Florida health officials on Wednesday confirmed the year’s second case of West Nile virus in Miami-Dade County.

Officials say a resident there contracted the virus from a local transmission.

The Miami-Dade Health Department declared a mosquito-borne illness alert on May 9, after the area’s first confirmed case of the year.

Because of a lack of preventative vaccines or medication, West Nile virus is considered to be the country’s leading cause of mosquito-borne disease, according to the health department.

Most people who become infected do not feel sick. Additionally, officials say that about one in five people end up experiencing symptoms such as pain, headache, fever and fatigue that usually appear around two to 14 days after an infected mosquito bites.

Fewer than one percent of infected people can develop a severe or potentially fatal illness. People over age 60 or people with weakened immune systems are also at an increased risk for severe cases of West Nile Virus.

The Miami-Dade Health Department is also asking residents to follow the “Drain and Cover” personal protection efforts, reminding them to drain any items or areas that can collect standing water, in order to keep mosquitos from populating near residencies.

Residents are also being reminded to cover their skin with long sleeves, pants and tall socks, and to apply mosquito repellent onto bare skin.