Tag: UV

Forcing Seasonality of influenza-like epidemics with daily Solar resonance

Publication date: 13/07/2020 – E&P Code: repo.epiprev.it/1923
Authors: Fabrizio Nicastro1, Giorgia Sironi2, Elio Antonello2, Andrea Bianco2, Mara Biasin3, John R. Brucato4, Ilaria Ermolli1, Giovanni Pareschi2, Marta Salvati5, Paolo Tozzi4, Daria Trabattoni3, Mario Clerici6

Abstract: Seasonality of acute viral respiratory diseases is a well-known and yet not fully understood phenomenon. Several models have been proposed to explain the regularity of yearly recurring outbreaks and the phase-differences observed at different latitudes on Earth. Such models take into account known internal causes, primarily the periodic emergence of new virus variants that evade the host immune response. Yet, this alone, is generally unable to explain the regularity of recurrences and the observed phase-differences. Here we show that seasonality of viral respiratory diseases, as well as its distribution with latitude on Earth, can be fully explained by the virucidal properties of UV-B and A Solar photons through a daily, minute-scale, resonant forcing mechanism. Such an induced periodicity can last, virtually unperturbed, from tens to hundreds of cycles, and even in presence of internal dynamics (host’s loss of immunity) much slower than seasonal will, on a long period, generate seasonal oscillations.

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UV-C irradiation is highly effective in inactivating and inhibiting SARS-CoV-2 replication

Publication date: 08/06/2020 – E&P Code: repo.epiprev.it/1750
Authors: Andrea Bianco1, Mara Biasin2, Giovanni Pareschi1, Adalberto Cavalieri3, Claudia Cavatorta3, Claudio Fenizia2, Paola Galli1, Luigi Lessio4 , Manuela Lualdi3, Edoardo Redaelli1, Irma Saulle2,5, Daria Trabattoni2, Alessio Zanutta1, Mario Clerici5,6

Abstract: The potential virucidal effects of UV-C irradiation on SARS-CoV-2 were experimentally evaluated for different illumination doses and virus concentrations (1000, 5, 0.05 MOI). Both virus inactivation and replication inhibition were investigated as a function of these parameters. At a virus density comparable to that observed in SARS-CoV-2 infection, an UV-C dose of just 3.7 mJ/cm2 was sufficient to achieve a 3 log inactivation, and complete inhibition of all viral concentrations was observed with 16.9 mJ/cm2. These results could explain the epidemiological trends of COVID-19 and are important for the development of novel sterilizing methods to contain SARS-CoV-2 infection.

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Modulation of COVID19 Epidemiology by UV-B and -A Photons from the Sun

Publication date: 08/06/2020 – E&P Code: repo.epiprev.it/1746
Authors: Fabrizio Nicastro1, Giorgia Sironi2, Elio Antonello2, Andrea Bianco2, Mara Biasin3, John R. Brucato4, Ilaria Ermolli1, Giovanni Pareschi2, Marta Salvati5, Paolo Tozzi4, Daria Trabattoni3, Mario Clerici6

Abstract: It is well known that 200-290 nm ultraviolet photons (hereinafter UV-C radiation) photo-chemically interacts with DNA and RNA and are endowed with germicidal properties that are also effective on viruses (1-8). Fortunately, Solar UV-C photons of this wavelength are filtered out by the Ozone layer of the upper Atmosphere, at around 35 km (9). Softer UV photons from the Sun with wavelengths in the range 290-320 nm (UV-B) and 320-400 nm (UV-A), however, do reach the Earth’s surface. The effect of these photons on Single- and Double-Stranded RNA/DNA viruses (9-12) and the possible role they play on the seasonality of epidemics (13), are nevertheless little studied and highly debated in alternative or complementarity to other environmental causes (14-20). Notably though, the effects of both direct and indirect radiation from the Sun needs to be considered in order to completely explain the effects of UV radiations in life processes (with e.g. the UV virucidal effect enhanced in combination to the concomitant process of water droplets depletion because of Solar heat). Herein we present a number of concurring circumstantial evidence suggesting that the evolution and strength of the recent Severe Acute Respiratory Syndrome (SARS-Cov-2) pandemics (21, 22), might be have been modulated by the intensity of UV-B and UV-A Solar radiation hitting different regions of Earth during the diffusion of the outbreak between January and May 2020. Out findings, if confirmed by more in depth data analysis and modeling of the epidemics, which includes Solar modulation, could help in designing the social behaviors to be adopted depending on season and environmental conditions.

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Applicazione di tecnologia “no-touch” UV a luce pulsata Xeno per il contrasto alla trasmissione nosocomiale della COVID-19 (Protocollo: NoTouch-XenoLuxCOVID19)

Publication date: 29/05/2020 – E&P Code: repo.epiprev.it/1713
Authors: Domenico Martinelli1, Giovanni Villone1, Francesca Fortunato1, Maria Angela Ioakim1, Alessandra Cozza1, Rosa Prato1, Vitangelo Dattoli1

Abstract: Nella storia naturale della pandemia di COVID-19 è apparso da subito evidente il ruolo di cluster nosocomiali nell’amplificazione di eventi epidemici a livello locale. In questo scenario, le pratiche essenziali dei Programmi di Prevenzione e Controllo delle Infezioni (IPC) rivestono un’importanza cruciale per garantire il funzionamento dei servizi assistenziali e mitigare il carico di malattia nei gruppi di popolazione più a rischio. Uno degli interventi raccomandati è rappresentato dal contenimento della carica microbica a livello ambientale, al quale, oggi, possono contribuire in modo rilevante innovative tecniche di sanificazione. In particolare, i sistemi “no-touch” (automatizzati) a luce UV pulsata allo Xeno (PX-UV) si sono rivelati, a livello sperimentale, efficaci contro la contaminazione dell’aria e di diverse superfici da parte di microrganismi multifarmaco-resistenti, micobatteri e virus. In un’esperienza di campo condotta per alcuni mesi del 2019 in un quartiere operatorio ad elevata complessità dell’Azienda Ospedaliero Universitaria Policlinico Riuniti di Foggia, interventi di sanificazione PX-UV eseguiti ad intervalli predefiniti hanno mostrato un importante abbattimento della carica microbica pre-sanitizzazione finale.

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