Earlier this month, beaches in Sarasota, Manatee, and Hillsborough counties fell under a “no swim advisory. The presence of enterococcus bacteria comes from a variety of factors, health officials say. This includes pet waste, livestock, birds, land-dwelling and marine wildlife, stormwater runoff, and human sewage. However, there haven’t been any sewage spills reported within one mile of the beaches listed in the past two weeks.