At least eight confirmed and suspected cases of invasive meningococcal disease (IMD) have been reported in scouts from Scotland and Sweden after returning from a scout gathering in Yamaguchi City in Japan earlier this month.

 Gram-negative Neisseria meningitidis diplococcal bacteria/CDC
Gram-negative Neisseria meningitidis diplococcal bacteria/CDC

To date, only Sweden (4) and the UK (4) have reported cases in scouts who attended the 23rd World Scout Jamboree and their contacts which was held from 28 July to 8 August. To date, no other European countries have reported cases.

The European CDC reports, the meningococcal serogroup W (MenW) strain has been identified as the causative agent in two of the cases in the UK. Preliminary typing suggests that the strain is indistinguishable from the strain that has been increasingly seen in England since 2009. The index case has not been identified. It is not uncommon for young people to be asymptomatic carriers of meningococci, and because the majority of IMD cases result from recent transmission following close contact with an asymptomatic carrier, it is likely that one or several scouts attending the Jamboree were indeed carriers.

It has not yet been established if the Swedish and Scottish cases interacted and possibly shared a close contact. However, the number and frequency of close contacts between participants at a Jamboree is expected to be high. It is known that scout units from Finland, France, Sweden, Switzerland, and the US stayed in tents close to the UK units’ campsites. In addition, a disco was arranged every third day, where all groups at the Jamboree mixed.

Health Protection Scotland sent an ‘advise and inform’ letter to the participants from other units in Scotland who attended the Jamboree, and approximately 4000 letters were also issued to other participants in the rest of UK alerting them to the signs and symptoms of disease.

The Sweden Public Health Agency reported finishing giving prophylactic antibiotics against meningococcal to the scouts who attended a camp in Japan. Approximately 1900 adolescents and young adults attended the scouting event in Japan.