African trypanosomiasis, more commonly known as "sleeping sickness," is a disease spread by infected tsetse flies. As for most parasitic diseases, its effects can be devastating, going as far as causing personality changes and frightening behaviors.

Sleeping sickness is only found in sub-Saharan Africa, and it disproportionately affects the Democratic Republic of the Congo (DRC). In the last decade, over 70% of cases have occurred in the DRC, according to the World Health Organization (WHO).

This horrific disease is spread by tsetse flies infected with protozoan parasites. It is hard to diagnose because its early symptoms are pretty generic: fever, muscle and joint pain, headache, fatigue. Initially the parasite is found in the blood, but after a while it invades the brain, causing mental deterioration and neurologic problems. If it is not treated, it eventually leads to a coma or death, which is where it gets the name "sleeping sickness."

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Sleeping sickness can develop within a matter of weeks, or years, depending on which parasite caused the infection. The more acute East African form of sleeping sickness (caused by the parasite Trypanosoma brucei rhodesiense) usually leaves a small, painful, and itchy ulcer at the site of the bite. Symptoms come on much faster — from a few days to a few weeks — and what starts as a high fever, rash, severe headache and muscle ache can quickly develop into neurological symptoms like poor sleep, behavioral changes, and confusion. It can become fatal within weeks or months, if left untreated.

West-African sleeping sickness (caused by caused by the parasite Trypanosoma brucei Gambiense) takes much longer to appear. Symptoms are similar to rhodesiense but also include weight loss, swollen lymph nodes, and face swelling. It could take months or even years after the initial bite for these signs to show. This can also develop into neurological symptoms months later and, if left untreated, will become fatal after several years.

When 32-year-old Ange Bukabau started acting erratic and out of control, her family members became frightened.

"I was going crazy," Bukabau told NPR.

Bukabau, who lives in a small town in the DRC, didn’t know she had contracted sleeping sickness. She was admitted to a hospital in time and was one of the first patients to be treated with fexinidazole, a new oral medicine against sleeping sickness — but initially, her family thought she had been cursed.

"They worried I was a danger to my children, so they took them both away," she told NPR. "I was alone."

There have been accounts of people with sleeping sickness attacking family members, experiencing scary hallucinations and screaming with pain when coming into contact with water, according to the New York Times.

Due to sustained control efforts, only 1,447 cases of sleeping sickness were reported in 2017.

One of the best preventative measures in evading this disease is to avoid contact with tsetse flies, which means wearing clothing that covers the body, and avoiding bushes. There currently is no vaccine, but new drugs are constantly being discovered. In November, an all-oral treatment called fexinidazole was approved to be used against sleeping sickness, which could mean big things in the fight against NTDs.

"What You Don’t Know About X" is a new series focusing on neglected tropical diseases (NTDs). NTDs are a cluster of parasitic and bacterial diseases. While you may have heard of a few of them, it’s likely you know very little about their actual effects or why they are so often overlooked. This series looks to shed light on these devastating — and preventable — diseases.