Saliva has emerged as a promising diagnostic fluid for viral infections, enabling the direct analysis of viral genetic material and the detection of infection markers such as proteins, metabolites, microRNAs, and immunoglobulins. This comprehensive review aimed to explore the use of saliva as a diagnostic tool for viral infections, emphasizing its advantages and limitations. Saliva stands out due to its simplicity and safety in collection, along with the convenience of self-collection without the need for healthcare supervision, while potentially being comparable to urine and blood in terms of effectiveness. Herein, we highlighted the significant potential of saliva in assessing viral loads and diagnosing viral infections, such as herpesviruses, HPV, PyV, TTV, SARS-CoV-2, and MPXV. The detection of viral shedding in saliva underscores its utility in early diagnosis, the monitoring of infection progression, and evaluating treatment responses. The non-invasive nature of saliva collection makes it an appealing alternative to more invasive methods, promoting better patient compliance and facilitating large-scale screening and surveillance. As such, we further highlight current evidence on the use of saliva as a prognostic tool. Although a significant amount of data is already available, further investigations are warranted to more comprehensively assess the added benefit from the utilization of salivary biomarkers in the clinics. Salivary biomarkers show great promise for the early detection and prevention of viral infection complications, potentially improving disease management and control at the population level. Integrating these non-invasive tools into routine clinical practice could enhance personalized healthcare strategies and patient outcomes. Future studies should focus on establishing standardization protocols, validating the accuracy of salivary diagnostics, and expanding clinical research to enhance the diagnostic and monitoring capabilities of salivary biomarkers.

Background: Torque teno virus (TTV) is not known to cause disease in humans; however, chronic inflammatory conditions and immunosuppression states can favour TTV replication. This study aimed to verify the effectiveness of TTV as an immune biomarker.Methods: The protocol of this review was registered in PROSPERO (CRD42022331049) and performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines.Results: Thirty‐three articles were selected and different groups of patients were assessed. In the solid organ and hematopoietic stem cell transplant groups, most studies reported that TTV viral load (VL) was highly detectable after transplantation and compared to controls, but the association with immune parameters showed conflicting results. In melanoma patients, no statistical difference in TTV VL was identified between susceptible and treatment‐resistant patients. In lung cancer patients, viral load increases significantly with disease progression but decreases after chemotherapy. HIV‐positive patients showed a higher VL than controls, but an inverse correlation with CD4+ was observed in half of the studies. Although 57.14% of all studies presented a low risk of bias, significant differences were observed between studies, particularly in the choice of the analyzed outcome, the parameter used to evaluate the patient's immune status, the presence of a control group, and the sample collection time points.Conclusions: Although TTV seems to have the potential to be a promising biomarker of immunosuppression, further high‐quality prospective clinical studies are still needed.

Background. Torquetenovirus (TTV) is a small DNA virus constituting the human virome. High levels of TTV-DNA have been shown to be associated with immunosuppression and inflammatory chronic disorders. Aim. To assess the possible association between the salivary viral load of TTV-DNA in patients hospitalised due to COVID-19 and disease severity. Methods. Saliva samples collected from 176 patients infected with SARS-CoV-2 were used to investigate the presence of SARS-CoV-2 and TTV-DNA by use of real-time RT-PCR. Results. The majority of patients were male with severe COVID-19. Presence of SARS-CoV-2 was observed in the saliva of 64.77% of patients, showing TTV-DNA in 55.68% of them. Patients with impaired clinical conditions (p < 0.001), which evolved to death (p = 0.003), showed a higher prevalence of TTV-DNA. The median viral load in patients with severe condition was 4.99 log₁₀ copies/mL, in which those who were discharged and those evolving to death had values of 3.96 log₁₀ copies/mL and 6.27 log₁₀ copies/mL, respectively. A statistically significant association was found between the distribution of TTV-DNA viral load in saliva samples and severity of COVID-19 (p = 0.004) and disease outcomes (p < 0.001). Conclusions. These results indicate that TTV-DNA in saliva could be a useful biomarker of COVID-19 severity and prognosis.

The aim of this study was to evaluate the effect of X radiation in single and fractionated doses in tibias of rats by micro-computer tomography (µCT) analysis. The sample was consisted by 20 male rats, divided into 3 groups: Control, Single dose and Fractionated dose. The rats were submitted to a radiation X exposure on lower limbs. The single dose group was exposed to single radiation of 15 gray (Gy), while the fractionated group was submitted to three irradiation sessions of 5 Gy each, totaling 15 Gy. After 24 hours and 25 days, the rats were euthanized; the tibias were removed and scanned using a µCT unit, SkyScan 1174 Compact Micro-CT (Kontich, Bélgica). The parameters total bone area (Tt.Ar) , cortical bone area (Ct.Ar) , total cross-sectional bone area ratio (Ct.Ar / Tt.Ar) e cortical thickness (Ct.Th) for cortical bone, e bone volume ratio (BV / TV), trabecular number (Tb.N), trabecular thickness (Tb.Th) e trabecular separation (Tb.Sp), for trabecular bone analysis were evaluated. Data were submitted to one-way ANOVA and Tukey’s test (α = 0.05). The µCT evaluation showed significant differences on Tt.Ar and Tb.Sp parameters (p<0,05). It was observed a lower Tt.Ar in the fractionated group compared to control, and higher Tb.Sp in the group receiving a single dose when compared to the control and fractionated groups. It is concluded, in relation to bone microarchitecture, that the radiation X in fractionated doses presents more deleterious effects on the cortical bone and when in singe doses, more damage on trabecular spaces, leading to a higher porosity.