Subclinical Legionella infection in workers near the source of a large outbreak of Legionnaires disease.

A survey was conducted of exhibitors at a 1999 floral trade show, where a whirlpool spa on display caused a large outbreak of legionnaires disease (LD). In total, 742 exhibitors without LD returned a questionnaire on their whereabouts during the fair and their health afterward and supplied blood samples for the detection of IgM and IgG antibodies against Legionella pneumophila. The exhibitors had higher average antibody levels than did the general population. The closer to the whirlpool that the exhibitors worked, the higher their antibody levels. Both high-normal and high titer levels were found more frequently among workers with more exposure, suggesting that serosurveys among potentially exposed subjects are a valuable tool for outbreak investigation. Some differences in health complaints were observed between the more and less exposed groups, as estimated by the workplace location, but few differences were found between groups with different antibody levels.

Reemergence of pertussis in the highly vaccinated population of the Netherlands: observations on surveillance data.

We analyzed pertussis reporting, death, hospitalization, and serodiagnostic data from 1976 to 1998 to help explain the cause of the 1996 pertussis outbreak in the Netherlands. The unexpected outbreak was detected by an increase in pertussis reporting and by other surveillance methods. In 1996, according to reporting and serologic data, the increase in pertussis incidence among (mostly unvaccinated) children less than 1 year of age was similar to the increase in hospital admissions. Among older (mostly vaccinated) persons, the increase in hospital admissions was relatively small. The increase in pertussis incidence was higher among vaccinated than among unvaccinated persons of all ages. This resulted in lower estimates of vaccine effectiveness. The proportion of pertussis infections resulting in recognizable symptoms may have increased among vaccinated persons because of a mismatch of the vaccine strain and circulating Bordetella pertussis strains. The small immunogenicity profile of the Dutch vaccine may have resulted in greater vulnerability to antigenic changes in B. pertussis.

The incidence of pertussis in the Netherlands has remained high since an outbreak occurred in 1996.

The incidence of pertussis throughout the Netherlands, determined by notifications, rose suddenly in 1996 to reach 27.2 cases per 100 000 population, compared with 2.3/100 000 on average from 1989 to 1995. Earlier increases in 1989-1990 and 1994 reflected

Intensity, duration, and frequency of physical activity and coronary risk factors.

Relationships between coronary risk factors and intensity, duration, and frequency of leisure activity were studied in 5943 men and 6039 women, ages 25-69. Age, smoking, socioeconomics, season, body mass index (BMI), urbanization, occupational activity, and liquid, alcohol, and saturated/total fat intake were adjusted using multivariate regressions. Among men each 100 kcal.kg-1.wk-1 spent on vigorous activities (7.5-9.0 MET) was associated with: significant (P < 0.01) average differences of -0.36 mmol.L-1 total cholesterol, +0.17 mmol.L-1 HDL cholesterol (P < 0.001), +0.05 HDL/total cholesterol (P < 0.001), -0.33 mmol.L-1 triglycerides, -3 mm Hg diastolic blood pressure, -10 beats.min-1 heart rate (P < 0.001), +30 L.min-1 peak flow, and -1.1 kg.m-2 BMI. Among women it was associated with: -7 mm Hg systolic blood pressure, -6 beats.min-1 heart rate (P < 0.001), +50 L.min-1 peak flow (P < 0.001), and -1.4 kg.m-2 BMI (P < 0.05). Moderate activity (either 3.0-4.5 MET or 5.0-7.0 MET) was significantly (P < 0.05) associated with HDL cholesterol, BMI, and, for men, heart rate; for women, it was associated with HDL/total cholesterol, triglycerides, diastolic blood pressure, and peak flow. With duration and intensity constant, increasing frequency by one time per wk was significantly (P < 0.05) associated with -0.014 mmol.L-1 total cholesterol, +0.001 HDL/total cholesterol, -0.36 beats.min-1 heart rate, -0.093 kg.m-2 BMI among men, and +0.009 mmol.L-1 HDL cholesterol, +0.001 HDL/total cholesterol, -0.014 mmol.L-1 triglycerides, -0.31 beats.min-1 heart rate, and -0.098 kg.m-2 BMI among women. Serum lipids and BMI showed stronger associations with frequency than with intensity or duration.