Detection of Latino virus (Arenaviridae: Mammarenavirus) naturally infecting Calomys callidus

Structural and molecular biology of Sabiá virus

Brazilian mammarenavirus, or Sabiá virus (SABV), is a New World (NW) arenavirus associated with fulminant hemorrhagic disease in humans and the sole biosafety level 4 microorganism ever isolated in Brazil. Since the isolation of SABV in the 1990s, studies on viral biology have been scarce, with no available countermeasures against SABV infection or disease. Here we provide a comprehensive review of SABV biology, including key aspects of SABV replication, and comparisons with related Old World and NW arenaviruses. SABV is most likely a rodent-borne virus, transmitted to humans, through exposure to urine and feces in peri-urban areas. Using protein structure prediction methods and alignments, we analyzed shared and unique features of SABV proteins (GPC, NP, Z, and L) that could be explored in search of therapeutic strategies, including repurposing intended application against arenaviruses. Highly conserved catalytic activities present in L protein could be targeted for broad-acting antiviral activity among arenaviruses, while protein-protein interactions, such as those between L and the matrix protein Z, have evolved in NW arenaviruses and should be specific to SABV. The nucleoprotein (NP) also shares targetable interaction interfaces with L and Z and exhibits exonuclease activity in the C-terminal domain, which may be involved in multiple aspects of SABV replication. Envelope glycoproteins GP1 and GP2 have been explored in the development of promising cross-reactive neutralizing antibodies and vaccines, some of which could be repurposed for SABV. GP1 remains a challenging target in SABV as evolutive pressures render it the most variable viral protein in terms of both sequence and structure, while antiviral strategies targeting the Z protein remain to be validated. In conclusion, the prediction and analysis of protein structures should revolutionize research on viruses such as SABV by facilitating the rational design of countermeasures while reducing dependence on sophisticated laboratory infrastructure for experimental validation.

Serological evidence of arenavirus circulation in wild rodents from central-west, southeast, and south regions of Brazil, 2002-2006

Viral hemorrhagic fevers caused by arenaviruses are severe zoonotic diseases. In reservoirs, the presence of antibodies may indicate viral circulation in a population of a specific region, and these data can be used as an indicator for further investigations by molecular techniques. The present study aimed to detect the presence of arenavirus antibodies in wild rodents captured from 1998 to 2008 during epidemiological surveillance activities. A retrospective analysis of 2243 wild rodent blood samples using a broad cross-reactive in-house developed enzyme-linked immunosorbent assay (ELISA) revealed a 0.44% (10/2243) positive rate in wild rodents, which included Necromys lasiurus (6/1012), Calomys callosus (2/94), and Akodon sp. (2/273) species. These rodents were captured between 2002 to 2006 in Campo Alegre de Goiás/GO, Bodoquena/MS, Nuporanga/SP, and Mogi das Cruzes/SP. Our findings suggest the sylvatic circulation of arenavirus among wild rodents in the southeast region of Brazil. However, future virological and molecular studies are necessary to confirm the viral presence in these regions.

A Review of Mammarenaviruses and Rodent Reservoirs in the Americas

In the Americas, infectious viral diseases caused by viruses of the genus Mammarenavirus have been reported since the 1960s. Such diseases have commonly been associated with land use changes, which favor abundance of generalist rodent species. In the Americas-where the rates of land use change are among the highest worldwide-at least 1326 of all 2277 known rodent species have been reported. We conducted a literature review of studies between 1960 and 2020, to establish the current and historical knowledge about genotypes of mammarenaviruses and their rodent reservoirs in the Americas. Our overall goal was to show the importance of focusing research efforts on the American continent, since the conditions exist for future viral hemorrhagic fever (VHF) outbreaks caused by rodent-borne viruses, in turn, carried by widely distributed rodents. We found 47 species identified down to the species level, and one species identified only down to the genus level (Oryzomys sp.), reported in the Americas as reservoirs of mammarenaviruses, most these are ecological generalists. These species associate with 29 genotypes of Mammarenavirus, seven of which have been linked to VHFs in humans. We also highlight the need to monitor these species, in order to prevent viral disease outbreaks in the region.

