Person found sick after swimming in potentially harmful bacteria in Bull Creek

A person who played in Bull Creek over the weekend has developed symptoms that could be associated with exposure to harmful algae, the City of Austin reported on Thursday.

There has been no confirmation that the person's symptoms are correlated with algae from the creek or that there is harmful algae in the creek. Cyanobacteria, the blue-green algae that crops up in Central Texas waterways during warmer weather, can be harmful or fatal to dogs and has been the cause of several dog deaths in Austin in the past two years.

The report comes after Austin mother Leia Morris reported that her three-year-old son developed symptoms after playing at the Bull Creek Preserve on Sunday, although the city did not confirm that this was the case in question.

Morris told KXAN her son, Linus, woke up trembling on Monday and has experienced tremors and muscle twitches.

"When he woke up on Tuesday, once again I could see his muscles twitching — like I could visibly see that his fingers were twitchy," she told KXAN.

Although Bull Creek has no obvious signs of cyanobacteria, it is impossible to detect the presence of harmful algae without a lab sample. The City of Austin took algae and water samples Friday and expects to have preliminary lab results next week.

The city has been grappling with harmful algae outbreaks since 2019, when five dogs died after swimming in Lady Bird Lake in 2019. Small amounts of dihydroanatoxin, potentially dog-killing algae, has been found in an algae sample taken from Lake Austin near Mansfield Dam as well as two samples from Lady Bird Lake. Low levels of dihydroanatoxin have been detected in the Highland Lakes by the Lower Colorado River Authority this year, including Red Bud Isle in Jun. At least one dog has died in Lake Travis this year and many have been reported sick.

Toxins have only been detected in mats of algae growing on the bottom of the lake or floating on top and could become harmful if one swallows or touches visible algae. Swimmers should follow warning signs posted at these bodies of water and steer clear of warm, stagnant or foul-smelling water. Bacteria levels tend to be higher after rainfall.

In people, symptoms from the harmful bacteria could include:

• Dermatologic signs or symptoms such as rash, irritation, swelling, or sores
• Gastrointestinal signs or symptoms
• Respiratory signs or symptoms
• Fever
• Headache
• Neurologic signs or symptoms
• Ear symptoms
• Eye irritation

In dogs, symptoms may include:

• Excessive drooling, vomiting and diarrhea
• Foaming at the mouth
• Jaundice and hepatomegaly
• Blood in urine or dark urine
• Stumbling
• Loss of appetite
• Photosensitization in recovering animals
• Abdominal tenderness
• Progression of muscle twitches
• Respiratory paralysis