The Florida Department of Health in Volusia County has lifted a swimming ban at four beach approaches.
Water samples in late December found high levels of bacteria at the Seabreeze Boulevard, Main Street, International Speedway Boulevard and Silver Beach Avenue beach approaches.
The health department said migrating birds dropping waste led to the unsafe levels of enterococci bacteria.
The bacteria can cause gastrointestinal illness, upper respiratory infections or skin infections if in contact with open wounds or sores.