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Dairy, Veterinary & Animal Research

Research Article Volume 5 Issue 2

Prevalence of bovine trypanosomosis and its associated risk factors in Bambasi woreda, Western Ethiopia

Shimels Tikuye Yalew,1 Bosona Fantahun2

1National Agricultural Biotechnology Research Center, Ethiopia
2Regional Veterinary Diagnostic Laboratory, Ethiopia

Correspondence: Shimels Tikuye Yalew, EIAR, National Agricultural Biotechnology Research Center, Holleta, P. O. Box: 249, Ethiopia, Tel 251 913 79 63 89

Received: January 10, 2017 | Published: March 24, 2017

Citation: Yalew ST, Fantahun B. Prevalence of bovine trypanosomosis and its associated risk factors in Bambasi woreda, Western Ethiopia. J Dairy Vet Anim Res.2017;5(2):44-49. DOI: 10.15406/jdvar.2017.05.00132

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Abstract

A cross-sectional study was conducted in Bambasi woreda from November 2014 to May 2015 to determine the prevalence rate of trypanosomosis and its associated risks. Blood samples were collected from a total of 400 randomly selected cattle. The samples were examined by using Buffy coat technique and hematological procedures. The overall prevalence rate of trypanosomosis was 21.5%(n=85). The species specific trypanosomosis prevalence rate was; Trypanosome congolense 51.76%(n=44), Trypanosome vivax 28.23%(n=24), Trypanosome brucei 11.76%(n=10) and mixed 8.23%(n=7). There was statistically significant difference between trypanosome species (P<0.05). During the study period the prevalence of bovine trypanosomosis was assessed between sexes and age groups of animals. However, the prevalence of trypanosomosis with regard to study areas and body conditions were significantly different. The Mean packed cell volume (PCV) value of infected animals was lower (21.6%±3.20) than uninfected animals (24.32%±2.22). The only tsetse fly which was caught during the study period was Glossina morsitans sub morsitans and its mean apparent density was 4.95fly/trap/day. But mechanical vectors of trypanosomosis such as tabanus (1.83f/t/d), stomoxys (1.29 f/t/d) and haematopota (0.41f/t/d) were also found. The overall result of this research shows that the disease is severely affecting the agricultural productivity of the area so attention should be given to control trypanosomosis and its vectors.

Keywords: risk factor, bovine, PCV, trypanosomosis

Abbreviations

%, percent; EIAR, ethiopian institute of agricultural research; F/T/D, fly per trap per density; G. f. fuscipes, Glossina fuscipes fuscipes; G. longipennis, Glossina longipennis; G. morsitans sub morsitans, Glossina morsitans sub morsitans; G. pallidipes, Glossina pallidipes; G. tachnoids, Glossina tachnoids; KM, kilo meter; KM2, square kilo meter; MM, mille meter; NTTICC, national tsetse and trypanosomosis investigation and control center; Pas, peasant associations; PCV, packed cell volume; P-value, predictive value; Rpm, revolution per minute; SE, standard error; SPSS, statistical package for social science; T. congolense, Trypanosome congolense; T. Vivax, Trypanosome vivax; T.Brucei, Trypanosome brucei; US$, united states dollar; χ2, pearson chi square

Introduction

Diseases of livestock reduce agricultural output by up to 30% in developing countries.1 African animal trypanosomosis or Nagana represents a serious problem in most of Africa, specifically in sub-Saharan Africa.2 Nagana is a disease caused by Trypanosoma vivax, T. Congolense and T. Brucei species. The outcome of disease occurrence depends on the interplay of the host, the parasite and environmental factors. Animal trypanosomosis is a wasting disease of cattle as indicated by its name "Nagana" which is a Zulu word that means "powerless/useless".3 The economic loss which follows decreased productivity and death of livestock is enormous. Livestock production in Sub-Saharan Africa suffers from high prevalence of trypanosomosis with estimated annual losses due to direct and indirect consequences of the disease nearby billions of dollars.4

