Clinical signs can develop minutes after exposure, or they may not appear for hours. Symptoms of blue-green algae exposure include: 

• Vomiting and diarrhea
• Weakness 
• Itchy, red skin that develops into blisters 
• Drooling
• Disorientation
• Muscle tremors 
• Seizures
• Collapse
• Difficulty breathing 
• Paralysis 
• Death