Hepatitis E virus in central Argentina: Centralized and decentralized wastewater-based epidemiology as a complementary tool to clinical surveillance

FANTILLI A; GUADALUPE DI COLA, GONZALO CASTRO, PAOLA SICILIA, ARIANA MARIELA CACHI, MARÍA DE LOS ÁNGELES MARINZALDA, GUSTAVO IBARRA, LAURA LÓPE, CELINA VALDUVINO, GABRIELA BARBÁS, SILVIA NATES, GISELA MASACHESSI, MARÍA BELÉN PISANO, ; RÉ V.

Londres

Simposio; 2nd International HEV Symposium, IVI ? International Vaccine Institute; 2023

Background and aimsIt is believed that HEV infection is underestimated in Argentina. Although it is a notifiable disease, there is still a lack of updated epidemiological data. Wastewater-based epidemiology (WBE) allows effective surveillance to track information on trends of enteric viral circulation. This study aimed to perform molecular detection and genetic characterization of HEV over a 6-year-period in wastewater, and to correlate the results with those obtained from clinical surveillance.Methods From January-2017 to July-2022, 1049 raw wastewater samples from Córdoba, the second most populous province in Argentina, were collected with different sampling frequencies from wastewater treatment plants in four cities: Córdoba (BG-WWTP), Carlos Paz (CA-WWTP), La Falda (LF-WWTP) and Valle Hermoso (VH-WWTP) (n=499). Moreover, 7 local neighborhood collector sewers from the city of Córdoba were also included (n=550) (Fig.1). Besides, the number of hepatitis E (HE) cases reported to the official notification system of Córdoba province during 2017-2022 was consulted. Sewage samples were concentrated, and HEV molecular detection and quantification was performed by real time RT-qPCR, and genetic characterization by RT-Nested PCR (targeting two genomic regions: ORF-2 and ORF-1), Sanger sequencing and phylogenetic analysis. ResultsRNA-HEV was detected in sewage samples throughout the entire period studied. The overall HEV detection rate in BG-WWTP, in the capital city of Córdoba, was 15.3% (40/261), ranging from 0% to 22.6% according to the year. Overall, RNA-HEV detection rates in local neighborhoods were: 4,4% (15/341) in 2021 and 1,9% (4/209) in 2022. There was only one case of HE reported in this city: a patient with acute‑on‑chronic liver failure due to HEV in 2020, whose sample was analyzed at the laboratory. The overall RNA-HEV detection rates in the other 3 cities were: 2.9% (4/136) in CA-WWTP, 3.8% (2/52) in LF-WWTP, and 0% (0/50) in VH-WWTP. There were no reports of HE cases in these locations.Out of all the RNA-HEV+ samples, 7 and 13 sequences were obtained from the ORF-2 and ORF-1 genomic regions respectively. Viral loads varied between