Molecular taxonomic studies at CDC and elsewhere have identified 13 named and 4 unnamed species of pathogenic leptospires. Leptospirosis causes a wide range of symptoms, and some infected persons may have no symptoms at all. Symptoms of leptospirosis include high fever, severe headache, chills, muscle aches, and vomiting, and may include jaundice (yellow skin and eyes), red eyes, abdominal pain, diarrhea, or a rash.