CSA - Central Stastical Agency
DACA - Drug Administration and Control Agency
ETB - Ethiopian Birr
FAO - Food and Agricultural Organization
OR - Odd`s Ratio
USD - United State Dollar
MASL - Meters above sea level
PAs - Peasant Associations
Key words: Abattoir, Bovine, Ovine, Coprology, Economic significance, Fasciolosis, Prevalence. Debire Birhan.
Species identification of Fasciola is possible both grossly and microscopically at the adult level. F. hepatica is a leaf shaped fluke with broader anterior and cone shaped posterior projection. It is grayish brown in color changing to gray when preserved. The cuticle is armed with sharp spines. The mature adult flukes measure about 2.5-3.5cm in length and 1cm in width. F. gigantica is larger than F. hepatica and can reach up to 7.5cm length. The shape is more of leaf like, the conical anterior end is very short and the shoulder characteristic of F. hepatica is barely perceptible [37].
The distribution of Fasciolosis is dependent on the ecology of aquatic snail intermediate hosts. F. hepatica whose intermediate host is Galba truncatula has cosmopolitan distribution, mainly in temperate zones [21]. While F. gigantica whose intermediate host is the lymnaeid snail; Radix natalensis natalensis is an important Fasciola species in tropics and occurs throughout the western, sub-Saharan and eastern Africa [38]. In Ethiopia, it is found at altitude below 1200 - 2560 mean above masl. Mixed infection by two species can be encountered at 1200 to 1800 masl [41]. The disease is found in vast water lodged and marshy grazing field condition anticipated to be ideal for the propagation and maintenance of high prevalence of Fasciolosis.
In Ethiopia, the highlands contain pockets of water logged marshy areas and these provide suitable habitats year round for the snail intermediate hosts [33]. Following this Fasciolosis due to F. hepatica and F. gigantica has been reported to be one of the major disease problems of livestock industry especially in the highlands and the low land areas at which irrigation is the common practices in the country [17]. As previous studies shows that F. hepatica was shown to be the most important fluke species in Ethiopian livestock with distribution over three quarter of the nation except in the arid North, East and East of the country. On the other hand the distribution of F. gigantica was mainly localized in the Western humid zone of the country that encompasses approximately one fourth of the nations [35]. In recent years, small scale traditional irrigation scheme are expanding in many parts of Ethiopia, which has created favorable habitat for fluke transmitting snail vector. Different coprological and abattoir survey conducted so far in Ethiopia from (1988- 2007) indicated that the prevalence of bovine Fasciolosis varied from (15.77- 60.2%) and (14.4-90.7%), respectively. Meanwhile, the higher was recorded in Bahr Dar coprological finding (60.2%) and in Gondar abattoir survey (90.7%).
Fasciolosis causes high morbidity and mortality in most mammal species, but are of particular importance in sheep and cattle to livestock producers. Other than the herd-level losses, Fasciolosis also results in losses associated with liver condemnation in slaughtered animals, reduced weight gains, poor feed utilization and poor quality of meat and milk. Recently, worldwide productivity losses due to Fasciolosis were, F. hepatica infect more than 300 million cattle and 250 million sheep worldwide and, together with F. gigantica, causes significant economic losses to global agriculture estimated at more than US$3 billion annually through production loss, such as a reduction of milk and meat yields [24]. According to previous works done on coprology and abattoir survey by externship (DVM) and MSc students in Addis Ababa University College of Veterinary.
Medicine Ethiopia has lost from hundreds to half million ETB per year from a single municipal abattoir due to liver condemnation and carcass weight loss as a result of ruminant Fasciolosis [39].
Apart from its great veterinary importance throughout the world, F. hepatica has recently been shown to be emerging and wide spread zoonosis affecting numerous human populations in which they can being infected from accidental ingestion of parasite eggs/larvae passed into the environment with faeces from definitive hosts [31].
Confirmatory diagnosis for Fasciolosis is based on demonstration of characteristics Fasciola eggs through standard examination of faeces in the laboratory and demonstration of immature and mature flukes in the liver through postmortem examination [16].
