The figure above is a bar chart showing selected notifiable disease reports for the United States with comparison of provisional 4-week totals through December 22, 2018, with historical data. Reports of acute hepatitis A, acute hepatitis C, legionellosis and measles increased with acute hepatitis A and measles increasing beyond historical limits. Reports of giardiasis, acute hepatitis B, meningococcal disease, mumps and pertussis decreased.