Clin. Lab. 1+2/2012 117 Clin. Lab. 2012;58:117-123 ©Copyright ORIGINAL ARTICLE A Wide Variety of Diarrhea Viruses Circulating in Pediatric Patients in Thailand NATTHAWAN CHAIMONGKOL 1 , PATTARA KHAMRIN 1 , BOONPA SUANTAI 1 , WILAIPORN SAIKHREANG 1 , AKSARA THONGPRACHUM 2 , RUNGNAPA MALASAO 1 , NUTHAPONG UKARAPOL 3 , TIPACHAN KONGSRICHAROERN 4 , HIROSHI USHIJIMA 2 , NIWAT MANEEKARN 1 1 Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 2 Department of Developmental Medical Sciences, Institute of International Health, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan 3 Department of Pediatrics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 4 Pediatric Hematology Unit, Nakornping Hospital, Chiang Mai, Thailand SUMMARY Background: Viral gastroenteritis has been recognized as one of the most common illnesses that affects infants and young children all over the world. A wide variety of viruses associated with the disease are continually being re- ported. To investigate the epidemiological situation of diarrhea virus infection in Chiang Mai, Thailand, surveil- lance was conducted during January to December 2007. Methods: A total of 160 fecal specimens collected from pediatric patients admitted to the hospital with acute gas- troenteritis were tested for the presence of group A, B, and C rotaviruses, norovirus, sapovirus, astrovirus, adeno- virus, Aichi virus, enterovirus, bocavirus, and human parechovirus by RT-multiplex PCR. Results: Of 160 fecal specimens tested, 85 (53.1%) were positive for diarrhea viruses. Of these, group A rotavirus was the predominant with a prevalence of 27.5%, followed by norovirus GII (11.9%), sapovirus (3.1%), entero- virus (2.5%), human parechovirus (1.9%), and norovirus GI, astrovirus, adenovirus (each 0.6%). Mixed-infec- tions of 2 or 3 viruses were observed in 7 (4.4%) patients. However, none of groups B and C rotaviruses and Aichi virus were detected in this study. Monthly distribution analysis revealed that all those diarrhea viruses were de- tected continually throughout the year at a low level of infection except for group A rotavirus and norovirus infec- tions which appeared to peak in a cool season in January-March and December, respectively. Conclusions: This surveillance revealed a wide variety of diarrhea viruses currently circulating in pediatric pa- tients with acute gastroenteritis in Chiang Mai, Thailand. (Clin. Lab. 2012;58:117-123) KEY WORDS Epidemiology, gastroenteritis viruses, diarrhea INTRODUCTION Acute gastroenteritis continues to be a major public health problem worldwide. Children under 5 years old are particularly affected with more than 700 million cases every year [1]. Furthermore, annual mortality as- sociated with gastroenteritis has been estimated around 5 to 8 million cases [2]. Several groups of viruses have been reported, including rotavirus (RV), norovirus (NoV), sapovirus (SaV), astrovirus (AstV), and adeno- virus (AdV) [3,4], as pathogens that are responsible for numerous outbreaks of nonbacterial gastroenteritis in several settings such as hospitals, day care centers, nurs- ing homes, and schools [4,5]. Among different types of gastroenteritis viruses, RV is _____________________________________________ Manuscript accepted May 30, 2011