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Venezuelan Equine Encephalitis Virus Biological Agent Reference Sheet (BARS)

Disclaimer: Risk group, biosafety level, and all other precautions noted here are subject to change after a risk assessment by EHS.


Agent Type Risk Group Biosafety Level Animal Housing Biosafety Level
Virus RG-3 BSL-3 ABSL-3

Agent Characteristics 

Risk Group: RG-3 associated with serious or lethal human disease; preventive or therapeutic interventions may be available

Agent Type: Virus - USDA Select Agent

Description: Venezuelan equine encephalitis virus (VEEV) is a single-stranded, enveloped, message-sense RNA virus that is enzootic to South American countries such as Venezuela, Colombia and Peru. Recently, however, there have been emerging outbreaks in southern United States. VEEV is spread between host species primarily via mosquito vectors and could be mechanically transmitted through smaller arthropods such as lice and mites. Healthy adults may develop flu-like symptoms such as high fever and headaches; people with weakened immune systems can develop encephalitis which may result in death. There are some vaccines for both equines and humans but have limited functionality. There is only supportive therapy for infection with VEEV

Host Range: Equines (Horses, donkeys, etc.); Humans            

Host Shedding: Blood, Feces, Saliva, Urine                     

Route of Exposure to Humans: Aerosol/Inhalation, Arthropod Vectors, Mucous Membranes, Percutaneous, Broken Skin

Infectious Dose: One infectious viral particle can infect an individual if injected subcutaneously. Aerosol exposure of as little as 67,000 pfu can display flu-like symptoms.

Incubation Period: Usually anywhere between 2 to 6 days after exposure, but symptoms have been observed as short as 24 hours after exposure.

Health Hazards

Signs and symptoms of infection may include:

  • Flu-like symptoms (i.e. fever, headache, dehydration, weight loss, lethargy)
  • Gastrointestinal symptoms (i.e. loss of appetite, nausea, vomiting, diarrhea)
  • Neurological symptoms (i.e. loss of sensation, ataxia)
  • Reproductive Health concerns (i.e. abortion, fetal abnormalities) 

Immunizations: Available                            Prophylaxis*: Avoid and protect against mosquito bites.

*Formal medical advice is obtained during medical consultations with Cornell Health or primary healthcare provider as needed.

Agent Viability 

Survival Outside Host Disinfection Inactivation

Virus is stable in blood, exudates and freeze-dried
materials, which can spread via aerosols.

 1:10 bleach Dilution

70% Ethanol

4% formaldehyde, 2% glutaraldehyde, 3% hydrogen peroxide, and 2% peracetic acid

4% formaldehyde, 2% lutaraldehyde, 3% hydrogen peroxide, and 2% peracetic acid

For more guidance on disinfection see: disinfectant selection.

Laboratory Hazards 

  • High energy-creating activities (centrifugation, sonication, high pressure systems, vortexing, tube cap popping)
  • Handling of sharps (needles, scalpels, microtome blades, broken glass, etc.)
  • Splash/droplet-creating activities (shaking incubators, liquid culturing, mechanical pipetting)
  • Equipment contamination
  • Exposed skin/uncovered wounds

Laboratory Acquired Infection (LAI) History: Several laboratory-acquired cases of the VEE virus have been reported. As of 2006, a total of 186 cases and 2 deaths were documented. Most of these incidents were related to exposure of aerosols near infected equines.

Laboratory Handling Guidelines 

Laboratory Biosafety Level (BSL): BSL-3

Select Agent Requirements: If VEEV is encountered in a diagnostic or verification specimen or sample it is exempt from the requirements of the select agent regulations for as long as the following steps are taken.

  • Unless directed otherwise by AgSAS or DSAT, the select agent (all samples/specimens where it was identified) are to be transferred in accordance with Section 16 of the select agent regulations or the specimens are to be destroyed on-site by a recognized sterilization or inactivation process within seven (7) calendar days after identification of the select agent or toxin.
  • Before transfer or destruction, secure the select agent or toxin to prevent theft, loss, or release.
  • Immediately report the identification of specific select agents and toxins listed in the regulations (See immediate notification list).
  • Maintain copies of all APHIS/CDC Form 4A reports for a period of (3) three years.

