WASHINGTON - A total of 4,531 West Nile virus cases have been reported across the United States through Oct 16, including 183 death, researchers with the US Centers for Disease Control and Prevention (CDC) said Wednesday.

This is the second-worst year on record for the mosquito-borne disease since the record outbreak of 2003, when 9,862 cases were reported.

Almost 70 percent of the cases have been reported in eight states: Texas, California, Louisiana, Mississippi, Illinois, South Dakota, Michigan and Oklahoma.

West Nile virus is transmitted to people by infected mosquitoes. In the United States, most people are infected from June through September, and the number of these infections usually peaks in mid- August.

Approximately one in five people who are infected with West Nile virus will develop symptoms such as fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Less than one percent will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). About 10 percent of people who develop neurologic infection due to West Nile virus will die. There are no medications to treat, or vaccines to prevent, West Nile virus infection.

According to the CDC, the best way to prevent West Nile virus disease is to avoid mosquito bites: use insect repellents when you go outdoors; wear long sleeves and pants during dawn and dusk; install or repair screens on windows and doors; use air conditioning.