The Nigeria Centre for Disease Control and Prevention has alerted the public to fresh cases of diphtheria recorded in Lagos, Kano, Osun, and Oyo states.

Ifedayo Adetifa, NCDC’s director-general, issued the alert in a health advisory on Friday.

According to the alert, there is a high risk of diphtheria infection for children, adults who have not yet received the pentavalent vaccine, and people who reside in congested areas.

“People most at risk of contracting diphtheria: children and adults who have not received any or a single dose of the pentavalent vaccine (a diphtheria toxoid-containing vaccine); people who live in a crowded environment, people who live in areas with poor sanitation and healthcare workers and others who are exposed to suspected/confirmed cases of diphtheria,” the NCDC’s advisory stated.

The NCDC explained that diphtheria could spread from one person to another through coughing or sneezing droplets, close contact with an infected individual, or contact with contaminated objects like clothes.

“The onset of signs and symptoms usually starts after two to 10 days of exposure to the bacteria. Symptoms of diphtheria include fever, runny nose, sore throat, cough, red eyes (conjunctivitis), and neck swelling,” the agency said.

But in severe cases, according to the NCDC, “a thick grey or white patch appears on the tonsils and/or at the back of the throat associated with difficulty breathing.”

It recommended that infected persons “be closely monitored given antibiotics prophylaxis and started on diphtheria antitoxin treatment when indicated.”

Additionally, it was advised that healthcare professionals who might be exposed to confirmed cases while on the job get vaccinated.