Benjamin Dahl: Sleeping Sickness is Major East African Killer When Undiagnosed

Human African Trypanosomiasis (HAT) is a parasitic disease transmitted through the bite of the tsetse fly and is found in 36 countries in sub-Saharan Africa, including Tanzania. HAT is commonly known as sleeping sickness. Many people are surprised to hear that it is still a problem and in many ways it has been forgotten since sleeping sickness now usually only sickens poor farmers or honey gathers living at the end of the road. Occasionally a tourist on safari will also get sick but that is rare. The name sleeping sickness may sound benign but in reality it is devastating disease, first often misdiagnosed as malaria, HIV/AIDS or mental illness. Untreated it is 100% fatal.

From 2002 until 2009 I worked with a hospital in Kaliua, Tanzania (about 90 km west of Tabora, in central TZ) to establish sub-regional surveillance for HAT. The area around Tabora is the historical foci for sleeping sickness in TZ though cases had dropped off dramatically from the epidemics seen in the first half of the 20th century. In the late 1990s there started to
be an increase in cases and by 2002 there were more cases than had been seen in a generation. The investigation showed that this was linked to people moving into areas where they had more contact with tsetse flies and the wild animals that are the host of the parasite in East Africa as well as a lack of control efforts against the tsetse.

The project demonstrated the need for more control and better efforts to treat those infected with the parasite. The Ministry of Health and the local health center have responded and the number of cases is starting to decline. This situation will have to monitored and health officials will have to remain vigilant in order to prevent new epidemics. The primary challenge will be that the rural population has limited access to the specialized treatment needed for HAT.

Benjamin Dahl is an epidemiologist with the US Centers for Disease Control, based in Atlanta, GA.