North Texas Counties Announce Collaborative Strategy To Combat West Nile Virus In 2014

Four North Texas county health departments have jointly announced, that they will be melding their planning, research, information, and efforts to better make a collective impact on this year’s West Nile virus (WNV) season.

Similarities of strategic approach are reflected in Dallas and Tarrant counties plans to trap and test mosquitoes earlier than they did in previous years, to add more staff members, to conduct year-round trapping and testing, and a request to their respective Commissioners Courts for additional funding.

“Our initial meetings and discussions led us to the consensus that shifting the focus to the emergence of positive mosquitoes as an early indicator of West Nile virus activity would be a key first step. This step will help reduce the mosquito population and hopefully reduce the number of human cases,” says Tarrant County Public Health Director Dr. Lou Brewer.

“Increased vigilance by all of us will help identify and eliminate mosquito breeding locations throughout the area and also give us an edge in our collective battle against West Nile,” explains Dallas County Health and Human Services Director Zachary Thompson.

All four counties will echo the prevention messages, which if followed, can help reduce human cases and reduce the opportunities for mosquitoes to breed.

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Two years ago the 2012 West Nile virus season hit the North Texas region especially hard, with ground and aerial spraying employed to lower the population of mosquitos potentially carrying the virus. For 2013, the four North Texas health departments ramped up their collaborative efforts and resources in hope of preventing a potential recurrence, with Dallas and Tarrant counties commencing their trapping and testing of mosquitoes earlier than they had in 2012 and continuing with additional joint activities on a limited basis throughout the year.

For example, beginning in mid-November, 2013, off-season WNV surveillance in Tarrant County has consisted of monitoring 15 static trap locations countywide. Mosquito samples from these locations are sampled and tested at the North Texas Regional Laboratory at Tarrant County Public Health (TCPH) once a month. Cities with WNV positive samples during the off-season WNV surveillance will continue to be notified by TCPH. After the fierce WNV outbreak of 2012, Denton County Health Department also began trapping and testing mosquitoes in 2013.

For the coming 2014 WNV season, reporting requirements, dubbed “case definitions,”will change how human WNV cases are counted, which may result in an increased number of cases reported.

“Knowing that people are crossing county boundaries daily makes it more important for us to be strategic in our actions,” comments Collin County Health Care Services Director Candy Blair.

“This approach equals a combination of expertise and data collection that can only yield positives for the entire region,” said Dr. James Zoretic, Regional Director of Texas Department of State Health Service Regions 2/3. “Moving forward, it will provide the needed continuity of information to identify the successes as well as the areas that need improvement.”

 

wnvusgshumantexasImage Courtesy U.S. Geological Survey

West Nile Virus

West Nile Virus (WNV) is a potentially serious illness. Experts believe WNV is a seasonal epidemic of the summer months, just like influenza is to winter. West Nile virus can be transmitted year-round whenever mosquitoes are biting, which is why it is best to protect yourself all year. Everyone is at risk of being affected by West Nile virus.

According to the Centers for Disease Control and Prevention , West Nile virus is most commonly transmitted to humans by mosquitoes. Most people infected with WNV will have no symptoms, but about one in five people who are infected will develop a fever with other symptoms. Fewer than 1% of these infected people develop a serious, sometimes fatal, neurologic illness.

Symptoms

Symptom-free in most people (70-80%) who become infected with West Nile virus. Febrile illness in some people. About one in five people infected will develop fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.

A few WNV human victims will develop severe symptoms, and fewer than one percent of people infected will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). Symptoms of neurologic illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis.

txwnvneuroImage Courtesy Texas Dept. Of State Health Services

Persons with certain medical conditions, such as cancer, diabetes, hypertension and kidney disease are also at greater risk for serious illness. Recovery from severe disease may take several weeks or months. Some of the neurologic effects may be permanent. About 10 percent of people who develop neurologic infection due to West Nile virus will die.

People over 50 and those with weakened immune systems are at a higher risk of becoming ill if they become infected with the virus.

Treatment

No vaccine or specific antiviral treatments for West Nile virus infection are available. Over-the-counter pain relievers such as Acetylsalicylic Acid (e.g. Aspirin) Acetaminophen (e.g. Tylenol), or Ibuprofen (e.g. Advil) can be used to reduce fever and relieve some symptoms. In severe cases, patients often need to be hospitalized to receive supportive treatment, such as intravenous fluids, pain medication, and nursing care.

