Nigerian health officials are issuing warnings over a cholera outbreak that has killed at least 30 people, many of them in the commercial capital Lagos, since the start of the year.

Cholera is an acute intestinal infection that spreads through contaminated food and water. It typically causes severe diarrhoea, vomiting and muscle cramps -- and sometimes death.

Lagos State health officials reported 15 deaths so far and 350 suspected cases, according to a statement on X, formerly Twitter this week.

Lagos Water Corporation warned against consuming water from unreliable or untreated courses.

"According to the Lagos State Ministry of Health, the primary cause of the cholera outbreak has been linked to the consumption of contaminated water and inadequate sanitation," it said in a statement.

Last week, the Nigerian Centre for Disease Control and Prevention alerted the public of the increasing trend in cases of the disease across the country as the rainy season intensifies.

The agency said 30 people had died since the start of the year. An outbreak killed 128 people with more than 3,600 suspected cases across Africa's most populous country last year compared to two deaths in 2022.

Nigeria is particularly vulnerable to cholera outbreaks.

In 2021, an epidemic killed more than 2,300 people, especially children under the age of 14, according to health authorities.