Microscopic and molecular evaluation of Strongyloides venezuelensis in an experimental life cycle using Wistar rats

Abstract

Introduction: Strongyloides venezuelensis is a nematode whose natural host is rats. It is used as a model for the investigation of human strongyloidiasis caused by S. stercoralis. The latter is a neglected tropical disease in Ecuador where there are no specific plans to mitigate this parasitic illness.Objective: To evaluate the stages of S. venezuelensis in an experimental life cycle using Wistar rats.Materials and methods: Male Wistar rats were used to replicate the natural biological cycle of S. venezuelensis and describe its morphometric characteristics, as well as its parasitic development. Furthermore, the production of eggs per gram of feces was quantified using two diagnostic techniques and assessment of parasite load: Kato-Katz and qPCR. Results: Viable larval stages (Lr L2, L3) could be obtained up to 96 hours through fecal culture. Parthenogenetic females were established in the duodenum on the fifth day postinfection. Fertile eggs were observed in the intestinal tissue and fresh feces where the production peak occurred on the 8th. day post-infection. Unlike Kato-Katz, qPCR detected parasitic DNA on days not typically reported.Conclusions: The larval migration of S. venezuelensis within the murine host in an experimental environment was equivalent to that described in its natural biological cycle. The Kato-Katz quantitative technique showed to be quick and low-cost, but the qPCR had greater diagnostic precision. This experimental life cycle can be used as a tool for the study of strongyloidiasis or other similar nematodiasis.