Morphology An icosahedral, enveloped virus of 40 to 50 nm in diameter. It has a single stranded, positive-sense RNA genome.
Growth Conditions Tissue culture
Health Hazards
Host Range Humans, mosquitoes, ticks, horses, alligators, rodents,
Modes of Transmission  Primarily from infected mosquitoes. Other possible routes include: blood transfusion, vertical transmission, breast milk, organ transplantation, contact of the conjunctiva with contaminated bodily secretions from infected birds, and laboratory accidents involving sharps.
Signs and Symptoms  Sudden onset fever with chills, headache, backache, malaise, arthralgia, myalgia and eye pain. Nausea, vomiting, diarrhea, sore throat and cough. Less than 1 % of WNV infected individuals develop meningitis, encephalitis and/or acute flaccid paralysis.
Infectious Dose Unknown
Incubation Period  2-6 days, but could extend to 14 days.
Medical Precautions/Treatment
Prophylaxis None available.
Vaccines None available.
Treatment None currently available for WNV fever. Supportive therapy for encephalitis include: intravenous fluid, electrolyte management, assisted respiration, anticonvulsants, management of cerebral edema, and prevention of secondary bacterial infections.
Surveillance Monitor for symptoms, confirm via virus isolation from blood or cerebrospinal fluid.
MSU Requirements  Report any exposures.
Laboratory Hazards
Laboratory Acquired Infections (LAIs) Twenty cases have been reported of workers who acquired WNV following percutaneous inoculation while handling infected fluids and tissues with no deaths.
 Sources Blood, cerebrospinal fluid, tissues, infected arthropods, oral and cloacal swabs and feather pulp.
Supplemental References
BMBL:5th Edition
Canadian MSDS
Containment Requirements
BSL2 For all procedures involving known or potentially infected cultures.
ABSL2 For all procedures utilizing infected animals.
Spill Procedures
Small Notify others working in the lab. Remove and don new PPE. Cover area of the spill with absorbent material and add 10 % Bleach. Allow 30 minutes hour of contact time. After 30 minutes and then cleanup and dispose of materials.
Large For assistance, contact MSU's Biosafety Officer: Ryan Bartlett,, (406) 994-6733
or Safety and Risk Management (406-994- 2711).
Exposure Procedures
Mucous membrane
Flush eyes, mouth or nose for 5 minutes at eyewash station.
Other Exposures
Wash area with soap and water for 5 minutes.
Immediately report incident to supervisor, complete a first report of injury report, and submit to Safety and Risk Management.
Medical Follow-up
During business hours: Bridger Occupational Health 3406 Laramie Drive. Weekdays 8am -6pm.  Weekends 9am-5pm
After business hours: Bozeman Deaconess Hospital Emergency Room 915 Highland Blvd Bozeman, MT
Disinfection Susceptible to 10 % Bleach, 70 % ethanol, and 2 % gluteraldehyde, 3% formaldeyde.
Inactivation Inactivated by moist heat (15 minutes at 121° C) and dry heat (1 hour at 160-170°C).
Survival Outside Host Low temperatures preserve infectivity, with stability being greatest below -60° C.
Personal Protective Equipment (PPE)
Minimum PPE Requirements At minimum, gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with West Nile Virus. Respiratory protection is also be required. Additional PPE may be required depending on lab specific SOPs
Additional Precautions Not applicable.