Acta Tropica 154 (2016) 1–5 Contents lists available at ScienceDirect Acta Tropica journal homepage: www.elsevier.com/locate/actatropica Giardia duodenalis in Damascus, Syria: Identification of Giardia genotypes in a sample of human fecal isolates using polymerase chain reaction and restriction fragment length polymorphism analyzing method Dania Skhal, Ghalia Aboualchamat, Samar Al Nahhas ∗ Department of Animal Biology, Faculty of Science, Damascus University, Damascus, Syria a r t i c l e i n f o Article history: Received 2 June 2015 Received in revised form 6 October 2015 Accepted 12 October 2015 Available online 30 October 2015 Keywords: Giardia duodenalis Genotype Assemblage -gardin PCR-RFLP a b s t r a c t Giardia duodenalis is a common gastrointestinal parasite that infects humans and many other mammals. It is most prevalent in many developing and industrialized countries. G. duodenalis is considered to be a complex species. While no morphological distinction among different assemblages exist, it can be genetically differentiated into eight major assemblages: A to H. The aim of this study was to determine the genetic heterogeneity of G. duodenalis in human isolates (a study conducted for the first time in Syria). 40 fecal samples were collected from three different hospitals during the hot summer season of 2014. Extraction of genomic DNA from all Giardia positive samples (based on a microscopic examination) was performed using QIAamp DNA Stool Mini Kit. ˇ-giardin gene was used to differentiate between different Giardia assemblages. The 514 bp fragment was amplified using the Polymerase Chain Reaction method, followed by digestion in HaeIII restriction enzyme. Our result showed that genotype A was more frequent than genotype B, 27/40 (67.5%); 4/40 (10%) respectively. A mixed genotype of A + B was only detected in 9 isolates (22.5%). This is the first molecular study performed on G. duodenalis isolates in Syria in order to discriminate among the different genotypes. Further expanded studies using more genes are needed to detect and identify the Giardia parasite at the level of assemblage and sub-assemblage. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Giardia is the most common of intestinal parasites worldwide. It is estimated that in developing countries, where poor levels of hygiene, sanitation, and overcrowding enhance Giardia transmis- sion, about 200 million individuals develop symptomatic giardiasis and 500,000 new cases are reported each year (WHO 1996; Adam 2001). Giardia genus comprises of six species: G. duodenalis (syn: G. intestinalis or G. lamblia), G. muris, G. microli, G. agilis, G. psittaci, and G. ardeae (Adam 2001). Giardia duodenalis has a variety of mammalian hosts including humans (Gardner and Hill, 2001). It is transmitted to individuals via fecal-oral route by direct contact or by ingestion of resistant cysts from contaminated food or water (Karanis et al., 2007). The clinical ∗ Corresponding author at: B.O. Box 10718, Damascus, Syria. Fax: +963 11 3732338. E-mail address: samar.nahhas@yahoo.com (S. Al Nahhas). manifestations of giardiasis vary between asymptomatic infection to severe diarrheal illness with or without mal-absorption, weight loss, and abdominal cramps (Gardner and Hill, 2001). Conventional diagnostic methods are used widely in many lab- oratories for the detection of Giardia cysts or trophozoites in stool samples using a light microscope (Adam, 1991). However, these methods are of low sensitivity, time consuming, and require micro- scopic experience. In addition, the identification of G. duodenalis genotypes is not possible using these simple methods, due to its morphological homogeneity (Amar et al., 2002). Recently, a variety of molecular techniques, such as PCR-based diagnostic system, PCR-RFLP, cloning and sequencing analysis of a specific set of Giardia genes [glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi), elongation factor 1 alpha (efla), beta giardin (bg) and 18S RNA genes] proved to be sensitive, pow- erful, and specific analytical tools for detection of Giardia parasites in stool samples as well as for genotyping this complex parasite (Caccio et al., 2002; Wielinga and Thompson, 2007; Sprong et al., 2009; Soliman et al., 2011; Torres-Romero et al., 2014). By means http://dx.doi.org/10.1016/j.actatropica.2015.10.008 0001-706X/© 2015 Elsevier B.V. All rights reserved.