Affiliation:
1. Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
2. University of Basel, Basel, Switzerland
3. Department of Public Health and Epidemiology, Swiss Tropical and Public Health Institute, Basel, Switzerland
Abstract
ABSTRACT
Triclabendazole resistance is continually documented from livestock, and hence new treatment strategies for
Fasciola hepatica
infections are needed. We investigated the effect of triclabendazole combined with artesunate, artemether, or OZ78 compared to that of monotherapy against adult and juvenile
F. hepatica
in rats.
In vitro
experiments with triclabendazole and its sulfoxide and sulfone metabolites, each in combination with the peroxides, complemented our study.
F. hepatica
-infected rats were subjected to single drugs or drug combinations 3 to 4 weeks (juvenile flukes) and >8 weeks (adult flukes) postinfection. Negative binomial regressions of worm and egg counts were used to analyze dose-response relationships and whether the effects of drug combinations were synergistic or antagonistic. The
in vitro
assays were evaluated by means of viability scales based on fluke motility. Fifty percent effective dose values of 113.0, 77.7, 22.9, and 2.7 mg/kg of body weight were calculated for monotherapy with artesunate, artemether, OZ78, and triclabendazole, respectively, against adult
F. hepatica
. Likelihood ratio tests revealed synergistic interactions (
P
< 0.05) of combinations of triclabendazole (2.5 mg/kg) plus artesunate or artemether on adult worm burden. Antagonistic effects on the adult burden and egg output were observed when a lower triclabendazole dose (1.25 mg/kg) was combined with the artemisinins. No significant interactions (
P
= 0.07) were observed for OZ78 and triclabendazole combinations and between the triclabendazole effect and the effects of the other partner drugs on juvenile worms. Our
in vitro
studies of adult worms agreed with the
in vivo
results, while the
in vitro
analysis of juvenile worms revealed greater interactions than observed
in vivo
. In conclusion, single-agent triclabendazole demonstrated a more potent
in vivo
and
in vitro
fasciocidal activity than the experimental drugs artesunate, artemether, and OZ78. When combined, synergistic but also antagonistic effects depending on the doses administered were observed, which should be elucidated in more detail in future studies.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
34 articles.
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