Prevalence of Bovine Trypanosomosis and Apparent
Density of Tsetse Fly at Sekoru District, Jimma Zone,
Ethiopia

Takele S; Kedir M; Yusuf A; Nesru A; Desa G; Tafesse A

Research Article

Austin J Vet Sci & Anim Husb. 2020; 7(1): 1068.

Prevalence of Bovine Trypanosomosis and Apparent Density of Tsetse Fly at Sekoru District, Jimma Zone, Ethiopia

Takele S¹, Kedir M¹, Yusuf A¹, Nesru A¹, Desa G¹* and Tafesse A²

¹National Institute for Control and Eradication of Tsetse Fly and Trypanosomosis, Kaliti Tsetse Fly Mass Rearing and Irradiation Center, Addis Ababa, Ethiopia

²Jimma Zone Sekoru Woreda Livestock and Fishery Development Office, Jimma, Ethiopia

*Corresponding author: Garoma Desa, National Institute for Control and Eradication of Tsetse Fly and Trypanosomosis, Kaliti Tsetse Fly Mass Rearing and Irradiation Center, P.O. Box 19917, Addis Ababa, Ethiopia

Received: January 28, 2020; Accepted: March 02,, 2020; Published: March 09, 2020

Abstract

A cross-sectional study was conducted from January 2019 to March 2019 at Sekoru districts to determine the prevalenceof bovine trypanosomosis and apparent densities of Tsetse fly Vectors. Standard isolation and identification procedures were performed to identify Trypanosome isolates. Baited Monoconical, Biconical and pyramidal traps were used for the vector survey. The overall prevalence of Trypanosomosis was found to be 5.5%. Two Trypanosome species were identified during the study period T. vivax and T. congolense. The highest Trypanosome prevalence (30%) was seen in animals with poor body condition than that of those with good (6.25%) and medium (3.42%) body condition. The higher infection rate was observed in female cattle (72.7%) than males (27.3%). The study revealed that packed cell volume (PCV) values of parasitaemic (22.7%) cattle were significantly lower than aparasitaemic (77.3%) cattle. During the entomological survey, two species of tsetse fly: G. morsitsns submorsitans and G. pallidipes were caught. The overall apparent density of tsetse flies was 4.36fly/trap/day. Trypanosome and tsetse fly pose a great threat to cattle residing in study areas. Thus, appropriate intervention measures need to be taken.

Keywords: Cattle; Prevalence; Sekoru district; Trypanosome; Tsetse fly

Background

Trypanosomosisis one of the diseases that are caused by flagellated protozoan parasites belong to the genus Trypanosome. Trypanosomosis limits the extension of natural herds particularly in Africa where the presence of tsetse fly density access to fertile woody and savannah lands with good grazing potential and livestock rearing [1,2]. It is a serious constraint to agricultural production in extensive areas of the tsetse infested regions which accounts over 10 million square kilometers of the tropical Africa [3,4]. The most economically important Trypanosome in livestock are the tsetse transmitted species: T. congolense, T. vivax and T. brucei [5,7]. Tsetse flies in Ethiopia are confined to southwestern and northwestern regions between longitude 33° and 38°E and latitude 5° and 12°N covers an area of 220,000km2 [8]. The low lands and in the river valleys of Blue Nile, Baro, Akobo, Didessa, Ghibe, and Omo are tsetse fly infested part of Ethiopia. The country is infested with five species of tsetse fly including G. morsitans submorsitans, G. pallidipes, G. tachinoides, G. fuscipes and G. longipennis and the first four are widely distributed and economically important[9]. According to the reports Tsetse transmitted animal trypanosomosis still remain as one of the largest causes of livestock production losses in Ethiopia [9]. The effects of trypanosomosis is not only the direct losses resulting from mortality, morbidity, infertility of the infected animals and costs of controlling the disease, but also includes indirect losses, which involves livestock and animal power based crop production from the huge fertile tsetse infected areas [10]. However, the distribution and the magnitude of the disease and its vectors are not well understood. Therefore, the aim of this research was to estimate the prevalence of Trypanosome in cattle and relative abundance tsetse fly in Jimma zone Sekoru district, southwest, Ethiopia.

Materials and Methods

Study area and period

The study was conducted at the Jimma zone Sekoru district from January 2019 to March 2019. Jimma zone is located 352km southwest of Addis Ababa at latitude of about 70 13’–80 56’N and longitude of about 35,052’–37,037’E.

Study design and population

A cross sectional study was conducted to find out the prevalence of bovine trypanosomosis and apparent density of tsetse fly at the Jimma zone Sekoru district. The study animals were selected by using simple random sampling method.

