"The Silent Epidemic: African Sleeping Sickness Unmasked"

 

AFRICAN TRYPANOSOMIASIS is a disease caused by an infection with parasitic protozoa(Trypanosoma spp.) transmitted by tsetse flies of the genius Glossina. It is distributed in Sub-Saharan Africa.

SPECIES: 

Trypanosoma brucei  - rhodesiense – distributed in east and southern Africa

                                                        gambiense – distributed in west and central Africa

                                                        gambiense is more chronic and rhodesiense is acute.

OTHER SPECIES: 

trypanosoma brucei brucei

trypanosoma brucei lewisi

trypanosoma brucei congolense

trypanosoma brucei evansi

SYMPTOMS:

STAGE 1( early infection )

Trypanosomal chancre appears a week post-bite, characterized by a well-circumscribed, rubbery, and painful lesion. A transient rash follows after 6-8 weeks. In the lymphatic system, T. Brucei Gambiense causes painless enlargement of posterior cervical lymph nodes, known as "Winterbottom's sign," while T. Brucei Rhodesiense affects submandibular, axillary, and inguinal lymph nodes with less prominence.

STAGE 2( late infection )

Untreated CNS involvement in Trypanosoma brucei gambiense infection leads to a 100% mortality rate. It is characterized by elevated white blood cells (>5 cells/microliter) in the cerebrospinal fluid. This results in progressive, diffuse meningoencephalitis with widespread focal white matter demyelination and meningeal inflammatory infiltrates. Symptoms include headaches, difficulty concentrating, personality changes, psychosis, tremors, and ataxia

OTHER SYMPTOMS:

In Trypanosoma brucei rhodesiense infection, alterations in circadian rhythm occur, leading to daytime somnolence progressing to coma. Symptoms develop rapidly within weeks, characterized by acute, severe, and febrile presentation. Additionally, myocarditis and pericarditis may occur.

LIFECYCLE:

DIAGNOSIS:

Diagnosing human African trypanosomiasis (HAT) requires specialized training and expertise. Initially, detecting the parasite relies on techniques such as lymph node puncture or blood film examination. Molecular or serological tools have not replaced these classic methods, though the card agglutination test can be useful in west African HAT. Staging via lumbar puncture is necessary to confirm central nervous system involvement, distinguishing between stage 1 and stage 2 disease, which is crucial for treatment selection.

TREATMENTS:

Drugs used to treat human African trypanosomiasis

West African trypanosomiasis

Stage I

• First line: pentamidine
• Second line: eflornithine or melarsoprol

Stage 2

• First line: melarsoprol
• Second line: eflornithine

East African trypanosomiasis

Stage 1

• First line: suramin
• Second line: melarsoprol

Stage 2

• First line: melarsoprol
• Second line: nifurtimox combined with melarsoprol

REFERENCE:

*Human African trypanosomiasis August Stich, Paulo M Abel, Sanjeev Krishna  doi: 10.1136/bmj.325.7357.203.

*Human African trypanosomiasis Reto Brun, Johannes Blum, Francois Chappuis, Christian Burri https://doi.org/10.1016/S0140-6736(09)60829-1

IMAGE CREDITS:

*Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People