Full length article Nitazoxanide anthelmintic activity against the enteral and parenteral phases of trichinellosis in experimentally infected rats Dalia S. Ashour a, * , Dina M. Abou Rayia a , Abeer E. Saad a , Reda H. El-Bakary b a Medical Parasitology Department, Faculty of Medicine, Tanta University, Egypt b Histology Department, Faculty of Medicine, Tanta University, Egypt highlights graphical abstract  Nitazoxanide affects both the enteral and parenteral phases of trichinellosis.  Treated rats showed significantly reduced Trichinella adult and larval counts.  They showed mild inflammation with decreased iNOS expression in the intestine.  Nitazoxanide induced destruction of encysted larvae and their surround- ing capsules. article info Article history: Received 27 May 2016 Received in revised form 14 August 2016 Accepted 29 August 2016 Available online 30 August 2016 Keywords: Trichinella spiralis Nitazoxanide In vivo efficacy Parasite burden iNOS abstract Most of the drugs used for the treatment of trichinellosis show a limited bioavailability and a high degree of resistance. Therefore, this study aimed to characterize the anthelmintic potential activity of nitazox- anide (NTZ) in a rat model of experimental trichinellosis. Animals were divided into three groups; group I, infected and non-treated; group II, received NTZ for three days post-infection (dpi) and group III, received NTZ 30 dpi for 14 consecutive days. Treatment efficacy was assessed by Trichinella spiralis adult and larval counts, histopathological studies of the small intestine and muscles and inducible nitric oxide synthase (iNOS) expression in the small intestine. T. spiralis adult count was reduced in NTZ -treated group (66.6%) and the larval count decreased to 68.7 and 76.7% in the early and late treatment, respectively. The infected non-treated rats showed massive inflammatory cellular infiltration in the small intestines and muscles. This inflammatory response was minor in the treated groups and was accom- panied by a decrease in iNOS expression. Moreover, in group III, the larvae were replaced by homoge- nized substance with some destructive changes in the capsule. In conclusion, NTZ showed a promising activity against enteral and more effect in parenteral phases of trichinellosis. © 2016 Elsevier Inc. All rights reserved. 1. Introduction Trichinellosis is a zoonotic disease caused by nematode species of the genus Trichinella. Following the ingestion of meat containing the infective Trichinella larvae, they are released from their capsules in the stomach and activated in the intestine. Then, the larvae penetrate the host's intestinal epithelium where they molt and develop to adult worms that mate and produce the newborn larvae (Gagliardo et al., 2002). The adult parasites establish an intra multicellular niche that is composed of numerous epithelial cells. Therefore, the intestinal mucosa is the first natural barrier to encounter the parasites, and mucosal immunity is likely to be * Corresponding author. Medical Parasitology Department, Tanta Faculty of Medicine, Tanta, Gharbiya, Egypt. E-mail address: ashourdalia@yahoo.com (D.S. Ashour). Contents lists available at ScienceDirect Experimental Parasitology journal homepage: www.elsevier.com/locate/yexpr http://dx.doi.org/10.1016/j.exppara.2016.08.009 0014-4894/© 2016 Elsevier Inc. All rights reserved. Experimental Parasitology 170 (2016) 28e35