African Trypanosomiasis, also known as sleeping sickness, is caused by the parasite Trypanosoma brucei and transmitted by the bite of the tsetse fly. There are two subspecies that cause different forms of the disease - T. b. rhodesiense which causes a more acute form in East Africa and T. b. gambiense which causes a chronic form in West Africa. Without treatment, infection can spread from the bloodstream to the central nervous system and be fatal. Control relies on minimizing contact with tsetse flies, early diagnosis, and drug treatment depending on the parasite subspecies and stage of disease.

1. African Trypanosomiasis
Sleeping Sickness

2. Trypanosoma brucei.
Transmitted by the Tsetse fly (Glossina species - rural
Africa),
Serious Public health problem : sub-Saharan Africa.
About 10,000 new cases each year are reported (WHO).
Curable - medication, but is fatal if left untreated.
African Trypanosomiasis (sleeping sickness)

3. Epidemiology & Risk Factors
Two subspecies
T. b. rhodesiense (East African sleeping sickness)
< hundred cases are reported (WHO).
Animals are the primary reservoir of infection.
Cattle have been implicated in the spread of the disease to new
areas and in local outbreaks.
A wild animal reservoir is thought to be responsible for sporadic
transmission to hunters and visitors to game parks.
T. b. gambiense (West African sleeping sickness)
Most of the sleeping sickness in Africa is caused by this form of
the parasite.
Humans are the important reservoir of infection, although the
parasite can sometimes be found in domestic animals (e.g., pigs,
dogs, goats).

4. Both forms - transmitted by the bite of the Tsetse fly (Glossina
species).
Habitat: rural areas, living in the woodlands and forests and
vegetation along streams.
Tsetse flies bite during daylight hours.
Both male and female flies can transmit the infection
Other modes of transmission are possible.
Eg. A pregnant woman can pass the infection to her unborn baby.
by blood transfusion or sexual contact (rare)
Tsetse fly (Glossina spp).

5. Geographical Distribution

6. Life Cycle

7. Two stages.
First stage- peripheral circulation,
Second stage - central nervous system
T. b. rhodesiense - infection progresses rapidly.
 Large sore (a chancre). Some develop a rash.
 Fever, headache, muscle and joint aches, and generalized
enlarged lymph nodes within 1-2 weeks of the infective bite.
 After a weeks infection - the parasite invades CNS - mental
deterioration and other neurological problems.
 Death ensues usually within months.
Disease in Humans

8. Disease in Humans contd..
T. b. gambiense infection - progresses more slowly.
 At first- mild symptoms. Such as intermittent fevers,
headaches, muscle and joint aches, and malaise.
 Itching of the skin, swollen lymph nodes (winterbottom
sign – posterior cervical lymph node), and weight loss
can occur.
 After 1-2 years- central nervous system involvement, with
personality changes, daytime sleepiness with nighttime sleep
disturbance, and progressive confusion.
 Other Neurologic signs - partial paralysis as well as
hormonal imbalances.
 Untreated infection rarely lasts longer than 6-7 years and
more often kills in about 3 years

9. T. congolense, T. vivax and T. brucei subsp. brucei.
T. congolense : classified 3 types
•Savannah
•Forest
•Kilifi
T. simiae and T. godfreyi
All domesticated animals are affected
Incubation period: 4 days to approx. 8 weeks
Most cases : are chronic, but acute cases may occur.
African Animal Trypanosomiasis

10. Clinical Signs in Animals
First sign - localized swelling (chancre) at the site of bite
Intermittent fever, anemia, lymphadenopathy and weight loss.
Milk yield : decreased
Reproduction: abortions, premature births and testicular damage
An acute hemorrhagic syndrome (T. vivax in Cattle): enlarged lymph
nodes, severe anemia, widespread visceral and mucosal hemorrhages
Rarely: bleeding from the ears and severe weight loss.

11. Serological testing – screening purpose
Microscopic – Demonstration of parasite in blood, CSF or lymph
node aspirate (posterior cervical lymph node)
Criteria for second stage :
- observation of trypanosomes in CSF or a
- white cell count of 6 or higher.
Other indications of second stage :
- elevated protein
- increase in nonspecific IgM in CSF.
Diagnosis

12. Treatment
Species
Drug of
choice
Adult Dosage Pediatric Dosage
T. b.
rhodesiense,
hemolymphatic
stage
Suramin1 1 g IV on days 1,3,5,14, and 212 20 mg/kg IV on days 1, 3, 5, 14, and 213
T. b.
rhodesiense,
CNS
involvement
Melarsoprol4
2-3.6 mg/kg/d IV x 3 days.5 After 7
days, 3.6 mg/kg/d x 3 days. Give a
3rd series of 3.6 mg/kg/d after 7
days.
2-3.6 mg/kg/d IV x 3 days.5 After 7 days,
3.6 mg/kg/d x 3 days. Give a 3rd series of
3.6 mg/kg/d after 7 days.
T. b. gambiense,
Hemolymphatic
stage
Pentamidine6 4 mg/kg/d IM or IV x 7-10 d 4 mg/kg/d IM or IV x 7-10 d
T. b. gambiense,
CNS
involvement
Eflornithine7 400 mg/kg/d in 4 doses x 14 d 400 mg/kg/d in 4 doses x 14

13. Control Measures
 No vaccine
 Minimizing contact with tsetse flies
 Protective clothing – avoid bright or dark colour and light weight
 Use insect repellent - Permethrin-impregnated clothing
 Reducing the disease reservoir and controlling the tsetse fly vector
 Disease reservoir: T. b. gambiense
 controlling the tsetse fly vector : T. b. rhodesiense