# Investigation of neurotropic arboviruses in wild and domestic animals in Amazon region, 2023-2024

## TL;DR

This study found evidence of two arboviruses in animals in the Amazon region, highlighting their potential public health threat.

## Contribution

The study reports the detection and characterization of arboviruses in wild and domestic animals in the Amazon region.

## Key findings

- Two arboviruses were detected in nervous tissue samples from animals in the Amazon region.
- One sample was identified as Saint Louis encephalitis virus (SLEV), and the other as Madariaga virus (MADV).
- The isolated virus was classified as lineage III of EEEV, closely related to strains from Guyana and Argentina.

## Abstract

Arboviruses represent a potential threat to global public health due to their ability to infect various vertebrate hosts and vectors, as well as their adaptability to diverse ecosystems, allowing them to expand geographically across continents.

The present study aimed to describe the molecular epidemiology of encephalitic arboviruses, including Venezuelan equine encephalitis virus (VEEV), Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV), West Nile virus (WNV), Saint Louis encephalitis virus (SLEV), Toscana virus (TOSV), and Rift Valley fever virus (RVFV) in nervous tissue samples from domestic and wild animals from the Northern region of Brazil, between February 2023 and June 2024.

Samples negative for rabies virus were analysed by reverse transcription real-time polymerase chain reaction (RT-qPCR) targeting Alphavirus, Orthoflavivirus and Phlebovirus species.

Positive samples were subjected to viral isolation in cell culture and whole-genome sequencing using next-generation sequencing.

Phylogenetic and molecular clock analyses were performed to characterise viral lineages and evolutionary relationships.

Two samples tested positive for arboviruses by RT-qPCR: one SLEV sample from the state of Amazonas, which showed a low viral load, preventing virus isolation and sequencing, and one Madariaga virus (MADV) sample from the state of Pará, which could be isolated and sequenced.

The isolated agent belongs to lineage III of EEEV, showing most similarity to strains from Guyana and Argentina.

The present study detected two arboviruses in animals, suggesting its circulation in the study area.