The first human cases of West Nile virus this year was diagnosed recently in Livingston Parish, Louisiana Department of Health and Hospitals reported Tuesday.

The three cases were from people who didn’t know they were infected and found out after donating blood or having blood work done.

The mosquito-borne West Nile virus affects people in different ways, with some people having no symptoms, some getting a fever-like condition and a few people contracting the most serious neuroinvasive disease where the virus attacks nerve cells.

This neuroinvasive form can cause brain damage or death.

Most people, about 90 percent, infected with the virus don’t get any symptoms at all while about 10 percent can get a fever, according to information from DHH. Very few people can get the most serious form. Last year, there were 34 cases of this severe form in the state.

“These three infections serve as reminders that West Nile virus is here and all residents are at risk,” Raoult Ratard, state epidemiologist, said in a news release. “Everyone should take simple steps to protect themselves, their families and their homes from mosquitoes, which spread West Nile virus to humans when they bite.”

Precautions including wearing mosquito repellent and dumping any standing water that might be around the home that can serve as a breeding ground for mosquitoes.