26

0
MINISTRY OF EDUCATION AND TRAINING
THAI NGUYEN UNIVERSITY
DO THI VAN GIANG STUDY ON EPIDEMIOLOGICAL FEATURES, APPLICATION OF
DIAGNOSTIC KIT FOR DETECTION OF TRYPANOSOMIASIS
CAUSED BY TRYPANOSOMA EVANSI IN CATTLE AND
BUFFALOES IN A FEW NORTHERN MOUNTAINOUS
PROVINCES AND RECOMMENDATION FOR
PREVENTIVE AND TREATMENT MEASURES
Speciality: Veterinary parasitology and microbiology
Code: 62 64 01 04

SUMMARY OF PhD DISSERTATION IN VETERINARY MEDICINE

THAI NGUYEN - 2014

1


1. Đỗ Thị Vân Giang, Nguyễn Thị Kịm Lan, Nguyễn Quốc Doanh,
Nguyễn Thị Bích Ngà (2013), “ Đặc điểm bệnh do T. evansi gây
ra trên động vật thí nghiệm (chuột bạch)”, Tạp chí khoa học kỹ
thuật Thú y, tập 20, số 2, trang 49 - 55.
2. Đỗ Thị Vân Giang, Nguyễn Thị Kim Lan, Nguyễn Thu Trang,
Trương Thị Tính (2013), “Đặc điểm bệnh lý do T. evansi gây ra
trên thỏ thí nghiệm”, Tạp chí khoa học kỹ thuật chăn nuôi, số
tháng 8, năm 2013, trang 83 - 90.
3. Phạm Thị Tâm, Bùi Thị Hải Hòa, Nguyễn Thị Kim Lan, Đỗ Thị Vân
Giang (2013), “Nghiên cứu thiết lập phản ứng ELISA chẩn đoán
bệnh tiên mao trùng cho trâu, bò Việt Nam”, Tạp chí Nông nghiệp và
phát triển nông thôn, kỳ 2, tháng 8, năm 2013, trang 41 - 45.
4. Nguyễn Thị Kim Lan, Đỗ Thị Vân Giang, Nguyễn Văn Quang,
Nguyễn Thị Ngân, Lê Minh, Phan Thị Hồng Phúc, Phạm Diệu
Thùy (2013), “Thử hiệu lực một số thuốc trị Trypanosoma evansi
qua thử nghiệm in vitro và in vivo”, Tạp chí khoa học kỹ thuật
Thú y, tập XX, số 6, trang 69 - 77. 24
- Lesions in viscera of buffaloes experimentally infected with T.
evansi have been found in heart, lungs, spleen, liver, kidneys (20 -
100 %). Microscopic lesions have been found in the internal organs
of the buffaloes experimentally infected with T. evansi
1.3. Application of serological test kits for diagnosis of trypanosomiasis
- Detection rates of CATT kit and ELISA kit in positive serum

various places.
- The preventive and control of trypanosomiasis caused by T.
evansi in buffaloes and cattle should be allowed to be applied in
Thai Nguyen, Lang Son, Hoa Binh, Lai Chau and other provinces.
1
INTRODUCTION
1. Urgency of the project
Trypanosomiasis or Trypanosomosis is a common disease in cattle and
buffaloes causing a great losses for cattle husbandry in our country and many
of other countries in the world.
According to Phan Dich Lan (2004) cattle and buffaloes infected
with Trypanosoma evansi are often show emaciation, anemia, decrease
of disease resistance and death in winter and spring.
In our country, many authors have studied trypanosomiasis (Phạm Sy
Lang, 1982; Le Duc Quyet, 1995; Nguyen Quoc Doanh, 1996; Luong To
Thu and Le Ngoc My, 1996; Vuong Thi Lan Phương, 2004; Phan Van
Chinh, 2006…). However only few studies of trypanosomiasis have
been performed in mountainous provinces.
In order to make contribution to the control of trypanosomiasis in
buffaloes and cattle in mountainous provinces we implement the project:
“Study on epidemiological features, application of diagnostic kit for
detection of trypanosomiasis caused by Trypanosoma evansi in cattle
and buffaloes in a few northern mountainous provinces and
recommendation for preventive and treatment measures ”.
2. Objective of the project
Identification of Trypanosomes causing trypanosomiasis
epidemiological and pathological features of the disease; using Kit for
detection of trypanosomes and recommendation of preventive and
control measures of trypanosomiasis in cattle and buffaloes.
3. Scientific and practical significance of the project

