It is not clear where the word "dengue" came from. Some people think that it comes from the Swahili phrase "Ka-dinga pepo". This phrase talks about the disease being caused by an evil spirit. The Swahili word "dinga" is thought to come from the Spanish word "dengue", which means "careful." That word may have been used to describe a person having bone pain from dengue fever; that pain would make the person walk carefully. However, it is also possible that the Spanish word came from the Swahili word, and not the other way around.