KEY POINTS:
Somali Islamist militants have killed four people at a school in Baladwayne, two of them Somalis holding British passports, and two Kenyans.
Somali Islamist militants have killed four people at a school in Baladwayne, two of them Somalis holding British passports, and two Kenyans.
A significant portion of deaths take place within 48 hours of the onset of symptoms.