Abstract Emerging
arthropod-borne viruses (
arboviruses), such as chikungunya and Zika
viruses, are a major threat to
public health in countries like
Brazil where
biodiversity is high and
medical care is sometimes precarious.
West Nile fever is a
disease caused by the
West Nile Virus (WNV), an
RNA virus belonging to the
Flaviviridae family. It is transmitted by infected
mosquitoes to numerous
animals like
birds,
reptiles and
mammals, including
human and non-
human primates. In the last decade, the number of reported cases of
WNV infection in
humans and
animals has increased in the
Americas. Circulation of WNV in
forests and
rural areas in
Brazil has been detected based on serological surveys and, in 2014, the first case of
West Nile fever was confirmed in a
patient from Piauí
State. In 2018, the
virus was isolated for the first
time from a
horse from a
rural area in the
state of Espírito Santo presenting with a
neurological disorder; this raises the possibility that other cases of WNV
encephalitis may have occurred without clinical recognition and without
laboratory diagnosis by specific assays. The imminent WNV outbreak poses a challenge for Brazilian clinicians and
researchers. In this
review, we summarize the basic
biological and ecological characteristics of this
virus and the clinical presentation and
treatment of febrile illnesses caused by WNV. We also discuss the epidemiological aspects, prophylaxis of
WNV infections, and
monitoring strategies that could be applied in the possibility of a WNV outbreak in
Brazil.