ABUJA, June 15 (Xinhua) -- A cholera outbreak in Nigeria has killed more than 90 people and infected thousands since May, with the country's northeastern region bearing the brunt of the disease, local authorities have said.

The northeastern state of Borno recorded more than 85 deaths and 8,457 cases between May 1 and June 7, according to the state government, with Maiduguri, the state capital, being the hardest-hit area due to high population density and overcrowded displacement camps.

In the central state of Plateau, health officials confirmed on Sunday that five people had died, while 11 confirmed cases and 53 suspected cases were reported.

Saleh Kaza, head of the Borno State Contributory Healthcare Management Agency, described the situation as "a serious public health emergency that has overwhelmed the health infrastructure and emergency response systems."

Health authorities said the outbreak has been fueled by the onset of the annual rainy season and compromised water infrastructure.

In April, the Nigeria Centre for Disease Control and Prevention placed 10 states on high alert over the risk of cholera outbreaks linked to heavy rainfall and flooding, warning that the affected regions face an elevated risk of cholera.

The Nigerian government has activated its incident management system and deployed health teams to affected regions. International organizations, including the World Health Organization, the United Nations Children's Fund, and the medical charity Doctors Without Borders, have joined in the fight against the outbreak.

Bukar Tijjani, secretary to the Borno State Government, said the state has implemented emergency measures, including restricting access to water sources such as local dams and reservoirs, and expanding the supply of safe drinking water through tankers, while investigations into the source of the outbreak are underway.

Cholera, an acute diarrhoeal disease caused by contaminated food or water, remains a significant public health challenge in Nigeria, particularly in states affected by flooding and poor water and sanitation infrastructure.