Transmission

West Nile virus is most commonly transmitted to humans by mosquitoes. Additional routes of human infection have also been documented. It is important to note that these methods of transmission represent a very small proportion of cases:

• Blood transfusions
• Organ transplants
• Exposure in a laboratory setting
• From mother to baby during pregnancy, delivery, or breastfeeding

cdcwnvtransImage Courtesy CDC

West Nile virus is not transmitted:

• From person-to-person or from animal-to-person through casual contact.
• Normal veterinary infection control precautions should be followed when caring for a horse suspected to have this or any viral infection.
• From handling live or dead infected birds. You should avoid bare-handed contact when handling any dead animal. If you are disposing of a dead bird, use gloves or double plastic bags to place the carcass in a garbage can.
• Through consuming infected birds or animals. In keeping with overall public health practice, and due to the risk of known food-borne pathogens, always follow procedures for fully cooking meat from either birds or mammals.

Horses and household pets like dogs and cats may also be affected.

txwnvhorseImage Courtesy Texas Dept. Of State Health Services

Prevention & Control

The CDC and The Texas Dept. Of State Health Services advise that the most effective way to avoid West Nile virus disease is to prevent mosquito bites. Be aware of the West Nile virus activity in your area and take action to protect yourself and your family.

• Avoid Mosquito Bites
• Use an approved insect repellent every time you go outside. Approved repellents are those that contain DEET, picaridin, IR3535, or oil of lemon, eucalyptus, and some para-menthane-diol products provide longer-lasting protection.
• To optimize safety and effectiveness, repellents should be used
• When weather permits, wear long sleeves, long pants, and socks when outdoors, especially at dawn and dusk when mosquitoes are most active.. Mosquitoes may bite through thin clothing, so spraying clothes with repellent containing permethrin or another EPA-registered repellent will give extra protection. Don’t apply repellents containing permethrin directly to skin. Do not spray repellent on the skin under your clothing.
• Take extra care during peak mosquito biting hours. Take extra care to use repellent and protective clothing from dusk to dawn or consider avoiding outdoor activities during these times.

Mosquito-Proof Your Home

“A major component of our unified approach will be the residents in each county,” says Dr. Bing Burton, Denton County’s Health Director. “We need their help in eliminating and reducing mosquito breeding areas in and around their homes.” Burton also noted that this year would be the first time that Denton County has conducted mosquito surveillance.

• Install or repair screens on windows and doors to keep mosquitoes outside. Use your air conditioning, if you have it.
• Mosquitoes must have standing water in which to begin their life cycle. Almost any container or area of standing water presents a potential “mosquito nursery” in which eggs can be laid. Residents are encouraged to eliminate mosquito-breeding areas from their yard and community. Help reduce the number of mosquitoes around your home by regularly draining standing water from flowerpots, gutters, buckets, pool covers, pet water dishes, saucers under potted plants, discarded tires, buckets, and birdbaths, on a regular basis.

Help Your Community West Nile Virus Surveillance and Control Programs

Support your local community mosquito control programs. Mosquito control activities are most often handled at the local level, such as through county or city government. The type of mosquito control methods used by a program depends on the time of year, the type of mosquitoes to be controlled, and the habitat structure. Methods can include elimination of mosquito larval habitats, application of insecticides to kill mosquito larvae, or spraying insecticides from trucks or aircraft to kill adult mosquitoes. Your local mosquito control program can provide information about the type of products being used in your area. Check with your local health department for more information.

Collin County Health Care Services

Collin County Health Care Services (CCHCS) protects and promotes the health of the people of Collin County by providing quality, preventive Public Health Services to county residents. CCHCS is committed to continuous improvement in patient care and responsiveness to our community’s needs.

Dallas County Health and Human Services

Dallas County Health and Human Services strives to protect the health of the citizens of Dallas County through disease prevention and intervention, and through promotions of a healthy community and environment. This is done through assessment, community input education, disease monitoring, regulation, and health services that help control the spread of disease.

Denton County Health Department

Denton County Health Department provides preventive public health services by: Assuring disease surveillance and working to prevent the spread of disease; protecting against environmental hazards; promoting and encouraging healthy behaviors; preparing and responding to disasters and assisting communities in recovery efforts.

Tarrant County Public Health
Tarrant County Public Health (TCPH) provides services to all Tarrant County residents aimed at promoting, achieving and maintaining a healthy standard of living. With a client base and scope of services as diverse as the county’s population, TCPH services truly touch everyone, every day, everywhere.

Sources:
Collin County Health Care Services
Dallas County Health and Human Services
Denton County Health Department
Tarrant County Public Health
The Centers for Disease Control and Prevention
Texas Dept. Of State Health Services

Image credits:

The Centers for Disease Control and Prevention
Texas Dept. Of State Health Services

U.S. Geological Survey

About Charles Moore

Charles Moore
Charles Moore is a syndicated columnist for several major Canadian print newspapers and the Science and Research Section editor for BioNews Texas.
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