A 73-year-old New Castle County man has died of the West Nile Virus — making him the first Delawarean to die from the disease since 2012.

The state is experiencing the highest number of West Nile cases in the past three years with five cases for far this year.

The last West Nile-related death was six years ago when a 76-year-old New Castle County woman died.

The worst year for West Nile that health officials could recall was 2012, when nine Delawareans were diagnosed with the virus. The virus is spread by mosquito bites, and peak mosquito season traditionally ends with cooler weather at the end of October.

The other 2018 cases involved four older Delawareans. Three are from New Castle County, and the other is from Sussex.

Health officials are urging people to apply Environmental Protection Agency-approved bug repellent whenever they go outside and to cover their arms and legs.

Because a majority of people who have the virus do not develop symptoms, it is likely there are more reported cases in Delaware, health officials said.

Symptoms in humans include headache, body aches, a skin rash on the chest or back and swollen lymph glands, health officials said. Those who experience these symptoms should see their doctor immediately.

The virus is particularly hard on people who are older and have weaker immune systems.

About 80 percent of the people infected with the virus will not become ill, officials said. Less than 20 percent of people infected will develop West Nile fever with mild symptoms. One in 150 people infected will develop a severe infection, which can include meningitis.

There are no human vaccines, but there are vaccines for horses.

People who are older and have weaker immune systems tend to experience the most serious consequences of the virus.

This summer, the Department of Natural Resources and Environmental Control has seen an increase in the virus found in wild birds and sentinel chickens, officials said. The large amount of rain Delaware experienced this spring and summer led to an increase in mosquito activity.

DELAWARE HEALTH

State: Flu confirmed in all three counties; 1 hospitalized

Pancreatic cancer battle: To give her husband a chance, this Wilmington woman is all business

State: Millsboro resident bitten by rabid cat, undergoing treatment

Contact Meredith Newman at (302) 324-2386 or mnewman@delawareonline.com and on Twitter @MereNewman.