ABSTRACT
An outbreak of Pontiac fever occurred among 34 of 56 people attending conferences at a hotel in Santa Clara County, California, in 1988. Two groups had an acute febrile upper respiratory illness, with a mean attack rate of 82% and a mean incubation period of 56 hours. Symptoms resolved spontaneously within 5 days. Legionella anisa, which had not previously been associated with outbreaks of Pontiac fever or legionnaires' disease, was isolated from a decorative fountain in the hotel lobby. In addition, 5 of 8 pairs of serum samples from cases showed a more than fourfold rise in antibody titre to the L anisa recovered from the fountain. 42% of hotel employees had titres greater than or equal to 256 against L anisa, whereas none of 48 serum samples from matched controls had titres greater than or equal to 128. The findings raise concern about water treatment protocols for extent of disease that might be caused by exposure to aerosols containing L anisa and other Legionella species.
Subject(s)
Disease Outbreaks , Fever/epidemiology , Legionellosis/epidemiology , Acute Disease , Aerosols , Antibodies, Bacterial/analysis , California/epidemiology , Fever/etiology , Follow-Up Studies , Humans , Legionella/immunology , Legionella/isolation & purification , Legionellosis/complications , Legionellosis/immunology , Legionellosis/transmission , Water MicrobiologyABSTRACT
An outbreak of Neisseria meningitidis sero-group C disease occurred in four eighth grade students and in a younger sibling of another eighth grade student attending an intermediate school (seventh and eighth grades) in Santa Clara County, CA. Four cases had onset within 3 days in January, 1989, with the fifth case occurring approximately 10 days later. A case-control study was performed to determine risk factors associated with serogroup C meningococcal infection (disease or carriage) in this eighth grade class. Students were more likely to be infected if they had had a preceding viral-like respiratory illness characterized by fever (odds ratio (OR) 5.3, P = 0.03) or cough (OR 5.1, P = 0.048). A ski trip (OR 6.3, P = 0.01) and a poster-making session for a school dance (OR 3.7, P = 0.08) were identified as possible settings for a common exposure. Spending time with two specific students during lunchtime or outside of school was associated with an increased risk of infection (OR 7.0, P = 0.054; OR 5.8, P = 0.04).
