This 1966 microscope photo shows five colonies of Group-B Neisseria meningitidis bacteria. On Thursday, March 28, 2024, the CDC issued an alert to U.S. doctors about an increase in cases of one type of invasive meningococcal disease, mostly due to the serogroup Y strain of the bacteria. Four hundred and twenty two cases were reported in 2023, which was the most in a single year since 2014. There have been 143 reported this year so far. (Dr. Brodsky/CDC via AP)