Hepatitis A virus infection is often described as mild or asymptomatic, particularly in children. The failure of most adults who are found to be immune to remember symptoms of an illness suggestive of hepatitis A virus supports this belief. In 1982, two large outbreaks occurred in well documented populations of military personnel. These outbreaks were each extensively studied epidemiologically and serologically. It was found that 28/29 (96.6%) hepatitis A infections recognized prior to immune serum globulin in Outbreak A and 35/46 (76.1%) infections in Outbreak A were symptomatic. Symptomatic cases failed to occur beyond eight days of immune serum globulin administration to these predominantly susceptible groups. Between 40 and 70% of patients were icteric. Apparent contrasts in symptoms associated with hepatitis A infection in adults and children suggest a basic age-dependent difference in immune response to such infection.

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People with type 2 diabetes appear to experience incremental decrements in work performance that may affect their current and future health and performance. Lower incomes of participants with diabetes suggest that both people with diabetes and their employers bear the cost of any work efficiency losses.

Airborne transmission of infectious agents and associations of indoor air pollutants with respiratory illnesses are well documented. We hypothesized that energy conservation measures that tighten buildings also increase risks of respiratory infection among building occupants. At four Army training centers during a 47-month period, incidence rates of febrile acute respiratory disease were compared between basic trainees in modern (energy-efficient design and construction) and old barracks. Rates of febrile acute respiratory disease were significantly higher among trainees in modern barracks (adjusted relative risk estimate, 1.51; 95% confidence interval, 1.46 to 1.56), and relative risks were consistent at the four centers. These results support the hypothesis that tight buildings with closed ventilation systems significantly increase risks of respiratory-transmitted infection among congregated, immunologically susceptible occupants.