Animal trypanosomosis known as Ghendi in Ethiopia is also one of the main constraint to livestock production and preventing full use of land to feed the rapidly increasing human population. This disease is found throughout Ethiopia with the exception of the highlands and transmitted by cyclical or mechanical means. Most of the infection is transmitted mechanically by biting flies such as Tabanids and Stomoxy’s. Cyclically, Glossina (tsetse flies) transmitted trypanosomosis holds 180,000-200,000km2 agriculturally fertile land of west and south west part of the country.5,6 Five species of Glossina namely G. Morsitans sub morsitans, G. Pallidipes, G. f. Fuscipes, G. Tachnoids and G. Longipennis are widely found in Ethiopia.7,8 The cyclically transmitted trypanosome species affecting cattle, sheep and goats are Trypanosome congolense, T. Vivax and T. Brucei.9 In bovine cyclically-transmitted trypanosomosis is very im­portant.10

Bambasi woreda is located in Benishangul Gumuz Regional State of Ethiopia, which is most severely trypanosome affected area. In this region, almost all domestic animals in and adjacent are at risk of acquiring the disease at any time. Recent population movements including resettlement, as well as climate change is favoring the expansion of the tsetse habitat and brought domestic animals particularly cattle, in direct contact with the fly thereby exposing a significant number of animal populations to trypanosomosis infection. Therefore the objective of this research was to determine the Prevalence, Vector Density and Associated Risks of Bovine Trypanosomosis in Bambasi woreda, Benishangul Gumuz Regional State, Western Ethiopia.

Materials and methods

Study area

This study was conducted in selected kebelles of Bambasi woreda. Bambasi woreda is located in Benishangul Gumz Regional State of Ethiopia at 614km far from the capital city Addis Ababa and it is found between latitude 90-100N and longitude 0340-0350 E.11 Native grasses and bamboo forests are dominantly available vegetation. Under the effect of socio-economic activities, the vegetation is increasingly dominated by shrubs and herbs. Crop production by using animal traction is the main activities of the people followed by animal husbandry such as cattle and small ruminants. The production system of cattle in the region is characterized by an extensive management system.

Study design and sampling method

A cross sectional study design was used to determine the prevalence of bovine trypanosomosis from November 2014 to May 2015. Blood samples from both sexes were collected by using simple random sampling technique. During sampling kebelles (PAs), age, and body condition score of animals were also recorded. Body condition score was grouped in to poor, medium and good conditioned animals based on the appearance of ribs and dorsal spines applied for Zebu cattle.12 The study district and peasant association was purposively selected. The animals were sampled at watering, grazing points and veterinary clinics. Desired sampling size was calculated using 50% expected prevalence according to the formula given by Thrusfield MV13 But to improve the degree of precision a total of 400 samples were taken.

Hematology and parasitological study

Blood samples were collected aseptically from ear veins using heparin zed micro-haematocrit capillary tube and sealed on one end by crystal seal. The samples were properly labeled and submitted to Assosa Regional Veterinary Diagnostic laboratory for further examination. The capillary tube was spun in a haematocrit centrifuge for 5min at 1200rpm and read by micro-hematocrit reader for determination of PCV.14 The centrifuged capillary tubes were cut with diamond pointed pen 1mm below and 3mm above. The Buffy coat were poured onto a slide, mixed and covered with cover slip (22mmx22mm). The samples were examined by using a 10x magnification in combination with 40x objective microscope for identification of motile trypanosomes.15

Entomological survey

A total of 73 monoconical traps were deployed for trapping the vector during the study period. These traps were constructed from locally made blue and black cloth with white mesh on the top. The traps were odor baited by acetone and cow urine; the distance between traps, altitude and type of vegetation were considered. Collection of flies was held after 48hours of deployment and the flies which were captured in the collecting cage were categorized by species.

Data analysis

The collected data were analyzed by using SPSS version 20 software. Descriptive statistics was used to determine the prevalence of trypanosomosis in cattle and Chi-square test (χ2) was used to assess associated risk factors. In all analyses, the confidence interval level was 95% and P value less than 0.05 was considered as significance.

