What are the other Names for this Condition? (Also known as/Synonyms)

• African Sleeping Sickness
• Human African Trypanosomiasis
• West African Sleeping Sickness

What is Sleeping Sickness? (Definition/Background Information)

• Sleeping Sickness (or African Trypanosomiasis) is a disease caused by Trypanosoma brucei. These parasites are predominantly found in sub-Saharan Africa. They are transmitted to humans by the bite of a tsetse fly (Glossina species)
• After being bitten by the fly, individuals develop a red sore. Later, fever, fatigue, rash and pain in the joints and muscles may set in. As the disease progresses, excessive sleepiness and other neurologic abnormalities may develop
• The African Sleeping Sickness is treated using medications; however, periodic follow-up checks are necessary to ensure a complete cure
• With prompt diagnosis and treatment, the prognosis is good. In the absence of treatment, the condition may progressively worsen with the involvement of the central nervous system, resulting in death

There are two known subspecies of the parasite that can cause Sleeping Sickness. Each of these is found in different regions of Africa:

• Trypanosoma brucei gambiense: It is responsible for the West African Sleeping Sickness and accounts for the largest number of cases of Sleeping Sickness. If left untreated, it eventually leads to death within a few years
• Trypanosoma brucei rhodesiense: It is responsible for the East African sleeping sickness. In this condition, the symptoms arise within 1 to 2 weeks of the infectious bite. If left untreated, it could lead to death within weeks to months

Who gets Sleeping Sickness? (Age and Sex Distribution)

• Any individual, irrespective of age, gender, race, and ethnicity, could get Sleeping Sickness, if they are exposed to bites from the tsetse fly (in the endemic regions of Africa)
• In 2010, it was reported that about 10,000 new cases of Sleeping Sickness emerge each year. However, because the condition is prevalent among poor populations and in rural areas, not all cases of the infection may be diagnosed or even reported
• West African Sleeping Sickness is predominant in rural regions of western and central Africa, with most cases occurring in Democratic Republic of Congo, Angola, Sudan, Central African Republic, Chad, and northern Uganda. T. b. gambiense parasites are commonly found in forests, along rivers and streams. Prolonged stay in these rural areas poses a risk to both natives and tourists
• East African Sleeping Sickness (T. b. rhodesiense) is common in areas of eastern and southern Africa, especially Uganda, Malawi, and Zambia. The tsetse flies and the T. b. rhodesiense parasite are typically found in the grassy savannah areas, placing the local population, tourists, and hunters at risk

Individuals in the urban regions generally do not have an increased risk of acquiring Sleeping Sickness.

What are the Risk Factors for Sleeping Sickness? (Predisposing Factors)

The risk factors associated with Sleeping Sickness include:

• Residing in or traveling to African regions where the disease is prevalent
• Infants born to women with Sleeping Sickness may also be at risk for contracting the disease 
• Rarely, the disease can be transmitted via sexual activities or blood transfusions

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Sleeping Sickness? (Etiology)

• Sleeping Sickness is caused by two different parasitic subspecies of Trypanosoma brucei species, namely T. b. rhodesiense and T. b. gambiense. The trypanosomes are single-celled protozoan parasites
• Sleeping Sickness is spread most commonly through the bite of the tsetse fly found in rural Africa, after they feed on wild and domestic animals that primarily host the parasitic Trypanosoma brucei species
• The tsetse flies are large flies (somewhat resembling houseflies) about a quarter to half an inch in size, found all over mid-continental Africa. They typically feed on the blood of animals
• In the case of West African Sleeping Sickness, humans are the primary reservoirs (sources) of the T. b. gambiense parasite. But, it can also be found in animals including pigs, dogs, and goats
• However, in East African Sleeping Sickness, both animals and humans are sources of the T. b. rhodesiense parasite
• There is also a chance for unborn babies to acquire the infection from their mothers
• Sexual contact and blood transfusions are also other possible, but rare transmission routes

What are the Signs and Symptoms of Sleeping Sickness?

There are two stages of Sleeping Sickness in humans.

When an infected tsetse fly bites a human, it injects trypanosomes (parasites) into the individual’s lymphatic system, which eventually enter the bloodstream. A red sore (called a chancre) can form at the bite site. This is the first stage of infection and may last a few weeks to month with the following symptoms:

• Fever, sweating
• Severe headache                                                                            
• Rash
• Aching muscles and joints
• Swollen lymph nodes all over the body
• Fatigue and anxiety

When the parasites enter the central nervous system, the infection has advanced to the second stage and the following symptoms are noted:

• Sleepiness (may be uncontrollable or excessive, especially with West African Sleeping Sickness); drowsiness during the day
• Night time sleep disturbances
• Personality changes
• Progressive confusion, irritability
• Mental deterioration
• Slurred speech
• Difficulty walking
• Coma

In East African Sleeping Sickness, the infection can spread to the central nervous system (CNS) in a span of few weeks; whereas, the West African Sleeping Sickness progresses much slowly. It can take several months to a year before symptoms appear. Spreading of the infection to the CNS usually does not occur until about 1-2 years after the initial infection.

