Video:Venezuelan equine encephalitis
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Description
Venezuelan equine encephalitis is a mosquito-borne viral disease caused by an alphavirus that affects humans and other animals in Central and South America. In humans it presents as a flu-like illness but can progress to encephalitis. Transmission involves mosquitoes feeding on infected rodents, with horses serving as amplifying hosts during outbreaks. Diagnosis relies on serology or PCR.As of now treatment is supportive.[1]
Presentation
In terms of the presentation of VEE we find the following:[1] leukopenia, tachycardia, fever, interstitial pneumonia, pharyngeal inflammation, muscle tenderness and retro-orbital headache.
Complications
As to complications in an individual with VEE we find the following :[1] seizures, confusion, intellectual disabilities, and behavioral changes. We find that in pregnancy complications include miscarriage , stillbirth and offspring may have neurological sequelae.[1]
Virology
The virion is spherical and approximately 70 nanometers in diameter. It has a lipid membrane with glycoprotein surface proteins spread around the outside. Surrounding the nuclear material is a nucleocapsid that has an icosahedral symmetry of T equals 4, and is approximately 40 nanometers in diameter.Serology testing performed on this virus has shown the presence of six different subtypes . These have been given names, including Mucambo, Tonate, and Pixuna subtypes. There are seven different variants in subtype I, and three of these variants, A, B, and C are the epizootic strains.[2][3][4]
Mechanism
In terms of the mechanism of Venezuelan Equine Encephalitis we find it begins with a mosquito bite, where it first infects dendritic cells and macrophages in skin. The virus uses these immune cells to travel to regional lymph nodes, where it replicates, leading to high-titer viremia and systemic spread to other lymphoid tissues, often causing lymphocyte depletion. In some cases the high viral load facilitates neuroinvasion, either by crossing the blood-brain barrier or via peripheral nerves . VEEV replicates in neurons and other cells, causing severe meningoencephalitis, neuronal damage, and inflammation which can cause long-term neurological sequelae.[5][6][1]
Diagnosis
In terms of diagnosis we find that virus detection can be conducted in serum or cerebrospinal fluid using serological analysis. VEEV-specific blocking ELISA has high efficacy in identifying the serotype. [1]
Differential diagnosis
As to the differential diagnosis of VEE in an infected individual we find the following:[1] Lyme disease, Malaria, bacterial meningitis, Chikungunya, Dengue and Eastern equine encephalitis.
Treatment
In terms of management presently there is no specific treatment available for Venezuelan equine encephalitis. Management of these conditions relies completely on supportive or palliative care.[1]
Epidemiology
An outbreak of this disease occurred in Colombia in September 1995. This outbreak resulted in more than 14 thousand human cases that were attributable to Venezuelan equine encephalitis virus with 26 human deaths.[7] A possible explanation for the serious outbreaks was the particularly heavy rain that had fallen; this could have caused increased numbers of mosquitoes that could serve as vectors for the disease. [7]
History
As to history the Venezuelan equine encephalitis virus was first isolated and described in 1938 by Fred L. Soper, and William C. Reeves, during an outbreak in Venezuela. The virus was identified as the cause of a severe epizootic disease affecting horses, with occasional spillover into humans.[8][9]
Society and culture
In April 2009, the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick reported that samples of Venezuelan equine encephalitis virus were discovered missing during an inventory of a group of samples left by a departed researcher. The report stated the samples were likely among those destroyed when a freezer malfunctioned.[10]
Research
A 2024 study demonstrated the efficacy of a potent neutralizing antibody targeting the E2 glycoprotein of VEEV.The antibody showed strong therapeutic potential in treating established encephalitic alphavirus infections, emphasizing the role Fc effector functions.[11]
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References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Crosby, Brianna; Crespo, Maria E. (2025). "Venezuelan Equine Encephalitis". StatPearls. StatPearls Publishing.
- ↑ Vlak, Just M. (July 2007). "Gernot H. Bergold (1911–2003)". Journal of Invertebrate Pathology. 95 (3): 231–232. Bibcode:2007JInvP..95..231V. doi:10.1016/j.jip.2007.03.015.
- ↑ "VENEZUELAN EQUINE ENCEPHALOMYELITIS STANDARD OPERATING PROCEDURES" (PDF). USDA. Retrieved 23 October 2025.
- ↑ Guzmán-Terán, Camilo; Calderón-Rangel, Alfonso; Rodriguez-Morales, Alfonso; Mattar, Salim (December 2020). "Venezuelan equine encephalitis virus: the problem is not over for tropical America". Annals of Clinical Microbiology and Antimicrobials. 19 (1). doi:10.1186/s12941-020-00360-4.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ↑ Gardner, Christina L.; Burke, Crystal W.; Tesfay, Mulu Z.; Glass, Pamela J.; Klimstra, William B.; Ryman, Kate D. (November 2008). "Eastern and Venezuelan equine encephalitis viruses differ in their ability to infect dendritic cells and macrophages: impact of altered cell tropism on pathogenesis". Journal of Virology. 82 (21): 10634–10646. doi:10.1128/JVI.01323-08. ISSN 1098-5514. PMC 2573165. PMID 18768986.
- ↑ Sharma, Anuj; Knollmann-Ritschel, Barbara (18 February 2019). "Current Understanding of the Molecular Basis of Venezuelan Equine Encephalitis Virus Pathogenesis and Vaccine Development". Viruses. 11 (2): 164. doi:10.3390/v11020164. ISSN 1999-4915. PMC 6410161. PMID 30781656.
- ↑ 7.0 7.1 Beaman, Joseph R.; Turell, Michael J. (1 January 1991). "Transmission of Venezuelan Equine Encephalomyelitis Virus by Strains of Aedes albopictus (Diptera: Culicidae) Collected in North and South America". Journal of Medical Entomology. 28 (1): 161–164. doi:10.1093/jmedent/28.1.161. PMID 2033608.
- ↑ "09.20.2004 - William C. Reeves, professor emeritus and giant in arbovirology, dies at 87". newsarchive.berkeley.edu. Archived from the original on 24 January 2025. Retrieved 17 October 2025.
- ↑ Soper, F. L., & Reeves, W. C. (1938). Venezuelan equine encephalitis epidemic: Report on virus isolation and outbreak investigation. U.S. Public Health Service.https://stacks.cdc.gov/view/cdc/62709 Archived 2025-05-14 at the Wayback Machine
- ↑ Shaughnessy, Larry (22 April 2009). "Army: 3 vials of virus samples missing from Maryland facility". CNN.
- ↑ Schwedler, Jennifer L.; Stefan, Maxwell A.; Thatcher, Christine E.; McIlroy, Peter R.; Sinha, Anupama; Phillips, Ashlee M.; Sumner, Christopher A.; Courtney, Colleen M.; Kim, Christina Y.; Weilhammer, Dina R.; Harmon, Brooke (31 December 2024). "Therapeutic efficacy of a potent anti-Venezuelan equine encephalitis virus antibody is contingent on Fc effector function". mAbs. 16 (1) 2297451. doi:10.1080/19420862.2023.2297451. PMC 10766394. PMID 38170638.