country with high infection rates (13 - 30 % of buffaloes and 7 - 14 % of
cattle), mortality rate of affected animal was 6,3 - 20 %.
Verma B. B. (1978), Payne R. C. (1992), Wuyts (1994), Nguyen
Dang Khai (1995), Da Silva A. S. (2010) indicate that clinical signs in
trypanosome infected buffaloes and cattle include falling and rising
fever, emaciation, anemia, edema, corneal inflammation, swelling of
the testes and testitis, swollen lympho nodes, limb paralysis, abortion.
According to Damayanti R. (1994), Reid S. A. (2001), Mekata H.
(2013) gross lesions in T. evansi infected buffaloes include hemorrhage in
pericardium membrance, pneumonia, hepatitis, swelling and edema of the
spleen, swollen lympho nodes, enlarged bone marrow.
Many authors have studied trypanosomiasis in different animal
species (horses, dogs, cats, mice…): Hagos A. (2010), Aquino L. P.
(2010), Tamarit A. (2010), Habila N. (2010), Gari F. R. (2010), Haridy
F. M. (2011), Desquesnes M. (2011), Ramirez Iglesias J. R. (2011),
Tonin A. A. (2011), Dalla Rosa L. (2012), Elshafie E. I. (2012), Sharma
P. (2012), Takeet M. I. (2012), Kundu K. (2013), Rosa L. D. (2013),
Nguyen Q. D. (2013), Faccio L. (2013) …
Doan Van Phuc (1981), Nguyen Quoc Doanh and Pham Sy Lang
(1996 - 1997), Phan Van Chinh (2006) used several drugs for
treatment of trypanosomiasis in cattle and buffaloes in Viet Nam and
show that trypamidium, berenil, trypazen are high effective and safe
in treating trypanosomiasis in cattle and buffaloes.
23
- There are 3 sucking fly and gadfly species transmitting
trypanosomes to cattle and buffaloes.
1.2. Ability of T. evansi to cause disease in some animals experimentally
infected
* In white mice:
- T. evansi appears in mouse blood 3 - 7 days after being

.
- Buffaloes infected with T. evansi manifest waves fever.
Averagely, 3 - 8 days a fever appears.
- 5 buffaloes infected with T. evansi all appear clinical signs with
percentage of 20 - 100 %.
- In trypanosome infected buffaloes there are apparently decreased
amount of erythrocytes and increased amount and rates of granulocytes
compared with the control buffaloes.
22
+ Examination and treatment for trypanosomiasis in buffaloes and
cattle infected with T. evansi in summer and Autumn in order to limit
outbreak of trypanosomiasis and mortality rates of buffaloes and cattle in
Winter and Spring
2. Exterminating sucking flies and gad flies that transmit
tripanosomiasis
- Exterminating flies and gad flies by changing their habitat,
clearing plants in each area, not letting water stagnate; composting
manure in order to kill eggs and larva of flies and gad flies; housing
animals with nets to prevent flies and gad flies from sucking
buffaloes and cattle. These methods are effective ones, creating
unfavourite conditions for the life of flies and gad flies to prevent
them from growth and complete their life cycle.
- Using chemiclals to exterminate sucking flies and gad flies: The
chemicals such as endosulfan, brophos,tetracloreinphos can be used…
3. Using chemicals for prevention of trypanosomiasis
Using trypamidium samorin at dose 0.5 mg /kg B.W twice a year
( in early summer and at the end of Autumn) in order to prevent
trypanosomiasis in the local places.
4. Improvement of caring, feeding and management of buffaloes and
cattle (especially in Autumn and Winter, when the weather is

