First Sporadic Cases of Non-pneumonic Legionellosis, Pontiac Fever in Japan

Pontiac fever has rarely been found in sporadic cases. Here, we report the first sporadic cases of non-pneumonic legionellosis, Pontiac fever in Japan. Case 1. A 53-year-old man with spinocerebellar degeneration was presented to our hospital. He had an acute onset of high fever and consciousness disturbance. A chest X-ray film on admission was normal, but transient bilateral pleural effusions were revealed on hospital day 14. Case 2. A 77-year-old woman with gastric ulcer was presented to our hospital. She had an acute onset of high fever. A chest X-ray film on admission was normal, but transient bilateral pleural effusions were revealed on hospital day 7. High fever, resistant to β-lactam antibiotics, continued in both cases. Both had serologic confirmation of legionellosis by indirect fluorescent antibody assay for Legionella pneumophila without seroconversion for Mycoplasma pneumoniae, and Chlamydia pneumoniae, and had a good prognosis. Both were thought to be sporadic community-acquired cases rather than epidemics. (Internal Medicine 37: 1068-1071, 1998)