RESUMO
Cattle have a significant impact on human societies in terms of both economics and health. Viral infections pose a relevant problem as they directly or indirectly disrupt the balance within cattle populations. This has negative consequences at the economic level for producers and territories, and also jeopardizes human health through the transmission of zoonotic diseases that can escalate into outbreaks or pandemics. To establish prevention strategies and control measures at various levels (animal, farm, region, or global), it is crucial to identify the viral agents present in animals. Various techniques, including virus isolation, serological tests, and molecular techniques like PCR, are typically employed for this purpose. However, these techniques have two major drawbacks: they are ineffective for non-culturable viruses, and they only detect a small fraction of the viruses present. In contrast, metagenomics offers a promising approach by providing a comprehensive and unbiased analysis for detecting all viruses in a given sample. It has the potential to identify rare or novel infectious agents promptly and establish a baseline of healthy animals. Nevertheless, the routine application of viral metagenomics for epidemiological surveillance and diagnostics faces challenges related to socioeconomic variables, such as resource availability and space dedicated to metagenomics, as well as the lack of standardized protocols and resulting heterogeneity in presenting results. This review aims to provide an overview of the current knowledge and prospects for using viral metagenomics to detect and identify viruses in cattle raised for livestock, while discussing the epidemiological and clinical implications.
RESUMO
Livestock plays a crucial role in ensuring food security and driving the global economy. However, viral infections can have far-reaching consequences beyond economic productivity, affecting the health of cattle, as well as posing risks to human health and other animals. Identifying viruses present in fecal samples, a primary route of pathogen transmission, is essential for developing effective prevention, control, and surveillance strategies. Viral metagenomic approaches offer a broader perspective and hold great potential for detecting previously unknown viruses or uncovering previously undescribed agents. Ubaté Province is Colombia's dairy capital and a key center for livestock production in the country. Therefore, the purpose of this study was to characterize viral communities in fecal samples from cattle in this region. A total of 42 samples were collected from three municipalities in Ubaté Province, located in central Colombia, using a convenient non-probabilistic sampling method. We utilized metagenomic sequencing with Oxford Nanopore Technologies (ONT), combined with diversity and phylogenetic analysis. The findings revealed a consistent and stable viral composition across the municipalities, primarily comprising members of the Picornaviridae family. At the species level, the most frequent viruses were Enterovirus E (EVE) and Bovine Astrovirus (BoAstV). Significantly, this study reported, for the first time in Colombia, the presence of viruses with veterinary importance occurring at notable frequencies: EVE (59%), Bovine Kobuvirus (BKV) (52%), and BoAstV (19%). Additionally, the study confirmed the existence of Circular replicase-encoding single-stranded (CRESS) Virus in animal feces. These sequences were phylogenetically grouped with samples obtained from Asia and Latin America, underscoring the importance of having adequate representation across the continent. The virome of bovine feces in Ubaté Province is characterized by the predominance of potentially pathogenic viruses such as BoAstV and EVE that have been reported with substantial frequency and quantities. Several of these viruses were identified in Colombia for the first time. This study showcases the utility of using metagenomic sequencing techniques in epidemiological surveillance. It also paves the way for further research on the influence of these agents on bovine health and their frecuency across the country.
