Current Research Journal of Biological Sciences 4(4): 414-416, 2012
ISSN: 2041-0778
© Maxwell Scientific Organization, 2012
Submitted: February 02, 2012
Accepted: March 01, 2012
Published: July 10, 2012
Haematological Changes Following Acute Trypanosoma brucei brucei
Infection in Rabbits
1
O.G.C. Ezebuiro, 2J.A. Yohanna, 2A. Abdulya’aq, 3H.O. Osue, 4J.N. Abenga,
2
M.A. Yakasai and 1A. Attahir
1
Vector and Parasitology Department, N.I.T.R, P.M.B, 2077, Kaduna
2
Applied Science Department, C.S.T. Kaduna Polytechnic, Kaduna
3
Trypanosomiasis Department, N.I.T.R, P.M.B, 2077, Kaduna
4
Federal University of Agriculture, Makurdi, Benue-State
Abstract: This study assessed the haematological changes following acute T. brucei brucei infection in 10
rabbits during a period of six weeks post infection. Six rabbits were inoculated intraperitoneally (IP) with 0.5
mL of blood containing about 1x104 trypanosomes and four rabbits served as uninfected control. All infected
rabbits developed acute trypanosomiasis with the following clinical signs and symptoms: slight weight loss,
intermittent pyrexia, weakness, lethargy, dull and rough coats, pale mucous membranes, enlarged superficial
lymph nodes and anaemia. The difference in mean+standard deviation of Packed Cell Volume (PCV), body
weight, temperature, Haemoglobin (Hb) Red Blood Cell (RBC) count of infected and control animals were not
statistically significant (p>0.05). However, the mean+standard deviation of total White Blood Cell (WBC)
count and differential WBC showed significant differences (p<0.05). The mean percentage (%) +standard
deviation of neutrophil count were 35.35+10.74 and 55.58+2.46, lymphocyte were 60.52+9.40 and 34.28+4.80.
The platelet count varied significantly with 7.44+1.20 and 10.98+0.85. The result from this study showed
that T. brucei brucei infection decreases both platelet (Thrombocytopenia) and neutrophil (Neutropenia), while
lymphocyte population is increased (lymphocytosis).
Keywords: Acute, T. brucei brucei, haematological changes, Trypanosoma
Mechanization, Afaka, Kaduna State and brought to NITR
Kaduna for this study. Feed (rabbits’ cubes) and water
were fed ad libitum. At the end of two months
acclimatization, they were grouped into two (A and B) of
infected (n = 6) and control (n = 4).
Trypanosoma brucei brucei (Lafia) was obtained
form NITR Vom, Plateau State. This strain was
maintained by several passages in rats.
Infection-The parasite was inoculated into donor rats.
On the fourth day of patent parasitaemia, about 0.5 mL of
blood containing about 1x104 trypanosomes was
inoculated Intraperitoneally (IP) into each rabbit.
Blood samples were collected from the ear vein into
vacutainer tubes using EDTA as an anticoagulant. Rectal
temperatures were taken between 8.00 and 9.00 am before
the collection of blood samples. Blood samples were
analysed for parasitaemia by the Hematocrit Centrifuge
Technique (HCT), as described by Woo (1971); Buffy
Coat Method (BCM) Murray et al. (1977) and also Thin
Film (TF) examination were made for differential count.
Other parameters monitored are body weight, Packed Cell
Volume (PCV), Heamoglobin (Hb), White Blood Cell
(WBC), Red Blood Cell (RBC), Platelet and differential
WBC counts.
INTRODUCTION
African trypanosomiasis remains a disease of major
socio-economic consequence. The exact factors
responsible for its pathogenesis are yet to be fully
understood. Anaemia remains a dominant and consistent
feature in trypanosomiasis of man and his domestic
animals. (Anosa, 1988).
The severity of anaemia differs from one species of
trypanosome to another (Anosa, 1988). Also, anaemia has
been shown to be more responsive in T. brucei infections.
(Anosa et al., 1977; Jenkins et al., 1974) than those of
T. vivax and T. congolense (Mackenzine and Cruickshark,
1973; Anosa, 1988). Haematological changes including
anaemia, leucopaenie and increased immunoglobin levels
have been reported by many investigators (Morrison
et al., 1981; Esievo and Saror, 1983; Ogwu et al., 1987).
Therefore, in this investigation, haematological changes
following acute T. b. brucei infection in Rabbits were
investigated.
MATERIALS AND METHODS
Ten (10) healthy rabbits of about two months old
were purchased from Federal College of Forestry
Corresponding Author: O.G.C. Ezebuiro, Vector and Parasitology Department, N.I.T.R, P.M.B, 2077, Kaduna
414
Curr. Res. J. Biol. Sci., 4(4): 414-416, 2012
decreased to 25.1% post infection. Also, lymphocytes had
34% pre-infection and increased to 70.10% post infection
while control were 38.1% and decreased to 26.0%.
The final analysis was done using Analysis Of
Variance (ANOVA). From the analysis mean+standard
deviation of packed cell volume, body weight,
temperature, heamoglobin, red blood cell count of
infected and control animals were not statistical
significant (p>0.05). while the mean+standard deviation
of total white blood cell count and differential WBC
showed significant differences (p<0.05). The Neutrophil
count showed Neutropenia with mean percentage+
standard deviation of 35.35+10.74 and 55.58+2.46; and
lymphocytosis with mean percentage+ standard deviation
of lymphocyte 60.52+9.40 and 34.28+4.80. Also,
thrombocytopenia was observed with platelet count of
7.44+1.20 and 10.98+0.85 which was highly significant
(p<0.05).