- Animals experimentally infected with Trypanosoma evansi:
rats, rabbits, buffaloes.
- Recombinant antigen based-ELISA diagnostic kit and CATT kit using
antigens of T. evansi species isolated from four of provinces of study.
- Drugs for treatment of trypanosomiasis: azidine, trypamidium
samorin, diminavet and suppotive drugs.
- Auto hematology analyser Cellta - Mek - 6420K - Nihon
Kohden (Japanese).
- Microtome.
- Light microscope, chemicals and other experimental instruments.
2.2. PLACES AND TIME PERIOD OF STUDY
* Places of study:
- places where samples were collected: Thai Nguyen, Lang Son,
Lai Chau, Hoa Binh provinces.
- Places where samples were tested: Thai Nguyen, university of
agriculture and forestry, National veterinary institute, veterinary
centre of disease diagnosis, biotechnological institute.
* Time period of study: From 2011 to 2013.
2.3. CONTENTS OF STUDY
2.3.1. Studying epidemiological features of trypanosomiasis in
cattle and buffaloes in 4 of Northern mountainous provinces
2.3.2. Ability of T. evansi to cause disease in several experimentally
infected animals
4
2.3.3. Application of diagnostic kit to diagnosis of trypanosomiasis
in various places
2.3.4. Susceptibility testing of T. evansi to several drugs in white mice
2.3.5. Establishing treatment regimens of trypanosomiasis and
recommendation of preventive and treatment measures of this disease
2.4. METHODS OF STUDY

C.
+ Dissection and examination of internal organs of animals
experimentally infected which were dead (rabbits and mice) or were
still alive(buffaloes). Observing internal organs by naked eyes or by
using magnifier, taking pictures of sections in the body that manifested
typical gross lesions.
+ Testing blood indices by using auto hematology analyzer-Cellta -
Mek - 6420K - Nihon Kohden (Japan).
+ Preparations were made based on Histology Technique of cutting
tissues: tissues are hardened by replacing water with paraffin. The
21
Table 3.31. Efficacy of 3 treatment regimens of trypanosomiasis in
cattle and buffaloes
Treatment
regimen
Treament drug
and supportive
drug
Dose
Number of
buffaloes
treated
(buffalo)
Number of buffaloes
from which
Trypanosomes were
cleared (buffalo)*
Percentage

(%)


2
2.5%vitamin B1

20 ml/ animal

30 26 86,67
Adizine
4,0 mg/ kg
body weight

Physiological
saline solution
200 ml/
animal
20% caffein 15 ml/ animal

5% vitamin C 20 ml/ animal

3
2.5% vitamin B1

20 ml/ animal

30 24 80,00
Notes: * at examination, there were no T. evansi 15 days and và 30 days after treatment
3.5.2. Recommendation of preventive and control measures of
trypanosomasis caused by T. evansi in buffaloes and cattle in
mountainous provinces
Combining results of our sutdy and results of study of other authors

After the trial of susceptibility of T. evansi to 4 drugs in
laboratory we found that 3 drugs, trypamidium samorin, diminavet
and azidine were effective to treat trypanosomiasis caused by T.
evansi with different extents (trypamidium samorin and diminavet
were more effective to kill T. evansi at the recommended dose,
azidine was more effective at dose higher than the recommended
dose). Therefore we designed 3 treatment regimens (each regimen
including drug against trypanosomes at effective dose that had been
determined added with supportive drugs) to treat T. evansi infection
in several T. evansi infected buffaloes and cattle. 15 and 30 days
post treatment, efficacy of treatment regimen 1 was examined by
taking blood from buffaloes to inoculate white mice. The results of
efficacy in 3 treatment regimens were illustrated in table 3.31.
Table 3.31 shows that 3 regimens were all effective for treatment
of trypanosomiasis in buffaloes and cattle. Clearance rates of T.evansi
post treatment were 80 - 100 %, of which regimen 1 had the highest
efficacy of treatment, regimen 3 had the lowest efficacy. That was why
we chose regimen 1 for recommendation of using in treating
trypanosomiasis in cattle and buffaloes in various areas.
5
tissue is then cut in the microtome From there the tissue can be
mounted on a microscope slide stained with Hematoxylin - Eosin. and
examined under light microscope magnification of 200-400 times to
observe microscopic changes in the slide.
- Flies and gad-flies were classified based on classification key by
Stekhoven Ricardo (1959).
- Using CATT kit and ELISA kit in order to detect antibody
against T. evansi in the positive samples, then using these two kits to
determine infection rate of T. evansi in buffaloes in Thai Nguyen.
- Testing susceptibility of T. evansi to 4 drugs by injecting them in