Results and discussion

Prevalence of trypanosomosis

A total of 400 cattle blood sample were examined to determine the presence of trypanosomosis by Buffy coat technique and thin blood smear. Trypanosomosis were detected in 85 cattle with an overall prevalence of 21.25%. The result indicated that a given cattle were infected with three Trypanosome species and most of the infection were caused by T. congolense 51.76% (n=44/400), followed by T. vivax 28.23% (n=24/400), T. brucei 11.76% (n=10/400) and mixed infection 8.23% (n=7/400). The species-specific prevalence of trypanosome showed that statistically significant difference (Table 1).

Trypanosome Species

No Examined

No of Positives

Prevalence %

X2 (P-value)

T. congolense

400

44

51.76

182.75(0.0001)

T. vivax

400

24

28.23

T. brucei

400

10

11.76

Mixed Infection

400

7

8.23

Table 1 Prevalence of trypanosomosis in terms of species level

T. congolense: Trypanosome congolense; T. vivax: Trypanosome vivax; T. brucei: Trypanosome brucei

Prevalence of trypanosomosis varied among age groups (Table 2) and the highest prevalence was observed in cattle aged 2<x<7 years (21.6%), Where X- represent age in terms of years. The prevalence of trypanosomes infection varied between age categories but not significantly (P>0.05). The prevalence of trypanosomosis was higher in male (23.5%) than female cattle (19.6%) (Table 3) but there was no statistically significant difference (p>0.05). The incidence of bovine trypanosomosis on the basis of body condition score was graded as good, medium, poor, and were found to be 9.25%, 17.9 %, and 41.2% respectively (Table 4). And the rate shows significant (P <0.05). So, the body condition was inversely related to infection rate. The prevalence of trypanosome species in cattle within kebelles (PAs) in the study areas showed that Musa and Mender 45 as the highest and lowest trypanosome infection rate recorded areas respectively (Table 5). And the rate showed that significant (P <0.05).

Age Groups

No Examined

No of Positives

Prevalence %

X2 (P-value)

x< 2

72

15

20.8

0.110(0.946)

2 <x< 7

282

61

21.6

x > 7

46

9

19.56

Total

400

85

21.25

Table 2 Trypanosomosis in different age category

Sex

No Examined

No of Positives

Prevalence %

X2(P-value)

Male

166

39

23.5

0.85(0.35)

Female

234

46

19.6

Total

400

85

21.25

Table 3 Sex wise Prevalence of bovine Trypanosomosis

Body condition

No Examined

No of Positives

Prevalence %

X2 (P-value)

Good

108

10

9.25

32.75(0.000)

Medium

195

35

17.94

Poor

94

40

41.2

Total

400

85

21.25

Table 4 Prevalence of bovine trypanosomosis based on body condition

Kebelles (PAs)

No Examined

No of Positives

Prevalence %

X2 (P-value)

Musta

54

20

37.03

11.101(0.049)

Keshimando

53

11

20.75

Mender 49

70

11

15.7

Mender 45

90

14

15.55

Bambasi

64

14

21.87

Dabuse

69

15

21.7

Total

400

85

21.25

Table 5 Prevalence of bovine trypanosomosis based on kebelles (PAs)

The research showed that the mean PCV value for examined animals was 23.75 ± 3.97 SE. But the mean PCV value for negative and positive animals was 24.32 ± 2.22 SE and 21.6± 3.20 SE respectively. Significant difference (P <0.05) was observed (Table 6). The overall prevalence of anemia was 54 % (n=216). The incidence of anemia was higher in trypanosome positive animals (77.64%) than negative animals (47.62). Among the anemic animals 16.5% (n=66) was trypanosome positive but 37.5% (n=150) of animals had anemia without trypanosome infection. However, 4.75% (n=19) of animals having normal PCV value were also found trypanosome positive (Table 7).

