Quinhas Fernandes, the provincial chief doctor, said that at least 400 new cases have been reported in the past two weeks in Cabo Delgado.

"Cholera is always an emergency situation, it's still under control but we are going to boost campaigns ... in order to avoid its rapid spread," he told Reuters.

Last year over 44,000 cases of cholera were recorded in the province. Over 39,000 cases have been recorded since January this year, officials said.

The new outbreak has been blamed on contaminated water and poor sanitary conditions. Cholera is an extreme diarrheal disease caused by ingesting contaminated water or food.

Fernandes said most of the people have been drinking water from shallow rivers and wells that are close to toilets.

Health authorities in Cabo Delgado have warned that the outbreak could rise as the rainy season reaches its peak, particularly in the Impirre district, where most of the 15 deaths occurred.