EPIDEMIOLOGICAL AND MOLECULAR SURVEILLANCE OF ROTAVIRUS STRAINS IN ANIMALS IN THE CONTEXT OF ONE HEALTH: INTERSPECIES TRANSMISSION, EVOLUTION AND IMPACT ON VACCINE EFFICACY

• Grant number: 25/11692-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: January 01, 2026
• End date: December 31, 2028
• Field of knowledge: Health Sciences - Collective Health - Public Health
• Principal Investigator: Adriana Luchs
• Grantee: Leonardo Cecílio da Rocha
• Host Institution: Instituto Adolfo Lutz (IAL). São Paulo , SP, Brazil

Abstract

Acute gastroenteritis is a significant public health issue, especially among children, with group A rotavirus (RVA) being the leading viral cause of the disease in children under five. In addition to humans, RVA also affects various animal species, causing diarrhea with considerable economic impact. Its segmented genome promotes genetic diversity through reassortment and interspecies transmission, potentially leading to the emergence of novel viral variants. Animals serve as important reservoirs of RVA genetic diversity, and close contact between humans and animals increases the risk of zoonotic infections. The introduction of the Rotarix¿ vaccine in Brazil led to a substantial reduction in RVA infections in humans; however, it may also exert selective pressure on circulating atypical strains. Coinfections between human and animal strains can give rise to hybrid viruses, as observed in the equine-like G3P[8] and bovine-like G8P[8] DS-1-like variants, which emerged through interspecies reassortment and spread globally, including in Brazil. These variants raise concerns about the effectiveness of current vaccines, as selective pressure may favor the emergence of immune escape genotypes. In this context, animal-derived strains emerge as potential sources of new introductions into the human host, underscoring the importance of integrated human-animal surveillance. However, genotypic surveillance in animals in Brazil remains limited. This study aims to detect and molecularly characterize RVA strains in fecal samples from wild (capybaras), livestock (pigs), and companion animals (dogs and cats), through phylogenetic analysis of the virus's 11 genomic segments. The investigation seeks to understand the genetic relationship between human and animal strains, clarify the role of animals as reservoirs, and contribute to the strengthening of surveillance and control strategies aligned with the One Health approach. A total of 1,131 fecal samples will be analyzed: 517 from dogs, 84 from cats, 338 from capybaras, and 192 from pigs. Dog and cat samples were collected between 2012 and 2021 from veterinary clinics in the municipalities of São Paulo, Guarulhos, Mogi das Cruzes, Osasco, Barueri, and Jundiaí (São Paulo state). Capybara samples were collected between 2018 and 2020 from four urban parks in two municipalities in São Paulo state: Yacht Club Santo Amaro and Novo Rio Pinheiros bike path (southern São Paulo city), Tietê Ecological Park (eastern São Paulo city), and Municipal Reservoir Park (São José do Rio Preto). Pig samples were collected between 2013 and 2025 from small farms in Mogi das Cruzes and Engenheiro Marsilac (São Paulo) and in Itapejara d'Oeste (Paraná). The first stage of the study will involve standardizing an RT-qPCR technique for RVA detection in animal feces. Once standardized, samples will be screened by RT-qPCR, and positives will undergo polyacrylamide gel electrophoresis (PAGE), conventional RT-PCR amplification, and sequencing. Molecular characterization will include defining the complete genomic constellation, performing phylogenetic analyses, and assessing VP7 and VP8* epitope variability compared to vaccine and currently circulating human strains. The viability and infectious potential of detected strains will also be evaluated through cell culture. Despite the proven effectiveness of vaccination in reducing RVA-related morbidity and mortality, genomic surveillance is essential to ensure the continued efficacy of immunization strategies. Considering that most emerging infectious diseases are of zoonotic origin, monitoring viral diversity in animals and their interactions with humans is crucial for public health. The findings from this study will contribute to understanding RVA genetic diversity across animal species, the potential for interspecies transmission, and strengthening integrated surveillance strategies in line with the One Health concept.