Species Detection within the Echinococcus granulosus sensu lato Complex by Novel Probe-Based Real-Time PCRs

Infections with eggs of Echinococcus granulosus sensu lato (s.l.) can cause cystic echinococcosis
in intermediate host animals and humans. Upon ingestion of viable eggs, oncospheres hatch from
the eggs and subsequently develop into fluid-filled larval cysts, most frequently in the liver or the
lungs. The slowly growing cysts progressively interfere with organ function. The risk of infection is
determined by the host range of the parasite, its pathogenicity and other epidemiologically relevant
parameters, which differ significantly among the five species within the E. granulosus s.l. complex. It is
therefore essential to diagnose the correct species within E. granulosus s.l. to help understand specific
disease epidemiology and to facilitate effective implementation of control measures. For this purpose,
simple, fast and cost-effective typing techniques are needed. We developed quantitative real-time
polymerase chain reactions (qPCRs) to target polymorphic regions in the mitochondrial genome of
E. granulosus s.l. In a single-step typing approach, we distinguished E. granulosus s.l. members in four
epidemiologically relevant subgroups. These were E. granulosus sensu stricto, E. equinus, E. ortleppi
and the E. canadensis cluster. The technique also allowed identification and differentiation of these
species from other Echinococcus or Taenia taxa for samples isolated from cysts or faeces.