West Nile Virus (WNV)

Characteristics
Morphology	A member of the genus Flavivirus, and Flaviviridae family, West Nile Virus (WNV) belongs to the Japanese encephalitis antigenic complex. WNV is an icosahedral, enveloped virus of 40 to 50 nm in diameter and has a single-stranded, positive-sense RNA genome.
Growth Conditions	Vero E6 and BHK21 cell lines

Health Hazards
Host Range	Humans, mosquitoes, ticks, birds, horses, small mammals (wild and domestic), and alligators. Has a very wide host range overall
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. Virus can even be isolated from urine from infected patients
Signs and Symptoms	Most people infected are asymptomatic. About 1 in 5 people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most recover completely, but fatigue and weakness can last for weeks or months. Symptoms of severe illness include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. About 1 out of 10 people who develop severe illness affecting the central nervous system die.
Infectious Dose	Will vary depending on the strain of WNV, but one bite from a mosquito is enough to infect
Incubation Period	2-6 days, but could extend to 14 days

Medical Precautions/Treatment
Prophylaxis	To prevent WNV infection, the best prevention method is to protect against mosquito bites
Vaccines	None publically available
Treatment	There is no specific medicine to treat WNV. Treat the symptoms by taking non-aspirin pain relievers and drink plenty of water. Seek medical attention if they become severe.
Surveillance	Monitor for symptoms. WNV infection can be confirmed by genome detection or virus isolation.
GWU Requirements	Report all incidents to the Office of Risk Management as well as the Office of Research Safety (ORS) IMMEDIATELY FOLLOWING THE OCCURRENCE.

Containment
BSL-2+	Risk Group 3 classification is applied to WNV. BSL-2 practices, containment equipment, and facilities are now recommended for all manipulations of WNV. Additional primary containment and personnel precautions, such as those described for BSL-3, may be indicated for activities with potential for droplet or aerosol production and for activities involving production quantities or concentrations of infectious materials.
BSL-3/ABSL-3	For procedures involving production quantities of infectious material (over 10L of culture) and activities with high potential for aerosol production and work with animals.

Containment

BSL-2+

Risk Group 3 classification is applied to WNV. BSL-2 practices, containment equipment, and facilities are now recommended for all manipulations of WNV. Additional primary containment and personnel precautions, such as those described for BSL-3, may be indicated for activities with potential for droplet or aerosol production and for activities involving production quantities or concentrations of infectious materials.

BSL-3/ABSL-3

For procedures involving production quantities of infectious material (over 10L of culture) and activities with high potential for aerosol production and work with animals.

Spill Procedures
Small Spills (<1 liter)	If the spill occurred inside a biological safety cabinet, close the sash and allow the cabinet to operate for 15 minutes before continuing with the spill cleanup. While WNV exposure via aerosol transmission is unlikely, but caution should still be taken during a spill outside of a BSC. Leave the room immediately and allow the aerosols to dissipate for 15 minutes. Notify others working in the lab. Don appropriate PPE. Cover area of the spill with paper towels or any absorbent material and apply an EPA registered disinfectant effective against enveloped viruses (bleach, glutaraldehyde, and hydrogen peroxide), working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.
Large Spills	Alert lab personnel in the laboratory to the spill and keep people out of the area to prevent spread of the contamination. Check if you have been contaminated or if any of your PPE has been breached. If so follow exposure procedures. Remove any contaminated clothing and place it the biohazard waste. Wash your hands and post a sign on the door. Notify your supervisor of the incident and call ORS (4-8258) for assistance. If the situation involves an imminently life-threatening injury or has catastrophic potential, call 911.

Spill Procedures

Small Spills (<1 liter)

If the spill occurred inside a biological safety cabinet, close the sash and allow the cabinet to operate for 15 minutes before continuing with the spill cleanup.

While WNV exposure via aerosol transmission is unlikely, but caution should still be taken during a spill outside of a BSC. Leave the room immediately and allow the aerosols to dissipate for 15 minutes. Notify others working in the lab. Don appropriate PPE. Cover area of the spill with paper towels or any absorbent material and apply an EPA registered disinfectant effective against enveloped viruses (bleach, glutaraldehyde, and hydrogen peroxide), working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.

Large Spills

Alert lab personnel in the laboratory to the spill and keep people out of the area to prevent spread of the contamination. Check if you have been contaminated or if any of your PPE has been breached. If so follow exposure procedures. Remove any contaminated clothing and place it the biohazard waste. Wash your hands and post a sign on the door. Notify your supervisor of the incident and call ORS (4-8258) for assistance. If the situation involves an imminently life-threatening injury or has catastrophic potential, call 911.

Exposure Procedures
Mucus Membrane	Flush eyes, mouth or nose for 15 minutes at eyewash station.
Other Exposure	Wash area with soap and water for 15 minutes.
Reporting	Report ALL injuries to the PI immediately and reported to the Office of Risk Management at [email protected] IMMEDIATELY FOLLOWING THE OCCURRENCE. Exposures that involve a bloodborne-pathogen or recombinant DNA also need to be reported to the Office of Research Safety at [email protected]. If the injury requires immediate medical attention, call GWPD at 202-994-6111 or call 911.
Medical Monitoring	Seek immediate medical evaluation, treatment, and post exposure follow-up at the Employee Health Office at GWU Hospital (900 23rd St., NW, Suite G-1090, Phone: 202-715-4275). Students should go to the Students Health Office at Marvin Center. After hours treatment can be received at the GWU hospital emergency room.

Stability
Disinfection	Susceptible to disinfectants such as 3 to 8% formaldehyde, 2% glutaraldehyde, 2 to 3% hydrogen peroxide, 500 to 5,000 ppm available chlorine, alcohol, 1% iodine, and phenol iodophors.
Inactivation	Inactivated by heat (50 to 60°C for at least 30 minutes), ultraviolet light, and gamma irradiation
Survival Outside Host	WNV RNA can still be isolated from mosquito excreta up to 14 days deposited in tropical conditions of high heat and humidity

Personal Protective Equipment (PPE)
Minimum PPE Requirements	At minimum, personnel are required to don gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with WNV. Additional PPE may be required depending on lab specific SOPs.
Additional Precautions	Additional protection may be worn over laboratory clothing when infectious materials are directly handled, such as solid-front gowns with tight fitting wrists, gloves, and respiratory protection.

References
CDC (https://www.cdc.gov/westnile/index.html) BMBL 6th Edition (https://www.cdc.gov/labs/BMBL.html) Isolation of West Nile Virus from Urine Samples (https://journals.asm.org/doi/10.1128/JCM.01328-14) Stability of West Nile Virus (https://academic.oup.com/jme/article-abstract/56/4/1135/5425292?redirec…) Canadian PHAC (https://www.canada.ca/en/public-health/services/laboratory-biosafety-bi…)