Status

Frequency

Mean PCV (%)

SE

Overall PCV

X2(p-value)

Positive

85

21.6

3.20

1836

25.37(0.000)

Negative

315

24.32

2.22

7662

Total

400

23.75

3.97

9498

Table 6 Mean PCV value of trapanosomosis positive and negative animals

Trypanosome Status

Anemia

Frequency

Percent (%)

Percent Share per Strata

Positive

Anemic

66

16.5

77.64

Non-anemic

19

4.75

22.35

Negative

Anemic

150

37.5

47.62

Non-anemic

165

41.25

52.38

Table 7 Status of anemia in trypanosomosis positive and negative animals

Entomological findings

From a total of 1239 captured flies during the study period 58.35 % (n=723) were tsetse flies belonging to the genus glossina, 21.54% (n=267) tabanid, 15.25% (n=189) Stomoxys and 4.84% (n=60) haematopota. The apparent density of G.mor. sub. morsitans was 4.95 F/T/D (fly/trap/day). The highest and lowest fly density were recorded in Musta and Mender 45 (334 (11.13 F/T/D) and 196 (6.53 F/T/D)) respectively (Table 8).

Kebelles (PAs)

Tsetse Fly

Biting Fly

G. M. sub moristance

Tabanid

Stomoxys

Hematopota

Total No

F/t/d

Total No

F/t/d

Total No

F/t/d

Total No

F/t/d

Musta

81

4.05

39

1.95

31

1.55

12

0.6

Keshimando

63

3.5

32

1.77

19

1.05

9

0.5

Mender 49

103

5.15

28

1.4

15

0.75

11

0.55

Mender 45

111

3.7

48

1.6

23

0.76

14

0.46

Bambasi

150

5.35

53

1.89

55

1.96

8

0.28

Dabuse

215

7.16

67

2.23

46

1.53

6

0.2

Total

723(58.35%)

4.95

267(21.54%)

0.079

189(15.25%)

0.056

60(4.84%)

0.0178

Table 8 Tsetse and biting fly density

F/t/d: Fly Per Trap per Day
G. M. sub moristance: Glossina moristance sub moristance

The current study conducted for a period of six month in Bambasi woreda revealed that trypanosomosis is the most prevalent disease causing considerable direct and indirect economic losses in the study area. The overall prevalence of bovine trypanosomosis was 21.25% which was higher when compared with previous reports in different parts of the country, such as 1.3% in Arbaminch by Girma et al.16 6.9% in Chena district by Alemayehu et al.17 6.3% in Kindo Koish District by Adale & Yasine18 and 8.57% in western oromia by Tasew & Dugma.19 This might be due to difference in using controlling methods of trypanosomosis, climate and ecological conditions such as altitude, rainfall, and temperature and livestock management system. But the research was agreed with NTTICC20 with prevalence of 22% in Gari settlement area.

The research showed that out of 85 positive cattle for trypanosomosis, T. Congolense was found to be the causative agent in 51.8%(n=44), T. Vivax 28.23%(n=24), T. Brucei 11.76%(n=10) and mixed infection accounted for 8.23%(n=7). The predominate species causing bovine trypanosomosis was T. Congolense and this finding agreed with previous report from south-western Ethiopia by Abebe & Jobre,9 Duguma et al.21 Zecharias & Zeryehun,22 Teka et al.23 This might be because the research area is suitable for the multiplication of biological vector (tsetse flies). Vector born trypanosome species are disseminated in most parts of Western and South Western parts of Ethiopia Abebe,7 Mulaw et al.24 Meanwhile, the current finding disagrees with Nabulime et al.25 in Mulanda, eastern Uganda. This difference may be caused by the variation in agro ecology, vegetation and environment of research areas.

