Identification and Assemblage Types of Giardia duodenalis from Patients in Thrace, Turkey

Objective: Giardiasis is a common disease, and clinical forms can vary based on the assemblage types of the parasite. Detailed information on the subgenotypes may indicate the transmission routes and enlighten the gaps in the epidemiology of the disease. This study aims to reveal the occurrence of giardiasis in Thrace, Turkey, and assemblage types of Giardia duodenalis. Materials and Methods: In total, 573 stool samples taken from the individuals applied to Tekirdağ Central State Hospital in 2009, were examined by wet-mount and zinc sulfate floatation methods. Giardia-positive 26 samples and 64 samples taken from the individuals with gastrointestinal complaints were analyzed by nested PCR-RFLP to differentiate the assemblage types. Sequence analysis was employed for confirmation of assemblage types and subgenotypes. Results: Giardia spp. cysts were detected in 3.66% and 4.54% of the samples with wetmount and zinc sulphate floatation techniques respectively. A total of 27 samples were found positive by nested PCR-RFLP out of 90 samples. Fifteen samples were determined as assemblage A, 2 and 10 samples as B and B/E mix respectively. Sequence analysis showed that the latter assemblage (B/E mix) as A3-B3 mix. Conclusion: Fast identification techniques, namely zinc sulphate flotation can be used for screening stool samples in order to determine Giardia cysts with considerably high sensitivity and specificity. Based on this method, the occurrence rate of giardiasis was found as 4.54% in the studied group. DNA sequencing is necessary to distinguish assemblages and confirm the results of PCR-RFLP.