Several control methods against ruminant Fasciolosis are available and can either be used independently and or as a combination of two or more of them. These methods involve elimination of the intermediate host, control of the parasite itself, adoption of good grazing practices (avoiding marshy pastures), regular and rational use of anthelmintics or a combination of all these strategies. However, anthelmintics are the most preferred due to the private nature of such treatments [15].
Fasciolosis is the priority disease in the highland as well as in lowland areas of Amhara region [33]. Particularly in Debire Birhan, Fasciolosis is considered to be endemic disease requiring immediate intervention. Even if there were a number of studies presented about the prevalence of bovine and ovine Fasciolosis in the same study site, the present study was designed to fill the gap occurred as a result of work done by Dagne [7] to assess the economic losses due to liver condemnation and body weight loss in cattle some 20 years ago. However, the absence of studies on the economic loss due to liver condemnation in sheep slaughtered at Debire Birhan Municipal Abattoir is the point of initiation to undertake the current study. Furthermore, the study is meant to assess the current status of bovine and ovine Fasciolosis. Therefore the specific objectives of the preset study are:
Where
N= required sample size
d = desired absolute precision
1.962 = z- value for 95% confidence
P exp = expected prevalence
To determine the sample size previous studies in the same site revealed that the prevalence of bovine and ovine Fasciolosis was 64.23% [46] and ovine Fasciolosis 62.7% [45]. So the required sample size to the present study was 320 cattle and 325 sheep. However, to increase the precision 430 sheep and 600 cattle were sampled [36].
(ALC) = NAL X CL X Prev (Ogunrinade 1980).
Where:
NAL = Average number of cattle slaughtered in Debire Birhan Municipal Abattoir
CL = Mean cost of one liver in Debire Birhan town
Prev = Prevalence of totally condemned liver due to Fasciolosis in Debire Birhan municipal abattoir
Species |
No. Animal Examined |
No. Positive (%) |
Prevalence |
P-value |
OR |
95% confidence interval for OR |
Bovine |
300 |
187 |
62.33 |
1 |
||
Ovine |
280 |
170 |
60.71 |
0.95 |
1.01 |
0.7 - 1.5 |
Total |
580 |
357 |
61.5 |
Results of coprological examination from different localities showed variation in infection rate. The overall prevalence of Bovine and ovine Fasciolosis was found to be 56.96 (Kebele 07), 59.77% (kebele 08), 60.71% (Kebele 09), 63.51% (Birbisa), 77.81% (Kormargefia), 6.1.25% (Woshawushign) and 62.5% (Woynye). Relatively the prevalence rate in Kormargefia (76.81%) was higher followed by Birbisa (63.51%) and Woynye (62.5%) and lower in Kebele 07 of Debire Birhan town (56.96). However, the difference was not statically significant (P >0.05 (see table 3).
Species |
Seasons |
No. Positive |
P-value |
OR |
95% CI for OR |
Bovine |
Autumn (105) |
73 (69.52 % |
1 |
..... |
.... |
Winter (134) |
72 (53.73%) |
0.045 |
0.5 |
0.24-0.98 |
|
Spring (61) |
42 (68.85%) |
0.54 |
1.3 |
0.56-3.00 |
|
Sub. Total (300) |
187 (62.33%) |
||||
Ovine |
Autumn (108) |
75 (69.44% |
1 |
....... |
........ |
Winter (126) |
63 (50.00%) |
0.014 |
0.48 |
0. 27- .87 |
|
Spring (46) |
32 (69.56%) |
0.8 |
1 |
0.48- 2.4 |
|
Sub total |
170(60.71) |
||||
Ground total |
580(61.55%) |
Kebeles |
Total No. positive |
P-value |
OR |
95% confidence interval |
Kebele 07 (86) |
49 (56.96%) |
1 |
..... |
.... |
Kebele 08 (87) |
56 (59.77%) |
0.38 |
1.4 |
0.7-2.7 |
Kebele 09 (112) |
68 (60.71% |
0.46 |
1.2 |
0.6-2.23 |
Birbisa (74) |
47 (63.51%) |
0.92 |
1.4 |
0.51-2.12 |
Kormargefia (69) |
53 (76.81%) |
0.16 |
1.7 |
0.8-3.5 |
Woshawushign (80) |
49 (61.25%) |
0.4 |
1.4 |
0.8-2.75 |
Woynye (72 |
45 (62.5%) |
0.168 |
1.6 |
0.8-3.4 |
Total (580) |
357(61.55%) |
Therefore female cattle and sheep had a chance of getting infection 2.74 and 1.5 times higher than their respective male animals with equal exposure, respectively (see table 4). The prevalence of bovine Fasciolosis based on age group was 70.76%, 55.62% and 68.08 for young, adult and old cattle, respectively. On the other hand the prevalence in ovine was 66.66%, 52.55% and 72.34% for young, adult and old aged sheep, respectively. In young cattle the prevalence of bovine Fasciolosis was relatively higher than old and adult. In contrast to this ovine Fasciolosis was more prevalent in old aged group as compared to young and adult sheep. The analysis of data demonstrated that, there was no significant difference between prevalence of Fasciolosis among different age group in both animal species (P >0.05) (see table 5).