The prevalence of bovine trypanosomosis was assessed between age group of animals and there was no significance difference with in age groups (Table 2). Similarly, the prevalence of trypanosomosis in male was slightly higher than female but the difference was not statistically significant (Table 3). This may be due to both sexes and age groups are equally susceptible to the disease. This finding agreed with Adale & Yasine18 in Wolaita Zone Kindo Koish District of Ethiopia and Bedada et al.26 in Addisamba and Amarit District of West Gojjam Zone.

The occurrence of disease in three different body condition (poor, medium and good) animals shows the highest prevalence in poor body condition (41.2%) followed by in medium (17.9 %) and good body condition (9.25%). The finding showed that infection rates in poor body condition animals were significantly higher than that of medium and good body condition animals (Table 4). This is due to poor body condition animals are susceptible to the infectious disease. The reason behind is may be due to reduced performance of the animals created by lack of essential nutrients and poor management by the animal owner. In contrast, trypanosomosis is a chronic disease as stated by Urquhart et al.27 the observed emaciation and weight loss might be caused by the disease itself. This result agreed with previously reported findings by Girma et al.16 Teka et al.23 Fayisa et al.28 and Bitew et al.29

The prevalence of bovine trypanosomosis between kebelles (PAs) was significantly different (Table 5). High prevalence of trypanosomosis was recorded in Mutsa kebelle than other kebelles. This might be due to controlled animal movements between PA’s, presence of favorable environment, moisture and vegetation for replication of vectors.

The mean PCV value for all examined animals was 23.75±3.97 SE. However, the mean PCV value of trypanosome positive animals was significantly lower (21.6±3.20 SE) than that of negative animals (24.32±2.22 SE) (Table 6). This finding is aligned with previous works by Ali & Bitew30 and Rowlands et al.31 The overall incidence of anaemia was 54% in the research area and the presence of anemia was higher in trypanosome positive animals (77.64%) than negative animals (47.62%) (Table 7). This is due to the contribution of trypanosomosis for causing anemia in infected animals. This finding agreed with previous reports by Tewelde32 in western Ethiopia and Desta33 in upper Dedesa valley of Ethiopia. Among the anemic animals 37.5% of them were negative to trypanosome infection. This is because the observed anemia can be caused by other means such as blood sucking gastrointestinal parasites and malnutrition.34 However, 4.75% of the cattle with normal PCV value were also found infected by trypanosome and this result is in line with Garoma35 report from East Wollega Zone. This might happen due to the ability of trypanosome positive animal to maintain their PCV value and technical errors of diagnosis methods used.36

 Monoconical traps were deployed for trapping both biological and mechanical vectors. Among the total trapped tsetse flies only Glossina morsitans sub morsitans (58.35%) with 4.95 f/t/d mean apparent density were found (Table 8). This finding is lower than Dagnachew et al.37 in Abay (Blue Nile) basin but higher than that of Desta33 in upper Didessa valley western Ethiopia. This difference might be due to variation of agro ecology and vegetation. However, different types of biting flies (mechanical vectors) were also identified among these tabanus (21.51%), stomoxys (15.25%) and hematopota (4.84%) with apparent densities of 0.079f/t/d, 0.056f/t/d, and 0.0178f/t/d respectively. Fayisa et al.28 in Didesa district and Efrem et al.38 in Gimbi district also reported the presence of biting flies. This result showed that the effect of biting flies for transmission of trypanosomosis in the study area.

Conclusion

Generally the research confirms that trypanosomosis is a major threat in the research area. The research showed that bovine trypanosomosis is mainly caused by T. Congolense. Neither sex nor age groups have seen significance difference but kebelles (PAs) and body conditions showed significance difference in the research area. The mean PCV value of trypanosome positive animals was significantly lower than negative animals indicating the effect of trypanosomosis in lowering the PCV value. The only tsetse fly caught was G. Moristans sub morsitans but mechanical transmitters of the disease such as stomoxys, tabanus and haematopota were found during entomological survey. Therefore awareness creation and appropriate control methods of trypanosomosis on its vectors and against the parasites should be designed and implemented.

