Marcelo Mandile, Universidad Nacional de Quilmes

Mandile, MG(1)(2), Diaz, RV(3), Gigliello, MA(1), Peri Ibáñez, ES(1)(2), Tomás Fariña, J(1)(2), Carzoglio, MC(1)(4), Silvestre, D(1)(2), Temprana CF(1)(2), Argüelles, MH(1), Castello AA(1)(3). (1) Laboratorio de Inmunología y Virología, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes; (2) Consejo Nacional de Investigaciones Científicas y Técnicas; (3) Instituto de Ciencias de la Salud, Universidad Nacional Arturo Jauretche; (4) Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación.

Epidemiology, Evolution, and Diversity

Acute gastroenteritis is a major public health concern, causing approximately 10% of deaths in children under five years old, primarily in low- and middle-income countries. Group A rotaviruses (RVA) are the leading etiological agents. Despite significant reductions in disease burden and mortality following the introduction of vaccines, RVA continues to cause approximately 128,500 annual deaths in young children worldwide as of 2016. Surveillance and strain monitoring are crucial for detecting emerging strains and assessing the impact of the monovalent vaccine, which has been widely used in Argentina since 2015. For nearly 30 years, our laboratory has conducted RVA epidemiological research using samples from hospitals in Buenos Aires City (CABA) and Greater Buenos Aires (GBA). This study analyzes an equine G3 strain detected in patients at Ricardo Gutiérrez Children's Hospital in 2022. Fecal samples underwent RNA extraction, RT-PCR amplification, and sequencing via the Sanger method. Genomic segments were analyzed using NIH's BLASTn online tool to determine genotypes, and phylogenetic trees were constructed using MEGA X. The identified strain corresponds to the equine G3 genotype, associated with P[8], and belongs to genotype constellation 2 (DS-1-like). Phylogenetic analysis revealed links to equine G3 strains from Russia (since 2019) and Brazil (2015–2016). Ongoing RVA surveillance in Buenos Aires enabled us to detect equine G3 strains and determine their phylogenetic relationships. Future research will explore whether their emergence is linked to Rotarix vaccination and trace their introduction into Argentina.