Dallas County Reports First West Nile Virus Positive Mosquito Trap

April showers bring May flowers and Texas-sized mosquitos. The Dallas County Health and Human Services (DCHHS) announced the first positive West Nile Virus mosquito trap for 2021. Public health officials monitor mosquito traps throughout Texas to help prevent human transmission.

The West Nile Virus was detected through PCR testing of Culex quinquefasciatus mosquitoes. No humans have been infected at this time, but typically human cases begin to appear in communities two to three weeks after West Nile Virus appears in mosquito surveillance.

The identification of the first positive trap on May 11 in Grand Praire prompted officials to remind Dallas Fort Worth residents to take mosquito bite precautions.

Mosquitos contract West Nile Virus from biting birds. The infected mosquitos then spread the virus to humans when they bite our skin. The CDC reports West Nile virus is the leading cause of mosquito-borne disease in the continental United States.

West Nile Virus cases increase in communities during the Mosquito season from late Spring to early Fall. Most people who contract West Nile Virus will be asymptomatic. About 20% of people infected will develop signs and symptoms.

Common symptoms included fever, headache, muscle aches, joint pain, weakness, vomiting, diarrhea, or a rash. The fever resolves within a few days, but muscle aches and fatigue can linger for months. As we are learning from Long Covid, any viral illness can lead to long-term problems from the post-viral syndrome.

West Nile Virus cases severe and sometimes fatal disease in about 1 in 150 people. Anyone who contracts the virus is at risk for serious illness, but the risk is higher in those 50 years old and older. People with suppressed immune systems are also at higher risk. Immune suppression occurs from diseases such as cancer, diabetes, hypertension, kidney disease, HIV, and organ transplants.

The CDC lists the symptoms of severe illness, including “high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis.”

West Nile Virus sometimes infects the membranes surrounding the brain or spinal cord, causing encephalitis and meningitis. When West Nile Virus affects the central nervous system, symptoms sometimes become permanent. 10% of people with central nervous system infections do not survive.

There is no vaccine or specific treatment for West Nile Virus. Doctors treat patients with over-the-counter pain relievers such as Acetaminophen or Nonsteroidal anti-inflammatory medication to reduce fever and alleviate symptoms. Physical rehabilitation is helpful for those who develop lingering symptoms after infection.

People who develop viral symptoms after a mosquito bite can undergo specialized testing for West Nile Virus.

Prevention is the best medicine for West Nile Virus.

We can reduce our risk by avoiding mosquito bites. Long sleeve shirts and long pants protect the skin from exposure when in a high-risk area.

Spraying the skin with Environmental Protection Agency (EPA)-registered insect repellents, such as DEET, are safe and effective ways to reduce our risk.

EPA-registered repellants must have at least one of the following ingredients:

• DEET
• Picaridin (known as KBR 3023 and icaridin outside the US)
• IR3535
• Oil of lemon eucalyptus (OLE)
• Para-menthane-diol (PMD)
• 2-undecanone

In our homes, we can take steps to control mosquitos. Screens on windows and doors prevent bugs from entering the house. Air conditions and home cooling systems make rooms less hospitable to mosquitos. Monitoring areas outside for stagnant water can reduce the risk. Old tires, buckets, and children’s toys often contain small amounts of water where mosquitos can lay eggs.

Dallas County Health Service will continue to monitor mosquito traps in the area. Local officials work with State public health services to detect any spike in West Nile cases. Any resident in Dallas County may report mosquito problems by calling 214-819-2115.

People can request a free service request here.