2Benishangulgumuz Metekel zone livestock development bureau
Keywords: Bulen district; Risk factor; Trypanosomosis
Trypanosomiasis is a devastating disease of livestock caused by protozoal parasites of the genus trypanosoma that inhabits blood and other tissues of vertebrates including animals, wildlife and human [3]. It is a vector borne disease that is transmitted biologically by tsetse flies and mechanically by other biting flies [4]. It is a major constraint contributing to direct and indirect economic losses to crop and livestock production and has a significant negative impact on economic growth in many parts of the world particularly in sub-Saharan Africa [5,6].
The disease is characterized by severe anemia, weight loss, reduced productivity, infertility and abortion, with death occurring in some animals during the acute phase of the disease. Animals which survive often remain infected for several months or years, exhibiting a low level of fluctuating parasitaemia which serves as a reservoir for the disease occasionally; however, the infected animals may undergo spontaneous recovery [7].
The most important trypanosome species affecting livestock in Ethiopia are Trypanosoma congolenses, Trypanosoma vivax, and Trypanosoma brucei in cattle, sheep and goats, Trypanosoma evansi in camels and Trypanosoma equiperdium in horses [5]. The influence of tsetse on African agriculture through the transmission of trypanosomosis continues to be a major constraint to the development of national economies and their achievement of self sufficiency in basic food production. The general distribution of tsetse flies is determined principally by climate and influenced by altitude, vegetation, and presence of suitable host animals [8].
Ethiopia is situated at the East end of the African tsetse belt. In Ethiopia, tsetse flies are confined to south western and north western regions between longitude 33⁰ and 38⁰ E and latitiude 5⁰ and 12⁰ N that covers an area of about 22,000 km2 [9]. Tsetse infested areas lies in the low lands and also in the river valleys of Blue Nile, Baro Akobo, Didessa, Ghibe and Omo. Benishangul Gumuz is one of the five regions of Ethiopia infested with more than one species of tsetse flies. Five species of Glossina (Glossina morsitans submorsitans, G. Pallidipes, G. tachnoides, G. f. fuscipes and G. longipennis) have been registered in Ethiopia [10]. In the study region of Benishangul Gumuz regional state, four glossina species namely, G. tachinoides, G.morsitant submorsitances, G. pallidipes and G.fuscipes were found [11]. Apart from the cyclical transmission of trypanosomosis by Glossina species, it is highly considered that mechanical transmission is a potential threat to livestock production and productivity in some parts of Ethiopia [5].
Bulen is one the seven districts of Metekel zone of the Benishangul Gumuz regional state, western Ethiopia with a serious problem of trypanosomosis. Controlling this economically important disease in this area could have a number of benefits to improve the livelihood of the poor people of the district by increasing milk, meat, surplus capital from the sale of livestock and livestock products and improving the availability of draft power (oxen).Although the disease is one of the main obstacles of livestock production and productivity in the district, the prevalence and situation of the disease was assessed only once by and no further strategic and participatory control measures of have been made and the problem of the disease is still continuing in the district [12]. Therefore, the present studies were designed with the following objectives:
• To determine the prevalence of bovine trypanosomosis in the district;
• To identify associated risk factors for the occurrence of the disease;
• To forward possible prevention and control measures against the disease in the district.
Pexp = expected prevalence
d = desire absolute precision
1.962 = z-value for the 95% confidence level
The prevalence of bovine trypanosomosis in Bulen district was reported to be 5.6 % by [10]. Therefore, an expected prevalence of 5.6 % was taken to estimate the sample size. Taking 95 % confidence level, 5 % precision and 5.6 % expected prevalence 81 animals were needed to study the prevalence. However, 306 cattle were sampled to increase the level of precision and randomness.
Trypanosomes |
No. positive |
Prevalence (%) |
X2 |
(P-value) |
T. congolense |
11 |
66.11 |
182.5627 |
0 |
T. vivax |
6 |
33.33 |
||
T. brucei |
1 |
5.56 |
||
Total |
18 |
100 |
The Prevalence of trypanosomosis varies in both sexes; the infection in female is higher 13/164 (7.93 %) than male 5/142 (3.52 %) however, the association was not statistically significant (P>0.05) (table 3). In the present study animals examined were categorized in different age groups as < 2 years, 2-5 years and >5 years. Out of the total sampled animals, 67, 107 and 132, were < 2 years, 2-5 years and> 5 years old respectively and the prevalence was found to be 3/67(4.48 %) for animals < 2 years, 5/107 (4.67 %) for animals 2-5 years and 10/132(7.58 %) for tested animals>5 years old and the difference in the prevalence was not statistically significant (p >0.05) (Table 3).
