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

Abstract

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.

Sapovirus prevalence in children less than five years of age hospitalised for diarrhoeal disease in South Africa, 2009–2013

“…These results are similar to a Malawian study which demonstrated an autumn peak (MarchApril) [9] and a Kenyan study where SaVs were detected all year round [4]. These results are in contrast to studies from the northern hemisphere (Canada, United Kingdom, Denmark and Japan) where SaVs are more frequent during the cold winter season [27].…”

“…In these studies, SaVs were common during the winter months and in younger children [1]. Sapovirus prevalence has only been described in a few sub-Saharan African countries, including Kenya (5.7% in <14 years) [6], Tanzania (5.7-6.4% in <5 years) [7,8], Malawi (8% in <5 years) [9], South Africa (SA; 4.1-8.4% in all ages) [10,11], Gabon (9.5% in <5 years) [12] and Burkina Faso (18% in <5 years) [13]. These studies utilized molecular methods for SaV detection with an average prevalence of 7.5% (95% CI 3.4%-11.5%) among diarrhoeal cases.…”

Diverse sapovirus genotypes identified in children hospitalised with gastroenteritis in selected regions of South Africa

“…Mixed infections, involving SaVs and other enteric viruses such as RV, AdV and NoV, at frequencies ranging from 17-26% have been reported previously [17,30,33].…”

“…In Tunisia, SaVs were reported in paediatric outpatients with gastroenteritis and only GI.1 was identified [15]. Sapoviruses have also been reported in patients hospitalised with gastroenteritis in Tanzania [16] and in Malawi [17]. Genotypic characterisation was not conducted in the Tanzanian study [16] and in Malawi, only GII strains were identified [17].…”

“…Sapoviruses have also been reported in patients hospitalised with gastroenteritis in Tanzania [16] and in Malawi [17]. Genotypic characterisation was not conducted in the Tanzanian study [16] and in Malawi, only GII strains were identified [17]. Five different SaV genotypes were identified in HIV-seropositive children in Kenya [18].…”