samorin
Merial
(France)
Isometamidium
chloride hydrochloride

0,8 1,0 1,2
I M
Diminavet
VMD
(Belgium)
Diaceturate diminazene
and antipyrine
3,0 3,5 4,0
I M
Monitoring in order to identify time from experimal treatment to
clearance of trypanosomes in mouse body in both the control group
and the experimental group. Based on results obtained identify
susceptibility of trypanosomes to 4 drugs used.
- Establishment of trypanosome treatment regimens for cattle and
buffaloes in the investigated places, each regimen consists of drugs
against trypanosomes (at effective dose to kill trypanosomes) added
supportive drugs.
2.5.TREATMENT OF DATA
Data collected is treated by methods of biostatistics (According to
document of Nguyễn Van Thien, 2008), on Excel software 2003 and
Minitab software 14.0.
6
Chapter 3
RESULTS OF STUDY

Table 3.1 shows that 11/11 trypanosomes isolated from infected cattle
and buffaloes in four of northern mountainous provinces all belonged to
T. evansi, no other trypanosome species were found. Thus, T. evansi was
the only parasite species of trypanosomes causing trypanosomiasis in
cattle and buffaloes in northern mountainous provinces.
3.1.2. Trypanosoma infection in cattle and buffaloes in four of
Northern mountainous provinces
3.1.2.1. Infection rates of Trypanosoma in cattle and buffaloes in
various places
Table 3.2. Infection rate of Trypanosoma in cattle and buffaloes in
four of northern mountainous provinces
Bufaloes Cattle
Place
(province)
Number of
buffaloes
tested
(buffalo)
Number of
buffaloes
infected
(buffalo)
Infection
rate
(%)
Number
of cattle
tested
(buffalo)
Number

diminavet drug was used
Group
Control Experimental
Drug dose (mg / kg/ body
weight)
0
2,5 3,5 4,5
Number of mice
10 10 10 10
Number of T. evansi
/microscopic field area
prior drug was used
(
X
mX 
)
91,10 ± 1,22 90,60 ± 1,79 86,20 ± 1,89 93,60 ± 1,80
Indication
Results
of monitoring
afterthe drug
was administered
Number of
mice cleared of
trypanosomes

Number
of mice
killed
Number of

10 days
0 10/10

9/10 1/10

9/10 1/10

9/10 1/10

15 days
0 10/10

6/10 4/10

7/10 3/10

7/10 3/10

Number of mice in which
trypanosomes were still
surviving on day 15, 20 and
30 after drugs was used
- 2/6 0/7 0/7
Table 3.30 shows that at dose lower than recommended dose
(3.0 mg /kg B.W) the drug was able to kill trypanosome (6/10 of
mice from which T. evansi were cleared), but in 2/6 of mice T. evansi
reappeared 20 days after the drug was used. At recommended dose
(3.5 mg /kg B.W) or higher (4.0 mg /kgB.W), the drug had good
efficacy to kill T. evansi (7/10 of mice from which T. evansi were
18

(
X
mX 
)
92.5 ± 1,92 93.6 ± 2,21 88.2 ± 1,60 92.2 ± 1.30
Indication
Results
of monitoring
afterthe drug
was administered
Number of
mice cleared of
trypanosomes

Number
of mice
killed
Number of
mice cleared of
trypanosomes

Numbe
r of
mice
killed
Number of
mice cleared
of
trypanosomes


15 days
0 10/10

3/10 7/10

10/10 0/10 10/10 0/10
Number of mice in which
trypanosomes were still
surviving on day 15, 20 and
30 after drugs was used
- 2/3 0/10 0/10
Table 3.29 shows that at dose lower than recommended dose:
(0,8 mg /kg B.W), trypamidium samorin was less effective to kill T.
evansi in mouse body (3/10 of mice from which T. evansi was removed,
2/3 of mice in which T. evansi reappeared 20 days after being infected).
7
highest infection rate of trypanosomes was in buffaloes in Hoa Binh
(19,82 %), the second highest was in Lang Son (15,53 %) and Lai Chau
(14,91 %); the lowest was in Thai Nguyen province (12,14 %). The
highest infection rate of trypanosomes in cattle was in Hoa Binh province
(10,26 %), the second highest was in Thai Nguyen (10,20 %) and the
lowest was in Lang Son (6,67 %).
3.1.2.2. Infection rates of trypanosomes with aging in cattle and buffaloes
Trypanosome infection rates with aging in cattle and buffaloes
was illustrated in figure 3.2.