Sample collection, isolation and identification procedure

Parasitological survey: For parasitological examination a total of 397 blood sample were collected from ear vein of each cattle using microhaematocrit/capillary tube. During blood collection, the necessary bio-data of each animal was recorded. The microhaematocrit/capillary tubes were filled with blood to 2/3 of their length and centrifuged for 3min at 1500rpm and examined for trypanosomes by cutting the capillary tube slightly below the Buffy coat to include erythrocytes. The content of the Buffy coat was poured on a slide and covered with cover slip and examined using a microscope. Species identification was done by morphological examination of trypanosomes on Giemsa stained thin blood smears prepared from the positive animals and examined under a microscope using the oil immersion objective [10].

Hematological survey: Blood samples for packed cell volume (PCV) were also collected from the selected cattle using heparinized capillary tubes. The packed cell volume (PCV) was measured after centrifugation of the tubes for 5min at 12,000rpm in microhaematocrit centrifuge and the results were observed using microhaematocrit reader following the standard procedure [11].

Entomological survey: For the entomological study, tsetse flies were collected by 87 traps (8 Biconical, 75 monoconical and 4 Pyramidal) deployed in different positions of the study areas of different Kebele. Traps were deployed in the riverside at approximately 100m apart for 3 consecutive days. In all the traps Phenol and Acetone was used as a bait to attract the flies. Fly catch per trap per day (f/t/d) was determined to calculate the fly density and distribution. Species of the caught flies were identified. Sexing was also done for the flies just by observing the posterior end of the ventral aspect of abdomen by hand lens as a result male flies easily identified by enlarged hypophygeum [12,13].

Data quality assurance and analysis: All the instruments used for sample processing were checked prior to the study. Data consistency and completeness were made all the way during data collection, data entry and analysis. Data were edited, and checked for its completeness and entered into Epi Data 3.1 then exported to Statistical Packages for Social Sciences (SPSS) version 16 for analysis.

Result

Parasitological survey

From the total of 397 blood samples collected in Sekoru district (Ghibe kela, Medale Goraw and Doyo Kobata village) 22 (5.54%) samples were found to be positive for trypanosomes with the lowest prevalence was observed in medale Goraw (2.8%) and the highest was recorded in Doyo kobota (8.82%) villages as indicated in Table 1.

Table 1: The prevalence of Trypanosomeon the basis of study village.




  
    Factors
    Trypanosomespecies
    Total
    Prevalence (%)
    P-value
  
  
    Negative
    Positive
  
  
    Village
  
  
    Ghibe kela
    115
    4
    119
    3.4
    0.046
  
  
    Medale Goraw
    105
    3
    108
    2.8
  
  
    Doyo kobota
    155
    15
    170
    8.82
  
  
    Total
    375
    22
    397
    5.54
  
  
    PCV Value
  
  
    PCV = 24
    119
    5
    124
    4.03
    0.26
  
  
    PCV > 24
    256
    17
    273
    6.22
  
  
    Total
    375
    22
    397
    5.54
  
  
    Body conditions
  
  
    Poor
    21
    9
    30
    30
    0
  
  
    Medium
    339
    12
    351
    3.42
  
  
    Good
    15
    1
    16
    6.25
  
  
    Total
    375
    22
    397
    5.54



Table 1: The prevalence of Trypanosomeon the basis of study village.

As shown in Table 2 T. Congolese 14 (63.63%) was the most prevalent trypanosome species followed by T. viviax 6 (27.3%) and mixed infection 2 (9.1%).

Table 2: The prevalence of Trypanosome on the Basis of Trypanosome species Involved.




  
    Trypanosome species
    Rate of infection 
    Prevalence (%) 
  
  
    T. congolense
    14
    63.63
  
  
    T. vivax
    6
    27.3
  
  
    T. congolense and T. vivax
    2
    9.1
  
  
    Total
    22
    100



Table 2: The prevalence of Trypanosome on the Basis of Trypanosome species
Involved.

Depending on body conditions, (9) 30%, (12) 3.42% and (1) 6.25% was recorded in poor, medium and good body condition of animals respectively with statistically significant difference in the infection rate between poor, medium and good body condition (p‹ 0.05) (Table 1).

Hematological findings

The analysis of PCV value in the animals examined for trypanosome infection showed that the mean PCV value for the parasitemic cattle was 23.45 ± 0.84 SE whilst the mean PCV value for the aparasitemic cattle was (26.5 ± 0.21 SE) and cattle having PCV ≤24% (anemic) was 4.03% whilst in the cattle having PCV›24% (nonanemic) was 6.22% as indicated in Table 1.

