Is there a vaccine for West Nile virus?

There is currently no human vaccine available for West Nile virus. Prevention relies on avoiding mosquito bites through repellent use, protective clothing, and eliminating mosquito breeding habitats.

Can you get West Nile virus from another person?

West Nile virus does not spread through casual contact between people. In rare cases, it can be transmitted through blood transfusion, organ transplant, or from a pregnant mother to her baby.

How long does West Nile virus last?

Mild West Nile fever typically resolves within a few days to weeks. Severe neuroinvasive disease may require prolonged recovery lasting weeks to months, and some neurological effects may be permanent.

InfectiousICD-10: A92.3Over 50,000 cases reported in the US since 1999; about 2,000 cases of neuroinvasive disease annually

West Nile Virus

Also known as: WNV, West Nile fever

West Nile virus is a mosquito-borne flavivirus that can cause a range of illness from mild fever to severe neurological disease including encephalitis and meningitis. Most people infected with WNV have no symptoms, and about 1 in 5 develop a febrile illness. Severe neuroinvasive disease occurs in about 1 in 150 infections and can be life-threatening, particularly in older adults.

Symptoms

Fever

Headache

Body aches and muscle pain

Joint pain

Vomiting and diarrhea

Skin rash

Severe symptoms include high fever, neck stiffness, disorientation, and paralysis

Most infected people have no symptoms

Causes

Infection with West Nile virus transmitted through mosquito bites
Mosquitoes becoming infected by feeding on infected birds
Rarely through blood transfusion, organ transplant, or from mother to child

Risk Factors

Outdoor activities during mosquito season
Living in areas with active WNV transmission
Age over 60 for severe neuroinvasive disease
Immunocompromised state
Lack of mosquito protection measures

Diagnosis

Serologic testing for WNV-specific IgM antibodies in blood or CSF
Plaque reduction neutralization test for confirmation
CSF analysis for signs of encephalitis or meningitis
MRI to detect brain inflammation

Treatment

No specific antiviral treatment available
Supportive care with pain relievers and rest for mild illness
Hospitalization for severe neuroinvasive disease
Intravenous fluids and respiratory support as needed
Physical and occupational therapy during recovery

Prevention

Using EPA-registered insect repellents containing DEET or picaridin
Wearing long sleeves and pants during dawn and dusk
Eliminating standing water where mosquitoes breed
Installing or repairing window and door screens

When to See a Doctor

Severe headache, high fever, and neck stiffness after mosquito exposure
Muscle weakness or paralysis
Confusion or altered consciousness
Symptoms that worsen or do not improve within a week

Frequently Asked Questions

Related Conditions

Zika Virus

Infectious

Dengue Fever

Infectious

Malaria

Infectious

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