species identification of birds nasal trichobilharzia in sari, north of iran

b ackground: cercarial dermatitis is known as an endemic parasitic disease in north of iran, a hy- persensitive skin reaction to the penetration of nonhuman schistosome larvae into human skin. in recent studies in this region, final and intermediate hosts were recognized and trichobilharzia was identified as the main causative agent of cercarial dermatitis in this region, but to date the parasite species haven’t been identified. therefore this study was performed to species identification of nasal trichobilharzia in infected birds for the first time. m ethods: a total of 45 anas clypeata birds identified as final host, were collected from sari in north of iran and infected nasal tissues analyzed using molecular techniques. genomic dna was isolated by phenol/chloroform extraction method and its region of rdna were amplified with specific pri- mers its5trem and its4trem, then sequenced area were compared with existing records in genbank. results: twelve samples were infected with trichobilharzia and results of pcr reaction indicated that all of them belonged to t. regenti . the sequence alignment of present work isolates and those depo- sited in genbank showed differences in nucleotide sequences of repeat region in its1. c onclusion: trichobilharzia regenti is the most frequent parasite of anatid birds in north of iran. this corresponds to the distribution of this parasite along the flyway of migratory birds, which annually migrate from siberia and northern countries of caspian sea to wintering areas in southern regions of it.