Epidemiological Surveillance of Norovirus and Rotavirus in Sewage (2016-2017) in Valencia (Spain).

Cristina Santiso-Bellón,Alba Pérez-Cataluña,Roberto Gozalbo-Rovira,Susana Vila-Vicent,Jesús Rodríguez Díaz,Walter Randazzo,Gloria Sanchez,Carlos Muñoz,Javier Buesa

doi:10.3390/microorganisms8030458

Cristina Santiso-Bellón, Alba Pérez-Cataluña + Show 7 more

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https://doi.org/10.3390/microorganisms8030458

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Abstract

The aim of the present study was to perform the molecular epidemiology of rotaviruses and noroviruses detected in sewage samples from a large wastewater facility from the city of Valencia, Spain. A total of 46 sewage samples were collected over a one-year period (September 2016 to September 2017). Norovirus and rotavirus were detected and quantified by RT-qPCR, genotyped by semi-nested RT-PCR and further characterized by sequencing and phylogenetic analyses. Noroviruses and rotaviruses were widely distributed in sewage samples (69.6% for norovirus GI, 76.0% norovirus GII, and 71.7% rotaviruses) and viral loads varied from 4.33 to 5.75 log PCRU/L for norovirus GI, 4.69 to 6.95 log PCRU/L for norovirus GII, and 4.08 to 6.92 log PCRU/L for rotavirus. Overall, 87.5% (28/32) of GI noroviruses could not be genotyped, 6.25% (2/32) of the samples contained GI.2 genotype, and another 6.25% (2/32) were positive for GI.4 genotype. The most common genotype of GII noroviruses was GII.2 (40%, 14/35), followed by GII.6 (8.6%, 3/35) and GII.17 (5.7%, 2/35) while the remaining GII strains could not be typed (45.7%, 16/35). Rotavirus VP4 genotype P[8] was the only one found in 19 out of 33 rotavirus-positive samples (57.7%). G2 was the most prevalent rotavirus VP7 genotype (15.2%, 5/33) followed by G3, G9, and G12, with two positive samples for each genotype (6.1%, 2/33). In one sample both G1 and G2 genotypes were detected simultaneously (3%). The results presented here show that the surveillance of noroviruses and rotaviruses in sewage is useful for the study of their transmission in the population and their molecular epidemiology.

Highlights

Diarrheal disease is the second cause of death in children under five years of age worldwide, producing around 525,000 deaths, with rotavirus and norovirus being responsible for the majority of the cases of non-bacterial acute gastroenteritis [1]
The aim of the present study was to perform the molecular epidemiology of rotaviruses and noroviruses detected in sewage samples from a large wastewater facility from the city of Valencia, Spain
Noroviruses and rotaviruses were widely distributed in sewage samples (69.6% for norovirus GI, 76.0% norovirus GII, and 71.7% rotaviruses) and viral loads varied from 4.33 to 5.75 log PCR unit (PCRU)/L for norovirus GI, 4.69 to 6.95 log PCRU/L for norovirus GII, and 4.08 to 6.92 log PCRU/L for rotavirus

Summary

Introduction

Diarrheal disease is the second cause of death in children under five years of age worldwide, producing around 525,000 deaths, with rotavirus and norovirus being responsible for the majority of the cases of non-bacterial acute gastroenteritis [1]. Norovirus is the leading cause of sporadic cases and outbreaks of acute gastroenteritis in children and adults [2,3], while rotavirus mainly causes disease in neonates and children under 5 years of age. Noroviruses are the main cause of foodborne gastroenteritis outbreaks with an estimate of 120 million cases in 2010 [7]. Most of the human isolates belong to genogroups GI and GII that are further subdivided in 36 genotypes (GI., GII., and GII. has been withdrawn) [9]. The VP1 protein can be divided in two regions, the shell (S) domain and the protruding (P) domain [12]

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