ABSTRACT
The majority of <i>Giardia</i> infections are transmitted by the fecal-oral route and cause giardiasis. Children who live in crowded conditions or low socio-economic areas are the risk group for <i>Giardia</i> infection. Interestingly, most of them are asymptomatic or only mildly infected and can shed the <i>Giardia</i> cysts in the environment. Thus, the diagnosis of <i>Giardia</i> infection in asymptomatic or mild infection plays an important role in achieving control of <i>Giardia duodenalis</i> transmission. The objective of this study was to examine parasitic infections using microscopy and to develop a real-time PCR method for detection of <i>Giardia</i> infection in the stool samples of children living on the Thai-Myanmar border. Both species-specific primers and fluorescent labeled <i>G. duodenalis</i> probe were designed using small-subunit ribosomal RNA (<i>ssrRNA</i>). The results showed that 10 (7.69%) and 40 (30.77%) of 130 stool samples were positive for <i>G. duodenalis</i> by microscopy and real-time PCR respectively. Only 3 out of 9 liquid stools revealed <i>G. duodenalis</i> positive using microscopy, but all of them were <i>G. duodenalis</i>-positive using real-time PCR. The detection limit of real-time PCR for <i>G. duodenalis</i> was 0.1 pg/25 µl reaction. It can detect both mild and asymptomatic <i>Giardia</i> infections in children living on the Thai-Myanmar border.