Background: The burden of COVID-19 was extremely severe in Northern Italy, an area characterized by high concentrations of particulate matter (PM), which is known to negatively affect human health. Consistently with evidence already available for other viruses, we initially hypothesized the possibility of SARS-CoV-2 presence on PM, and we performed a first experiment specifically aimed at confirming or excluding this research hyphotesys. Methods: We have collected 34 PM10 samples in Bergamo area (the epicenter of the Italian COVID-19 epidemic) by using two air samplers over a continuous 3-weeks period. Filters were properly stored and underwent RNA extraction and amplification according to WHO protocols in two parallel blind analyses performed by two different authorized laboratories. Up to three highly specific molecular marker genes (E, N, and RdRP) were used to test the presence of SARS-CoV-2 RNA on particulate matter. Results: The first test showed positive results for gene E in 15 out of 16 samples, simultaneously displaying positivity also for RdRP gene in 4 samples. The second blind test got 5 additional positive results for at least one of the three marker genes. Overall, we tested 34 RNA extractions for the E, N and RdRP genes, reporting 20 positive results for at least one of the three marker genes, with positivity separately confirmed for all the three markers. Control tests to exclude false positivities were successfully accomplished. Conclusion: This is the first evidence that SARS-CoV-2 RNA can be present on PM, thus suggesting a possible use as indicator of epidemic recurrence.

The study of any intervention able to counteract SARS‐CoV‐2 pandemic is considerably envisaged. It was previously shown, in in vitro models of infections, that the LED blue light is able to decrease the viral load of HSV‐1 and ZIKV. In our study, LED photobiomodulation therapy (PBMT) at blue wavelengths (450, 454 and 470 nm) was tested in an in vitro model of SARS‐CoV‐2 infection, employing three experimental settings: SARS‐CoV‐2 was irradiated and then transferred to cells; already infected cells were irradiated; cells were irradiated prior to infection. A decrement of the viral load was observed when previously infected cells were irradiated with all three tested wavelengths and relevant effects were registered especially at 48 hours post‐infection, possibly suggesting that the blue light could interfere with the intracellular viral replication machinery. Our in vitro findings could represent the starting point for translational applications of PBMT as a supportive approach to fight SARS‐CoV‐2.

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Chlamydia trachomatis and HPV coinfections in the male population are often a disregarded issue. We performed a study to evaluate the prevalence of such infections in heterosexual HIV negative men from a Northern Italy multi-ethnic area at high prevalence for cervical malignancies. Urethral swabs (US) or first-voided urine were evaluated retrospectively from 1317 patients attending Sexually Transmitted Infections (STI) clinic and from 3388 outpatients attending private clinics. Informations about participants' demographic characteristics and attributes of C. trachomatis, including chronic infection, and HPV genotypes testing, were collected. Exact Fisher test, bivariate, and multivariate logistic regressions were carried out. The prevalence of C. trachomatis was 1.7% in the outpatients and 16.9% in the STI group (P < 0.0001) in which the highest frequency was observed in men of age ≤25 years. Among patients with C. trachomatis, asymptomatic HPV co-infection was detected in 33% of men from the STI clinic and in 2% of the outpatients. Out of all coinfections, 56% were due to single HPV, with a prevalence of 73% in young STI men. The distribution of HPV genotypes confirmed the increased circulation of LR-HPV42, HR-HPV51, HR-HPV52 and prHR-HPV82, and the decreasing of HR-HPV16. African nationalities and leucorrhea were significantly associated risk factors, while the regular condom use offered an effective protection. This study highlights the high prevalence of C. trachomatis and HPV asymptomatic co-infection in young HIV negative men attending the STI clinic, representing a reservoir of new HPV genotypes with potential oncogenic risk.

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is mainly transmitted through respiratory droplets from positive subjects to susceptible hosts or by direct contact with an infected individual. Our study focuses on the in vitro minimal time of viral absorption as well as the minimal quantity of virus able to establish a persistent infection in Vero E6 cells. We observed that 1 min of in vitro virus exposure is sufficient to generate a cytopathic effect in cells after 7 days of infection, even at a multiplicity of infection (MOI) value of 0.01. Being aware that our findings have been obtained using an in vitro cellular model, we demonstrated that short-time exposures and low viral concentrations are able to cause infection, thus opening questions about the risk of SARS-CoV-2 transmissibility even following short contact times.