An outbreak of cholera in the Republic of Congo has spread to the capital, Brazzaville, pushing the overall death toll to 53.

Health officials said Sunday that four of the nine people diagnosed with the disease in Brazzaville had died.

The cholera outbreak began in the coastal city Pointe Noire, where at least 49 people have died since early January. Special treatment centers have been set up, and health officials have urged citizens to follow basic hygiene guidelines.

Cholera is a waterborne disease that can occur in areas with poor sanitation and crowding. It is characterized by severe diarrhea, which can cause death from dehydration.