Detection and characterization of human caliciviruses in hospitalized children with acute gastroenteritis in Blantyre, Malawi

The human caliciviruses (HuCVs), including Norovirus and Sapovirus , are recognized causes of acute gastroenteritis in children and adults. A 1‐year study was undertaken in Blantyre, Malawi, to examine the prevalence, and genetic diversity, of human caliciviruses (HuCVs) amongst children under 5 years of age hospitalized with acute gastroenteritis. Using the reverse transcription‐polymerase chain reaction (RT‐PCR), combined with nucleotide sequencing of the RT‐PCR products, HuCVs were detected in 34/398 (8.5%) of children. Twelve (35.3%) of the children were co‐infected with additional enteric viruses (predominantly rotavirus). The HuCVs comprised 26 Noroviruses (6.5%) and 8 Sapoviruses (2.0%). Each of the Noroviruses belonged to genogroup II, and could be further classified into six genotypes, including GII/3 (18 strains), GII/4 (2 strains), GII/11 (1 strain), GII/13 (1 strain), GII/16 (2 strains), and a putative new genotype GII/20 (2 strains). Each of the Sapoviruses belonged to genogroup GIII. HuCVs are the second most commonly identified viral enteropathogens (after rotavirus) among hospitalized children with gastroenteritis in Malawi. J. Med. Virol. 77:522–527, 2005. © 2005 Wiley‐Liss, inc.