Identification of Pulmonary Infections With Porcine Rotavirus A in Pigs With Respiratory Disease

Assessing environmental exposure to viruses in wastewater treatment plant and swine farm scenarios with next-generation sequencing and occupational risk approaches

Occupational exposure to pathogens can pose health risks. This study investigates the viral exposure of workers in a wastewater treatment plant (WWTP) and a swine farm by analyzing aerosol and surfaces samples. Viral contamination was evaluated using quantitative polymerase chain reaction (qPCR) assays, and target enrichment sequencing (TES) was performed to identify the vertebrate viruses to which workers might be exposed. Additionally, Quantitative Microbial Risk Assessment (QMRA) was conducted to estimate the occupational risk associated with viral exposure for WWTP workers, choosing Human Adenovirus (HAdV) as the reference pathogen. In the swine farm, QMRA was performed as an extrapolation, considering a hypothetical zoonotic virus with characteristics similar to Porcine Adenovirus (PAdV). The modelled exposure routes included aerosol inhalation and oral ingestion through contaminated surfaces and hand-to-mouth contact. HAdV and PAdV were widespread viruses in the WWTP and the swine farm, respectively, by qPCR assays. TES identified human and other vertebrate viruses WWTP samples, including viruses from families such as Adenoviridae, Circoviridae, Orthoherpesviridae, Papillomaviridae, and Parvoviridae. In the swine farm, most of the identified vertebrate viruses were porcine viruses belonging to Adenoviridae, Astroviridae, Circoviridae, Herpesviridae, Papillomaviridae, Parvoviridae, Picornaviridae, and Retroviridae. QMRA analysis revealed noteworthy risks of viral infections for WWTP workers if safety measures are not taken. The probability of illness due to HAdV inhalation was higher in summer compared to winter, while the greatest risk from oral ingestion was observed in workspaces during winter. Swine farm QMRA simulation suggested a potential occupational risk in the case of exposure to a hypothetical zoonotic virus. This study provides valuable insights into WWTP and swine farm worker's occupational exposure to human and other vertebrate viruses. QMRA and NGS analyses conducted in this study will assist managers in making evidence-based decisions, facilitating the implementation of protection measures, and risk mitigation practices for workers.

Identification of a Novel Astrovirus Associated with Bovine Respiratory Disease

Astroviruses (AstVs) cause gastrointestinal disease in mammals and avians. Emerging evidence suggests that some AstVs have extraintestinal tissue tropism, with AstVs detected in the liver, kidney, central nervous system, and the respiratory tract variably associated with disease. In cattle, AstV infection has been linked to gastroenteric or neurologic disease. Here, metagenomic sequencing of a lung from a bovine with respiratory disease identified a novel AstV with a predicted capsid-encoding ORF2 amino acid sequence with 66% identity to caprine astrovirus (CAstV G2.1). A quantitative reverse transcription PCR (qRT-PCR) targeting ORF2 found four out of 49 (8%) lungs and one out of 48 (2%) enteric samples obtained from bovine diagnostic submissions positive for the novel bovine astrovirus (BAstV). In two strongly qRT-PCR-positive lung samples, intense novel BAstV nucleic acid signals were mainly localized in the cytoplasm of alveolar macrophages and mononuclear cells using RNAscope® in situ hybridization (ISH). Genetic analysis of two novel BAstV genomes determined from qRT-PCR positive samples found high similarity for ORF1ab nucleotide sequence (92.1% and 93.9%) to BAstV strain BSRI-1, while ORF2 nucleotide sequence was most similar to CAstV G2.1 (74.6% and 77.6%). Phylogenetic analysis of the novel BAstV sequences found a close genetic relationship to the single BAstV (BSRI-1) previously identified from a bovine respiratory sample as well as bovine and caprine AstVs identified from various tissues. Further research is needed to determine the clinical significance of BAstV in respiratory diseases.