Chapare Hemorrhagic Fever and Virus Detection in Rodents in Bolivia in 2019

Treatment of highly virulent mammarenavirus infections-status quo and future directions

INTRODUCTION

Mammarenaviruses are negative-sense bisegmented enveloped RNA viruses that are endemic in Africa, the Americas, and Europe. Several are highly virulent, causing acute human diseases associated with high case fatality rates, and are considered to be significant with respect to public health impact or bioterrorism threat.

AREAS COVERED

This review summarizes the status quo of treatment development, starting with drugs that are in advanced stages of evaluation in early clinical trials, followed by promising candidate medical countermeasures emerging from bench analyses and investigational animal research.

EXPERT OPINION

Specific therapeutic treatments for diseases caused by mammarenaviruses remain limited to the off-label use of ribavirin and transfusion of convalescent sera. Progress in identifying novel candidate medical countermeasures against mammarenavirus infection has been slow in part because of the biosafety and biosecurity requirements. However, novel methodologies and tools have enabled increasingly efficient high-throughput molecular screens of regulatory-agency-approved small-molecule drugs and led to the identification of several compounds that could be repurposed for the treatment of infection with several mammarenaviruses. Unfortunately, most of them have not yet been evaluated in vivo. The most promising treatment under development is a monoclonal antibody cocktail that is protective against multiple lineages of the Lassa virus in nonhuman primate disease models.

A review of emerging health threats from zoonotic New World mammarenaviruses

Despite repeated spillover transmission and their potential to cause significant morbidity and mortality in human hosts, the New World mammarenaviruses remain largely understudied. These viruses are endemic to South America, with animal reservoir hosts covering large geographic areas and whose transmission ecology and spillover potential are driven in part by land use change and agriculture that put humans in regular contact with zoonotic hosts.We compiled published studies about Guanarito virus, Junin virus, Machupo virus, Chapare virus, Sabia virus, and Lymphocytic Choriomeningitis virus to review the state of knowledge about the viral hemorrhagic fevers caused by New World mammarenaviruses. We summarize what is known about rodent reservoirs, the conditions of spillover transmission for each of these pathogens, and the characteristics of human populations at greatest risk for hemorrhagic fever diseases. We also review the implications of repeated outbreaks and biosecurity concerns where these diseases are endemic, and steps that countries can take to strengthen surveillance and increase capacity of local healthcare systems. While there are unique risks posed by each of these six viruses, their ecological and epidemiological similarities suggest common steps to mitigate spillover transmission and better contain future outbreaks.

Chapare virus infection and current perspectives on dentistry

OBJECTIVES

This narrative review addresses relevant points about Chapare virus (CHAV) entry in oral cells, CHAV transmission, and preventive strategies in dental clinical settings. It is critical in dentistry due to the frequent presence of gingival hemorrhage occurred in CHAV-infected patients.

MATERIALS AND METHODS

Studies related to CHAV were searched in MEDLINE/PubMed, Scopus, EMBASE, and Web-of-Science databases without language restriction or year of publication.

RESULTS

Recently, the PAHO/WHO and CDC indicate a presence of human-to-human transmission of CHAV associated with direct contact with saliva, blood, or urine, and also through droplets or aerosols created in healthcare procedures. CHAV was detected in human oropharyngeal saliva and gingival bleeding was confirmed in all cases of CHAV hemorrhagic fever, including evidence of nosocomial CHAV transmission in healthcare workers. We revisited the human transferrin receptor 1 (TfR1) expression in oral, nasal, and salivary glands tissues, as well as, we firstly identified the critical residues in the pre-glycoprotein (GP) complex of CHAV that interacts with human TfR1 using cutting-edge in silico bioinformatics platforms associated with molecular dynamic analysis.

CONCLUSIONS

In this multidisciplinary view, we also point out critical elements to provide perspectives on the preventive strategies for dentists and frontline healthcare workers against CHAV, and in the implementation of salivary diagnostic platforms for virus detection, which can be critical to an urgent plan to prevent human-to-human transmission based on current evidence.

CLINICAL RELEVANCE

The preventive strategies in dental clinical settings are pivotal due to the aerosol-generating procedures in dentistry with infected patients or suspected cases of CHAV infection.

