Epidemiological study of human calicivirus infection in children with gastroenteritis in Lanzhou from 2001 to 2007.

Stool specimens were collected from 1,195 young children with acute diarrhea in Lanzhou, China, from 2001 to 2007. RT-PCR was used to detect human calicivirus (HucV). One hundred seventeen specimens were found positive for HucV. The infection rate was noticeably higher during 2006-2007 compared to the other years studied. Ninety-six specimens were sequenced to determine the genotypes of HucV. Eighty-six were norovirus and 10 were sapovirus, while GII/4 was the predominant strain of NV, followed by GII/3. The subtype of NV GII/4 changed from the Farmington Hills strain to the Bristol strain, and then to the Hunter strain and variant 2006b strain, over time. Variant 2006b has become the major epidemic strain in Lanzhou and should be closely monitored in the coming years.