In March 2020, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. At the genus rank, 20 new genera were added, two were deleted, one was moved, and three were renamed. At the species rank, 160 species were added, four were deleted, ten were moved and renamed, and 30 species were renamed. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.

Since the recognition of hantavirus as the agent responsible for haemorrhagic fever in Eurasia in the 1970s and, 20 years later, the descovery of hantavirus pulmonary syndrome in the Americas, the genus Hantavirus has been continually described throughout the World in a variety of wild animals. The diversity of wild animals infected with hantaviruses has only recently come into focus as a result of expanded wildlife studies. The known reservoirs are more than 80, belonging to 51 species of rodents, 7 bats (order Chiroptera) and 20 shrews and moles (order Soricomorpha). More than 80genetically related viruses have been classified within Hantavirus genus; 25 recognized as human pathogens responsible for a large spectrum of diseases in the Old and New World. In Brazil, where the diversity of mammals and especially rodents is considered one of the largest in the world, 9 hantavirus genotypes have been identified in 12 rodent species belonging to the genus Akodon, Calomys, Holochilus, Oligoryzomys, Oxymycterus, Necromys and Rattus. Considering the increasing number of animals that have been implicated as reservoirs of different hantaviruses, the understanding of this diversity is important for evaluating the risk of distinct hantavirus species as human pathogens.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of COVID-19, a pandemic associated with substantial morbidity and mortality. Despite of this, no vaccine or approved drug is available to eradicate the virus. In this manuscript, we present an alternative study area that may contribute to development of diagnostic biomarkers and therapeutic targets for COVID-19. We analyzed sixty SARS-CoV-2 genomes to identify regions that could work as virus-encoded miRNA seed sponges and potentially bind to human miRNA seed sites and prevent interaction with their native targets thereby relieving native miRNA suppression. MicroRNAs (miRNAs) are evolutionally conserved single-stranded RNAs that regulate gene expression at the posttranscriptional level by disrupting translation. MiRNAs are key players in variety of biological processes that regulate differentiation, development and activation of immune cells in both innate and adaptive immunity. We find 34 miRNAs for positive-sense viral RNA and 45 miRNAs for negative-sense that can strongly bind to certain key SARS-CoV-2 genes. The disruption and dysfunction of miRNAs may perturb the immune response and stimulate the release of inflammatory cytokines altering the cellular response to viral infection. Previous studies demonstrate that miRNAs have the potential to be used as diagnostic and therapeutic biomarkers. Therefore, its discovery and validation are essential for improving the diagnosis of infection and clinical monitoring in COVID-19.

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BackgroundThe role of bats as reservoirs of zoonotic agents, especially pathogenic bacteria such as Bartonella and Coxiella, has been discussed around the world. Recent studies have identified bats as potential hosts of species from the proteobacteria phylum. In Brazil, however, the role of bats in the natural cycle of these agents is poorly investigated and generally neglected. In order to analyze the participation of bats in the epidemiology of diseases caused by Bartonella, Coxiella, Rickettsia, Anaplasma and Ehrlichia, we conducted a descriptive epidemiological study in three biogeographic regions of the Brazilian Atlantic Forest.ResultsTissues of 119 bats captured in preserved areas in the states of Rio de Janeiro, Bahia and Santa Catarina from 2014 to 2015 were submitted to molecular analysis using specific primers. Bartonella spp. was detected in 22 spleen samples (18.5%, 95% CI: 11.9–26.6), whose phylogenetic analysis revealed the generation of at least two independent clusters, suggesting that these may be new unique genotypes of Bartonella species. In addition, four samples (3.4%, 95% CI: 0.9–8.3) were positive for the htpAB gene of C. burnetii [spleen (2), liver (1) and heart (1)]. Rickettsia spp., Anaplasma and Ehrlichia were not identified. This is the first study reporting C. burnetii and Bartonella spp. infections in bats from the Atlantic Forest biome.ConclusionsThese findings shed light on potential host range for these bacteria, which are characterized as important zoonotic pathogens.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1603-0) contains supplementary material, which is available to authorized users.

