Nigerian health authorities said Wednesday that four people have died following an outbreak of cerebrospinal meningitis in central Nigeria and warned the disease could spread due to the hot weather.

Laboratory tests have confirmed 31 additional cases of meningitis, an acute inflammation of the brain and spinal cord, in some areas of the central state of Niger.

The state's health commissioner, Mustapha Jibril, said the cases and deaths recorded so far are all from Niger. However, he said there could be a more severe outbreak and higher mortality rate due to the intensely hot weather.

Cerebrospinal meningitis outbreaks usually occur in the dry season due to low humidity and dusty conditions and end with the onset of the rainy season.

Last year, 17 states in Nigeria were affected, with Niger recording 33 deaths, according to official data, reports Xinhua.