Figure 3.2. Infection rates of trypanosomes in buffaloes and cattle
were illustrated by the line graph in figure 3.2
Infection rates of trypanosomes in cattle and buffaloes in
mountainous provinces tended to increase gradually with aging of

Lang Son
Van Lang + + +
Frequency of appearance (%)

100 100 100
3.1.3.2. Rates of blood sucking flies and gad flies in collected samples
Table 3.7. Rates of blood sucking flies and gad flies in collected
samples in the investigated places
Province

Number of flies and gad-
flies collected (fly)
Fly and gad-fly species
Number
(fly)
Percentage
(%)
Stomoxys calcitrans 374 47,77
Tabanus kiangsuensis 158 20,18
Thai
Nguyen

783
Tabanus rubidus 251 32,05
Stomoxys calcitrans 63 46,67
Tabanus kiangsuensis 40 29,63
Lai
Chau
135
Tabanus rubidus 32 23,70

3.8. Rule of activities of blood sucking fly and gadfly species in
various months
17
effective to kill T. evansi in mouse body. 10/10 mice were all killed
by T. evansi.
At dose recommended by the manufecturer (1.0 mg /kg body
weight), the drug was less active to kill T. evansi (only 1/10 mice from
which T. evansi were cleared ( number of mice killed was 9/10 ).
- At higher dose (1.2 mg //kg body weight), the drug killed T.
evansi better than recomended dose (3 mice from which T. evansi
was cleared, 7 mice were killed). However, after 15 days T. evansi
reappeared in 2/3 mice.
As the result Trypanosoma drug had low efficacy to kill T. evansi.
Thus, T. evansi might have been resistant to Trypanosoma drug.
3.4.2. Determination of susceptibility of T. evansi to azidine tested
in white mice
Table 3.28. Time from using the drug to clearance of T. evansi from
white mice after azidine was used
Group
Control Experimental
Drug dose (mg / kg/ body
weight)
0 3,0 3,5 4,0
Number of mice
10 10 10 10
Number of T. evansi
/microscopic field area
prior drug was used
(
X

killed
Number of
mice cleared of
trypanosomes

Number
of mice
killed
24 hours
0 2/10 0 2/10

3/10 1/10 5/10 1/10
48 hours
0 7/10 1/10 5/10

4/10 1/10 7/10 1/10
72 hours
0 10/10

2/10 5/10

6/10 3/10 9/10 1/10
10 days
0 10/10

1/10 7/10

6/10 4/10 9/10 1/10
15 days
0 10/10

samples (+)

percent
age
(%)
Thai Nguyen city

50 7 14,00 7 14,00
Dong Hy 50 6 12,00 6 12,00
Vo Nhai 50 10 20,00 10 20,00
Phu Binh
50 8 16,00 8 16,00
Total 200 31 15,50 31 15,50
Table 3.26 shows that when 2 types of kits were used for diagnosis
31/200 samples were detected to be positive with T. evansi; accounting
for 15.5 % (varied from 12 to 20 %). The results of mice inoculation
were similar. Thus, ability of these 2 kits to detect T. evansi infection in
buffaloes is equivalent to method of white mice inoculation.
3.4. TESTING SUSCEPTIBILITY OF T. EVANSI TO SOME
DRUGS TESTED IN WHITE MICE
3.4.1. Testing susceptibility of T. evansi to trypanosoma drug
Table 3.27. Time from using the drug to clearance of T. evansi from
white mice following trypanosoma drug was used
Group
Control Experimental
Drug dose (mg / kg/ body
weight)
0
0,8 1,0 1,2
Number of mice

Number of
mice cleared
of
trypanosomes

Number
of mice
killed
Number of
mice cleared of
trypanosomes

Number
of mice
killed
24 hours
0 3/10 0 2/10

0 4/10

0 1/10
48 hours
0 8/10 0 5/10

0 4/10

4/10 2/10
72 hours
0 10/10



12

S. calcitrans - - + ++

+++

+++

+++

+++

+++

++

+ +
T. kiangsuensis - - - + +++

+++

+++

+++

+ + - -
T. rubidus - - - + +++

+++

S. calcitrans - + + + ++ + -
T. kiangsuensis - - + + + - - April
T. rubidus - - + ++ + + -
S. calcitrans + ++ +++ +++ +++ ++ +
T. kiangsuensis + + ++ +++ ++ + -
May -
August
T. rubidus + + ++ +++ ++ + -
S. calcitrans + + ++ ++ ++ + +
T. kiangsuensis + + ++ ++ + + -
September-

