Maricopa County has identified its first case of West Nile (WNV) virus for 2023. Practitioners evaluating patients presenting with the following symptoms should consider both WNV and St. Louis encephalitis virus (SLEV).

• All cases of viral encephalitis.
• All cases of acute flaccid paralysis or Guillain-Barré syndrome of unknown etiology, with or without presence of viral meningitis or viral encephalitis.
• Cases of aseptic meningitis, especially those with at least one of the following:
  • Altered mentation
  • Profound muscle weakness
  • Neuropathic symptoms
  • Flaccid paralysis
  • Spastic paralysis
  • Guillain-Barré syndrome
  • Seizure
• Cases of febrile illness of unknown etiology, with or without presence of other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash.

For more information, visit the Maricopa County Public Health Department’s page on West Nile virus and St. Louis encephalitis virus.

The Arizona Department of Health Services has provided resources on prevention of West Nile virus and other illnesses spread by mosquitos. 

Here are some tips:

• Utilize EPA-approved insect repellents
• Wear long sleeve shirts and pants when outside
• Use air conditioning or screened windows and doors to keep mosquitos out
• Remove excess water from around your home/outdoor plants
• Keep your yard clear of debris
• Utilize larvicides in non-drinking water

For additional information, please visit the Arizona Department of Health Services website.