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Detection of Lymphocytic Choriomeningitis Virus in House Mouse (Mus musculus) in Brazil
Gabriel Rosa Cavalcanti1, Jorlan Fernandes1, Fernando de Oliveira Santos2
1Laboratory of Hantaviruses and Rickettsiosis, Oswaldo Cruz Foundation, Oswaldo Cruz Institute, Rio de Janeiro 21040-360, Rio de Janeiro, Brazil.
Abstract:
The lymphocytic choriomeningitis virus (LCMV) is an under-investigated rodent-borne arenavirus primarily associated with its natural reservoir, the cosmopolitan rodent Mus musculus. Although widely distributed in mice worldwide, human cases are rare, likely under-reported, and often misdiagnosed. While typically asymptomatic or self-limiting, infection can progress to neurological disease, severe congenital outcomes, or fatal illness in transplant recipients. Despite its public health relevance, this study provides the first detection and characterization of LCMV in Brazil. We analyzed 236 rodent serum samples and 78 tissue samples from synanthropic rodents (Mus musculus, Rattus rattus, and Rattus norvegicus) collected during seven independent expeditions across the state of Rio de Janeiro, Southeastern Brazil. Using ELISAs, IgG anti-LCMV antibodies were detected in 20% of rodents, including two R. rattus (2/10), two R. norvegicus (2/95), and forty-five M. musculus (45/131). The LCMV's RNA was amplified and partially sequenced from fourteen M. musculus, and complete S segment sequences were obtained from two mouse samples. Phylogenetic analyses revealed that these Brazilian strains belong to lineage I, which is composed of strains that induce disease in humans. Our results underscore the importance of implementing integrated surveillance for this zoonosis in Brazil.
Insights
The lymphocytic choriomeningitis virus (LCMV) was detected in Brazil for the first time. This rodent-borne arenavirus was found in mice and rats, highlighting the need for integrated zoonotic disease surveillance in the region.
Area of Science:
- Virology
- Zoonotic Diseases
- Public Health
Background:
- Lymphocytic choriomeningitis virus (LCMV) is a rodent-borne arenavirus with a global distribution in mice.
- Human LCMV infections are rare but can lead to severe neurological disease, congenital outcomes, or fatal illness in immunocompromised individuals.
- Despite its potential public health impact, LCMV has not been previously detected or characterized in Brazil.
Purpose of the Study:
- To report the first detection and characterization of LCMV in Brazil.
- To investigate the presence of LCMV in synanthropic rodents in Rio de Janeiro.
- To determine the genetic lineage of Brazilian LCMV strains.
Main Methods:
- Analysis of 236 rodent serum and 78 tissue samples from Mus musculus, Rattus rattus, and Rattus norvegicus.
- Detection of IgG anti-LCMV antibodies using ELISAs.
- Amplification, partial sequencing, and phylogenetic analysis of LCMV RNA, including complete S segment sequencing.
Main Results:
- LCMV antibodies were detected in 20% of rodents sampled (50/247), with the highest prevalence in Mus musculus (45/131).
- LCMV RNA was successfully amplified and sequenced from fourteen Mus musculus samples.
- Phylogenetic analysis placed the Brazilian LCMV strains within lineage I, known to be associated with human disease.
Conclusions:
- This study confirms the presence of LCMV in Brazil, specifically in the state of Rio de Janeiro.
- The identified Brazilian LCMV strains belong to a lineage associated with human pathogenicity.
- Integrated surveillance for this zoonosis is crucial for public health in Brazil.
