ABSTRACT
OBJECTIVE: To characterize a species of the genus Tricula and parasitized trematodes in schistosomiasis-endemic areas of Yunnan Province using a molecular analysis, so as to understand their taxonomic positions. METHODS: Tricula spp. and Oncomelania snails were collected from Xiangyun County, Yunnan Province, and cercaria parasitizing snails were observed using crushing followed by microscopy. Cercaria parasitizing Tricula snails at various morphologies were sampled using a shedding method. Genomic DNA was extracted from snail soft tissues and cercariae, and the 16S rRNA, COI, 28S rDNA genes in snails and the ND1 and 28S rDNA genes in cercariae were amplified using a PCR assay and sequenced. The species of Tricula snails and their parasitized trematodes was characterized using sequence alignment and phylogenetic analysis. RESULTS: Among 382 Tricula snails detected, there were three types of trematode cercariae found, including the non-forked (20.94%, 80/382), double-forked (3.40%, 13/382) and swallow shapes (7.07%, 27/382). Sequence and phylogenetic analyses showed that the 16S rRNA, COI and 28S rDNA gene sequences of this species of Tricula had high homology to those in Delavaya dianchiensis, and were clustered in a branch. Sequencing analysis of the ND1 and 28S rDNA genes revealed that the non-forked cercariae belonged to the family Pleu- rogenidae, the swallow-shaped cercariae belonged to the family Opecoelidae, and the double-forked cercariae belonged to another species of the genus Schistosoma that was different from S. sinensium and S. ovuncatum. CONCLUSIONS: The species and taxonomy of Triculla spp. and their parasitized trematodes are preliminarily determined in schistosomiasis-endemic areas of Yunnan Province; however, further studies are required to investigate the more definite taxonomy and pathogenicity.
Subject(s)
Cercaria , Phylogeny , Snails/classification , Snails/parasitology , Trematoda , Animals , Cercaria/genetics , Cercaria/isolation & purification , China , Electron Transport Complex IV/genetics , Endemic Diseases , NADH Dehydrogenase/genetics , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 28S/genetics , Schistosomiasis/epidemiology , Schistosomiasis/parasitology , Snails/genetics , Trematoda/genetics , Trematoda/isolation & purificationABSTRACT
OBJECTIVE: To investigate the role of rodents in the transmission of schistosomiasis in endemic areas in Yunnan Province. METHODS: Kato-Katz method was used to study the infection rate of rodents, humans and domestic animals. RESULTS: The infection rate was 0.9% (32/3,411) for rodents, 15.6% (461/2,964) for humans, and 9.6% (239/2,482), for domestic animals. The EPG(mean) was 5.8 for rodents, 1.8 for humans, 0.1 for cattle, 0.1 for horses and 0.02 for pigs. CONCLUSION: The rodents played a minor role in the transmission of schistosomiasis in the plateau area of Yunnan province.
