Caught red handed: iDNA points to wild source for CITES-protected contraband leeches

In October of 2018, Canada Border Services Agency (CBSA) at Pearson International Airport in Toronto notified the Wildlife Enforcement Branch of Environment and Climate Change Canada that a passenger had arrived aboard a flight from Russia with a large quantity of live leeches. The leeches had been discovered in the passenger’s carry-on luggage. An enforcement officer with Environment and Climate Change Canada detained the leeches to identify the species in order to determine whether the import was lawful. We identified the leeches as Hirudo verbana and extracted DNA from the bloodmeals of a subsample of 240 leeches and used metabarcoding of 6 mitochondrial loci to determine the vertebrate host species on which the leeches had previously fed. Sixteen undomesticated vertebrate host species were identified from the bloodmeals of the imported leeches, indicating that these leeches were collected from wild habitats. Furthermore, the overlap of host species’ distributions point to a possible collecting source in the Volga delta, the Danube delta, or the coastal area region on the east side of the Sea of Azov. Our findings support the utility of invertebrate-derived DNA (iDNA) as a valuable tool in forensic evaluation of trafficked wildlife and provide new evidence regarding illegal exploitation of the European medicinal leech.