The city of Austin says tests taken Aug. 12 at Red Bud Isle, Auditorium Shores and Barton Creek each found a higher level of harmful neurotoxins from algae than were present a week before. In an Aug. 14 press release, the city asked residents to keep pets away from Lady Bird Lake. In addition to the warnings about Lady Bird Lake, the city said pets should stay out of Barton Creek where algae is present. The “Barking Springs” area that is open to dogs near Barton Springs Pool is upstream of the area where neurotoxins were found, according to the city, and at this time the city said “people and pets can continue to swim in the area at their own risk,” according to the release. The city first warned residents not to let their pets swim in or drink from Lady Bird Lake on Aug. 4 after it was notified that a dog died after swimming in the lake. Since then, according to the city’s Aug. 14 news release, it has learned of three additional dogs who have died after swimming in the lake. The city closed Red Bud Isle on Aug. 7 and put up signs warning pet owners about the dangers of neurotoxins in the blue-green algae. 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. Lady Bird Lake is not used as a source of drinking water, and at this time drinking water is unaffected by the situation. It is illegal for people to swim in Lady Bird Lake.