Should a water distribution system harboring Legionella anisa be disinfected?
The majority (>90%) of cases of Legionnaires’ disease reported in the U.S. are caused by Legionella pneumophila. L. anisa is frequently isolated from environmental specimens but almost never causes disease. L. anisa is generally nonpathogenic and disinfection is not necessarily indicated for this particular species (Yu VL, J Infect Chemother 2004).