Severe Meningococcal Disease Caused by Serogroups X and Z

The minor serogroups ofNeisseria meningitidis(X,Y, and Z-W135 and 29 E) were initially considered to be of low virulence and were thought to produce very mild clinical disease. However, since 1974, many reports have appeared in the literature that clearly document that severe meningococcal disease does occur with group Y and group W135.¹⁻⁷To our knowledge, there have been no previous reports of severe meningococcal disease in children caused by serogroups X or Z. We report two such cases. One case is that of severe meningococcemia and meningitis with disseminated intravascular coagulation (DIC) caused by group XN meningitidisand one is that of fatal fulminant meningococcemia and meningitis with DIC caused by group ZN meningitidis. Report of Cases.—Case1.—A 9-month-old infant was well until one day prior to admission, when she experienced fever, vomiting, and a rash. The child was seen at a local