BATON ROUGE (AP) — State officials confirmed Friday four more West Nile virus deaths, bringing the total to six in Louisiana.

The Department of Health and Hospitals said 68 cases — 15 of them new — have been detected so far this year. More than half — 37 — are of neuro-invasive disease, the more serious form of the virus that infects the brain and spinal cord and can cause brain damage or death. DHH said that’s the highest total of neuro-invasive infections in the state since 2006.

The new infections include eight cases of neuro-invasive disease reported in Bossier, Caddo, Concordia, Jefferson, Tangipahoa, Union, Washington and Webster parishes and five cases of the milder West Nile fever reported in Livingston, Orleans, Ouachita and St. Tammany parishes.

Two new asymptomatic cases, where people had no symptoms and only discovered the infection when they had blood work done for an unrelated reason such as blood donation, were reported from East Baton Rouge and Rapides parishes.

“The increased cases we are seeing this year are a firm reminder that West Nile Virus is a serious disease, and people need to be vigilant about protecting themselves,” said Dr. Raoult Ratard, the state’s epidemiologist. “We know from 10 years of surveillance that this disease is active in every corner of the state, and people are at risk of getting it regardless of whether cases or deaths occurred in their parishes. Everyone should own their own health and take precautions against mosquito bites.”

St. Tammany Parish has reported the most West Nile Virus infections so far, with six neuro-invasive disease cases, four West Nile fever cases and one asymptomatic case. East Baton Rouge Parish has reported five neuro-invasive disease cases, two West Nile fever and two asymptomatic cases, and Tangipahoa Parish has four neuro-invasive disease cases, two West Nile fever cases and three asymptomatic cases.

DHH urged residents to protect themselves against mosquitoes by applying repellent, wearing long-sleeved shirts and pants and avoiding perfumes and colognes when outdoors for long periods.

In addition, officials said residents can help reduce the mosquito population by eliminating standing water, which is where mosquitoes breed.