Previous studies have demonstrated that SARS-CoV-2 is stable on surfaces for extended periods under indoor conditions. In the present study, simulated sunlight rapidly inactivated SARS-CoV-2 suspended in either simulated saliva or culture media and dried on stainless steel coupons. Ninety percent of infectious virus was inactivated every 6.8 minutes in simulated saliva and every 14.3 minutes in culture media when exposed to simulated sunlight representative of the summer solstice at 40°N latitude at sea level on a clear day. Significant inactivation also occurred, albeit at a slower rate, under lower simulated sunlight levels. The present study provides the first evidence that sunlight may rapidly inactivate SARS-CoV-2 on surfaces, suggesting that persistence, and subsequently exposure risk, may vary significantly between indoor and outdoor environments. Additionally, these data indicate that natural sunlight may be effective as a disinfectant for contaminated nonporous materials.

To date, 12 distinct filoviruses have been described 1. The seven filoviruses that have been found in humans belong either to the genus Ebolavirus (Bundibugyo virus (BDBV), Ebola virus (EBOV), Reston virus (RESTV), Sudan virus (SUDV) and Taï Forest virus (TAFV); Fig. 1) or to the genus Marburgvirus (Marburg virus (MARV) and Ravn virus (RAVV)) 2. The WHO International Classification of Diseases Revision 11 (ICD-11) of 2018 recognizes two major subcategories of filovirus disease (FVD): Ebola disease caused by BDBV, EBOV, SUDV or TAFV, and Marburg disease caused by MARV or RAVV. Ebola virus disease (EVD) is defined as a disease only caused by EBOV. This subcategorization of FVD is largely based on the increasing evidence of molecular differences between ebolaviruses and marburgviruses, differences that may influence virus-host reservoir tropism, pathogenesis and disease phenotype in accidental primate hosts 2. Since the discovery of filoviruses in 1967 (reF. 3), 43 FVD outbreaks (excluding at least five laboratoryacquired infections) have been recorded in or exported from Africa 4. The epidemiological definition of outbreak is one or more cases above the known endemic prevalence. For example, the single case of TAFV infection recorded in a setting in which FVD had never been reported before (Côte d'Ivoire) 5 is still considered an outbreak. All FVD outbreaks, with the exception of that caused by TAFV, were characterized by extremely high case-fatality rates (CFRs, also known as lethality). Until 2013, the most extensive outbreak, caused by SUDV, involved 425 cases and 224 deaths (CFR 52.7%) 6. The overall limited numbers of FVD cases (1967-2013: 2,886 cases including 1,982 deaths 4), the typical remote and rural locations of outbreaks and the often delayed announcement of new outbreaks to the international community 7 have prevented the systematic study of clinical FVD in humans. Thus, the commonly used description of FVD was derived either from observation of small groups of patients in care settings that were not well-equipped for diagnosis, treatment and disease characterization, or from observations of even smaller samples, such as individuals who were transferred from Equatorial Africa to Europe and the USA or who fell sick in Europe or the USA after contracting the virus elsewhere. Pathological characterization of FVD via autopsies has been rare 7,8. In the absence of extensive human clinical data, FVD could only be defined further via the use of experimental animal infections 9,10 .

Replication-competent recombinant vesicular stomatitis viruses (rVSVs) expressing the type I transmembrane glycoproteins and selected soluble glycoproteins of several viral hemorrhagic fever agents (Marburg virus, Ebola virus, and Lassa virus) were generated and characterized. All recombinant viruses exhibited rhabdovirus morphology and replicated cytolytically in tissue culture. Unlike the rVSVs with an additional transcription unit expressing the soluble glycoproteins, the viruses carrying the foreign transmembrane glycoproteins in replacement of the VSV glycoprotein were slightly attenuated in growth. Biosynthesis and processing of the foreign glycoproteins were authentic, and the cell tropism was defined by the transmembrane glycoprotein. None of the rVSVs displayed pathogenic potential in animals. The rVSV expressing the Zaire Ebola virus transmembrane glycoprotein mediated protection in mice against a lethal Zaire Ebola virus challenge. Our data suggest that the recombinant VSV can be used to study the role of the viral glycoproteins in virus replication, immune response, and pathogenesis.

In 2016, the order Mononegavirales was emended through the addition of two new families (Mymonaviridae and Sunviridae), the elevation of the paramyxoviral subfamily Pneumovirinae to family status (Pneumoviridae), the addition of five free-floating genera (Anphevirus, Arlivirus, Chengtivirus, Crustavirus, and Wastrivirus), and several other changes at the genus and species levels. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).