Species |
Sex |
No. Examined |
No. positive |
P-value |
OR |
95% confidence Interval for OR |
Bovine |
Male |
157 |
80(50.95%) |
1 |
… |
… |
Female |
143 |
107 (74.82%) |
0.001 |
2.74 |
1.5-5 |
|
Subtotal |
300 |
187 (62.33%) |
||||
Ovine |
Male |
132 |
74 (56.06%) |
1 |
... |
... |
Female |
148 |
96 (64.86%) |
0.014 |
1.5 |
0.8-2.5 |
|
Subtotal |
280 |
170 (60.71%) |
||||
Total |
580 |
357 (61.55%) |
Species |
Age |
No. Examined |
No. positive |
P-value |
OR |
95% confidence Interval for OR |
Bovine |
Young |
93 |
66 (70.76%) |
1 |
||
Adult |
160 |
89 (55.62%) |
0.73 |
0.14 |
0.5-1.2 |
|
Old |
47 |
32 (68.08%) |
||||
Ovine |
Young |
96 |
64 (66.6) |
1 |
... |
... |
Adult |
137 |
72 (52.55) |
0.85 |
0.14 |
0.9-2.5 |
|
Old |
47 |
34 (72.34%) |
||||
Total |
580 |
357(61.55%) |
The prevalence of Fasciolosis based on poor body condition in cattle and sheep was 81.0% and 94.7% respectively. However, animals with good body condition showed the prevalence of 47.3% and 24.0% in sheep and cattle respectively. The prevalence was significantly higher in poor body conditioned cattle (81.0%) and sheep (94.7%). The difference was statistically significant (P < 0.05). As the OR indicated the risk estimated in poor vs. good body conditioned animals was more than 4.6 and 89 times (OR =4.6 and 89) higher in cattle and sheep, respectively (see table 7).
The major Fasciola species identified from cattle slaughtered in Debire Birhan Municipal Abattoir were F. hepatica (43.8%), F. gigantica (10.2%), mixed infection (29.0%) and immature flukes (17.0%). The relative proportion of those Fasciola species in sheep was F. hepatica (44.0%), F. gigantica (15.5%), mixed (26.6%) and immature (14.3%). F.hepatica was the mostabundant species in both cattle (43.8%) and sheep (44.0%) as compared to F. gigantica (see table 8).
Out of 300 inspected cattle livers, 124(41.3%) normal, 33(11%) lightly, 80(26.7) moderately and 63(21%) severely affected with Fasciolosis. Similarly post mortem finding shows that from 150 examined sheep livers 66(44%), 32(21.4%), 42(28.0%) and 10(6.6%) were found to be normal, lightly, moderately and severely affected, respectively (see table 9).
