Discrimination between E. granulosus sensu stricto, E. multilocularis and E. shiquicus Using a Multiplex PCR Assay

Area of Science:

• Veterinary Parasitology
• Molecular Diagnostics
• Public Health

Background:

• Echinococcus granulosus sensu stricto (s.s), E. multilocularis, and E. shiquicus infections are co-endemic on the Qinghai-Tibet plateau.
• Accurate detection and species identification of Echinococcus are crucial for controlling these parasitic infections.

Purpose of the Study:

• To develop an efficient diagnostic tool for differentiating Echinococcus species.
• To enable species identification in both intermediate and definitive hosts.

Main Methods:

• A single-tube multiplex PCR assay was designed using primers targeting mitochondrial genes (nad1, nad5, cox1).
• The assay was validated using DNA from protoscoleces, worm eggs, and copro-DNA from experimentally infected dogs.
• Specificity was confirmed against other cestode species.

Main Results:

• The multiplex PCR accurately detected and differentiated E. granulosus s.s., E. multilocularis, and E. shiquicus without cross-reactivity.
• The assay detected Echinococcus DNA in protoscoleces and copro-DNA, with sensitivity thresholds as low as 10 pg DNA or 1 egg.
• Positive results from canine fecal samples were obtained as early as 17 days post-infection.

Conclusions:

• The developed multiplex PCR is an effective tool for discriminating between E. granulosus s.s., E. multilocularis, and E. shiquicus.
• This assay facilitates the detection of Echinococcus infections in definitive hosts (canids) via fecal analysis.
• It also aids in identifying Echinococcus metacestode larvae in intermediate hosts, which is often challenging visually.