Amoebae: Hiding in Plain Sight: Unappreciated Hosts for the Very Large Viruses.

For decades, viruses have been isolated primarily from humans and other organisms. Interestingly, one of the most complex sides of the virosphere was discovered using free-living amoebae as hosts. The discovery of giant viruses in the early twenty-first century opened a new chapter in the field of virology. Giant viruses are included in the phylum Nucleocytoviricota and harbor large and complex DNA genomes (up to 2.7 Mb) encoding genes never before seen in the virosphere and presenting gigantic particles (up to 1.5 µm). Different amoebae have been used to isolate and characterize a plethora of new viruses with exciting details about novel viral biology. Through distinct isolation techniques and metagenomics, the diversity and complexity of giant viruses have astonished the scientific community. Here, we discuss the latest findings on amoeba viruses and how using these single-celled organisms as hosts has revealed entities that have remained hidden in plain sight for ages.

"Yaraviridae": a proposed new family of viruses infecting Acanthamoeba castellanii.

Here, we propose the creation of the family "Yaraviridae", a new taxon to classify a virus infecting Acanthamoeba castellanii cells. Recently, we described the discovery of a new virus infecting free-living amoebae, yaravirus, which has features that strongly differ from those of all other viruses of amoebae described to date. Yaravirus particles are about 80 nm in diameter and have a dsDNA genome of ~45 kbp containing 74 ORFs, most of which (>90%) have no homologs in current databases. Together, these data support the creation of a new species ("Yaravirus brasiliense"), a new viral genus (here proposed as "Yaravirus"), and a new viral family (here proposed as "Yaraviridae") to classify yaravirus and other related viruses that may be described in the future. All of them are to be included into the existing realm Varidnaviria and the kingdom Bamfordvirae, due to the presence of a major capsid protein containing a double jelly-roll fold.

Detection of SARS-CoV-2 RNA on public surfaces in a densely populated urban area of Brazil: A potential tool for monitoring the circulation of infected patients.

The world is experiencing the worst global health crisis in recent decades since December/2019 due to a new pandemic coronavirus. The COVID-19 disease, caused by SARS-CoV-2, has resulted in more than 30 million cases and 950 thousand deaths worldwide as of September 21, 2020. Determining the extent of the virus on public surfaces is critical for understanding the potential risk of infection in these areas. In this study, we investigated the presence of SARS-CoV-2 RNA on public surfaces in a densely populated urban area in Brazil. Forty-nine of 933 samples tested positive (5.25%) for SARS-CoV-2 RNA, including samples collected from distinct material surfaces, including metal and concrete, and distinct places, mainly around hospital care units and public squares. Our data indicated the contamination of public surfaces by SARS-CoV-2, suggesting the circulation of infected patients and the risk of infection for the population. Constant monitoring of the virus in urban areas is required as a strategy to fight the pandemic and prevent further infections.