Search

Simple Summary: Simple Summary: Water mites are a significant population of Arachnida in aquatic ecosystems, with over 7500 species described worldwide. The genus Unionicola, belonging to the family Unionicolidae, is known for its parasitic behavior, often consuming the mucus and tissue of its molluscan hosts. While most species in this genus parasitize mussels, some have been found in gastropods. In our study, we discovered water mites infesting two species of gastropods: Filopaludina sumatrensis polygramma and F. martensi martensi. Through a comparison with known species, we identified this mite as a new species within the genus Unionicola, subgenus Polyatax, and named it "Unionicola (Polyatax) kasetbangkhenensis sp. nov.". Two species of gastropods, Filopaludina sumatrensis polygramma and F. martensi martensi, were found infested with water mites of the genus Unionicola in Bangkok and Nonthaburi provinces, Thailand. Morphological studies on these water mites, based on the characteristics of their genital acetabular and female genital fields, identified them as a new member of subgenus Polyatax. Unionicola (Polyatax) kasetbangkhenensis sp. nov. was named after the first location where this parasitic water mite was discovered. This species is distinguished from others by the pattern of their female genital field, with their anterior acetabular plates each bearing two acetabula and a short thick spine on the inner margin. Additionally, it differs from other species by the structure of the spines in its pedipalps and legs, as well as in the shapes of its coxal plates. [ABSTRACT FROM AUTHOR]

The liver fluke Opisthorchis viverrini s.l. is associated with a long-term public health problem in Thailand. However, O. viverrini s.l. infection in Bithynia snails in the canal network system (CNS) in the Bangkok Metropolitan Region (BMR) has never been assessed. This study aimed to investigate the occurrence of B. siamensis siamensis and the prevalence of O. viverrini s.l. infection in this snail in the CNS in BMR along with morphological examination and molecular analyses on O. viverrini s.l. cercariae. The snails were randomly sampled from the CNS in all BMR areas from January 2018 to July 2019. Snail specimens were identified and examined for digenean infection by shedding and dissection. The cercariae were identified using morphology and molecular methods, including PCR with a species-specific primer and a Bayesian phylogenetic analysis of ITS2 sequences. Bithynia siamensis siamensis was found in almost all sampling localities, with different quantities and detected frequencies. From a total of 7473 B. s. siamensis specimens, O. viverrini s.l. infections were detected in the Northern Bangkok, Muang Nakhon Pathom, Krathum Baen, and Lam Luk Ka areas with an overall prevalence of 0.05% (4/7473) and prevalence of 0.22% (1/455), 0.21% (1/469), 0.40% (1/253), and 0.16% (1/614) in individual localities with positive snails, respectively. This study is the first investigation of digenean infection in the canal network system-type habitat in Thailand and revealed extremely low O. viverrini s.l. prevalence.