Respiratory syncytial virus (RSV) is an important etiological agent of respiratory infection in children for which no specific treatment option is available. The RSV virion contains two surface glycoproteins (F and G) that are vital for the initial phases of infection, making them critical targets for RSV therapeutics. Recent studies have identified the broad-spectrum antiviral properties of silver nanoparticles (AgNPs) against respiratory pathogens, such as adenovirus, parainfluenza, and influenza. AgNPs achieve this by attaching to viral glycoproteins, blocking entry into the host cell. The objective of this study was to evaluate the antiviral and immunomodulatory effects of AgNPs in RSV infection. Herein we demonstrate AgNP-mediated reduction in RSV replication, both in epithelial cell lines and in experimentally infected BALB/c mice. Marked reduction in pro-inflammatory cytokines (i.e., IL-1α, IL-6, TNF-α) and pro-inflammatory chemokines (i.e., CCL2, CCL3, CCL5) was also observed. Conversely, CXCL1, G-CSF, and GM-CSF were increased in RSV-infected mice treated with AgNPs, consistent with an increase of neutrophil recruitment and activation in the lung tissue. Following experimental antibody-dependent depletion of neutrophils, the antiviral effect of AgNPs in mice treated was ablated. To our knowledge, this is the first in vivo report demonstrating antiviral activity of AgNPs during RSV infection.

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Microbiomes have become an increasingly important field of study in the past decade, with data supporting microbial roles in disease control, metabolic efficiency, and more. Microbial DNA is detectable outside the digestive tract, including in blood. Bloodborne pathogens such as hemotrophic Mycoplasma are endemic in cattle. Hemoplasmas are associated with reduced male fertility and decreased milk production in dairy cattle, but their impact on beef cattle remains unclear. Strain variability, such as between the Massachusetts and INFAP01 strains of Mycoplasma wenyonii, may complicate detection. Coinfection with multiple species likely contributes to disease progression from latent to acute infection. To assess microbial DNA in blood and quantify erythrocytic M. wenyonii, blood was collected from 120 beef cattle in Erath County, Texas: 61 cows, 55 calves, and 4 bulls. DNA was extracted and used to prepare 16S rRNA V4 libraries and perform PCR. After rarefaction, ASVs were analyzed and separated into four groups: adult females (n = 61), adult males (n = 4), juvenile males (n = 27), and juvenile females (n = 28). Statistical analysis revealed differences in Actinobacteria by sex (p < 0.001) and higher Bartonella and Mycoplasma abundances in adults (p < 0.001). PCR revealed that M. wenyonii infection was more frequent in adult females (p = 0.006), suggesting age-related variation in infection.