Species |
No. Positive |
P-value |
OR |
95% Confidence interval for OR |
Bovine (300) |
176 (58.6%) |
1 |
... |
... |
Ovine (150) |
84 (56.0%) |
0.42 |
0.84 |
0.535-1.23 |
Total (450) |
260 (57.77%) |
Species |
Body Condition |
No. positive |
P-value |
OR |
95% Confidence |
Bovine |
Good (110) |
52 (47.3%) |
1 |
... |
... |
Medium (169) |
109 (64.5%) |
0.031 |
1.76 |
1.05-3.0 |
|
Poor (21) |
17 (81.0%) |
0.012 |
4.6 |
1.4-15.5 |
|
Subtotal (300) |
176 (58.6%) |
||||
Ovine |
Good (46) |
11 (24.0 %) |
1 |
... |
... |
Medium (85) |
55 (64.7) |
0 |
7.8 |
3.0-19.8 |
|
Poor (19) |
18 (94.7) |
0 |
89 |
96-829.5 |
|
Subtotal (150) |
84 (56.6 %) |
||||
Grand total (450) |
260 (57.77%) |
Fasciola Species |
Bovine (n=176) |
Ovine (n=84) |
||
Frequency |
Percent (%) |
Frequency |
Percent (%) |
|
F. hepatica |
77 |
43.8 |
37 |
44 |
F. gigantic |
18 |
10.2 |
13 |
15.5 |
Mixed |
51 |
29 |
22 |
26.2 |
Immature |
30 |
17 |
12 |
14.3 |
Total |
176 |
100 |
84 |
100 |
Lesion type |
Bovine (N= 300) |
Ovine (N=150) |
||
Frequency |
Percent (%) |
Frequency |
Percent (%) |
|
Normal |
124 |
41.3 |
66 |
44 |
Light |
33 |
11 |
32 |
21.4 |
Moderate |
80 |
26.7 |
42 |
28 |
Severe |
63 |
21 |
10 |
6.6 |
Total |
300 |
100 |
150 |
100 |
The prevalence of the disease with respect to localities was very closely similar of having 56.96% (Kebele 07), 59.77% (Kebele 08), 60.71% (Kebele 09), 63.51% (Birbisa), 76.81% (Kormargefia), 61.25% (Woshawushign) and 62.5% (Woynye) with no statistical significant difference (P>0.05). This might be attributed to nearly ecological similarities such as altitude (2780 masl) and an extensive type of farming system adapted by most farmers in the vicinity of Debre Birhan town. This inference is in agreement with that of [43] who suggested that distribution of Fasciolosis depends on altitude. The present study was consistent to the coprological finding of [28] on ovine species which stated that prevalence of Fasciolosis in different PAs of study areas was very closely similar.
The variation in sex prevalence of bovine Fasciolosis was found to be 50.95% (male) and 74.82% (female) whereas in sheep 56.06% and 64.96% prevalence rates were recorded in male and female animals, respectively. Sex as a variable do not shows significant difference (P < 0.05) in both animal species. As the study indicates that female cattle and sheep had a chance of 2.7 and 1.5 times higher to be infected by the disease than their sexual counterparts, respectively. This may be due to the fact that female animals at different reproductive pysological state such as pregnancy and lactation are immunologically suppressed from increased blood corisol level which favors the chance of exposure of female them to Fasciola infection. However, this conclusion is not in agreement with that of [32] who concluded that sex has no impact on the infection rate and hence both male and female animals are equally susceptible and exposed to Fasciolosis.
In an effort made to know the effect of season in the prevalence of Fasciolosis significantly higher (P > 0.05) prevalence was noted in Autumn in both cattle (69.52%) and sheep (69.44%). This might be due to the difference in weather conditions (optimum moisture and temperature that occurred in Autumn) that might affect the multiplication of intermediate host snails, the development of fluke eggs, and the dispersal of cercaria shed from the snails. Fasciola cercaria and Lymnae snails have been found to survive better at 25-300c which explains in parts at least; the much higher prevalence in Autumn compared to other seasons [2002]. This finding is supported by the work of Mastewal and Malede [25] from North Gonder.
The age group of the animals was geared to know the prevalence rate of Fasciolosis. In the finding it was relatively higher in young cattle (70.7%) and old sheep (72.34%). The reason for the higher prevalence in old sheep as compared to cattle could be attributed to the difference in acquiring resistance as the age increases. In general, sheep do not acquire resistance to parasitic disease [22].
