Genetic and evolutionary characterization of norovirus from sewage and surface waters in Córdoba City, Argentina

BLANCO FERNÁNDEZ, M.D.; TORRES, C.; MARTÍNEZ, L.; GIORDANO, M.; MASACHESSI, G.; BARRIL, P.; ISA, M.B.; CAMPOS,RH; NATES, S.; MBAYED, V.

Infection, Genetics and Evolution

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2011 p. 1631 - 1637

1567-1348

Noroviruses (NoVs) are among the most common viral agents that causegastroenteritis in humans of all ages from all over the world. They are excreted in the fecesand introduced into environmental waters as raw or treated sewage. In this work, sewageand environmental samples from the Suquía River in the city of Córdoba, Argentina, wereevaluated for NoV contamination as a reflection of the true circulation of this virus in thepopulation, not restricted to the symptomatic cases. The phylogenetic analysisdemonstrated that the main genotype detected was GII.4, belonging to the widelydistributed2006b variant, followed by isolates related to the putative recombinant GII.gvirus. Those isolates were more phylogenetically related with recent viruses from othercountries than with previous local sequences, suggesting a rapid and wide spread of viralstrains that prevents a geographically structured phylogeny. A Bayesian coalescent analysisdemonstrated that variants isolated in this work have a most recent common ancestorplaced in 2007-2008 with estimated substitution rates of 3.7-5.8 x 10-3 s/s/y. Environmentalsamples showed a mixture of both viral types, pointing up to the co-circulation and the riskof mixed infections and recombination. There are few reports regarding NoV epidemiologyin our country and this is the first surveillance report in environmental waters and sewagewith a genetic and evolutionary characterization.