RESULTS
Parasitaemia was first detected 3-4 days post
infection. The clinical signs that were pronounced were
rapid weight loss, intermittent pyrexia, lethargy,
weakness, dull and rough coats, pale mucous membranes,
enlarged superficial lymph nodes and anaemia.
The mean results of Packed Cell Volume (PCV),
Haemoglobin (Hg), temperature and weight of infected
and uninfected rabbits were shown in Table 1.
The mean rectal temperature at pre-infection was
38.5 against 39.50ºC for post infection, while that of
control were 38.2 to 38.05ºC. The values obtained for Red
Blood Cell count (RBC), White Blood Cell count (WBC),
platelet count, differential white blood cell count
(Neutrophil and Lymphocytes) of infected and uninfected
were as shown in Table 2. The PCV at pre-infection was
28.5% while post infectionhad 19.05% which showed the
significant decrease (p<0.05). The control had 27.8 to
32%.
Haemoglobin pre-infection value was 9.5 g/dL and
dropped to 6.35 g/dL to post infection, while that of
control were 9.27 to 10.67 g/dL. The weight of the
infected rabbits decreased from 0.81 to 0.68 kg, while that
of control was 0.70 to 1.40 kg. RBC value was
5.75×1012/L for pre-infection and decreased to 4.30×
1012/L post infection while its control were 4.0×1012/L to
8.0×1012/L. WBC values increased from 6.50×109/L to
9.0×109/L post infection. The control had 8.0×109/L to
10.20×109/L. The platelet had 9.0×109/L pre-infection to
6.0×109/L post infection and the control had 9.20×109/L
to 12.0×109/L. Neutrophil 54% pre-infection and
DISCUSSION
The result from this investigation showed there was
mild anaemia based on low PCV and RBC values. This
may be as a result of the acute nature of the course of
infection. Murray et al. (1982) have shown that the
severity of the anaemia which follows infection is affected
by several factors which include differences in virulence
that exist among different species of trypanosomes and
among the large number of strains belonging to each
species. At the same time, host factors such as age,
nutritional status and breed are important.
Table 1: Mean values of pcv, Hb, temperature, and body weight of rabbits infected with Trypanosoma brucei brucei
Weeks (post-infection)
------------------------------------------------------------------------------------------------------------Parameters
Pre-infection
1
2
3
4
5
6
PCV (%) infected
28.50
29.30
30.05
29.50
27.40
24.00
19.05
control
27.80
28.50
29.00
30.60
30.80
31.06
32.00
Hb (g/dL) infected
9.50
9.77
10.02
9.83
9.13
8.00
6.35
control
9.27
9.50
9.67
10.20
10.27
10.35
10.67
38.50
28.78
41.17
39.44
39.42
40.00
39.50
Temperature (oC)
infected control
38.20
38.20
38.50
38.02
38.12
38.08
38.05
Weight (Kg)
0.81
0.94
0.93
0.89
0.84
0.74
0.68
infected control
0.70
0.85
0.98
1.05
1.10
1.24
1.40
Table 2: Mean values of RBC, WBC, platelet, neutrophil and lymphocytes of rabbits infected with Trypanosoma brucei brucei
Weeks (post-infection)
------------------------------------------------------------------------------------------------------------Parameters
Pre-infection
1
2
3
4
5
6
5.75
6.00
6.20
6.00
5.50
5.00
4.30
RBC × 1012/L
infected control
4.00
4.80
5.60
6.00
6.20
7.30
8.00
6.50
6.70
6.90
7.30
8.40
8.50
9.00
WBC x 109/L
infected control
8.00
8.60
8.75
9.00
9.40
10.00
10.20
9.00
9.50
8.10
7.00
6.30
7.50
6.40
Platelet x 109/L
infected control
9.20
9.80
10.30
10.80
11.20
11.80
12.00
Neutrophil (%)
54.00
51.00
46.40
32.30
30.30
27.00
25.10
infected control
52.00
51.20
54.50
55.80
57.00
57.00
58.00
Lymphocytes (%)
34.00
48.00
50.00
62.00
64.40
68.60
70.10
infected control
38.10
36.80
36.40
34.00
40.00
32.50
26.00
415
Curr. Res. J. Biol. Sci., 4(4): 414-416, 2012
Other investigators have adduced causes of anaemia
to haemolysis (De Gruchy, 1970); Dyshaemopoiesis
(Dargie et al., 1979; Anosa, 1988; Anosa et al., 1992) and
haemodilution (Holmes and Jennings, 1976, 1975).
Anaemia was observed as a result of immune haemolysis
or erythrophagocytosis (Jenkins, 1980; Egbe-Nwiyi et al.,
2003). The onset of anaemia coincided with fever
appearance, intensity and duration of parasitaemia;
T. brucei brucei caused neutropenia, lymphocytosis and
thrombocytopenia in rabbits. This study showed that
T. brucei could be an important wasting disease in both
cattle and human as suggested by Cox (2004). Therefore,
it is suggested that more attention be given on this before
there will be an epidemic.
Esievo, K.A.N. and D.I. Sarror, 1983. Leukocytes
response in experimental Trypanosoma vivax
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Holmes, P.H. and F.W. Jennings, 1976, 1975. The Effect
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ACKNOWLEDGMENT
The authors wish to thank DR. I. Halid former
DG/CEO NITR for granting permission to publish the
study.
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