This week, the Louisiana Department of Health (DHH) confirmed 15 new cases of West Nile virus, of which five were neuroinvasive disease infections, bringing this year's total to 118 reported infections. There were no new deaths reported this week.

LDH issues a weekly Arbovirus Surveillance Report that details cases detected thus far by parish. This week's new infections include five neuroinvasive disease cases in Ascension (1), Bossier (1), East Baton Rouge Parish (1), Ouachita (1) and Pointe Coupee (1) parishes. There were nine new cases of West Nile fever; these cases were in Caddo (3), East Baton Rouge (5) and LaFourche (1) parishes, and one new asymptomatic case in East Baton Rouge (1) parish. This week's cases can be found in the weekly West Nile virus Surveillance report by clicking here

"During the fall, thousands of Louisiana residents head outside for athletic events, especially college football games. Before hitting the field or heading to a tailgate, we encourage residents to use mosquito repellent, and to wear long sleeves and pants," said LDH State Epidemiologist Dr. Raoult Ratard. "The best way to fight the bite is by being proactive. Keep mosquito repellent in your car or bag so that you have it with you when you need it most."

Humans contract West Nile when they are bitten by mosquitoes infected with the virus. When people are infected with West Nile, the virus will affect them one of three ways. West Nile neuroinvasive disease is the most serious type, infecting the brain and spinal cord. Neuroinvasive disease can lead to death, paralysis and brain damage. The milder viral infection is West Nile fever, in which people experience flu-like symptoms. The majority of people who contract West Nile will be asymptomatic, which means they show no symptoms. These cases are typically detected through blood donations or in the course of other routine medical tests.

About 90 percent of all cases are asymptomatic, while about 10 percent will develop West Nile fever. Only a very small number of infected individuals will show the serious symptoms associated with the neuroinvasive disease. Residents who are 65 years old and older are at higher risk for complications, but everyone is at risk for infection.

Last year, Louisiana saw 34 cases of West Nile virus neuroinvasive disease in the state, which was down from 2002's high of 204 cases of West Nile virus neuroinvasive disease. LDH has been tracking West Nile Virus for more than a decade, and statistics about its occurrence in Louisiana can be found online at


Protecting Yourself

  • If you will be outside, you should wear a mosquito repellent containing DEET. The American Academy of Pediatrics (AAP) recommends that repellents should contain no more than 30 percent DEET when used on children. Insect repellents also are not recommended for children younger than 2 months of age. CDC recommends that you always follow the recommendations appearing on the product label when using repellent.
  • Apply repellent on exposed skin and clothing. Do not apply under your clothes or on broken skin.
  • To apply repellent to your face, spray on your hands and then rub on your face, avoiding your eyes.
  • Adults should always apply repellent to children.
  • Wear long-sleeved shirts and pants when outdoors for long periods of time.
  • Avoid perfumes and colognes when outdoors for extended periods of time.
  • Make sure that your house has tight-fitting windows and doors, and that all screens are free of holes.  

Protecting Your Home

Reduce the mosquito population by eliminating standing water around your home, which is where mosquitoes breed.

  • Dispose of tin cans, ceramic pots and other unnecessary containers that have accumulated on your property. Turn over wheelbarrows, plastic wading pools, buckets, trash cans, children's toys or anything that could collect water.
  • Drill holes in the bottom of outdoor recycling containers. Drainage holes that are located on the container sides collect enough water for mosquitoes to breed.
  • Check and clean roof gutters routinely. They are often overlooked, but can produce millions of mosquitoes each season.
  • Aerate ornamental pools or stock them with fish. Water gardens can become major mosquito producers if they are allowed to stagnate.
  • Clean and chlorinate swimming pools that are not being used. A swimming pool that is left untended by a family for a month can produce enough mosquitoes to result in neighborhood-wide complaints. Be aware that mosquitoes may even breed in the water that collects on swimming pool covers.  

Eastern Equine Encephalitis

There are three (3) new cases of Eastern Equine Encephalitis (EEE) in Louisiana this week, a disease that can also affect humans; there have been 10 total cases this year. The number of cases among horses is similar to last year as displayed on Page 2 of the weekly Arbovirus Surveillance Summary. To date, there have been zero (0) reported human cases of EEE in Louisiana this year.

Eastern equine encephalitis virus (EEEV) is transmitted to humans and horses by the bite of an infected mosquito. After humans are infected with the virus, they can develop encephalitis. EEE is a rare illness in humans, and only a few cases are reported in the United States each year. Most cases occur in the Atlantic and Gulf Coast states (see map). Most persons infected with EEEV have no apparent illness. Severe cases of EEE (involving encephalitis, an inflammation of the brain) begin with the sudden onset of headache, high fever, chills, and vomiting. The illness may then progress into disorientation, seizures, or coma. EEE is one of the most severe mosquito-transmitted diseases in the United States with approximately 33 percent mortality and significant brain damage in most survivors. This infection is preventable in horses with prior vaccination.

EEE is one of several mosquito-transmitted diseases that are reason for people to take precautions against mosquito bites.

Chikungunya Fever/Dengue Fever

LDH continues to monitor chikungunya fever and dengue fever, and include any reported cases in its weekly Arbovirus Surveillance Summary.  This week, there was one (1) new case of dengue fever imported to Louisiana; it was contracted while the individual was traveling to Southeast Asia. There were no new cases of chikungunya fever. So far this year, there have been 10 cases of chikungunya fever and two (2) case of dengue fever. All of Louisiana's reported chikungunya fever and dengue fever infections took place while the individuals were outside of the United States.


Anyone traveling abroad should also take the precautions listed above to protect themselves from mosquitoes in other countries. Mosquitoes in other parts of the world including the Caribbean, South America, Asia, Africa or Europe might infect you with chikungunya or dengue fever. For more information about these diseases, visit the CDC's website by clicking here.