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 that affects Ecuador, where there are no specific plans to mitigate this parasitic illness. Objective: To evaluated 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 characteristics, both morphometric and 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 (L1, L2, L3) could be obtained until 96 hours through fecal culture. Parthenogenetic females were established in the duodenum at the 5th Day Post Infection. Fertile eggs were observed in the inspected intestinal tissue and fresh feces, where it was determined that the production peak was 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 a natural biological cycle. The Kato-Katz formed an immediate and low-cost quantitative technique, 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.