MAIDUGURI, Nigeria (AP) — A cholera outbreak in northeastern Nigeria has killed 74 people and infected more than 7,000 others since it started in early May, medical charity Doctors Without Borders said Tuesday.

The outbreak, reported in 14 of Borno state’s 27 local governments, is unfolding in communities with health systems made fragile by nearly two decades of violent extremism from the Boko Haram insurgent group.

The illness is endemic and seasonal in the country, where only 14% of Nigeria’s population of more than 200 million have access to safely managed drinking water supply services, according to government data from 2020.

The situation is sometimes worse in Borno, both in Maiduguri, the state’s capital, which is densely populated, and in remote communities with poor sanitation and hygiene due in part to being out of the close reach of health authorities.

The medical group said that it has treated 7,439 cholera patients at its facilities, representing an average of 185 admissions per day. It said that it recorded 500 patients last week on Friday, a single-day record in the outbreak.

“Open defecation is making it worse also, and there is less partners (on the ground),” said Jessie Kurnurkar, a project coordinator with Doctors Without Borders, known by its French acronym MSF.

“By the time we know the cases in the community, the local transmission has happened, and it is difficult to respond, because the spread has become more,” Kurnurkar said.

Patients at an MSF treatment center in Maiduguri spoke to The Associated Press about their experiences in the outbreak.

Aisha Ibrahim, a cholera patient at the facility, said that she has been defecating nonstop since she became ill with cholera and had been in admission for more than four days.

“When they discharged me, the vomiting stopped, and when I got home, I started stooling again, and it became severe (so) I was rushed back to the center,” Ibrahim said.