The Louisiana Department of Health and Hospitals (DHH) confirmed 12 new cases of West Nile virus this week, of which three were neuroinvasive disease infections, bringing this year’s total to 92 reported infections.

Image/CDC
Image/CDC

DHH issues a weekly Arbovirus Surveillance Report that details cases detected thus far by parish. This week’s new infections include three neuroinvasive disease cases in East Baton Rouge Parish (3). There were seven new cases of West Nile fever; Caddo (2), East Baton Rouge (2), Livingston (1), Orleans (1) and St. Tammany (1) parishes, and two new asymptomatic cases in East Baton Rouge (1) and Iberville (1) parishes. This week’s cases can be found in the weekly West Nile virus Surveillance report by clicking here.

“Mosquitoes are still biting, and that means we are all still at risk of getting West Nile virus and other mosquito-borne diseases,” said DHH State Epidemiologist Dr. Raoult Ratard. “If you’re going to be outside this weekend, it’s a good idea to protect yourself and your children with mosquito repellent. You can also fight the bite by wearing long sleeves and pants. Avoid being bitten by mosquitoes. Help reduce the mosquito population by dumping standing water from containers around your yard.”

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.

In addition, the DHH was informed by the Louisiana Department of Agriculture and Forestry that two horses in Louisiana were reported with confirmed cases of Eastern Equine Encephalitis (EEE), a disease that can also affect humans, bringing this year’s total to seven horses.

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.

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.