A preliminary investigation into the genetic variation and population structure of Taenia hydatigena from Sardinia, Italy

Cysticercosis caused by the metacestode stage of Taenia hydatigena is endemic in Sardinia. Information
on the genetic variation of this parasite is important for epidemiological studies and implementation of
control programs. Using two mitochondrial genes, the cytochrome c oxidase subunit 1 (cox1) and the
NADH dehydrogenase subunit 1 (ND1) we investigated the genetic variation and population structure of
Cysticercus tenuicollis from Sardinian intermediate hosts and compared it to that from other hosts from
various geographical regions.
The parsimony cox1 network analysis indicated the existence of a common lineage for T. hydatigena and
the overall diversity and neutrality indices indicated demographic expansion. Using the cox1 sequences,
low pairwise fixation index (Fst) values were recorded for Sardinian, Iranian and Palestinian sheep C.
tenuicollis which suggested the absence of genetic differentiation.
Using the ND1 sequences, C. tenuicollis from Sardinian sheep appeared to be differentiated from those
of goat and pig origin. In addition, goat C. tenuicollis were genetically different from adult T. hydatigena
as indicated by the statistically significant Fst value. Our results are consistent with biochemical and
morphological studies that suggest the existence of variants of T. hydatigena.