Human caliciviruses are a significant pathogen of acute sporadic diarrhea in children of Santiago, Chile

Human caliciviruses (HuCVs) are increasingly recognized as common pathogens that cause acute sporadic diarrhea in children; however, regional antigeni c and genetic diversity complicate detection techniques. Stool samples from children seeking medical attention in 2 out-patient clinics, a large emerg ency department, and 2 hospital wards were evaluated for HuCVs by reverse t ranscription-polymerase chain reaction, using primers based on a conserved sequence of the polymerase region of a previously sequenced Chilean strain, HuCVs were detected in 53 (8%) of 684 children 1 month to 5 years of age ( mean, 13 months). Detection occurred year-round without a clear seasonal pe ak, and detection frequency declined from 16% in 1997 to 2% in 1999. The de cline may have been due to a change in virus genotype, HuCVs are a signific ant pathogen of acute sporadic diarrhea in Chilean children, and continuous characterization of genetic diversity will be crucial for appropriate dete ction.