Investigating the Invasive Contamination of Lymnaeidae Snails with Trematodes According to Species and Sampling Location in Lorestan province, Iran, Middle East.

Radicine snails are of considerable medical and veterinary importance as termatode vectors. These snails are responsible for transmission of the zoonotic trematodes including Schistosoma turkestanicum and Fasciola gigantica in Iran. This study investigates Lymnaedae infestation by termatodes, considering the species and sampling locations. 1,700 snails were collected from the suburbs of Borujerd, Khorram Abad, and Dorud in Lorestan, Iran from April to August 2018. Round snails were separated, and Snail species were identified by measuring length, width, spire, and valve, using the shape of the radula as an identification key. To separate the radula, snails soft tissue was removed from the shell using forceps, then incubated in a 7% potassium solution for 24 hours at room temperature. The isolated radula was placed in a 15% acetic acid solution. It was then placed in Mallory's dye solution for 3 minutes and sunsequently washed with an oxalic acid solution. After dehydration with 96% ethanol, the samples were examined under a light microscope. To investigate trematode larvae in snails, 10% of the snail samples (a total of 170 Lymnaeidae snails) were selected and examined using the crushing method on a slide. The morphological results showed that in Dorud and Borujerd, the highest distribution of Lymnaea gedrosiana was 24.09% and 19.72%, while the lowest distribution of Bulinus truncatus was 4.72% and 4.48%, respectively. Lymnaea species were the most abundant in plain villages, whereas Bithynia and Physa were more commonly observed in mountain villages. In Khorram Abad, the highest distribution was related to Lymnaea truncatula (20.15%), while the lowest distribution was related to Lymnaea stagnalis (5.56%). The genera Bithynia and Physa showed a significant increase in mountainous villages of Khorram Abad compared to those in Borujerd and Dorud. The overall infectionrate of Lymneidae snails with termatodes was 32.94%, including 18.23% in Borujerd, 8.23% in Dorud, and 6.47% in Khorramabad. According to the chi-square test (p<0.05), a significant difference was observed in the rate of trematode infection in Lymneade snails. In this regard, the Borujerd region exhibited the highest rate of infection, whereas Khorram Abad showed the lowest.