Importance of Land Snails in Dicrocoeliosis Epidemiology.

Dicrocoeliosis is a helminthosis caused by the small liver fluke Dicrocoelium spp. (Trematoda, Dicrocoeliidae) parasitizing in the bile ducts and gall bladder of ruminants as well as many other animal species including humans. In the biological life cycle of Dicrocoelium, land snails are first intermediate hosts and ants are second intermediate hosts. Sporocysts and cercaria, which are larval stages, live in the hepatopancreas of land snails and metacercaria, which is also the larval stage, lives in the abdomen and brain of ants. Land snails, which are the first intermediate host of this parasite in Turkey, include Helicopsis derbentina, Helicopsis protea, Helicopsis krynickii, Cernuella virgata, Trochoidea pyramidata, Cochicella acuta, Monacha carthusiana, Helicella candicans, Helix aspersa, Helix lucorum, and Chondrus tournefortianus. Dicrocoeliosis is widespread in ruminants and affects their liver, which can lead to weight loss and reduced milk production. The number of reports on dicrocoeliosis is increasing due to the expansion of dry habitats and parasites becoming resistant to antihelminthic drugs. This study provides information on the epidemiology and control methods of Dicrocoelium.

Preliminary protective capacity study of a Dicrocoelium dendriticum antigenic protein in hamsters.

The purpose of this study was to evaluate the protective capacity of 130 kDa Dicrocoelium dendriticum protein in hamsters experimentally infected with this parasite. Forty hamsters divided into four groups of ten animals each were used: G1 (control), G2 (infected), G3 (immunized with Freund's adjuvant and infected), G4 (130 kDa protein vaccinated + adjuvant and infected). Infection with 40 metacercariae/hamster was carried out 4 weeks after the last immunization. Parasitological studies [number of eggs per gram (epg) and worm burden] and biochemical parameters (total proteins, albumin, and total bilirubin), hepatic enzymes [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)], and total IgG levels were determined. A reduction in epg in G3 and G4 was observed 16 weeks postinfection with the higher reduction percentage in the latter (25.2%). No statistically significant differences were detected in the number of recovered worms among groups, although the mean was slightly less in G4 (12.2 +/- 2.08, mean +/- SE) than in G2 (15.4 +/- 2.90). In G4, global protection was 20.9% and an increase in AST and ALT levels was observed. Total IgG levels were similar in the three infected groups. The protection obtained was inadequate, so the antigen dose, immunization-infection period, adjuvants, and immunization route must be optimized.