# Evaluation of the Efficacy of Anthelmintic Drugs Against Trichinella spiralis Larvae

## TL;DR

This study evaluates drugs against Trichinella spiralis larvae and finds tribendimidine (TBD) to be more effective than albendazole.

## Contribution

A validated in vitro assay and evidence that TBD is more effective against T. spiralis larvae than current drugs.

## Key findings

- TBD had the lowest IC50 value of 135.2 μM against T. spiralis larvae in vitro.
- TBD reduced larval burdens and histopathological changes in mouse muscles more effectively than ABZ.
- XTT assay effectively quantified larval viability and correlated with larval numbers.

## Abstract

Background: Albendazole, mebendazole, and ivermectin are effective against adult Trichinella spiralis but show limited efficacy against encapsulated muscle stage larvae. This limitation highlights the need for improved experimental approaches to evaluate anthelmintic activity at this stage and to identify alternative therapeutic candidates. Methods: Seven antiparasitic drugs, albendazole (ABZ), miltefosine (MLT), ivermectin (IVM), tribendimidine (TBD), praziquantel (PZQ), artesunate (ART), and mefloquine (MEQ), were evaluated for in vitro activity against T. spiralis muscle larvae. Larval viability was quantified using a tetrazolium salt XTT assay to determine IC50 values and compare with microscopic assessments. Based on in vitro activity, TBD was selected for in vivo evaluation in a mouse model, where efficacy was assessed by muscle larval burden and histopathological changes. Results: TBD, MEQ, IVM, and ABZ exhibited measurable in vitro efficacies against T. spiralis larvae, with TBD showing the lowest IC50 value at 135.2 μM. XTT formazan absorbance correlated strongly with larval number and incubation time. In vivo, TBD treatment significantly reduced larval burdens in diaphragm and gastrocnemius muscles and was associated with reduced collagen capsule thickness, inflammation, and fibrosis compared with ABZ-treated controls. Conclusions: This study validated an assay for quantitative evaluation of T. spiralis muscle larvae and demonstrates robust in vitro and in vivo activity of TBD against this stage.