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Introduction:Over the last recent years, the number of Q fever cases have has increased throughout the world. An epidemiological investigation was performed in the area in which the fi rst molecular documentation of Q fever in Brazil was previously reported. Methods: Indirect immunofl uorescence assay (IFA) and PCR of Coxiella burnetii targeting the htpAB gene were performed in samples from 14 dogs (blood); 1 cat (blood); 10 goats (blood, milk, vaginal swab and anal swab); 3 sheep (blood); and 2 horses (blood). Results: Two dogs, two sheep and fi ve goats were seroreactive. DNA was amplifi ed from 6 milk and 2 blood samples from goats and from dogs, respectively. The sequence of the amplicons exhibited 99% sequence similarity with the homologous sequence of the htpAB gene of C. burnetii RSA 331 (GenBank -CP000890). Conclusions: The results confi rm C. burnetii infection in animals in Rio de Janeiro and reinforce the need for the surveillance of Q fever in Brazil.

A lethal case of Brazilian spotted fever (BSF) is presented. Clinical features were initially of gastrointestinal involvement and evolved with progression to septic shock, meningoencephalitis and death on the 6 th day of illness. Indirect immunofluorescence assay (IFA) for spotted fever group rickettsia (SFGR) was non-reactive. Diagnosis was confirmed by the polymerase chain reaction (PCR) and the nucleotide sequencing of a fragment of the ompA gene showed 100% homology to Rickettsia rickettsii. BSF has not been reported in the city of Rio de Janeiro in the last three decades, and the present description should alert the clinicians to its presence in urban Rio de Janeiro, and to the differential diagnosis with dengue fever, gastroenteritis, leptospirosis and bacterial septic shock, among others. Key-Words: Brazilian spotted fever, spotted fever group rickettsia, Rickettsia rickettsii, lethal case, Rio de Janeiro city, indirect immunofluorescence, polymerase chain reaction, central nervous system involvement.Brazilian spotted fever (BSF) is a systemic disease caused by Rickettsia rickettsii, a bacterium transmitted by the horse tick Amblyomma cajennense. It is endemic in the Southeast of Brazil (Rio de Janeiro, São Paulo, Minas Gerais and Espírito Santo states) and affects exposed children and adults [1][2][3][4]. Case presentation mimics several conditions which are endemic in the area, such as dengue fever, leptospirosis, gastroenteritis, meningococcal meningits and severe sepsis [1][2][3][4]. This paper reports a fatal case of BSF, occurring in July, in the metropolitan area of Rio de Janeiro, with prominent sepsis, rash and neurological and cerebrospinal fluid (CSF) findings. Case ReportA 48 year-old white male presented, six days prior to hospital admission, with acute onset of high-grade fever, myalgia, headache, nausea, vomiting and diarrhea. He was a heavy smoker, but past medical history was otherwise unremarkable. He sought medical attention and was treated symptomatically. Two days later his symptoms persisted and he developed jaundice: he was given sulfamethoxazole-trimethoprim and was sent home. The following day he sought the Emergency ward because of hematemesis and melena; he was oliguric. He was transferred to an infectious diseases reference hospital with the presumptive diagnosis of leptospirosis. He was a porter in the north area of Rio de Janeiro, and had frequent contact with rodents. He had been bitten by ticks in Campo Grande (west area of Rio Janeiro) two weeks previously, while visiting his brother, who was a horse cart driver. On arrival he was jaundiced, in deep coma with no neck stiffness, systolic blood pressure was 60 mmHg, heart rate =128 bpm, and a generalized purpuric rash was noted. He was intubated, mechanically ventilated, given rapid intravenous fluid, noradrenaline, ceftriaxone, oxacillin and chloramphenicol. Myoclonus was observed, and two hours after admission he presented a generalized tonic-clonic seizure. Initial investigation showed leukocytosis (18,200 cells/mm 3 , di...