Similarly, during the study, animals were categorized in to different body conditions as good, medium and poor. From the total 306 animals examined 79,147 and 80, were registered as good, medium and poor body condition respectively and out of which 2/77 (2.60 %), 5/147 (3.40 %), and 11/82(13.75 %) prevalence of trypanosomosis were recorded for animals with good, medium
Status |
Frequency |
Mean PCV (%) |
SD |
Overall PCV |
X2 |
p-value |
Parasitaemic |
18 |
18.21 |
4.11 |
327.78 |
||
Aparasitaemic |
288 |
28.12 |
2.67 |
8098.56 |
9.4117 |
0.002 |
Total |
306 |
24.48 |
3.34 |
7490.88 |
Risk factors |
No. examined |
No. positive |
Prevalence (%) |
χ2 |
p-value |
Sites |
|
|
|
|
|
Mata |
60 |
2 |
3.33 |
6.9073 |
|
Addis Alem |
55 |
4 |
7.27 |
0.228 |
|
Bekuji |
47 |
3 |
6.38 |
||
Chilanko |
38 |
0 |
0 |
||
Dobi |
45 |
2 |
4.44 |
||
Badore |
61 |
7 |
11.48 |
||
Total |
306 |
18 |
5.88 |
||
Sex |
|
|
|
|
|
Female |
164 |
13 |
7.93 |
||
Male |
142 |
5 |
3.52 |
||
Total |
306 |
18 |
5.88 |
2.6682 |
0.102 |
Age(years) |
|
|
|
|
|
<2 |
67 |
3 |
4.48 |
||
5-Feb |
107 |
5 |
4.67 |
||
>5 |
132 |
10 |
7.58 |
||
Total |
306 |
18 |
5.88 |
1.2052 |
0.547 |
Body conditions |
|
|
|
|
|
Good |
77 |
2 |
2.6 |
||
Medium |
147 |
5 |
3.4 |
||
Poor |
82 |
11 |
13.75 |
||
Total |
306 |
18 |
5.88 |
12.1809 |
0.002 |
Of the total cases registered, 11/18(66.11 %),6/18(33.33 %) and 1/18(5.56 %) were found to be caused by T. congolense, T. Vivax, T. brucei respectively. This indicates statistically significant difference among the distribution of trypanosome species (p< 0.05). This finding was in consistent with the previous finding of who reported 63.64%, 27.27%, and 9% for trypanosome species of T [28]. congolense, T. vivax, and T. brucei respectively During their study in Dale Wabera district of Kellem Wollega Zone of Oromia Region, Western Ethiopia, similarly, it was in concordance with whose finding showed proportional prevalence of T. congolense to be 53.33 %, T. vivax 30 % and T. brucei 16.66 % in their study on Prevalence of Bovine Trypanasomosis in Guto Gida District of East Wollega Zone of Oromia Region, Western Ethiopia [21].
Among the study sites, the highest and the lowest prevalence of trypanosomosis were recorded in Badore PA 7/61(1148 %) and MataPA 2/60(3.33 %) respectively and no trypanosome infection was registered in Chilanko study site. However there was no significant difference (p>0.05) in the prevalence of trypanosomosis and the study sites. This finding was in agreement with the finding of in their study on Bovine Trypanosomosis and Apparent Vector density in Bambasi District of Benishangul Gumuz Region, Western Ethiopia, in their study on Post Control Survey on Prevalence of Bovine Trypanosomosis and Vector Distribution in Ameya District, South West Shewa, Ethiopia According to there is difference in prevalence of trypanosomosis in different study sites and the difference among kebeles/study sites/is due to difference in vegetation cover; reproduction and development of flies are highly influenced by climatic conditions [29,30 31].
The prevalence of trypanosome infection was higher in female animals 13/163(7.93 %) than males 5/142(3.52 %), although it was not statistically significant (p>0.05). This finding was in agreement with the previous findings of found higher infection rate in females animals than males in some parts of Ethiopia. The possible reason for this difference might be due to physiological difference between female and male animals because female animals are more exposed to physiological stresses than males [32].
Higher prevalence of trypanosomosis was observed 11/80(13.75 %) in animals with poor body condition when compared with animals with medium 5/147 (3.40 %) and good 2/77 (2.60 %) body condition and the association was found statistically significant (p< 0.05) and this finding was in agreement with study carried out by and who reported higher trypanosome infection rate in animals with poor body condition than in animals with good and medium body condition. Similarly, higher prevalence was registered in animals aged > years 10/132(7.58 %) when compared with animals 2-5 years5/107(4.68 %) and < 2 years3/67(4.48 %) and statistically significant associations were not observed (p>0.05) and this finding was in agreement with previous worker who reported higher prevalence of trypanosome infection in adult animals than young in their study on Prevalence of bovine trypanosomosis in Chilga District, Northwest Ethiopia [20,33,34,35].
The overall mean PCV value of all examined animals was (24.48% ± 3.34 SD). The mean PCV of non infected cattle was higher (28.12% ± 2.67 SD) than that of infected animals (18.21% ± 4.11%) and the association was statistically significant. This finding was in agreement with the previous works and who reported lower mean PCV value in infected animals than non infected ones [27,36]. Similarly, (Daud and Molalegne, 2011) and reported lower mean PCV value in infected than in the noninfected animals [25,37].
Therefore, the based on the above conclusion, the following recommendations were forwarded:
1. All available, acceptable and conventional technologies should be used effectively to control and eradicate the parasites and the vectors;
2. Creation of awareness to the rural communities with the relation of parasite and vector and their impact on live stock production should be considered by the concerned body;
3. Epidemiological studies should be conducted in the area in order to decide control strategies and determine its economic impact at large.
4. Laboratory facility and skilled veterinary professionals should be fulfilled in the clinic and animal health post to avoid tentative diagnosis which is a challenge for drug resistance.
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