Acknowledgements

The authors would like to thank Assosa Regional Veterinary Diagnostic Laboratory for logistic support and my colleague Dr. Yohannes Equar for his unlimited technical advice.

Conflict of interest

Author declares that there is no conflict of interest.

References

  1. FAO. Cost-benefit analysis for animal health programmes in developing countries. FAO expert consultation. Rome, Italy; 1990. 56p.
  2. Connor RJ, Van Den Bossche P. African animal trypanosomosis, In: Coetzer JAW, editors. Infectious diseases of livestock. 2nd ed. UK: Oxford university press; 2004;1:251‒296.
  3. Steverding D. The history of African trypanosomiasis. Parasit Vectors. 2008;1(1):3.
  4. Torgerson PR, Macpherson CN. The socioeconomic burden of parasitic zoonoses: global trends. Vet Parasitol. 2011;182(1):79‒95.
  5. Langridge W. Tsetse and Trypanosomosis survey of Ethiopia Ministry of overseas Department. UK; 1976:1‒40 p.
  6. Ministry of Agriculture and Rural Development of the Government of Ethiopia (MoARD). Tsetse and trypanosomiasis prevention and control strategies, Ethiopia; 2004.
  7. Abebe G. Trypanosomosis in Ethiopia. Ethiop J Bio Sci. 2005;4(1):75‒121.
  8. Keno M. The current situation of tsetse and trypanomosis in Ethiopia, Ministry of Agriculture and Rural Development, Veterinary service department. Proceeding of 28th meeting of International Scientific Council for Trypanosomosis Research and Control (ISCTRC). 2005.
  9. Abebe G, Jobre Y. Trypanosomosis: A threat to cattle production in Ethiopia. Rev Vet Med Vet. 1996;12(147):897‒902.
  10. Taye M, Belihu K, Bekana M, et al. Assessment of impacts of tsetse and trypanosomosis control measures on cattle herds composition and per¬formance in Southern region, Ethiopia. Trop Anim Hlth Prod. 2012;44(7):1759‒1763.
  11. BWOARD. Bambasi Woreda Office of Agriculture and Rural Development profile document. 2015.
  12. Nicholson MJ, Butterworth MH. A guide to scoring of zebu cattle. Addis Ababa, Ethiopia; 1986.
  13. Thrusfield MV. Veterinary Epidemiology. 3rd ed. Oxford, UK: Blackwell Publishing; 2005. p. 233‒250.
  14. Uilenberg G. A field guide for diagnosis, treatment and prevention of African animal trypanosomosis. WP Food and agriculture organization of United Nations (FAO). Rome, Italy; 1998. p. 43‒135.
  15. Paris J, Murray M, Mcodimba F. A comparative evaluation of the parasitological technique currently available for the diagnosis of African Trypanosomosis in cattle. Acta Trop. 1982;39(4):307‒316.
  16. Girma K, Meseret T, Tilahun Z, et al. Prevalence of Bovine Trypanosomosis, its Vector Density and Distribution in and Around Arbaminch, Gamogofa Zone, Ethiopia. Acta Parasitologica Globalis. 2014;5(3):169‒176.
  17. Alemayehu B, Bogale B, Fentahun T, et al. Bovine trypanosomosis: A threat to cattle production in Chena district, Southwest Ethiopia. Open Journal of Animal Sciences. 2012;2(4):287‒291.
  18. Adale E, Yasine A. Prevalence of bovine trypanosomosis in Wolaita Zone Kindo Koish District of Ethiopia. African Journal of Agricultural. 2013;8(49):6383‒6387.
  19. Tasew S, Duguma R. Cattle anemia and trypanosomosis in western Oro¬mia State, Ethiopia. Revue Med Vet. 2012;163(12):581‒588.
  20. NTTICC. National Tsetse and Trypanosomosis Investigation and Control center. 2003.
  21. Duguma R, Tasew S, Olani A, et al. Spatial distribution of Glossina sp. And Trypanosoma sp. in south-western Ethiopia. Parasit Vectors. 2015;8:430
