Diverse norovirus genotypes identified in polluted water sources in Kenya

N Kiulia,J Mans,J Mwenda,M Taylor

doi:10.1016/j.ijid.2014.03.936

N Kiulia, J Mans + Show 2 more

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https://doi.org/10.1016/j.ijid.2014.03.936

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Abstract

Background: Noroviruses (NoVs) have been identified as aetiologic agents of acute gastroenteritis across all age groups worldwide. They are highly infectious and transmitted primarily via the faecal-oral route. Worldwide, water and food-borne outbreaks of acute gastroenteritis associated with NoVs have been frequently reported. Noroviruses are genetically highly diverse and are divided into five genogroups (GI-V) which are further subdivided into genotypes by nucleotide sequence analysis. Genogroup GI and GII are responsible for most human infections. Norovirus GII.4 strains causesmajority ofNoVoutbreaksworldwide andnovel variants of GII.4 viruses appear to emerge almost annually. The main objective of this study was to investigate the prevalence and predominant genotypes of NoVs in environmental water sources from rural, urban and refugee settings in Kenya Methods & Materials: Ten liters (10L) each of river, household and borehole water were collected in urban (Nairobi and Mutoine river), rural (Mboone river) and refugee (Dadaab refugee camp) settings. Noroviruses were recovered from the water samples by glass-wool adsorption elution and/or PEG/NaCl precipitation. Nucleic acid was extracted using the automated MagNA Pure platform and screened using commercial singleplex real-time RTPCR assays. Norovirus strains were characterised by nucleotide sequence analysis. Results: Of the 40 samples analysed NoV genogroup II accounted for 60% (24/40) and NoV genogroup I 20% (8/40). The following NoV genotypes were identified NoV GI.1, NoV GI.3 and NoV GI.9. The NoV GII genotypes detected were GII.4, GII.6, GII.12, GII.16 and GII.17. Conclusion: This study is the first report of NoV strains circulating in environmental waters in Kenya. Norovirus GII.17 was the predominant strain identified which differs to other studies in Africa. Therefore, continued research is needed to establish why this genotype is prevalent in Kenya and also to monitor other circulating NoV strains.

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