Assessment of the Genetic Diversity of Echinococcus multilocularis from Copro-Isolated Eggs.

Jenny Knapp,Laurence Millon,Sandra Courquet,Abdou Malik Da Silva

doi:10.3390/pathogens10101296

Abstract

The genetic diversity of the parasite Echinococcus multilocularis, the infectious agent of alveolar echinococcosis, is generally assessed on adult worms after fox necropsy. We aimed to investigate E. multilocularis polymorphism through the microsatellite EmsB marker using a noninvasive approach. We tested batches of isolated eggs (1, 5, and 10) from 19 carnivore fecal samples collected in a rural town located in a highly endemic area in France to determine the best strategy to adopt using a minimal quantity of parasite DNA while avoiding genetic profile overlapping in the analysis. Several molecular controls were performed to formally identify the Taeniidae eggs. In total, 112 egg batches were isolated and 102 EmsB electrophoregrams were obtained in duplicate. Quality sorting was performed through the Pearson correlation coefficient (r) between each EmsB duplicate. Forty-nine batches with r > 0.9 remained in the analysis, mainly 5- or 10-egg batches. Three EmsB profiles were emphasized by hierarchical clustering and matched those from human lesions and adult worms previously genotyped and collected in the same area. We show that the genetic diversity of the parasite can be assessed from isolated E. multilocularis eggs in a spatiotemporal context using a noninvasive approach.

Highlights

Echinococcus multilocularis is a cestode responsible for alveolar echinococcosis disease
The aim of the present study was (1) to develop a high-quality EmsB genotyping method that can be performed on E. multilocularis eggs isolated from carnivore fecal samples, and (2) to assess the feasibility of conducting a genetic diversity study on E. multilocularis from noninvasive environmental sampling
The total copro-DNA extracts of the 19 carnivore fecal samples selected for the study were positive for E. multilocularis rrnL by quantitative PCR, with Cq values from 28.66 to 41.04 and a mean Cq of 34.88 (95% confidence interval (CI): 32.99–36.76)

Summary

Introduction

Echinococcus multilocularis is a cestode responsible for alveolar echinococcosis disease. This parasite involves carnivores and herbivores in its life cycle, the red fox Vulpes vulpes being the main definitive host in Europe, and rodent micro-mammals as intermediate hosts [1]. Domestic animals, such as dogs (Canis lupus familiaris) and cats (Felis catus), can harbor the parasite, to a lesser extent [2], but can constitute a true threat in the spreading and transmission of the pathogen. It is well accepted that only 1% of people who ingest the parasite develop the disease [6]

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Conclusion