October
T. rubidus + + ++ ++ + + -
S. calcitrans - + + + ++ + -
T. kiangsuensis - - - - - - -
November
- December

T. rubidus - - - - - - -
Notes +++ : High activities
++ : average
+ :less activities
- :No activities have been seen
From the data obtained in table 3.8 and 3.9, we concluded that
sucking flies and gad flies were commonly found in the places
investigated. They were highly active from May to October of the
year ( in summer and autumn seasons), The highest active time was
from 10 to 16 o’clock of the day; This is time when animal producer
free buffaloes and cattle to graze in grazing land. S. Calcitrans flies

20 10
3
3 7 4,40 ± 0,32
Experimental

20 10
6
1 2 1,60 ± 0,12
1
Control 10 0 0 0 0,00
20 10
3
3 7 4,90 ± 0,31
Experimental

20 10
6
1 2 1,80 ± 0,09
2
Bontrol 10 0 0 0 0,00
The table 3.10 shows that at dose 10
3
T. evansi per mouse. It took
at least 3 days and longest 7 days for T. evansi to appear in blood
of mouse after being experimentally infected. At dose 10
6
T. evansi
per mouse, time of T. evansi to appear in blood of mouse was 1 - 2
days after being experimentally infected. .In the blood of the control
group of mice no T. evansi was found in peripheral blood.

Experimental
infected
group 1 + 2

Atrophy of testes
(male mice)
40 39 97,50
Control
group
Lesions mentioned
above
20 0 0,00
Table 3.13 shows that mice experimentally infected with T.evansi all
had lesions in internal organs, making up 33,75 - 100 %. At necropsy of
20 mice in the control group, no lesions were found in the internal
organs and subcutaneous tissues of the mice.
15
3.3.1.1. Detection rate of all positive samples performed by CATTT kit
The results were illustrated in table 3.24.
Table 3.24. Rate of positive samples of all positive samples
detected by CATT kit (+)
Serum of buffaloes infected with
trypanosomes
Serum of cattle infected with
trypanosomes
Positive
reaction ( +)
Negative
reaction (-)
Positive

Table 3.24 shows that 100 serum samples from cattle and
buffaloes experimentally infected with T. evansi, were all positive
when CATT kit was used (making up 100 %), of which 88/88 of
serum samples from the buffaloes and 12/12 of serum samples from
the cattle were positive (accounting for 100 %).
3.3.1.2. . Rate of positive samples detected by ELISA kit from all of
positive serum samples (+)
Table 3.25. Rate of positive samples detected by ELISA kit from all of
positive serum samples (+)
Serum from the experimentally
trypanosome infected buffaloes
Serum from cattle infected
with trypanosomes
reaction
( +)
reaction
(-)
reaction
( +)
reaction
(-)
Place
Number
of samples
used kit
n % n
%
Number of
samples
used kit

illustrated in table 3.22.
Table 3.22. Amount and proportion of various types of leucocytes
in the buffaloes experimentally infected compared with the control
buffaloes
Group Control buffaloes
Experimentally infected
buffaloes
Number of buffaloes
(buffalo)
3 5
Type of leucocytes

Amount
(
x
X± m
)
Percentage
(%)
Amount
(
x
X ± m
)
Percentage
(%)
Contrast the
control group
and
experimentally

