RESUMO
OBJECTIVE@#To analyze a phylogenetic tree for understanding the molecular systematic of trematode in Family Heterophyidae, which are highly distributed in Thailand.@*METHODS@#Based on thirteen sequences of mitochondrial cytochrome c oxidase subunit I (mCOI) gene from six genera of heterophyid trematodes, viz. Haplorchis, Stellantchasmus, Centrocestus, Metagonimus, Pygidopsis, and Haplorchoides were aligned automatically using the Clustal × 2.0 program. A phylogenetic tree was constructed by maximum likeinghood (ML) and neighbor-joining (NJ) methods, with 1 000 bootstrap using the 5.0 program.@*RESULTS@#The phylogenetic relationship from both methods was similar and separated into three groups consisting of Haplorchoides pumilio group, Haplorchoides taichui group and another heterophyid genera.@*CONCLUSIONS@#The sequence data of mtCOI can be used to investigate the phylogenetic relationships of trematodes at the genus level. Each clade of different genera of heterophyid trematodes can be separated into sister groups that correlated with the morphological characteristic, kind of secondary intermediate host and geographic distribution.
Assuntos
Animais , DNA de Helmintos , Genética , Complexo IV da Cadeia de Transporte de Elétrons , Genética , Peixes , Parasitologia , Proteínas de Helminto , Genética , Heterophyidae , Classificação , Genética , Filogenia , Infecções por Trematódeos , ParasitologiaRESUMO
Freshwater clams were collected in 16 sampling localities of 11 provinces in northeast Thailand. The clams were collected every 2 months, between February 2006 and August 2007, using the “counts per unit of time” sampling method. A total of 508 clam samples from 6 species were found–280 Corbicula sp, 23 Pilsbryoconcha sp, 136 Scabies crispate, 6 Pseudodon mouhoti, 51 Limnoperna siamensis, and 12 Physunio eximinus. Bucephalid (Gasterostome) cercariae were found from 3 clams belonging to 2 species, 1 Corbicula sp each at Rasi Salai and Lampao dams, and 1 Limnoperna siamensis at the Lampao River. The infection rate was 0.59% (3/508). Freshwater clams can serve as the first and second intermediate hosts for trematodes. This is the first study to report cercarial emergence from freshwater bivalves in this geographic region.