Development of a Rapid SNP PCR Assay to Differentiate between European and North American Haplotypes of Echinococcus multilocularis

Herein we describe a single nucleotide polymorphism-specific polymerase chain reaction (PCR) assay to rapidly detect and differentiate variants belonging to the European and North American lineages of Echinococcus multilocularis in clinical samples. This is an extremely relevant and applicable test in North America because the range of E. multilocularis continues to expand across the continent and because of a rise in prevalence in wildlife, domestic animals, and humans. The endemic North American (NA) and introduced European (EU) variants are believed to have different pathogenic potentials, with the EU variants being more infective and pathogenic than the NA variants. The rise of the EU variants of E. multilocularis increases the risk of spillover from wildlife to humans because of its increased potential for infectivity. Current PCR-based diagnostics can detect E. multilocularis deoxyribonucleic acid (DNA), but DNA sequencing is required to identify the specific variant. Our assay provides a straightforward conventional PCR method to differentiate the NA and EU variants, and we suggest this same approach could be used for the diagnosis of other parasites or variants that are genetically very similar. As surveillance continues for E. multilocularis across North America, identifying the different genetic variants from different geographic regions will become essential to understanding the current epidemiological shift that the parasite is experiencing, as well as informing public health decisions in affected areas.