etiology, local names, definition, transmission, source of infection, epidemiology, pathogenesis, clinical signs, diagnosis, differential diagnosis, treatment prevention and control

1. Faculty of Veterinary Medicine &
Animal Husbandry
Somali National University
Mogadishu, Gaheyr Campus
Nov. 24. 2019
INFECTIOUS DISEASES II (Protozoal Diseases)
TRYPANOSOMIOSIS

2. What is Trypanosomosis
• A group of diseases that afflict man and
his livestock. Transmitted cyclically by
flies belonging to the genus Glossina and
acyclically by haematophagus flies the
most important of which belong to the
families Tabanidae and Stomoxynae.

3. Tabanids and Stomoxys (biting flies)

4. TRYPANOSOMIOSIS
Synonyms ; surra, triversa, nagana
Its infectious disease characterized by
high rise of temperature, anemia, wasting
and cutaneous eruptions. Trypanosomes
are flagellated protozoan parasites that
live in the blood and body fluids of their
hosts.

5. Etiology
The disease is caused by protozoan
parasite trypanosoma evansi, T.evansi is
long slender organism having free
flagellum. The organism are actively
motile. They divide by binary
longitudinal fission. T.evansi can be
grown in novy macneal niccolle medium
(NMN) and in developing chick embryo

6. The Vector
This will be dealt with comprehensively in
other situation

8. The Parasite
• Nagana Causing:
• T.congolense, T.vivax, T.brucei
• Sleeping sickness agents:
• T.brucei gambiense, T.brucei rhodesiense
• Chagas Disease:
• T.cruzi

10. • As large as 8 RBCs:

11. T. congolense bloodstream form

12. T.Vivax bloodstream form

14. Undulating membrane

15. Flagella Pocket

16. • High affinity Ab attack the dominant variant

18. Non Cyclic Transmission
• T. vivax, T.evansi and T.equinum:
mainly Tabanides and Vampire bats in
South America.
* T.equiperdum:
coitus

19. Vampire bat

20. Epidemiology
the disease is widely distributed in
tropical and sub-tropical countries.
Prevalent in middle east, far east central
and south America and Africa. The
trypanosomes are insect-born disease of
cattle, buffalo, goat, sheep, pig, horses,
donkey, camel and dog.

22. In Africa:•Occupies greater than 10 million Km2

23. It occupies greater than 10 million Km2
7 million Km2 would otherwise be suitable
for livestock raising and mixed agriculture
37 countries are affected including Somalia
30% of the 150 million cattle are exposed to
the disease Sheep, goats, equine and
camels may suffer similar problems.

24. T.vivax is present in central and south
America. In India it was 1streported by
evansi in 1918 in camels. Whereas
T.congolence and T.vivax are responsible
for severe disease in cattle , sheep and
goats. T.brucei usually causes a sub-
clinical infection but a severe disease in
pigs.

25. • T. simiae causes a very acute and highly
fatal disease in pigs.
• Carrier animals remain as potential
source of disease transmission. It is an
important disease in camel and horses

26. Morbidity rate in cattle and pigs is 70%.
The disease is transmitted mechanically
through the bites of flies, tabanus,
haemotopota, lyperosia and stomoxys sp.
30 species of tabanus are able to transmit
T.evansi. it transmit trypanosome through
its saliva when feeds on new host..

27. • The direct impacts are those on:
• (a) Livestock productivity,
• (b) Livestock management
• (c) Migration and settlement

28. Pathogenesis
T.evansi multiply in blood circulation
and produce parasitimia. Metacylic
trypanosomes are infected in to the host
by the fly during feeding. They multiply
at the sub-cutaneous site, provoking a
local pronounced in a fully susceptible
host and may be slight or absent with
some strains or species of trypanosomes.

29. In some hosts metacylic parasites change to
trypomastigate form and enter the blood
stream directly or through the lymphatics.
T.vivax usually multiply in blood and is
eventually dispersed throughout the cardio-
vascular system, whereas T.congolence tends
to be aggregated in small blood vessels and
capillaries of the heart, brain and skeletal
muscle from where a small proportion of
parasites enter the blood circulation

30. On other hand emaciation T.brucei and
rarely T.vivax multiply in the intestinal
tissues and serous fluids of body cavities.

31. Clinical finding
The cattle and buffalo usually carry sub-
clinical infection but overt disease may
occur due to stress, intercurrent infection,
starvation and debility. Transient rise in
body temperature.

32. • Enlargement of superficial lymph glands,
emaciation, progressive weakness and
anemia are the common clinical finding.
In horses and donkeys fever, emaciation
and edema are more common.

33. In camel intermittent fever progressive
anemia, emaciation and edema of
dependent parts are seen. Dog may suffer
from acute form of trypanosomiasis.

37. Nagana: Sleeping sickness: Chagas Disease

38. Necropsy finding
The carcass is marked by anemia,
emaciation, anasarca and enlargement of
liver, spleen and lymph nodes. Both fat
stores are depleted around the heart.
There may be corneal opacity and
testicular degeneration.

39. Diagnosis
The diagnosis is based on the history and
symptoms. Demonstration of parasites in
blood films is confirmatory. Movements
of the parasite under hanging drop
method can be also seen. Biological test
such as mice inoculation test can be
performed in doubtful cases.

40. • Serum protein level and beta and gamma
globulin level have been found to
increase in affected animals.

41. There will also be low blood glucose
level. Beside mercuric chloride test,
stibamidine test and several serological
test like, complement fixation test,
passive haemoagglutination test , indirect
fluorescent antibody test and enzyme
liked immune-sorbent assay (ELISA)
may be performed.

42. As for all trypanosome diseases, drug
resistance due to misuse and especially
by using too small doses or diluting the
drug with water or some other liquid is an
increasing problem.

44. Control
Detection of infected animals should be
done promptly and isolation of the
positive animals should be done from rest
of the herd. Treatment of the animals
should be performed as early as possible.
Vector should be controlled as far as
practicable. Quinapyramin can be used as
prophylaxis

45. Vaccination
• is not yet possible due to:
• the characteristic antigenic variation
phenomenon of trypanosomes.

46. Vaccine production is faced with the
phenomena of antigenic variation
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60
Days post infection
Parasitaemialevels(Log10)/ml
Sh. mean
Abz.mean

47. • Vector Control:

48. • Insecticide application:

49. Biconical Trap Ngu Trap

51. • Impregnated screens

52. Sterile Male Technique, …?

53. This disease is an infectious disease and it is
characterized by high rise of temperature,
anemia, and wasting and cutaneous eruptions.
The species of trypanosomes the infect
livestock generally not transmissible to
humans with the possible exception of
T.brucei. they can be treated but prevention
is quite difficult.