx6367 pig which had the lowest level of blood fluazuron showed the slowest reduction in juvenile stage mite counts with changes observed only on the 7th week post treatment. Of note, the baseline mite burden of this pig was heavy and the oral dosage (10 mg/kg) used may not have been sufficient to kill all mites present in the crusted skin. In comparison, the untreated pigs had an increase (> 1 fold change) in mite counts compared to baseline from 2 weeks onwards.

Bottom Line: In-vitro, biochemical and molecular studies have demonstrated that human mites are becoming increasingly resistant to both acaricides.Clinical scores, skin scrapings for mite counts and blood sampling for pharmacokinetic analysis were undertaken.No adverse effects were observed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Clinical Tropical Medicine Laboratory, Queensland Institute of Medical Research, Herston, Australia. Cielo.Pasay@qimr.edu.au

ABSTRACT

Background: The most common treatments for scabies in human and veterinary settings are topical 5% permethrin or systemic treatment with ivermectin. However, these treatments have very little activity against arthropod eggs, and therefore repeated treatment is frequently required. In-vitro, biochemical and molecular studies have demonstrated that human mites are becoming increasingly resistant to both acaricides. To identify alternate acaricides, we undertook a pilot study of the in vivo activity of the benzoylphenyl urea inhibitor of chitin synthesis, fluazuron, in pigs with sarcoptic mange.

Findings: Pigs (n = 5) were infested with S. scabei var suis, and randomised to treatment at the start of peak infestation with fluazuron at a dose of 10 mg/kg/day per os for 7 days (n = 3) or no treatment (n = 2). Clinical scores, skin scrapings for mite counts and blood sampling for pharmacokinetic analysis were undertaken. Fluazuron was well absorbed in treated pigs with measureable blood levels up to 4 weeks post treatment. No adverse effects were observed. Modest acaricidal activity of the compound was observed, with a reduction in severity of skin lesions in treated pigs, as well as a reduction in number of scabies mite's early life stages.

Conclusions: The moderate efficacy of fluazuron against scabies mites indicates a lead to the development of alternate treatments for scabies, such as combination therapies that maybe applicable for human use in the future.

Show MeSH
Related in: MedlinePlus