Nigeria

The tubers are essential to the country's economy and culture, but their quality keeps declining. Now, researchers have found a way to mass produce good seed yams — and it could save the industry.

But officials offered no further clarity on the illness that has repeatedly sidelined Muhammadu Buhari this year. In announcing the visit, a spokesman merely stated that "there is no cause for worry."

Nigerians are raising concerns about the health of Muhammadu Buhari, who hasn't been seen in public for more than a week and has missed his third straight cabinet meeting.

Doctors Without Borders says the death toll may be significantly higher, with the majority of the victims women and children. The government has said the strike in restive Borno state was an accident.