Novel Oliveros-like Clade C Mammarenaviruses from Rodents in Argentina, 1990-2020

Following an Argentine Hemorrhagic Fever (AHF) outbreak in the early 1990s, a rodent survey for Junín virus, a New World Clade B arenavirus, in endemic areas of Argentina was conducted. Since 1990, INEVH has been developing eco-epidemiological surveillance of rodents, inside and outside the Argentine Hemorrhagic Fever endemic area. Samples from rodents captured between 1993 and 2019 that were positive for Arenavirus infection underwent Sanger and unbiased, Illumina-based high-throughput sequencing, which yielded 5 complete and 88 partial Mammarenaviruses genomes. Previously, 11 genomes representing four species of New World arenavirus Clade C existed in public records. This work has generated 13 novel genomes, expanding the New World arenavirus Clade C to 24 total genomes. Additionally, two genomes exhibit sufficient genetic diversity to be considered a new species, as per ICTV guidelines (proposed name Mammarenavirus vellosense). The 13 novel genomes exhibited reassortment between the small and large segments in New World Mammarenaviruses. This work demonstrates that Clade C Mammarenavirus infections circulate broadly among Necromys species in the Argentine Hemorrhagic Fever endemic area; however, the risk for Clade C Mammarenavirus human infection is currently unknown.

[Recent advances in the development of vaccines against hemorrhagic fevers caused by arenaviruses]

Arenaviruses are a global threat, causing thousands of deaths each year in several countries around the world. Despite strong efforts in the development of vaccine candidates, vaccines against Lassa fever or Bolivian and Venezuelan hemorrhagic fevers are yet to be licensed for a use in humans. In this synthesis, we present the arenaviruses causing fatal diseases in humans and the main vaccine candidates that have been developed over the past decades with an emphasis on the measles-Lassa vaccine, the first Lassa vaccine ever tested in humans, and on the MOPEVAC platform that can potentially be used as a pan-arenavirus vaccine platform.

Development of reverse genetic tools to study Chapare and Machupo viruses

Arenaviruses are highly pathogenic viruses that pose a serious public health threat. Chapare virus (CHAV) and Machupo virus (MACV), two New World arenaviruses, cause hemorrhagic fevers with case fatality rates of up to 45%. Research on therapeutic drug targets and vaccines for these viruses is limited because biosafety level 4 containment is required for handling them. In this study, we developed reverse genetics systems, including minigenomes and recombinant viruses, that will facilitate the study of these pathogens. The minigenome system is based on the S segment of CHAV or MACV genomes expressing the fluorescent reporter gene ZsGreen (ZsG). We also generated recombinant CHAV and MACV with and without the ZsG reporter gene. As a proof-of-concept study, we used both minigenomes and recombinant viruses to test the inhibitory effects of previously reported antiviral compounds. The new reverse genetics system described here will facilitate future therapeutic studies for these two life-threatening arenaviruses.

The Arenaviridae Family: Knowledge Gaps, Animal Models, Countermeasures, and Prototype Pathogens

Lassa virus (LASV), Junin virus (JUNV), and several other members of the Arenaviridae family are capable of zoonotic transfer to humans and induction of severe viral hemorrhagic fevers. Despite the importance of arenaviruses as potential pandemic pathogens, numerous gaps exist in scientific knowledge pertaining to this diverse family, including gaps in understanding replication, immunosuppression, receptor usage, and elicitation of neutralizing antibody responses, that in turn complicates development of medical countermeasures. A further challenge to the development of medical countermeasures for arenaviruses is the requirement for use of animal models at high levels of biocontainment, where each model has distinct advantages and limitations depending on, availability of space, animals species-specific reagents, and most importantly the ability of the model to faithfully recapitulate human disease. Designation of LASV and JUNV as prototype pathogens can facilitate progress in addressing the public health challenges posed by members of this important virus family.

Ophthalmic consequences of viral hemorrhagic fevers: Insights from the clinic and laboratory

Viral hemorrhagic fevers (VHFs) are a diverse group of RNA virus-mediated systemic diseases with significant morbidity and mortality and represent a significant public health concern. Given the high systemic morbidity and mortality in a number of these entities, delays in diagnosis can lead to downstream public health consequences. Many viral hemorrhagic fevers have ophthalmic manifestations and ophthalmologists thus play a key role in disease recognition and the management of ocular complications associated with specific hemorrhagic fevers. This review summarizes the key ophthalmic consequences of viral hemorrhagic fevers, viral disease pathogenesis, disease findings, and areas of unmet research need.

Chikungunya Virus Shedding in Semen: A Case Series

Background: Chikungunya is a viral disease that is transmitted by mosquitoes. It is characterized by an acute onset of fever and severe arthralgia. Methods: We describe six cases of acute and post-acute chikungunya in which viral RNA was detected in semen. Conclusions: The most prolonged detection period was 56 days after illness onset. We attempted to cultivate positive semen samples, but virus isolation was unsuccessful in all cases.