How many Legionella species are known, and how many have been linked to Legionnaires' disease?

The correct answer highlights that there are more than 50 known species of Legionella, and out of these, less than half have been associated with cases of Legionnaires' disease. This distinction is significant because while numerous species exist in the Legionella genus, the majority are not pathogenic to humans. Legionnaires' disease is primarily linked to specific species, with Legionella pneumophila being the most prominent.

It is important to understand that the classification of over 50 species indicates the broad diversity within the family, yet it emphasizes that only a subset of these species pose a risk for human infection, which is crucial for assessing potential exposure and managing risks in plumbing systems and water sources. This knowledge helps public health officials and plumbing professionals focus their efforts on the relevant species that are of concern, ensuring more effective monitoring, prevention, and management strategies.

In summary, this answer correctly encapsulates the status of Legionella species in relation to their connection to Legionnaires' disease, underscoring the importance of targeted approaches in assessing and managing risks associated with these bacteria in water systems.