Mosquitoes are among the most important insect pests affecting the health of people. They are not just annoying; they can also transmit many diseases. A rainy spring proceded by a mild winter, can lead to an active mosquito season. 

Mosquitoes are one of the most important insect pests that affect people's health. They are not just annoying; they can also transmit many diseases. A rainy spring following a mild winter can lead to an active mosquito season.

Mosquitoes are present in Central Texas year-round, but the population is largest and most active from April through September. During this period, Austin Public Health monitors the population and tests for mosquito-borne viruses. Those that carry West Nile Virus (WNV) are of particular concern.

Incidence of West Nile

West Nile Virus is the most common mosquito-borne disease in the US. In 2012, there was a large outbreak of WNV with 5,674 human cases reported nationwide. In Travis County, 153 cases were reported that year, with 1,868 cases reported in Texas.  A majority (62%) of the cases in Travis County were males; the age range was 11 to 91 years; and most (58%) were 50 years of age or older. Six people in Travis County died that year of WNV, all 60 years of age or older.

In 2016, 370 WNV cases were reported in Texas, with only three in Travis County.  In 2017, only 135 West Nile cases were reported in Texas, and none in Travis County.

Symptoms

photo of culex mosquito

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Most people who are infected with the West Nile virus will not get sick. However, it is estimated that 20% of people who become infected will develop West Nile fever with mild flu-like symptoms, including fever, headache and body aches, a skin rash on the trunk of the body, and swollen lymph glands. 

About one in 150 people infected with WNV will develop severe illness. Those older than 50 are at higher risk for severe disease. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis.

Symptoms can last for as short as a few days, or may last several weeks, and neurological effects may be permanent.  Read more about symptoms from the Centers for Disease Control and Prevention (CDC).

Prevention

The most important way to prevent WNV is to reduce the number of mosquitos where people work and play.  Mosquitoes can only breed in standing water, and it can be in as little as one teaspoon. By draining all sources of standing water in and around your property, you reduce the number of places mosquitoes can lay their eggs and breed.

Using insect repellents and wearing protective clothing is the best way to prevent getting bitten by mosquitoes.

To fight mosquitoes, remember the Four Ds:

  • Dusk and dawn: Try to stay indoors at dusk and dawn. That is the time when mosquitoes likely to carry the infection are most active.
  • Dress: Wear pants and long sleeves when you are outside. Wear light colored, loose fitting clothing; mosquito repellent clothing is also available
  • DEET: Apply insect repellent that contains DEET. Read and follow label instructions. Spray both exposed skin and clothing with repellent.
  • Drain: Get rid of standing water in your yard and neighborhood. Old tires, flowerpots, clogged rain gutters, birdbaths and wading pools can be breeding sites for mosquitos. 

Ways to eliminate mosquito breeding sites:

  • Reduce standing water around your home and neighborhood (including plant saucers, toys, buckets, and clogged gutters)
  • Replace water at least once a week in pet dishes and bird baths
  • Repair leaky faucets and pipes
  • Keep window and door screens in good repair
  • Carefully screen rainwater harvesting cisterns to exclude mosquitos
  • Use “mosquito dunks” (Bacillus thuringiensis israeliensis)  to reduce mosquitos in rain barrels and permanent bodies of water. These products slowly release a biological larvicide that kills the pest