How is Sleeping Sickness Diagnosed?

The diagnosis of Sleeping Sickness may involve:

• Thorough evaluation of the individual’s medical history including recent travel history and a complete physical examination
• Sleeping Sickness is diagnosed through the examination of an individual’s blood, body fluids, or tissue sample under a microscope. The purpose of these diagnostic tests is to test for the presence of the infectious parasites in the body
•  T. b. rhodesiense parasites (causing East African Sleeping Sickness) are often easily detectable in blood. They  can also be detected by testing the lymph node, fluid, and/or biopsy from the chancre (sore formed from the bite of a tsetse fly)
• Diagnosing T. b. gambiense infection primarily involves examining the lymph node samples under a microscope, as these parasites, unlike T. b. rhodesiense, are not easily detectable in blood
• Serology tests may be used to diagnose T. b. gambiense to facilitate screening for the infection. Diagnostic microscopy may or may not be required based on the serology results.

Additionally, the cerebrospinal fluid of every patient diagnosed with Sleeping Sickness will need to be studied to assess, if the infection has spread to the central nervous system.

• Elevated protein levels and a white cell count of more than 5 (cells per microliter) in CSF indicates spread of the infection to the central nervous system
• Knowing the extent of spread of the infection can aid healthcare professionals in selecting the appropriate treatment for the individual

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Sleeping Sickness?

Complications of Sleeping Sickness or Human African Trypanosomiasis may include:

• Uncontrollable sleepiness is one of the key symptoms of Sleeping Sickness. A possible complication is injury due to falling asleep while engaging in activities such as driving, operating a machinery, etc.
• Progression of the disease to the second stage (spread of infection to the CNS) could lead to much more severe conditions such as coma or death

How is Sleeping Sickness Treated?

The type of drug treatment for Sleeping Sickness is dependent on the parasite responsible for the infection and stage of the disease. There are currently 4 types of medications available to treat the condition:

• Pentamidine - used to treat early-stage West African Sleeping Sickness
• Suramin - used to treat early-stage East African Sleeping Sickness
• Melarsoprol - used to treat advanced stage of both types of Sleeping Sickness
• Eflornithine - used to treat advanced stage of West African Sleeping Sickness

Even after treatment, individuals with Sleeping Sickness should have their cerebrospinal fluid examined periodically, for up to 2 years to monitor for potential relapse.

How can Sleeping Sickness be Prevented?

Currently, there are no vaccines to protect against Sleeping Sickness. Avoiding staying in or travelling to the endemic regions of the disease (particularly in the forests, along rivers and streams, and the savannah areas) is the best measure of prevention. If residing in or traveling to such areas cannot be avoided; then, the following are recommended:

• Wearing long-sleeved shirts and pants made of thick fabric, as the tsetse flies can bite through thinner material
• Wearing clothing with neutral colors, as the tsetse flies are attracted to bright and dark colors
• Keeping away from the bushes and grassy areas, so as to not to disturb the flies resting in them, particularly during the hottest part of the day
• Applying approved insect repellents while travelling, camping, or residing in such endemic regions
• Avoiding drives in open vehicles, such as jeeps, as the tsetse flies are attracted to the dust from moving vehicles

The following measures may also be utilized to control the spread of Sleeping Sickness:

• In the case of T. b. gambiense, where humans are the predominant reservoirs of infection, the population can be screened to identify and treat infected individuals. This strategy can help minimize the human transmission of Sleeping Sickness
• It is however more difficult to control the number of individuals infected with T. b. rhodesiense, as animals can also serve as reservoirs of the disease. In this case, the prevalent strategy used to control Sleeping Sickness involves reducing the number of tsetse fly vectors. This is typically done using insect traps and insecticides

What is the Prognosis of Sleeping Sickness? (Outcomes/Resolutions)

• Generally, the prognosis is favorable, if the individuals are promptly diagnosed and suitably treated
• Both the types of Sleeping Sickness, if left untreated, spread to the central nervous system and could lead to death
• In the case of East African Sleeping Sickness, the central nervous system is affected in a short span of time (within weeks) leading to CNS symptoms. Typically, death occurs within 6 months from the onset of infection
• Compared to East African Sleeping Sickness, the progression of West African Sleeping Sickness is much slower. It takes about 1 to 2 years before the CNS is infected, eventually leading to death within several years

Additional and Relevant Useful Information for Sleeping Sickness:

• Animal African Trypanosomiasis is known as “Nagana”
• In the United States, Sleeping Sickness is rarely diagnosed; about 1 case per year is reported among travelers