The state Department of Health and Hospitals has reported 55 cases of West Nile virus so far this year, less than half the number of cases in Louisiana during the same time span in 2014.
The state’s epidemiologist says this drop is primarily due to Louisiana’s cool spring. East Baton Rouge Parish accounts only for three of the confirmed cases, compared with 42 cases around this time last year, according to DHH statistics.
Despite the drop, DHH continues to urge people to take precautions even as the state enters colder months.
Louisiana has the fourth highest number of deaths by West Nile, with four. California has the most, with 11. Texas is second, with eight, and Oklahoma is third, with five, according to the Centers for Disease Control and Prevention. Arizona, Illinois and Maryland also have four deaths contributed to West Nile so far this year. There have been 63 deaths nationwide in 2015 so far, the CDC reports. State epidemiologist Dr. Raoult Ratard said these numbers fluctuate widely depending on the year.
These deaths result from the most severe form of the virus, neuroinvasive West Nile, which is less common and typically causes swelling of the brain or spinal cord and can result in brain damage or death.
Fewer than 1 percent of people estimated to be infected with West Nile develop a serious neuroinvasive form of the virus, but these are many of the cases that health authorities learn about because patients end up in the hospital, Ratard said.
“The virus gets pulled from the blood into the brain and attacks the brain cells,” Ratard said. About 1 in 10 people will die from this form of the virus.
DHH reported Thursday 34 neuroinvasive cases in Louisiana.
He said symptoms can include headaches, fever, a stiff neck, sensitivity to light and feeling weak, as well as a slightly altered mental state. If someone is experiencing these symptoms, Ratard said, that person should seek medical attention.
“You’ll know something is wrong,” he said.
Ratard said he sees death and complications more often in people 65 years of age or older.
“It’s very important for older people to avoid being bitten by mosquitoes,” Ratard said. “There’s no good treatment to kill the virus.”
The other two less severe forms of the virus include West Nile fever, which causes mild, flu-like symptoms, and asymptomatic West Nile, which has no symptoms and is only discovered if blood work reveals a person has it.
DHH has reported seven fever and 14 asymptomatic cases since January.
Ratard said only the neuroinvasive cases can be considered representative, though, as 80-90 percent of the cases are asymptomatic. Generally, the more serious cases are the only ones reported to the state.
At this point last year, there were already 57 neuroinvasive cases, compared with 34 this year.
People get the virus after they are bitten by a mosquito that picked up the virus from a bird infected with West Nile, Ratard said.
“If you have a warm spring, you’re going to have a lot of multiplication of birds,” Ratard said. “If you have a cool spring, you’re not going to have as much. This season is lower than usual.”
Louisiana saw its first case of the virus in 2002, Ratard said.
Ratard said people need to remain cautious during the winter months.
Some species of mosquito are present primarily during the colder months, according to East Baton Rouge Mosquito Abatement and Rodent Control.
Ratard has a three-phrase slogan for prevention: “Not in my house. Not in my yard. Not on my skin.”
He said to keep windows and doors closed if you notice mosquitoes, pour out small containers that might gather water in the yard, and wear long sleeves or a repellent when outside.
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