The abattoir prevalence of Fasciolosis was relatively higher in cattle (58.6%) as compared to sheep (56.0%). The finding showed that there was no statistical significant variation in the infection rate (P< 0.05) among species. This non significant difference is probably due to similarities of ecological and climatic conditions from where animals were brought to the current abattoir. In fact both cattle and sheep in Debire Birhan Municipal Abattoir originated from areas where there are similar climateecological conditions. Cattle have a tendency of grazing on highly marshy areas than sheep although deep gazing is common in sheep which can even gain access the hibernated metacercariae. That is why both cattle and sheep are equally likely exposed to Fasciolosis. Hence, the findings in the current coprological and abattoir survey results have confirmed the absence of variation in Fasciolosis infection in both cattle and sheep. However, the report of [40] which explained cattle have indiscriminate type of grazing behavior than sheep which increase the chance of exposure to infective stage of Fasciola which is commonly found on grasses around marshy areas contradict this finding.
In works done to know the effect of body condition score to the prevalence of Fasciolosis in the current study areas, it was encountered that the prevalence rate of Fasciolosis was higher in both poor body conditioned cattle (81.0%) and sheep (94.7%) than in good body condition. Therefore, the prevalence rates of the disease in good body conditioned cattle and sheep were (47.3%) and (24.0%), respectively. Statistical analysis of the data showed the presence of significant difference (p< 0.05) in the prevalence of Fasciolosis in cattle and sheep on the basis of body condition score. The risk estimations between poor and good body conditioned animals were more than 4.6 and 89 times higher in cattle and sheep, respectively. This disparity might be attributed to the variation in level of resistance among age groups that poor body conditioned animals are usually less resistant and consequently susceptible to infectious diseases including Fasciolosis. This finding is in agreement with study conducted by Alula et al. (2013) and [40] who confirmed the occurrence of higher infection rate in poor body conditioned animals.
Evaluation of Fasciola speciation in the present study revealed that F. hepatica was frequently abundant in cattle (43.8%) and sheep (44.0%). Whereas the abundance of F. gigantica was 10.2% and 15.5% in cattle and sheep, respectively. Apart from these individual Fasciola species, mixed and undifferentiated immature flukes were also identified in the study area. The higher relative abundance of F. hepatica from the study area might be associated with the existence of favorable ecological and climatic conditions for the survival of the intermediate host L. truncatula, and the parasite itself. In Ethiopia F. hepatica and F. gigantica infestations occur in areas above 1800 masl and below 1200 masl, respectively which has been attributed to variations in the climatic and ecological conditions such as altitude, rainfall, temperature and livestock management system [41]. The current finding was supported by studies performed by [7,13,46]. However, it in another study done by [12] the most common liver fluke species affecting cattle at Wolayita Sodo (2315masl) was F. gigantica.
In the present study, coprological examination through standard sedimentation technique revealed that prevalence’s of Fasciolosis in bovine (62.3%) and ovine (60.71%) were relatively higher than the findings from post mortem examination of cattle’s’ (58.6%) and sheep’s’ (56.0%) livers. The reason ascribed for this difference might be due to frequent deforming of both cattle and sheep with triclabendazole (fasionix) and albendazole against liver fluke soon after they are left to be fattened. It is customary, now-a-days, to fatten both cattle and sheep intensively for about three months before they are sold for slaughter. Therefore, the chance of getting liver fluke during post mortem examination is minimal. However, this finding is in disagreement with the work of [32] who reported single examination of faeces by sedimentation technique was found to be less sensitive as compared to post mortem examination.
The economic loss caused by bovine and ovine Fasciolosis was enormous in the study area. Pathological lesions caused by Fasciolosis were the causes of a considerable economic loss due to condemnation of moderately and severely affected livers. Considering the percentage of liver condemnation due to Fasciolosis during the study period and from the four years retrospective study on the average number of cattle and sheep slaughtered in Debire Birhan Municipal Abattoir, the direct economic loss was estimated to be on average 52,981ETB (2649 USD) from cattle and 6,406ETB (320USD) from sheep per annum. This finding is lower than the finding of [12,26,35] who reported 4,674.2 USD (Adwa), 6300 USD (Jimma) and 4000 USD (Wolyta soddo) abattoirs, respectively due to condemned cattle livers. However, the present finding (52,981ETB) is higher than the report confirmed by Dagne [7] from condemned cattle livers in the same study site. The possible reason for this might be the variation in the average number of animals slaughtered per year, the price of average sized liver and the total condemnation rate of liver from abattoir to abattoir.
there is a need to undertake further detailed studies in different seasons to generate a comprehensive data on the epidemiology of Fasciolosis and ecology of the snails;
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