For more information on reporting the identification of select agents, see the Federal Select Agent Program.


Lab Engineering Controls Personal Protective Equipment
  • EHS Laboratory Safety Training CULearn Course #2555
  • EHS Bloodborne Pathogens CULearn Course #1070
  • CVM BSL-3 Classroom Training CULearn Course #1333
  • CVM Working Safely in the Biosafety Cabinet and Hoods CULearn Course #1074
  • Lab-specific protocol training
  • Eye Protection
  • Single gloves
  • Additional gloves, required
  • Snap-front lab coat with cinch cuffs
  • Disposable solid front gown
  • Additional mucous membrane protection
  • Respiratory protection

Waste Management: Regulated Medical Waste (RMW)

Shipping Guidance: Refer to EHS Biological Materials Shipping 

Animal Vivarium Guidance

Animal Housing Biosafety Level (ABSL): ABSL-3

Animal Biosecurity: Experimental animals are housed separately

Perform InoculationsBiosafety Cabinet

Change CagesBiosafety Cabinet

Exposure and Spill Procedures 

Mucous Membranes: Flush eyes, mouth, or nose for 15 minutes at an eyewash station.See: responding to exposures.

Other Exposures: Wash with soap and water for 15 minutes (open wounds, sores, etc.) or a minimum of 20 seconds for areas with intact skin. See:  responding to exposures.

Small Spills: Notify others working in the lab. Evacuate area and allow 30 minutes for aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply disinfectant, working from the perimeter toward the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials. See:  spill cleanup

Large Spills: Request assistance from the EHS Spill Team by calling CUPD dispatch. Call 911 from a campus phone or 607-255-1111 from a mobile phone.

Incident Reporting: Immediately report the incident to supervisor and complete the EHS online injury/illness report as soon as possible.

Medical Follow-Up:

  • For students, seek medical attention at Cornell Health or local primary care provider. Call Cornell Health at 607-255-5155 (24-hour phone consultation line) or a local urgent care. 
  • For faculty and staff, seek medical evaluation with a local primary care provider or urgent care. Cornell Health does not see employees for post-exposure care. 
  • Emergencies: Call 911 from a campus phone or 607-255-1111 from a mobile phone. 
Cornell EHS would like to thank Emory University for the use of their Biological Agent Reference Sheet (BARS) format and some content. 

More Information


  1. CDC. (2009). Biosafety in Microbiological and Biomedical Laboratories.
  2. Patterson, E. I., Warmbrod, K. L., Bouyer, D. H., & Forrester, N.L. (2018). Evaluation of the inactivation of Venezuelan equine encephalitis virus by several common methods. Journal of Virological Methods, 254, 31-34.
  3. Rusnak, J. M., Dupuy, L.C., Niemuth, N. A., Glenn, A. M., & Ward, L. A. (2018). Comparison of Aerosol- and Percutaneous-acquired Venezuelan Equine Encephalitis in Humans and Nonhuman Primates for Suitability in Predicting Clinical Efficacy under the Animal Rule. Comparative Medicine, 68(5), 380-395.
  4. Staples, J. E., & Powers, A. M. (n.d.). SECTION B Viruses PART III Etiologic Agents of Infectious Diseases 217 Togaviridae: Alphaviruses.
  5. Vilcarromero, S., Aguilar, P. V., Halsey, E.S., Laguna-Torres, V. A., Razuri, H., Perez, J.,… Kochel, T.J. (2010). Venezuelan equine encephalitis and 2 human deaths, Peru. Emerging Infectious Diseases, 16 (3), 553-556.
  6. Reed, D. S., Lind, C. M., Sullivan, L. J., Pratt, W. D., & Parker, M. D. (2004). Aerosol Infection of Cynomolgus Macaques with Enzootic Strains of Venezuelan Equine Encephalitis Viruses. The Journal of Infectious Diseases, 189(6), 1013–1017.