Sleeping Sickness

Introduction to Sleeping Sickness

Sleeping sickness or human African ‘Trypanosomiasis’ is a tropical disease caused by an infection with the flagellate protozoan ‘Trypanosoma brucei gambiense'. It is spread by the Tsetse fly. This tsetse fly species is native to the African continent. The bite of the tsetse fly causes a red sore. This disease can be fatal as it is capable of affecting our nervous system and it changes the patient’s personality, alters his biological clock and the patient may find difficulty in walking. In the rural part of East, West, and Central Africa more than sixty million people are at high risk of being affected by this disease.

Definition of  Trypanosomiasis

Trypanosomiasis is the disease caused by the flagellate protozoan Trypanosoma, belonging to the family Trypanosomatidae. It belongs to the order Kinetoplastida. There are twenty known species of Trypanosoma and only two species cause sleeping sickness in humans which are  Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Every known species is known for a different disease. This uses tsetse fly as a vector. There are two stages in the life cycle of Trypanosoma, the tsetse fly stage, and the human stage. The parasite enters the human body at the infective stage due to the biting causes by the fly and completes its cycle.

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Causes of Sleeping Sickness 

Sleeping sickness is caused by two flagellate protozoan parasites: Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Among these two parasites, Trypanosoma brucei rhodesiense causes a more severe form of illness. This disease isn’t contagious, it only spreads by the bite of an infected Tsetse fly.

Symptoms of Sleeping Sickness

The symptoms of this disease are characterized in two stages, based on the severity.

  • The infected person experiences fever, headache, muscle, and joint pain, and inflammation of the lymph nodes in the first stage. 

  • In the second stage the brain and spinal cord of the patient are affected and the patient experiences profound lethargy, sleep disturbances, and change in personality. This may lead to death. The second stage of the disease may take several weeks or years to be observed.

Causative Vector of African Sleeping Sickness 

In rural Africa, the Tsetse fly is a vector of this disease. It is a biting arthropod which belongs to the Glossinidae family.  Sleeping sickness causes parasites to feed on the blood of vertebrates. 

There are Two Types of African Sleeping Sickness.

  • East African sleeping sickness – This sleeping sickness is also called Rhodesian sleeping sickness. It is an acute form of the disease caused by the subspecies of T. brucei rhodesiense. This causes mental illness and even death.

  • West African sleeping sickness - This sleeping sickness is also called Gambian sleeping sickness. It is a slower developing chronic form of the disease caused by T. brucei ambiance. This can affect the brain and causes mental deterioration, coma, and death.

Sleeping Sickness Meaning

Tropical disease human African ‘Trypanosomiasis' has symptoms of difficulty in walking, change in personality, disturbance in biological clock and the most vibrant symptom is difficulty in sleeping. Hence the name of this vector spread disease is sleeping sickness. 

Sleeping Sickness Disease

Not only humans but also animals, cattle are affected by these protozoan parasites. Animal Trypanosomiasis is also known as nagana pest. Trypanosoma brucei and Trypanosoma vivax. 

  • In the animal, the incubation period is 4 days to 8 weeks.  The parasite is only detected by a blood microscopic examination.

  • The symptoms in animals are significant weight loss, anemia, fever, edema, adenitis, and nervous disorder.

Spreading of Sleeping sickness 

The sleeping Sickness is spread by tiny parasites carrying insects or fly Tsetse. It causes swelling of the brain. The spread of this disease is generally limited to the African continent, but few cases can be observed in other places, like if a traveler who recently traveled to the tropical area has a high chance to get bitten by the vector of this disease and may be diagnosed through this disease.

Sleeping Sickness Prevention

The main way to prevent this disease is only by reducing the reservoirs of the infection or the number of the Tsetse fly. The screening of the patient at an early stage can help to cure the disease, as treatment of the second stage of this disease is more complicated, difficult, risky, and can be fatal. 

Sleeping Sickness Treatment

There are only four drugs that are registered to treat the sleeping sickness disease, those are Pentamidine, Suramin, Melarsoprol, and Efrolnithine. 

A drug named Nifurtimox is used in combination under special authorization. All of the drugs have a certain level of toxicity and the administration of these drugs is complex. Hence the treatment of this disease is difficult.

FAQ (Frequently Asked Questions)

1. Is Sleeping Sickness Disease Contagious? Why is this Disease Fatal to Humans?

Sleeping sickness disease is not contagious as it is only spread by biting off the vector named Tsetse fly and the fly is native to the African continent. So the rural area has several patients with this disease.

The parasite of these bacteria affects the nervous system of the patient at the second stage of the disease. It may lead to alteration of the biological clock, change in personality, difficulty in walking, and sleeping. There is the presence of only a few drugs that can cure this disease and those are termed to have a certain level of toxicity. So, the disease is fatal to humans.

2. What is the Meaning of the Reservoir of Infection?

Any living organism or, a substance in which the parasite lives or, multiply themselves through the process of reproduction without harming that organism or substance is known as the reservoir of infection. The reservoir of infection acts as a source of the infection from which other individuals are affected.  Basically, a vector is considered as a reservoir of infection. In the case of sleeping sickness, Tsetse fly is the reservoir of infection, as the flagellated protozoan is transmitted from it but the fly is not affected by the parasite.