Transmission of N. meningitidis Serogroup W, ST-11 During an International Flight

BACKGROUND: Following the 23(rd) World Scout Jamboree (WSJ) held in Japan from 28 July to 8 August 2015, a meningococcal disease outbreak due to Neisseria meningitidis (N. meningitidis) serogroup W, Sequence Type (ST) 11 occurred among scouts participating WSJ and their close contacts in Scotland and Sweden. On October 2, 2015, a doctor in Osaka city notified Osaka City Public Health Center an invasive meningococcal disease (IMD) case and a related carrier. They were married couple and were on the same international flight as Scottish scouts who had attended the WSJ and developed the disease later. In Japan, IMD is notifiable disease, however, it is rare (incidence rate of 0.028 per 100,000 person-years) and serogroup W is seldom reported. METHODS: National Institute of Infectious Diseases (NIID) interviewed the couple to collect detailed information about their travel history, degree of contact with the scouts on the flight, and her clinical course during their travel. In addition, NIID conducted molecular biological testing on the isolates derived from the couple and compared it with the strain from the scouts. RESULTS: Wife suddenly developed high fever and chills on 19 September. On 25 September, she visited a hospital and was diagnosed as septic arthritis and hospitalized the same day. Isolates collected from joint fluid were serogroup W, ST-11, the same strain isolated from Scottish scouts. Both the couple and the Scottish scouts were on approximately 12 hours flight from Japan to Germany departed on 8 August 2015. The Scottish scouts sat front of three rows of the couple as well as the seats directly across the aisle. The couple didn’t report a history of direct contact including conversation with the scouts, but noticed one scout seated right in front of them was coughing throughout the flight. The couple travelled to Spain and returned to Japan with neither contacting closely with local people nor attending large events. CONCLUSION: Our investigation and laboratory results strongly suggests that N. meningitidis was transmitted from the Scottish scouts to the couple during long international flight. Our investigation indicates the need to update the guidelines of in-flight transmission of meningococcal disease, including definition of close contacts. DISCLOSURES: All authors: No reported disclosures.