Metro Health Reports Positive West Nile Test on Mosquito Pool

Published on May 16, 2024

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SAN ANTONIO (May 16, 2024) – The City of San Antonio Metropolitan Health District (Metro Health) confirmed that a mosquito pool tested positive for the West Nile Virus (WNV). This is the first positive mosquito pool for this year.  

The infected mosquito pool trap was collected in the southwest area of San Antonio near the intersection of Ray Ellison Blvd and Loop 410.  Lab results from Metro Health were confirmed on May 15, 2024. Pest control treatment and fogging services will take place next week in the surrounding areas by Metro Health’s Vector Control program. Future positive WNV mosquito pools will be updated on Metro Health’s website.

Increased rainfall may result in increased hatching of mosquito eggs. Metro Health asks the community to follow these safety measures to prevent mosquitoes: 

Remove Standing Water

These actions can help reduce the number of mosquitoes in areas where people live. After heavy rain, individuals should empty and scrub, turn over, cover, or throw out containers that hold water, including: 

  • Vases
  • Pet water bowls
  • Flowerpot saucers
  • Discarded tires
  • Buckets
  • Pool covers
  • Birdbaths
  • Trash cans
  • Rain barrels

Improve Sanitation

When water is contaminated with organic matter (i.e. animal waste, grass, and leaves), the chances that mosquito larvae will survive may increase. Contaminated matter provides food for larvae to eat.

Protect Yourself

Using an insect repellent containing DEET or Picaridin on skin not covered by clothing is very important. Safety measures when using repellent include:

  • Spraying insect repellent on clothing (mosquitoes can bite through thin clothing) 
  • Insect repellents should not be used on young infants
  • Wearing long-sleeved shirts, long pants, and socks to protect exposed skin during dusk and dawn, which is when mosquitoes are active
  • Using air conditioning or making sure there are screens on all doors and windows to keep mosquitoes from entering an individual’s home

According to the Centers for Disease Control and Prevention (CDC), WNV is mostly spread to people from a bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes then spread WNV to people and other animals by biting them.

Cases of WNV occur during mosquito season, which starts in the summer and continues through fall. There are no vaccines or medications to prevent or treat WNV. 

Most people infected with WNV do not feel sick. About 1 in 5 people who are infected develop a fever and other symptoms such as headaches, body aches, joint pains, vomiting, diarrhea, or rashes. About 1 in 150 people who are infected develop a severe illness affecting the central nervous system such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). 

Severe illness can occur in people of any age; however, people over 60 years of age are at greater risk for severe illness if they are infected. People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and those who have received organ transplants are also at greater risk.