Phagicola longa (Heterophyidae) in dogs from Chile: morphological findings and taxonomical problems

Trematodes found in the intestines of dogs from Chillan, VIII region of Chile, were studied. The species identified was Phagicola longa, a fluke of the Heterophyidae family, parasites of fish-eating birds or mammals in several countries. P. longa is very similar to P. arnaldoi, a species described in dogs from South America. The number of vitelline follicles and the distribution of cuticular spines are the only distinctive features for the two species. However, many authors report the same number of vitelline follicles for P. arnaldoi and P. longa. Furthermore, the distribution of cuticular spines is very similar. P. longa has a small area devoid of spines when compared to P. arnaldoi but a wide variability of this generic character in the Heterophyidae was observed. As previously reported, P. arnaldoi could be a recent synonym of P. longa, which is the only species of Phagicola that can be found in South American dogs. This is in agreement with the study of metacercariae found in Mugilidae, the intermediate hosts of Phagicola, from American waters in which P. longa is the only species found. The authors emphasize the finding of this trematode in dogs, since it could possibly cause also human infection.