In legionellosis, which clinical presentation can occur?

• A. Person-to-person transmission is common
• B. Farm animals are important reservoirs
• C. Patients can present with a self-limited nonpneumonic febrile illness
• D. Specimens may be cold enriched to enhance recovery of the organism

Answer: (C)

Legionellosis can present in two main ways: a mild, self-limited febrile illness without pneumonia (Pontiac fever) and a more severe pneumonia (Legionnaires’ disease). The option describing a self-limited nonpneumonic febrile illness corresponds to Pontiac fever, which can occur after inhaling aerosols from contaminated water sources and typically resolves without pneumonia or specific antibiotic therapy.

Transmission is not person-to-person; Legionella spreads mainly through inhalation of aerosols from aquatic environments such as water systems, not by direct contact between people. The idea that farm animals are important reservoirs doesn’t fit, since Legionella’s main reservoirs are water systems and related biofilms, not livestock. Regarding laboratory processing, routine clinical diagnosis relies on specialized culture methods and other tests; cold enrichment is not a standard approach for routine recovery of Legionella from patient specimens.