,
Table 3.22 shows that amount and rates of granulocytes in the
buffaloes experimentally infected with trypanosomes were higher
than that in the control ones. In contrast, amount and rates of
lymphocytes and monocytes in the buffaloes experimentally infected
with trypanosomes were much lower than that in the control ones.
The differences were significant (P < 0,001).
3.2.3.5. Main gross lesions in buffaloes experimentally with Trypanosomes
Gross lesions in buffaloes experimentally with Trypanosomes
were similar to the lesions found in white mice and rabbits, varying
20 - 100 %.
3.2.3.6. Microscopic lesions in some internal organs of affected
buffaloes due to being experimentally infected with trypanosomes
Microscopic lesions in the internal organs of buffaloes
experimentally infected with trypanosome consisted of dilated
myocardium, enlargement of cadiac muscle fibers; dilated hepatic
sinusoid, hepatic vein like spokes being dilated, degeneration of liver
cells; congested lungs, accumulated with edema fluid; hemorrhage of
splenic tissues filtrated inflamatory cells and macrophages;
hemorrhagic kidney tissues, dilated and hemorrhagic renal ducts.
3.3. APPLICATION OF SEROLOGICAL TEST KIT FOR DIAGNOSIS
OF TRYPANOSOMIASIS IN CATTLE AND BUFFALOES
3.3.1. Rate of positive serum samples detected by the kit
11
3.2.2. Ability of T. evansi to cause diseases in rabbits
3.2.2.2. Time of T. evansi appearance in blood of rabbits experimentally
infected with T. evansi and time period of killing rabbits
Table 3.16. Frequency of T. evansi appearance in blood of rabbits
experimentally infected with T. evansi and time period of killing rabbits
Time of

CONTROL 5 rabbits 50 0 0,00 Not killed
1 10 10 100 40
2 10 9 90,00 48
3 10 10 100 38
4 10 10 100 61
Experimental
infected
5 10 9 90,00 75
2
CONTROL 5 rabbits 50 0 0,00 Not dead
Experimental
infected
10 rabbits 99 93 93,90 55,7 ± 5,14
Tính
chung
CONTROL 10 rabbits 100 0 0,00 Not killed
Table 3.16 shows that: there were many times that T. evansi was
detected in blood of rabbit. 93 of 99 times for being tested. in blood
of 10 rabbits T. evansi was found making up 93,90 %. Rabbits
experimentally infected with T. evansi were all killed on day 37 to
day 82 after being experimentally infected.
* In blood of rabbits in the control group in twice of experimental
infections T. evansi was nof found. At the end of the experiment no
rabbits were killed.
3.2.2.3. Time to appear clinical signs and develop symptoms
Table 3.17 shows that all of 10 rabbits experimentally infected with T.
evansi in twice of experiments manifested clinical signs accounting for 70
- 100 %. Time to appear the earliest clinical signs on day 15 and the latest
was on day 52 after being experimentally infected, generally 25 - 40 days
after being experimentally infected rabits presented clinical signs.

mX 
)(day)

Edematous ear
(ear was prone to
the back side)
10 100 15 49 27,5 ± 3,60
Respiration
disorder
10 100 16 44 25,2 ± 2,87
Swollen eyes with
rheum
10 100 21 41 33,3 ± 2,17
Swollen and
edematous lips
7 70,0 26 46 38,6 ± 2,42
Experimen-
tally
infected
Slow moving
10
8 80,0 31 52 40,9 ± 2,21
Control
Symptoms
mentioned above

10 0 0,0 0 0 0
All of 10 rabbits in the control group didn’t show any clinical
signs during the experiments.
3.2.2.4. Main gross lesions in rabbits experimentally infected with

Table 3.20. Main clinical signs of buffaloes experimentally infected
with trypanosomes
Experimental
groups
Main clinical signs
Number of
buffaloes
monitored
(buffalo)
Number of
buffaloes showing
clinical signs
(buffalo)
Percen-
tage
(%)
Undulant fever 5 100
Swollen eyes with mucus
running out of eyes
5 100
Dry,rough hair coat 5 100
Edema in jaws 4 80,00
Edema in chest and abdomen

3 60,00
Trembling 5 100
The group was
experimentally
infected with
T.

Comparison
between
control and
exprimental
groups
Number of erythrocytes
(million/ml of blood)
8,470 ± 142,11 6.936 ± 943,00
χ
2
= 290.353
P = 0.000
Number of leucocytes
(thousand/ml of blood)
13,600 ± 2250.53

17.260 ± 1344.70
χ
2
= 328.92
P = 0,000
Number of thrombocytes
(thousand/ml of blood)
213.,67 ± 89,88 342.80 ± 33.75
χ
2
= 175.43
P = 0.000
Hemaglobin content
(g/l)