14 research outputs found
Rapid emergence and predominance of a broadly recognizing and fast-evolving norovirus GII.17 variant in late 2014
Norovirus genogroup II genotype 4 (GII.4) has been the predominant cause of viral gastroenteritis since 1996. Here we show that during the winter of 2014–2015, an emergent variant of a previously rare norovirus GII.17 genotype, Kawasaki 2014, predominated in Hong Kong and outcompeted contemporary GII.4 Sydney 2012 in hospitalized cases. GII.17 cases were significantly older than GII.4 cases. Root-to-tip and Bayesian BEAST analyses estimate GII.17 viral protein 1 (VP1) evolves one order of magnitude faster than GII.4 VP1. Residue substitutions and insertion occur in four of five inferred antigenic epitopes, suggesting immune evasion. Sequential GII.4-GII.17 infections are noted, implicating a lack of cross-protection. Virus bound to saliva of secretor histo-blood groups A, B and O, indicating broad susceptibility. This fast-evolving, broadly recognizing and probably immune-escaped emergent GII.17 variant causes severe gastroenteritis and hospitalization across all age groups, including populations who were previously less vulnerable to GII.4 variants; therefore, the global spread of GII.17 Kawasaki 2014 needs to be monitored
Norovirus GII.17 Predominates in Selected Surface Water Sources in Kenya
In this study, the prevalence and genotypes of
noroviruses (NoVs) in selected water sources from rural,
urban and refugee settings in Kenya were investigated. Ten
litres each of river, household and borehole water was
collected in rural (Mboone River), urban (Nairobi and
Mutoine River) and refugee (Dadaab refugee camp) settings.
NoVs were recovered from the water samples by a
glass wool adsorption–elution technique and/or PEG/NaCl
precipitation. Nucleic acid was extracted using the automated
MagNA Pure platform. NoVs were detected with
singleplex real-time reverse transcription-polymerase chain
reaction assays and characterised by nucleotide sequence
analysis. NoVs were detected in 63 % (25/40) of the
selected water samples comprising GII (42.5 %), GI
(2.5 %) and mixed GI/GII (17.5 %) positive samples. The
prevalence of NoVs in the Mutoine River (urban area) was
higher than in the Mboone River (rural area) (P = 0.0013).
Noroviruses GI.1, GI.3, GI.9, GII.4, GII.6, GII.12, GII.16
and GII.17 were identified, with GII.17 accounting for
76 % (16/21) of the typed strains. The NoV GII.17 predominance
differs to other studies in Africa and further
surveillance of NoVs in clinical and environmental settings
is required to clarify/elucidate this observation. As information
regarding NoVs in Kenyan water sources is limited
this report provides valuable new data on NoV genotypes circulating in environmental water sources and the surrounding
communities in Kenya.The National Research Foundation, South Africa and the National Council
for Science and Technology, Kenya: South Africa/Kenya Research
Programme.http://link.springer.com/journal/12560hb2017Medical Virolog