Back groundTrichinellosis is a serious worldwide parasitic zoonosis. The available therapy for the treatment of Trichinella spiralis is not satisfactory. This work aimed at evaluating of the in vitro effect of silver Therefore, the recovery of effective treatment is required.nanoparticles (AgNPs) on muscle larvae of Trichinella.Methodology / principal findingThe present study investigated the larvicidal properties of chemical and myrrh AgNPs on muscle larvae (ML) of T. spiralis. The used AgNPs were chemically prepared using NaBH4 as reducing agent and biosynthesized using methanolic myrrh extract. Characterization of synthesized AgNPs was monitored via UV-Vis spectrophotometry, Fourier transform infrared spectroscopy and transmission electron microscopy (TEM) studies. The ML incubated with AgNPs at concentrations ranged from 1μg/ml to 20μg/ml.Conclusions /SignificanceChemical and biosynthesized AgNPs revealed marked larvicidal effect against ML of Trichinella. Additionally, this in vitro study showed degenerative changes affecting the cuticle of AgNPs treated ML. The effectiveness of AgNPs on the infectivity of Trichinella ML was also assessed. The results showed complete inhibition of the infectivity of ML exposed to sublethal doses of chemical and myrrh prepared AgNPs when used to infect animal models. This is the first report where myrrh synthesized AgNPs have been tested for their anthelminthic activity against Trichinella in an in vitro model.Author summaryTrichinellosis is a serious worldwide parasitic zoonosis. The available therapy for the treatment of Trichinella spiralis is not satisfactory. Therefore, the recovery of effective treatment is required. The present study investigated the larvicidal properties of chemical and myrrh AgNPs on muscle larvae (ML) of T. spiralis. The ML incubated with AgNPs at concentrations ranged from 1μg/ml to 20μg/ml. Chemical and biosynthesized AgNPs revealed marked larvicidal effect against ML of Trichinella. Additionally, this in vitro study showed degenerative changes affecting the cuticle of AgNPs treated ML. Also the results showed complete inhibition of the infectivity of ML exposed to sublethal doses of chemical and myrrh prepared AgNPs when used to infect animal models.