Observers say that Nigeria's security forces are rounding up large numbers of young men under dubious claims they are insurgents. Many are never seen again.
The group that claimed responsibility for the attack may have links to Boko Haram, a militant group known for its terror campaigns in the region.
The Islamist militant group Boko Haram is thought to be behind the recent gruesome attacks. But suspicion about vaccination campaigns has deeper historical roots in northern Nigeria, writes John Campbell.
Western nations and international agencies admire the reform efforts of Nigeria's new finance minister. But Ngozi Okonjo-Iweala faces daunting challenges in cleaning up embedded corruption.
Africa is booming with young entrepreneurs, but they don't always operate like their counterparts in the US.