  22. Zecharias A, Zeryehun T. Prevalence of bovine trypanosomosis in selected district of Arba Minch, SNNPR, Southern Ethiopia. Global Vet. 2012;8(2):168‒173.
  23. Teka W, Terefe D, Wondimu A. Prevalence study of bovine trypanosomosis and tsetse density in selected villages of Arbaminch, Journal of Veterinary Medicine and Animal Health. 2012;4(3):36‒41
  24. Mulaw S, Addis M, Fromisa A. Study on the prevalence of major trypano¬some affecting bovine on tsetse infested, Assosa district of Benshagul-Gumuz Re¬gional State, Western Ethiopia. Global Vet. 2011;7(4):330‒336.
  25. Nabulime L, Mbogua J, Zirintunda G, et al. Prevalence of Trypanosomiasis among Zebu Cattle in Mulanda, Tororo District, Eastern Uganda. Scholars Journal of Agriculture and Veterinary Sciences. 2014;1(4B):274‒278
  26. Bedada AH, Alem TC, Weldo BF, et al. Prevalence of Bovine Trypanosomosis in Addisamba and Amarit District of West Gojjam Zone, Amhara Regional State. American-Eurasian Journal of Scientific Research. 2012;7(3):112‒117.
  27. Urquhart GM, Armour J, Duncan JL, et al. Veterinary parasitology. 2nd edn, Oxford, UK: Blackwell Science; 1996. p. 212‒230.
  28. Fayisa G, Mandefro A, Hailu B, et al. Epidemiological Status and Vector Identification of Bovine Trypanosomiosis in Didesa District of Oromia Regional State, Ethiopia. International Journal of Nutrition and Food Sciences. 2015;4(3):373‒380.
  29. Bitew M, Amedie Y, Abebe A. Prevalence of bovine trypanosomosis in selected areas of Jabi Tehenan district, West Gojam of Amhara regional state, North western Ethiopia. African Journal of Agricultural Research. 2011;6(1):141‒144.
  30. Ali D, Bitew M. Epidemiology study of bovine trypanosomosis in Mao- Komo special district, Benishangul Gumuz, Regional State, Western Ethiopia. Global Veterinaria. 2011;6(4):402‒408.
  31. Rowlands GJ, Leak SGA, Peregrine AS, et al. The incidence of new and the prevalence of recurrent trypanosome infection in cattle in Southwest Ethiopia, exposed to a high challenge with drug-resistant parasite. Acta Trop. 2001;79(2):149‒163.
  32. Tewelde N. Study on the occurrence of drug resistant trypanosomes in cattle in the farming in tsetse control areas FITCA Project in western Ethiopia. MSc Thesis, Addis Ababa University, Faculty of Veterinary Medicine, Ethiopia. 2001.
  33. Desta M. Trypanosome infection rate of Glossina morsitans and trypanosomosis prevalence in cattle in upper Didessa valley western Ethiopia. Int J Curr Microbiol App Sci. 2014;3(3):378‒388.
  34. Van Den Bossche P, Rowlands GJ. The relationship between the parasitological prevalence of trypanosome infections in cattle and helped average packed cell volume. Acta Tropica. 2001;78(2):163‒170.
  35. Garoma D. The prevalence of bovine trypanosomosis in Gari settlement area of East Wollega Zone. Ethiopia: DVM Thesis, Jimma University, 2009.
  36. Murray, Dexter TM. Anemia of Bovine Africa Trypanosomosis. Acta Trop. 1988;45(4):389‒432.       
  37. Dagnachew S, Sangwan AK, Abebe G. Epidemiology of Bovine Trypanosomosis in the Abay (Blue Nile) Basin Areas of Northwest Ethiopia. Revue Élev Méd vét Pays Trop. 2005;58(3):151‒157
  38. Efrem DB, Yacob HT, Hagos AT, et al. Bovine trypanosomosis in Gimbi district of Western Oromia, Ethiopia. Animal Biol. 2010;60(2):123‒131.
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