Morphological and molecular identification of lymnaeid snail and trematodes cercariae in different water bodies in Perak, Malaysia

Lymnaeid snails play a crucial role in the transmission of trematode cercariae as an intermediate host that can infect humans, ruminants like buffalo, and other animals, resulting in serious economic losses. The purpose of the study was to identify the morphological and molecular characteristics of snails and cercariae collected from water bodies near buffalo farms that were integrated with palm oil in Perak, Malaysia. The presence or absence of snails in 35 water bodies was examined via cross-sectional study. From three marsh wetlands, 836 lymnaeid snails were gathered in total. Each snail's shell was morphologically identified to determine its family and species. The cercarial stage inside each snail's body was observed using the crushing method and trematode cercariae types were determined. In addition, the target gene Cytochrome c oxidase subunit 1 (Cox1) and the ribosomal internal transcribed spacer 2 (ITS2) region were used to identify the snail species and cercarial types according to the species level. The findings indicated that the collected snails belong to the family lymnaeidae and Radix rubiginosa species. In snails, the cercarial emergence infection rate was 8.7%. Echinostome, xiphidiocercariae, gymnocephalous, brevifurcate-apharyngeate distome cercariae (BADC), and longifurcate-pharyngeal monostome cercariae (LPMC) are the five morphological cercarial types that were observed. The cercariae were identified using morphological and molecular techniques, and they are members of the four families which are Echinostomatidae, Plagiorchiidae, Fasciolidae, and Schistosomatidae. Interestingly, this is the first study on R. rubiginosa and several trematode cercariae in Perak water bodies near buffalo farms that are integrated with palm oil. In conclusion, our research shown that a variety of parasitic trematodes in Perak use R. rubiginosa as an intermediate host.

Situation and Cercarial Infection of Freshwater Mollusk from Sirindhorn Reservoir, Ubon Ratchathani Province, Thailand

BACKGROUND

Most of trematodes need snails to complete their life cycles. Consequently freshwater snails are served as intermediate hosts of many parasites worldwide. There is a lack of report on snail diversity and parasitic infection in snails in Sirindhorn Reservoir, Ubon Ratchathani province, Thailand.

METHODS

Mollusk diversity and trematode cercariae infections were investigated in snails from 120 sampling sites surround Sirindhorn Reservoir from April 2018 to June 2018. Mollusk species were identified based on their shell morphology. The presence of cercariae infections in snails was examined by cercarial shedding methods. The interaction between snail species was analyzed by the correlation method.

RESULTS

Overall, 2076 mollusks were collected which comprised six species of snails and two species of bivalves. Snail species were identified as Bithynia siamensis goniomphalos, Anentome helena, Filopaludina sumatrensis spiciosa, F. martensi martensi, F. martensi munensis and Pomacea canaliculata. The overall rate of trematode cercariae infection was 1.69% (35/2,076). The cercariae found infecting snails were Cercariaeum cercaria, Virgulate cercaria, Cotylomicrocercous cercaria and Furcocercous cercaria. The most common snails found was the assassin snail, A. helena, which showed the negative relationship among other species interactions.

CONCLUSION

This finding indicated infection with animal's parasites in snails in this area are common, besides, we found many species of snails in Sirindhorn Reservoir are potentially be the host of parasite in animal and human.