Sleeping sickness: symptoms, causes and treatment

Sleeping sickness or African trypanosomiasis is a parasitic pathology dependent on a vector for transmission, in this case, a fly.

It is a disease that has generated several epidemics during the 19th and 20th centuries in various areas of Africa. Even so, today its distribution is focal, which is why it occurs endemically in 36 African countries. Like most invertebrate vector-dependent diseases, this pathology flourishes especially in warm environments with poor health conditions.

Despite how remote it may seem, knowing the facts about this disease is essential, both for a matter of wisdom and human empathy. Therefore, here we will see various data on sleeping sickness.

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Sleeping sickness and the fly, two inseparable concepts

Before entering fully into the clinical picture and the causal agent of this pathology, it is necessary to talk about its effect on vulnerable populations. The World Health Organization (WHO) throws us

various statistical data to take into account. They are as follows:

• African trypanosomiasis occurs endemically in 36 countries in sub-Saharan Africa.
• The inhabitants of rural areas are the most vulnerable demographic sector to this disease.
• In 1998, around 500,000 cases were estimated, most of them untreated.
• Due to control efforts promoted by Western countries, this figure has fallen to a total of 1,446 cases in 2017.
• In the past 10 years, more than 70% of cases have occurred in the Democratic Republic of the Congo.
• This place is the only region in the world where more than 1,000 cases are still diagnosed a year today.

As we can see, sustained control initiatives have had a very positive effect on the distribution and spread of sleeping sickness. Even so, until the number of infected is reduced to 0, we cannot say that this pathology is fully controlled.

Knowing the parasite: Trypanosoma brucei

Unlike other pathologies of parasitic origin, African trypanosomiasis is not caused by a single microorganism. In this case, we are before two hemoflagellate protozoa of the genus trypanosome. These are the species Trypanosoma brucei gambiense Y Trypanosoma brucei rhodesiense.

The first is the one of greatest epidemiological importance, since it is estimated that it is the cause of more than 98% of the reported cases. The second species only uses humans as a host occasionally, as it has specialized in infecting livestock and other domestic animals.

These small, wormy and semitransparent protozoa have a life cycle of vertigo. This is a summary of this process:

• The tsetse fly injects one of the parasites, trypomastigotes, into the blood of the host (which may be human).
• Thanks to the bloodstream, the parasites reach other organs and fluids (such as lymphoid), and multiply in them by binary fission.
• These blood trypomastigotes are ingested by the fly when it bites an infected person.

The trypanosome parasite undergoes various changes within the fly itself, but knowing that these protozoa multiply in various organs and are transported by the torrent host, it helps us to understand the situation of sleeping sickness at the clinical level.

We emphasize that we are going to delve into the symptoms and treatments of the pathology generated by the parasite t. b. gambiense, as it is the species that most affects human beings.

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Symptoms of African trypanosomiasis

According to various bibliographic sources, this pathology goes through three different phases.

1. Initial phase

At the site of the tsetse fly bite, a local inflammatory process, which gives rise to a structure called trypanoma or chancre. This is a painful skin ulcer, characterized by a white halo on the outskirts. Trypanoma ends with the appearance of a scar two or three weeks after the bite.

2. Hemolytic phase

After an incubation that can last from a few days to several years (with an average of 1-3 weeks), they begin to manifest in the patient clinical signs that respond to the spread and reproduction of the parasite through the lymphatic-blood system.

This supposes the appearance of very high intermittent fevers, arthralgias (joint pain), adenopathies (hard, painless and mobile lymph nodes), tachycardias, anemias, weight loss and itching between others. As we can see, it is not a very pleasant clinical picture, but the worst is yet to come.

3. Neurological phase

Is begins when the parasite crosses the blood-brain barrier, that is to say, a selective layer that isolates the central nervous system of the human being. As you can imagine, the presence of a flagellated protozoan in the nervous system causes striking and worrying symptoms.

From here, we move further into a clinical picture based on behavioral changes. The patient shows sensory problems (hyperesthesia, increased sensitivity to touch), psychic abnormalities (mood swings, irritability, emotional fluctuation), sleep disturbances and various motor problems and endocrine.

East change in the circadian clock of the infected person, which causes chronic insomnia in the patient, gives the name of sleeping sickness to this pathology.

As if that were not enough, in addition to having entered the central nervous system, some of the parasites still remain in the bloodstream of the individual, which causes the symptoms of the hemolytic phase to show also during the stage neurological. In the absence of treatment, this period leads to a profound alteration of the organism (cachexia), coma and death.

Treatment

Anyone diagnosed with African trypanosomiasis It must be treated according to the parasitic species that causes the disease and the stage of the disease.. Naturally, a person who presents these protozoa only in the blood and another in whom they have invaded the central nervous system will require different clinical approaches.

For example, according to the Centers for Disease Control and Prevention (CDC), Pentamidine is an antiprotozoal that acts by inhibiting the synthesis of proteins and nucleic acids of the parasite, which limits and inhibits its growth. This drug is administered, above all, to patients who are still in the hemolytic phase of the T parasite. b. gambiense. Suramin has the same function, but in this case, it acts against T. b. rhodesiense.

The neurological phase, due to its more delicate nature, requires more aggressive medications. In these cases, melarsoprol is usually administered, an arsenic derivative that can cause side effects, sometimes almost worse than the disease (such as reactive encephalopathy resulting in patient death in up to 10% of patients cases).

There are other possible treatments, but in summary, it can be said that this pathology requires a very specific clinical approach, to be carried out by specially qualified personnel.

Conclusions

It is not common for us to find a pathology of parasitic origin that affects so many levels of the patient's health. As we have seen, sleeping sickness causes symptoms ranging from fevers to mood swings, lack of sleep, and hypersensitivity to touch.

Of course, it is surprising to observe how the presence of a parasite in the bloodstream and the central nervous system (CNS) is able to modify the routine and lifestyle of the patient, to such an extent that he can no longer be considered a functional human being.

It is usual that, from a westernized point of view, this type of pathologies are alien and devoid of interest. Beyond the possible concerns that may generate a sporadic trip to the African continent as tourists, diseases like this require understanding and understanding for a mere matter of empathy.

These pathologies cannot be tackled due to the deficient monetary conditions of the countries in which they are originate, and therefore, the action of organizations such as the WHO has become more than necessary to reduce their prevalence.

Bibliographic references:

• de la Salud, A. M. (1983). Human African trypanosomiasis (No. WHA36. 31). World Health Organization.
• Sleeping sickness, World Health Organization (WHO). Picked up on August 7 at https://www.who.int/es/news-room/fact-sheets/detail/trypanosomiasis-human-african-(sleeping-sickness)
• Franco, J. R., Ruiz, J. A., & Simarro, P. African trypanosomiasis.
• Gomez, V. Trypanosoma brucei: characteristics, morphology, life cycle.
• Sleeping Sickness, CDC. Picked up on August 7 at https://www.cdc.gov/parasites/sleepingsickness/biology.html
• Torres, O. M., & Cá, G. (2003). African trypanosomiasis. Presentation of a case. MediCiego, 5 (1).