African Trypanosomiasis - Sleeping Sickness

               African Trypanosomiasis :

African Trypanosomiasis, also known as sleeping sickness, is a parasites of the genus Trypanosoma. It primarily affects humans and animals in sub-Saharan Africa.

Causative Agent : 

The disease is caused by two subspecies of Trypanosoma brucei :
  • Trypanosoma brucei gambiense - causes the chronic form of the disease, prevalent in West and Central Africa.
  • Trypanosoma brucei rhodesiense - causes the acute form, found in East and Southern Africa.

Transmission :

  • Transmitted through the bite of an infected tsetse fly (Glossina species), which acts as the vector.
  • The fly becomes infected by biting a host already carrying the parasite.

Pathophysiology :

Stage 1 : Hemolymphatic Phase 
  • The parasite multiplies in the blood and lymphatic system.
  • Symptoms include fever, headaches, joint pain, and swollen lymph nodes (especially in the neck, known as winterbottom's sign).
Stage2 : Neurological Phase 
  • The parasite crosses the blood-brain barrier, affecting the central nervous system (CNS).
  • Symptoms include confusion, behavioral changes, sleep disturbances (reversal of sleep patterns), and ultimately coma if untreated.

Symptoms :

Early Symptoms :
  • Fever
  • Severe headaches
  • Muscle aches
  • Fatigue
  • Enlarged lymph nodes
Advanced Symptoms :
  • Disruption of sleep-wake cycles (hence "sleeping sickness")
  • Neurological and psychiatric disorders
  • Seizures and eventual coma

Diagnosis :

  • Microscopy : Identification of parasites in blood, lymph node aspirates, or cerebrospinal fluid (CSF).
  • Serological Tests : Detect antibodies, especially for T. b. gambiense.
  • Lumbar Puncture : To assess CNS involvement by examining CSF.

Treatment :

Stage 1 :
  • Pentamidine for T. b. gambiense.
  • Suramin for T. b. rhodesiense.
Stage 2 (CNS involvement) :
  • Melarsoprol (effective but highly toxic).
  • Eflorithine (Safer alternative, especially for T. b. gambiense).
  • Combination therapy with nifurtimox and eflornithine (NECT) is now widely used.

Prevention :

  • Control of tsetse flies through insecticides and traps.
  • Wearing protective clothing to reduce exposure.
  • Surveillance programs to identify and treat cases early.

Epidemiology :

  • T. b. gambiense accounts for about 98 percents of reported cases.
  • WHO efforts have significantly reduced cases, with the goal of eliminating sleeping sickness as a public health problem by 2030.




No comments:

Post a Comment