ABUJA, NIGERIA/PARIS—A cholera outbreak is underway in camps for people displaced by the conflict with Boko Haram in Nigeria's Borno state, the international medical humanitarian organization Doctors Without Borders/Médecins Sans Frontières (MSF) said today, calling for other humanitarian organizations to join the effort to halt it.

More than 1.6 million people are now displaced in Borno state, the majority of whom are in the capital, Maiduguri. The first cases of cholera appeared a month ago in an internally displaced persons (IDP) camp in Maiduguri and then spread to two of the city's other IDP sites. As of yesterday, 172 cholera cases and 16 deaths have been officially recorded.

In cooperation with the Borno State health authorities, MSF is providing emergency medical and logistics services to fight the epidemic. From September 10 to 15, 187 patients were admitted to MSF's cholera treatment center, which has a 100-bed capacity. Sixty-four percent were severe cases. The least serious cases were treated in outpatient oral rehydration facilities.

In tandem with providing medical care, MSF initiated an effort in late August to improve hygiene and sanitation in the camp where the first cholera cases appeared. This includes the chlorination of water sources, provision of chlorine solution for hand-washing, and home disinfection when a case is identified.

Since then, MSF personnel have also worked in the second affected camp, where they identified a contaminated water source. In mid-September, MSF launched the same type of operation in the third affected camp.

"Once again, MSF and the International Committee of the Red Cross find themselves alone," as the only international organizations currently responding to the cholera outbreak, said Ghada Hatim, MSF head of mission in Nigeria.

In September 2014, MSF treated more than 4,000 patients after a cholera epidemic broke out in Borno State.

"The living and hygienic conditions in the camps were and remain ripe for the outbreak of this type of epidemic," said Chibuzo Okonta, MSF emergency projects manager in Paris. "We need more support. We have repeatedly called on other humanitarian and aid organizations to assist displaced persons in Borno State and are again issuing this appeal, which has gone unanswered."