Prevalence of Blastocystis protozoan infection in humans and domestic birds

Blastocystis is an anaerobic intestinal parasite that is prevalent among humans and various animals throughout the world. Different methods such as direct and staining stool smear examination as well as molecular methods can be used to diagnose Blastocystis.The main objective of the present work was to study Blastocystis infection in humans and domestic birds in Tafresh city and to compare three methods in diagnosing Blastocystis. The present study was designed and conducted as a cross-sectional descriptive study during the years 1399-1400 in Tafresh city. For this purpose, fecal samples were collected from pigeons (300 samples), hens and roosters (50 samples) and from their owners (100 samples). Stools were then examined microscopically (direct examination and trichrome staining) for Blastocystis detection. The positive samples were tested molecularly by PCR (18S rRNA amplification).In direct stool examination, 39 samples of pigeon feces (13%) and 13 samples of hen and rooster feces (26%) and 18 samples of human feces (18%) and in trichrome staining examination, 45 samples of pigeon feces (15%), 12 samples of hen and rooster feces (24%) and 15 samples of human feces (15%) were found to be positive for Blastocystis. In PCR test, only one sample (2.5%) of pigeon positive samples and 5 samples (38.46%) of hen and rooster positive samples and 4 samples (22.22%) of human positive samples were found to be positive. In the present study, only a limited number of positive samples related to direct stool examination and stained with trichrome were found to be positive in PCR experiment. This indicates that PCR method alone is not an appropriate method to determine the infection rate of Blastocystis. Therefore, it is suggested to use several different techniques for accurate diagnosis of Blastocysts.