A Retrospective Survey of Rodent-borne Viruses in Rural Populations of Brazilian Amazon

INTRODUCTION:

The Amazon tropical rainforest has the most dense and diverse ecosystem worldwide. A few studies have addressed rodent-borne diseases as potential hazards to humans in this region.

METHODS:

A retrospective survey was conducted using enzyme-linked immunosorbent assay for detecting mammarenavirus and orthohantavirus antibodies in 206 samples collected from rural settlers of the Brazilian Western Amazonian region.

RESULTS:

Six (2.91%) individuals in the age group of 16 to 36 years were found to possess antibodies against mammarenavirus.

CONCLUSION:

Evidence of previous exposure to mammarenavirus in the rural population points to its silent circulation in this region.

Clinical features of fatal cases of Chapare virus hemorrhagic fever originating from rural La Paz, Bolivia, 2019: A cluster analysis

INTRODUCTION

In 2003 an emerging mammarenavirus (formerly arenaviruses) was discovered in Bolivia and named Chapare (CHAPV). It was associated with severe and fatal hemorrhagic fever, being similar in clinical features to Machupo (MACV). In mid-2019, CHAPV was the cause of a cluster of five cases, two of them laboratory confirmed, three of them fatal. Here, we report the main clinical findings, epidemiological features and the potential ecological aspects, of that cluster of cases in rural La Paz, Bolivia.

METHODS

For this observational, retrospective and cross-sectional study, information was obtained from the Hospitals and the Ministry of Health for the cases that were laboratory-diagnosed and related, during 2019. RT-PCR was used for the detection of the RNA of CHAPV in the blood samples.

RESULTS

Two cases were RT-PCR + for CHAPV. The median age of patients was 42 y-old (IQR 25-45), four out of five were male. All patients were hospitalized, admitted to the ICU and had fever, upper digestive hemorrhage, with two of them, presenting ARDS, and requiring mechanical ventilation. Three patients died (case fatality rate, CFR 60%).

CONCLUSIONS

Mammarenaviruses led to a high fatality rate. These cases occurred in areas with suitable ecoepidemiological conditions for rodent-borne diseases, including CHAPV infection. Socioenvironmental and occupational factors in rural areas of Bolivia may contribute with the risk of zoonotic spillover and transmission to humans.

Seroprevalence of arenavirus and hantavirus in indigenous populations from the Caribbean, Colombia

INTRODUCTION:

In Colombia, there is insufficient epidemiological surveillance of zoonotic hemorrhagic viruses.

METHODS:

We performed a sero-epidemiological study in indigenous populations of Wayuü, Kankuamos, and Tuchin communities using Maciel hantavirus and Junin arenavirus antigens for IgG detection by ELISA.

RESULTS:

IgG antibodies to hantavirus and arenavirus were found in 5/506 (1%) and 2/506 (0.4%) serum samples, respectively.

CONCLUSIONS:

Arenavirus and hantavirus circulate in indigenous populations from the Colombian Caribbean region, and the results indicate that the indigenous populations are exposed to these zoonotic agents, with unknown consequences on their health, despite low seroprevalence.

Aporé virus, a novel mammarenavirus (Bunyavirales: Arenaviridae) related to highly pathogenic virus from South America

Here, we report the complete genome sequence of the Aporé virus (Bunyavirales: Arenaviridae), obtained from a wild rodent Oligoryzomys mattogrossae captured in Mato Grosso do Sul state, Brazil. The genome of this virus showed strong similarity to highly pathogenic mammarenavirus from South America.

Xapuri virus, a novel mammarenavirus: natural reassortment and increased diversity between New World viruses

Mammarenavirus RNA was detected in Musser’s bristly mouse (Neacomys musseri) from the Amazon region, and this detection indicated that rodents were infected with a novel mammarenavirus, with the proposed name Xapuri virus (XAPV), which is phylogenetically related to New World Clade B and Clade C viruses. XAPV may represent the first natural reassortment of the Arenaviridae family and a new unrecognized clade within the Tacaribe serocomplex group.