What are the symptoms of West Nile Virus (WNV) infection?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: March 31, 2025 • View editorial policy

From the Guidelines

West Nile virus symptoms can range from mild to severe, with approximately 20% of infected individuals developing West Nile fever, characterized by fever, headache, body aches, joint pain, vomiting, diarrhea, and fatigue, while less than 1% of infections can cause severe neuroinvasive disease, including encephalitis, meningitis, or acute flaccid paralysis, as seen in other viral infections such as Encephalitis Viruses 1.

Common Symptoms

  • Fever
  • Headache
  • Body aches
  • Joint pain
  • Vomiting
  • Diarrhea
  • Fatigue
  • Skin rash on the chest, stomach, and back

Severe Symptoms

  • High fever
  • Severe headache
  • Neck stiffness
  • Disorientation
  • Tremors
  • Seizures
  • Paralysis
  • Coma

Prevention and Treatment

Prevention involves avoiding mosquito bites through using insect repellent, wearing protective clothing, and eliminating standing water where mosquitoes breed. There is no specific treatment for West Nile virus infection; care is supportive, focusing on managing symptoms, similar to the approach for other viral infections such as Encephalitis Viruses, which also have no specific treatment and rely on supportive care 1.

From the Research

West Nile Virus Symptoms

  • The symptoms of West Nile virus (WNV) infections can be categorized into two main groups: constitutional symptoms and neuroinvasive symptoms 2
  • Constitutional symptoms include: + Fever + Fatigue + Myalgia + Rash + Arthralgia + Headache
  • Neuroinvasive WNV infections can manifest with signs and symptoms suggestive of: + Meningitis + Encephalitis + Meningoencephalitis + Acute flaccid paralysis
  • In addition to these symptoms, patients with neuroinvasive WNV infection may also develop movement disorders, including: + Tremor + Opsoclonus-myoclonus + Parkinsonism + Myoclonus + Ataxia + Chorea
  • These movement disorders often resolve within a few weeks to months with an indolent course 2

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.