When medical professionals think they’re seeing something new, or an unusual spike in cases of something known, disease detectives — epidemiologists — are generally tasked with solving the mysteries of the case. Some of these seeming events turn out to be nothing more than coincidence. Some, however, are very real and teach us more about what a known disease agent can do or introduce us to a new bug that poses a hitherto unrecognized threat.
Increasingly, it appears that the mounting reports of unusual pediatric hepatitis cases will turn out to be the latter type of event. As of May 1, at least 20 countries reported 228 cases of pediatric hepatitis of unknown etiology or origin, with more than 50 suspected cases still under investigation. At least 18 of the children have required liver transplants and at least one has died, the World Health Organization said Wednesday. The question is no longer “Is this real?” but “What is triggering severe liver inflammation in previously healthy little kids?”