High Prevalence of Rotavirus A in Raw Sewage Samples from Northeast Spain

Abstract

Rotavirus A (RVA) is the most common virus associated with infantile gastroenteritisworldwide, being a public health threat, as it is excreted in large amounts in stool and can persist inthe environment for extended periods. In this study, we performed the detection of RVA and humanadenovirus (HAdV) by TaqMan qPCR and assessed the circulation of RVA genotypes in threewastewater treatment plants (WWTPs) between 2015 and 2016 in Catalonia, Spain. RVA wasdetected in 90% and HAdV in 100% of the WWTP samples, with viral loads ranging between 3.96 ×104 and 3.30 × 108 RT-PCR Units/L and 9.51 × 104 and 1.16 × 106 genomic copies/L, respectively. RVAVP7 and VP4 gene analysis revealed the circulation of G2, G3, G9, G12, P[4], P[8], P[9] and P[10].Nucleotide sequencing (VP6 fragment) showed the circulation of I1 and I2 genotypes, commonlyassociated with human, bovine and porcine strains. It is important to mention that the RVA strainsisolated from the WWTPs were different from those recovered from piglets and calves living in thesame area of single sampling in 2016. These data highlight the importance of monitoring watermatrices for RVA epidemiology and may be a useful tool to evaluate and predict possibleemergence/reemergence of uncommon strains in a region.

Keywords: molecular characterization; rotavirus A; viral quantification; wastewater.

Figure 1

Correlation analysis between human adenovirus (HAdV) and rotavirus A (RVA) circulation in Catalonia. HAdV and RVA were detected and viral loads were estimated through qPCR (HAdV) and RT-qPCR (RVA) analysis of 42 mL raw sewage samples. The correlation analysis was performed using R software package.

Figure 2

Human adenovirus (HAdV) and rotavirus A (RVA) circulation in raw sewage samples by season. Seasonal distribution of HAdV and RVA detected by qPCR and RT-qPCR, respectively, in raw sewage samples collected between spring 2015 and spring 2016 in Catalonia.

Figure 3

Phylogenetic analysis of the rotavirus A (RVA) VP6 gene from raw sewage and animal samples. The raw sewage samples from the present study are indicated with a black dot followed by month, year and wastewater treatment plant of collection. Samples recovered from animals are indicated with white diamonds.