The city of Austin is advising people not to allow pets to swim in or drink water from Lady Bird Lake after being notified that three dogs died after swimming in the lake, according to an Aug. 5 news release. On Sunday, city scientists noted the presence of clumps of algae in Lady Bird Lake. Preliminary results indicate it is a type of blue green algae that can release a neurotoxin that can be harmful to pets and people if a sufficient quantity is ingested. The algae is especially prevalent near Red Bud Isle, where it covers up to 40% of the water surface, per the release. City officials closed Red Bud Isle and Barton Springs Greenbelt on Aug. 7 due to safety concerns. They have also posted signs around Lady Bird Lake indicating the danger and will be distributing information to residents, visitors and business on the lake. Updates can be found here. Dogs who ingest water contaminated with this toxin could have a number of symptoms within minutes or hours of exposure. Symptoms include excessive drooling; vomiting and diarrhea; foaming at the mouth; jaundice; bloody or dark urine; stumbling; loss of appetite; abdominal tenderness; a progression of muscle twitches; and respiratory paralysis. Austin Water regularly looks at algae levels on Lake Austin and Lake Travis and has not seen levels of concern for drinking water. Austin Water does not use Lady Bird Lake for drinking water. Austin Public Health tracks emergency department visits and has not seen any increases in unusual conditions that may be related to exposure to the water. It is illegal for people to swim in Lady Bird Lake.