Texas County Warns of West Nile Virus Threat After Record Levels in Mosquitoes Detected

Public health officials in Tarrant County, north Texas, have warned of an increased risk from West Nile virus after record levels of infection were detected in the local mosquito population.

West Nile Virus is a pathogen that causes a potentially serious disease known as West Nile fever. The virus is the leading cause of mosquito-borne disease in the continental United States, according to the Centers for Disease Control and Prevention (CDC.)

"We are continuing to see rapid increases in mosquito infection rates in Tarrant County, which means we have more human risk for West Nile Virus," Tarrant County Public Health (TCPH) Director Vinny Taneja said in a statement on Thursday.

As a result of the elevated risk to humans, county health officials are urging residents to take preventative measures to protect themselves. These include always using a mosquito repellent approved by the Environmental Protection Agency and wearing long sleeves and pants, if possible, when going outside to prevent bites.

TCPH said it will also take action to mitigate the risk of the virus being transmitted to humans. For example, public health officials will increase the spraying of pesticides in areas where the virus is likely to spread. Furthermore, the county will step up surveillance and monitoring of mosquito populations in certain areas.

On July 21, Tarrant County reported the first human death from West Nile Virus infection of the 2020 season.

According to the CDC, most people who become infected with the virus do not become sick. However, around one in five infected individuals will develop a fever along with other symptoms, including headache, body aches, joint pains, vomiting, diarrhea and rashes.

Most people with this form of West Nile fever recover fully on their own, although they may experience fatigue and weakness for weeks or months, according to TCPH.

Around one in 150 infected people develop a serious illness in which the brain and surrounding tissues become inflamed, causing symptoms such as headache, high fever, neck stiffness, disorientation, coma, tremors, seizures or paralysis. In the most severe cases, this type of disease can be fatal.

There is currently no vaccine to prevent West Nile Virus infections in people and there are no antiviral medications available. Hospitalized patients with severe disease are usually given supportive treatments, such as injections of intravenous fluids and pain medications.

Culex quinquefasciatus
A Culex quinquefasciatus mosquito on a human finger. Smith Collection/Gado/Getty Images

People with cancer, diabetes, hypertension and kidney disease are particularly vulnerable to West Nile Virus infection.

In north Texas, West Nile Virus is carried by the Culex quinquefasciatus mosquito, which is active and bites only from dusk till dawn. These mosquitoes usually pick up the virus after consuming the blood of infected birds.

West Nile Virus infections peak in the summer months in Texas, however, the virus can be transmitted all year round in the state. Any symptoms that develop usually appear two to six days after being bitten by an infected mosquito, however, the incubation period can be as long as two to 14 days.

Aside from using a DEET-based insect repellent when outdoors and wearing long sleeves and pants, it is also important to try and reduce the number of mosquitoes around the home. Mosquitoes can lay their eggs in almost any container or area of standing water, so experts say people should ensure that there are none in the vicinity of their homes.