More than 1,400 people across three provinces in Papua New Guinea are now confirmed to be suffering from cholera.
The illness, which can kill healthy people within hours, has claimed more than 30 lives in East Sepik, Morobe and Madang provinces.
Voitek Asztabski is the emergency coordinator for the PNG cholera outbreak with the organisation, Medecins Sans Frontieres.
He's concerned about the spread of the illness, particularly during the festive season.
"People will be moving in increased numbers and of course this is favourable for the spread of the disease. Hygiene is the main concern and plays a major role how to prevent the disease; washing hands after using toilet facilities, before cooking, before touching the food."
Voitek Asztabski says people should also make sure their food is stored properly.