Health officials are unsure how this year's outbreak began.
However, some believe it could be caused by the bubonic plague, which is endemic in the remote highlands of Madagascar.
If left untreated, it can lead to the pneumonic form, which is responsible for two thirds of the cases recorded so far in this year's outbreak.
Rats carry the Yersinia pestis bacteria that causes the plague, which is then passed onto their fleas.
Forest fires drive rats towards rural communities, which means residents are at risk of being bitten and infected. Local media reports suggest there has been an increase in the number of blazes in the woodlands.
Without antibiotics, the bubonic strain can spread to the lungs - where it becomes the more virulent pneumonic form.
Pneumonic, which can kill within 24 hours, can then be passed on through coughing, sneezing or spitting.
However, it can also be treated with antibiotics if caught in time.
Madagascar sees regular outbreaks of plague, which tend to start in September, with around 600 cases being reported each year on the island.
However, this year's outbreak has seen it reach the Indian Ocean island's two biggest cities, Antananarivo and Toamasina.
Experts warn the disease spreads quicker in heavily populated areas.