Entomological survey

A total of 742 flies were caught at the time of the study, out of these 452 (60.9%) belong to G. morsitans and the remaining is shared by G. pallidipes with score of 290 (39.1%). An overall apparent tsetse flies density in study area is 4.36 flies/trap/day. From total tsetse fly trapped, females occupied large ratio. Out of total of 742 tsetse flies captured, 260 (35%) flies where males and the rest 482 (65%) flies where females (Table 3).

Table 3: Apparent density of flies caught during the study period.




  
    Study Village
    Average    Altitude
    Duration of Trap on the    field (day)
    Total    No of Trap
    Tsetse fly species
    Flies/trap/day    (Apparent density)
  
  
    
    M
    F
    Total
    
  
  
    Ghibe kela
    1216
    2
    20
    G.morsitans
    40
    86
    126
    3.15
  
  
    G.pallidipes
    9
    35
    44
    1.1
  
  
    Medale goraw
    1101.3m
    2
    19
    G.morsitans
    16
    8
    24
    0.63
  
  
    G.pallidipes
    6
    8
    14
    0.37
  
  
    Doyo kobota
    1293.1m
    2
    46
    G.morsitans
    97
    205
    302
    3.28
  
  
    G.pallidipes
    92
    140
    232
    2.52
  
  
    Total
    
    2
    85
    
    260
    482
    742
    4.36



Table 3: Apparent density of flies caught during the study period.

Discussion

The present study revealed that from a total of 397 randomly selected cattle’s in the study area, 22 (5.54%) of cattle were positive for trypanosomes. These findings support previous studies undertaken in Lalo Kile district 5.43% [14] and 6.9% in Chena district, south west Ethiopia [15]. However, the prevalence reported in the current study is lower than other reports such as 20.40% in Wolyta and Dawero zones of southern Ethiopia [16] and 12.24% in Botor Tolay District, Jimma Zone [29]. This difference possibly arises from tsetse distribution, low fly–animal contact and parasite and vector control programs practiced in the study area.

The present finding showed that out of 22 positive cattle for trypanosomosis, T. congolense was found to be the causative agent in 63.63% (n=14), T. vivax 27.3% (n=6) and mixed infection accounted for 9.1% (n=2). The predominate species causing bovine trypanosomosis was T. congolense and this finding agreed with previous report from south-western Ethiopia [17-20]. This finding indicated that our study area is suitable for the multiplication of biological vector (tsetse flies) and also showed vector born trypanosome species are disseminated in southwest parts of Ethiopia [21,22]. However, the current finding disagrees with in Mulanda, eastern Uganda [23]. The occurrence of disease in three different body condition (poor, medium and good) animals shows the highest prevalence in poor body condition (30%) followed by in medium (3.42%) and good body condition (6.25%). The finding showed that infection rates in poor body condition animals were significantly higher than that of medium and good body condition animals. This is due to poor body condition animals are susceptible to the infectious disease. The reason might be due to reduced performance of the animals created by lack of essential nutrients and poor management by the animal owner [24]. The mean PCV value of trypanosome positive animals was significantly lower (23.45 ± 0.842 SE) than that of negative animals (26.5 ± 0.208 SE). This finding is aligned with previous works, which stated a low PCV value of individual animals is a good indicator of trypanosome infection [25,26].

The present study also showed that from 85 trap (monoconical, Biconical and Pyramidal) deployed in the study area for 48 hours, a total of 742 flies were trapped among this flies 452 G. morsitans and 290 G. pallidepes were trapped. The overall 4.36 flies/trap/day apparent density of the tsetse flies was recorded. The current finding is lower than previously reported in Daramallo district 19.14 flies/ trap/day [27], 14.97 flies/trap/day in Arbaminch district [28] and 10.9 flies/trap/day Botortolay district. This difference might be attributed to environmental conditions, agro ecological differences and seasonal variation of sampling.

Conclusion

The present work showed a relatively low prevalence of trypanosomosis and apparent density of tsetse flies in Mandura district. However, this is an evidence not to be neglected that tsetse and trypanosomosis has yet continued to pose a considerable threat to cattle of the study area warranting an integrated parasite and vector control to safeguard cattle production and productivity.

References

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Citation: Takele S, Kedir M, Yusuf A, Nesru A, Desa G and Tafesse A. Prevalence of Bovine Trypanosomosis and Apparent Density of Tsetse Fly at Sekoru District, Jimma Zone, Ethiopia. Austin J Vet Sci & Anim Husb. 2020; 7(1): 1068.

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Trypanosome species	Rate of infection	Prevalence (%)
*T. congolense*	14	63.63
*T. vivax*	6	27.3
*T. congolense* and T. vivax	2	9.1
Total	22	100