Abstract: Wenyonella philiplevinei is one of important pathogens of duck coccidiasis. To seek specific genetic marker of the protozoan, the fresh stool was obtained from a duck house in Guangdong, then coccidial oocysts were collected by Sheather’s sucrose floatation procedure, and these oocysts were identified as W. philiplevinei according to morphology. The partial 18S rDNA was amplified by PCR, cloned and sequenced after the genomic DNA was extracted. The genetic relationship between the isolate and other protozoan was compared. The results showed that the sequence was closer to other coccidians of Eimeriidae. Phylogenetic analysis indicated that duck-derived W. philiplevinei isolate belonged to another branch of Eimeriidae. It is concluded that the 18S rDNA sequence provided an useful genetic marker for the differentiation of W. philiplevinei from other related protozoa．

Key words: Wenyonella philiplevinei; morphology; 18S rDNA; PCR