Diphtheria is a highly contagious, infectious disease caused by a bacterium called Corynebacterium diphtheriae which makes a toxin. It is the toxin that can cause people to get very sick.
The infection affects the nose, throat, and sometimes, the skin of an individual
The Nigeria Centre for Disease Control and Prevention on Friday confirmed reports of diphtheria cases in Lagos and Kano states.
The NCDC also said it was monitoring the situation in Osun and Yobe states where cases are now being picked up.
Diphtheria is fatal in five to 10 per cent of cases, with a higher mortality rate in young children.
As of January 13, no fewer than 25 persons have been killed by the infectious disease, with 58 suspected cases in Kano state.
Data from the NCDC showed that there was an outbreak of the disease in Borno state in 2011 with a total of 98 cases, and 21 deaths (case fatality ratio was 21.4 per cent).