Health department urges beachgoers to not swim in affected waters at beaches, including Siesta Key, Lido, Venice and Manasota Key.

The harmful algal bloom was detected in background to medium levels up and down the coast in samples taken on Tuesday.

A health alert has been issued for multiple beaches in Sarasota County after low to medium levels of red tide were detected.

A red tide alert has been issued for multiple Tampa Bay area county beaches, the Florida Fish and Wildlife Conservation Commission announced Wednesday.

The reports of red tide are coming from an algae bloom that is more than 100 miles long, stretching along much of the Gulf Coast.

· Red tide can cause illness and death of other animals, such as pets and livestock. Keep animals away and out of the water and sea life and away from dead marine life. If your pet swims in waters with red tide, wash them with soap and water as soon as possible.

Red tide that has lingered miles offshore from the Sarasota and Manatee shoreline has been pushed closer to local beaches by a shift in the winds.

Low concentrations of red tide were detected this week at New Pass Dock in Sarasota Bay, on the north end of Lido Key. State environmental officials say higher concentrations are being found off the coast of Charlotte County, with the most found about three miles west of Little Gasparilla Island.