Viral landscape in saliva: Polyomavirus and Herpesvirus detection in HIV-positive and HIV-negative

Background: Saliva is a non-invasive way to study oral viruses, but we lack specific data on Human Polyomaviruses (HPyVs) and Herpesviruses (HHVs) in HIV-positive patients. Currently, the co-infection patterns and viral loads in this population are not well understood compared to healthy individuals. Our study fills this gap by analyzing these viral profiles and microRNAs in saliva. This work helps establish saliva as a dependable diagnostic method for these infections. Methods: A cross-sectional study assessed the prevalence of six Human Polyomaviruses (HPyVs) and five Human Herpesviruses (HHVs) in saliva samples collected from two cohorts: 20 HIV-positive individuals undergoing antiretroviral therapy (ART) and 37 HIV-negative subjects. Molecular analyses were performed using quantitative PCR (Q-PCR), with absolute quantification of viral loads and detection of JCPyV and MCPyV microRNAs (miRNAs). Results: The results showed higher overall prevalence of HPyVs (60 % vs. 32.4 %) and HHVs (75 % vs. 51.3 %) in the HIV-positive group compared to the HIV-negative group. MCPyV and EBV were the most frequently detected viruses in both cohorts, but their mean loads were significantly higher in the HIV-positive group. Viral co-infections were more common among HIV-positive individuals (40.0 % vs. 32.4 %), with a predominance of HPyV/HHV co-infections. Notably, HPyV miRNAs were detected also in samples negative for the corresponding viral genomes. Conclusion: Our findings confirm saliva's utility for detecting viral co-infections and highlight the need to determine if oral HPyVs and HHVs act as bystanders or pathogens in HIV-positive patients.