Hepatitis A in Pohnpei State, Federated States of Micronesia, 2008-2009.

An epidemic of infectious hepatitis caused by the hepatitis A virus was detected in Pohnpei State, Federated States of Micronesia (FSM), beginning in November 2008. Epidemiologic investigation revealed that the index case occurred in late June 2008 in a traveler from nearby Chuuk State, which itself had experienced an epidemic of hepatitis A in the first half of 2008. Most cases have been confirmed by IgM serology, the rest by a clinically compatible syndrome with either jaundice or elevated liver enzymes. The most commonly affected group has been school-aged children; it is likely that the paucity of patients in the 40-50 year age group represents immunity conferred during the previous epidemic of hepatitis A in the early 1970's, as hepatitis A is not thought to be endemic in Pohnpei. As of September 17, 2009 there have been 300 reported cases with 17 hospitalizations (6%) and one death (0.3%). The epidemic peaked in April 2009, with a sharp decline in cases in June attributable with the end of the school year, as schools were found to be the major focus of infection. Efforts to control the outbreak have centered on public awareness and improved hygiene initiatives, particularly in schools. The greatest challenge to ongoing diminution of the outbreak is the recent resumption of the school year; control efforts, especially improved hygiene, will need to be sustained with renewed vigor if we are to extinguish the outbreak.