encéphalite équine du Venezuela

Venezuelan equine encephalitis is a viral illness caused by a mosquito-borne Venezuelan equine encephalitis virus ^[1]. It produces encephalitis or encephalomyelitis in affected mammals, including horses, donkeys, zebras, and humans ^[1].

Infected equine animals may die suddenly or develop progressive central nervous system dysfunction ^[1]. Healthy adult humans typically show influenza-like manifestations such as high fever and headache, whereas immunocompromised individuals, young children, and older adults can suffer severe disease or death ^[1].

Across the Americas, 21 outbreaks of Venezuelan equine encephalitis virus have been recorded, occurring in Central and South American countries including Mexico, Colombia, Venezuela, and the United States ^[1]. Outbreaks commonly follow heavy precipitation that fosters dense mosquito populations, as seen in a 1992–1993 Trujillo state event with 28 cases and 12 deaths ^[1]. Enzootic viral subtypes remain confined to endemic areas via rodent–mosquito cycles, while epizootic subtypes can disseminate quickly through equine populations ^[1].

The causative virus is transmitted principally by Culex mosquitoes that acquire it from infected animals and subsequently feed on other animals or humans ^[1]. Equine species serve as primary amplifying hosts during epizootics, generating high viremia that blood-feeding insects pass onward ^[1]. Secondary amplification in domesticated animals is recognized as a mechanism in arboviral emergence for this pathogen ^[2].

Control measures should target uncontrolled mosquito vector populations to limit spread, given the role of vector density in outbreak timing and expansion ^[2]. Broader arboviral strategies note that limiting vector proliferation and mitigating drivers such as increased travel can reduce emergence risk ^[2].

1. 1 Wikipedia contributors. Venezuelan equine encephalitis virus - Wikipedia [Internet]. Wikipedia. cited 4 Sept 2026. Available from: https://en.wikipedia.org/wiki/Venezuelan_equine_encephalitis_virus
2. 2 Weaver SC et al. Zika, Chikungunya, and Other Emerging Vector-Borne Viral Diseases. Annu Rev Med. 2018 Jan 29. PMID: 28846489. doi: 10.1146/annurev-med-050715-105122. PubMed: https://pubmed.ncbi.nlm.nih.gov/28846489/