Trypanosoma
Trypanosoma - OMPATH
# TRYPANOSOMA
## OVERVIEW
- **Type**: Protozoan parasite (hemoflagellate)
- **Kingdom**: Protista
- **Phylum**: Sarcomastigophora
- **Class**: Zoomastigophora
- **Order**: Kinetoplastida
- **Family**: Trypanosomatidae
## GENERAL CHARACTERISTICS
- Elongated, motile parasites with undulating membrane
- Single flagellum arising from kinetoplast
- Kinetoplast contains mitochondrial DNA
- Polymorphic (different forms in different hosts)
- Obligate parasites requiring two hosts for complete life cycle
## MAIN SPECIES AND DISEASES
### 1. **T. brucei gambiense** → West African Sleeping Sickness (WASS)
### 2. **T. brucei rhodesiense** → East African Sleeping Sickness (EASS)
### 3. **T. cruzi** → Chagas Disease (American Trypanosomiasis)
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## AFRICAN TRYPANOSOMIASIS (SLEEPING SICKNESS)
### CAUSATIVE AGENTS
**T. brucei gambiense** and **T. brucei rhodesiense**
### MORPHOLOGY
- **Length**: 15-30 μm
- **Width**: 1.5-3.5 μm
- **Shape**: Elongated with pointed ends
- **Flagellum**: Single, arising from kinetoplast
- **Undulating membrane**: Present along body length
- **Nucleus**: Central, oval
- **Kinetoplast**: Near posterior end
### LIFE CYCLE - SIMPLE STEPS
#### **IN HUMAN HOST:**
- **Infection**: Metacyclic trypomastigotes injected by tsetse fly bite
- **Multiplication**: Parasites multiply in lymphatic system
- **Blood invasion**: Transform into slender blood trypomastigotes
- **Tissue invasion**: Spread to various organs including CNS
- **Antigenic variation**: Change surface proteins every 7-10 days
#### **IN TSETSE FLY VECTOR:**
- **Ingestion**: Fly takes blood meal containing trypomastigotes
- **Midgut development**: Transform into procyclic trypomastigotes
- **Migration**: Move to salivary glands
- **Transformation**: Become epimastigotes, then metacyclic trypomastigotes
- **Transmission**: Ready for injection into new host
**Total cycle time**: 3 weeks in vector
### COMPARISON: T.b. gambiense vs T.b. rhodesiense
### PATHOGENESIS AND CLINICAL FEATURES
#### **STAGE I DISEASE (Systemic - No CNS involvement)**
**Signs & Symptoms:**
- Painless chancre at bite site (trypanosomal chancre)
- Intermittent fever and chills
- Rash
- Anemia and weight loss
- Headache
- Hepatosplenomegaly
- Lymphadenopathy (especially posterior cervical - **Winterbottom's sign**)
- Myocarditis (common in T.b. rhodesiense)
**Laboratory findings:**
- Anemia
- Moderate leucocytosis
- Thrombocytopenia
- High immunoglobulin M (IgM) levels
#### **STAGE II DISEASE (CNS involvement - "Sleeping Sickness")**
**Signs & Symptoms:**
- Increasing headache
- Mental dullness and apathy
- Daytime sleepiness
- Behavioral changes
- Progressive coma
- Death from asthenia (weakness)
**Histopathology:**
- Chronic meningoencephalitis
- Lymphocytes, plasma cells, and morula cells in meninges
- Morula cells contain mulberry-shaped IgA masses
- Perivascular cuffing of brain vessels
- Neuronal degeneration
- Microglial proliferation
**CSF changes:**
- Raised intracranial pressure
- Pleocytosis (increased WBC)
- Raised protein levels
### DIAGNOSIS
#### **Non-specific findings:**
- Anemia and monocytosis
- Raised ESR (due to increased gamma globulins)
- Reversed albumin:globulin ratio
- Increased CSF pressure, cells, and proteins
#### **Specific diagnosis:**
**Demonstration of trypanosomes in:**
- Peripheral blood
- Bone marrow
- Lymph node aspirate
- CSF
- Chancre fluid
**Methods:**
- **Microscopy**: Wet mount, Giemsa stain
- **Culture**: Special media
- **Molecular**: PCR
- **Imaging**: CT (cerebral edema), MRI (white matter enhancement)
### TREATMENT
#### **STAGE I DISEASE:**
- **T.b. gambiense**: Pentamidine (3-4 mg/kg IM daily × 7-10 days)
- **T.b. rhodesiense**: Suramin (20 mg/kg IV, 5 injections at 5-7 day intervals)
*Note: Suramin doesn't cross blood-brain barrier but is nephrotoxic*
#### **STAGE II DISEASE:**
- **T.b. gambiense**: Eflornithine
- **T.b. rhodesiense**: Melarsoprol (Mel-B) 2-3 mg/kg/day (max 40mg) × 3-4 days
*Note: Melarsoprol crosses blood-brain barrier*
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## AMERICAN TRYPANOSOMIASIS (CHAGAS DISEASE)
### CAUSATIVE AGENT
**Trypanosoma cruzi**
### HOSTS AND VECTORS
- **Definitive host**: Humans
- **Vector**: Reduviid bugs (triatomine bugs) - "kissing bugs"
- **Reservoir hosts**: Armadillo, cats, dogs, pigs
### MORPHOLOGY
- Similar to T. brucei but smaller
- **Amastigote form**: Oval, 2-4 μm (intracellular)
- **Trypomastigote form**: C-shaped, 20 μm (in blood)
- **Epimastigote form**: In vector gut
### LIFE CYCLE - SIMPLE STEPS
#### **IN HUMAN HOST:**
- **Infection**: Metacyclic trypomastigotes from bug feces enter through skin/mucosa
- **Cell invasion**: Parasites enter cells and transform to amastigotes
- **Multiplication**: Amastigotes multiply in cells
- **Transformation**: Become trypomastigotes and rupture cells
- **Blood circulation**: Trypomastigotes in bloodstream
- **Tissue invasion**: Invade heart, digestive tract, nervous system
#### **IN REDUVIID BUG:**
- **Ingestion**: Bug takes bloo