Experimental Parasitology 217 (2020) 107961 Available online 7 August 2020 0014-4894/© 2020 Elsevier Inc. All rights reserved. The scabicide effect of moxidectin in vitro and in experimental animals: Parasitological, histopathological and immunological evaluation Mahmoud Sharaf a , Sanaa Antonios a , Samir Mina b , Kamal Eliwa a , Dina Abou Rayia a, * a Parasitology Department, Faculty of Medicine, Tanta University, Egypt b Histopathology Department, Faculty of Medicine, Tanta University, Egypt A R T I C L E INFO Keywords: Scabies Sacrcoptes scabiei Moxidectin Ivermectin Treatment ABSTRACT Scabies is considered one of the commonest dermatological diseases that has a global health burden. Current treatment with ivermectin (IVM) is insuffcient and potential drug resistance was noticed. Moxidectin (MOX), with a better pharmacological profle may be a promising alternative. The effcacy of moxidectin against Sar- coptes scabiei was assessed both in vitro and in vivo in comparison with ivermectin. For the in vitro assay, both drugs were used in two concentrations (50 μg/ml and 100 μg/ml). For the in vivo assay, twenty rabbits infected with Sarcoptes scabiei were divided into three groups: untreated, moxidectin-treated and ivermectin-treated with the same dose of 0.3 mg/kg once. Another four rabbits were used as a normal control non-infected group. Treatment effcacy was evaluated by clinical assessment, parasitological evaluation and histopathological ex- amination of skin samples using Hematoxylin and eosin and toluidine blue for mast cell staining. Immune response was also assessed by immunohistochemical staining of CD3 T cells in skin samples. Our results showed that moxidectin had a high effcacy (100%) in killing mites when used in both concentrations (50 μg/ml, 100 μg/ ml) in the in vitro assay. Concerning the in vivo assay, on day 14 post-treatment, all MOX-treated rabbits were mite-free with full clinical cure by the end of the study (D21) showing (100%) reduction of mites count. Also, marked improvement in the epidermis with absence of mites in skin samples were shown. Poor clinical and parasitological improvements were noted in the ivermectin-treated rabbits, when given as a single dose with a percentage reduction (60.67%) in the 2nd week and progressive increase in lesions and mites count in the 3rd week post-treatment. Regarding the immune response, MOX-treated group showed mild infltration with both mast cells and CD3 T cells in comparison to severe infltration with both types of cells in the untreated and IVM- treated group. On conclusion, our results demonstrated that a single dose of MOX was more effective than IVM, supporting MOX as a valuable therapeutic approach for scabies therapy. 1. Introduction Scabies is a skin disease caused by invasion of human skin by the Sarcoptes scabiei mite. It is considered among the 50 most common in- fectious diseases globally (Murray et al., 2012). It represents a major public health burden worldwide, affecting people of all races and social classes (Feldmeier and Heukelbach, 2009; Hay et al., 2014). The annual prevalence of scabies was estimated to be about 100–130 million cases worldwide (Karimkhani et al., 2017). Classically, intense generalized pruritus is the main complaint in ordinary scabies. However, secondary bacterial infection may occur, leading to serious complications as post streptococcal glomerulone- phritis, rheumatic fever and septicemia may occur (McDonald et al., 2004; Banerji, 2012 and Mulholland et al., 2015). In addition, Norwe- gian (crusted) scabies may occur, especially in immunocompromised individuals. Despite being less common, it is a very serious debilitating form of scabies and recrudescence and re-infestation are common (Currie et al., 2010). Therefore, efforts to control scabies especially in endemic poor communities are still needed. Most of the available treatment options for human scabies fail to completely control it. There are numerous effective topical acaricides as permethrin, benzyl benzoate, or malathion (Chosidow, 2006). However, they should be applied to the whole skin surface. This method is messy, diffcult in young children and multiple doses of these drugs are generally required, which is not ideal for mass treatment in outbreaks (McCarthy et al., 2004 and Strong et al., 2007). * Corresponding author. Elgeish Street, Faculty of Medicine, Parasitology Department, Third foor, Tanta, Egypt. E-mail addresses: dina_aboraya@yahoo.com, dina_aboraya@med.tanta.edu.eg (D.A. Rayia). Contents lists available at ScienceDirect Experimental Parasitology journal homepage: www.elsevier.com/locate/yexpr https://doi.org/10.1016/j.exppara.2020.107961 Received 25 December 2019; Received in revised form 7 July 2020; Accepted 24 July 2020