Veterinary Epidemiology

Permanent URI for this collection

http://etd.aau.edu.et/handle/123456789/112

Browse

Browsing Veterinary Epidemiology by Author "Abebe Wosene"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Effects of a Strategic Anthelmintic Treatment Intervention on Ruminant Fasciolosis in Upper Blue Nile Basin, Northwestern Ethiopia
    (2005-06) Solomon Wolde; Abebe Wosene
    This study was conducted from December 2004 to March 2005 in two selected woredas in northwestern Ethiopia, with the objective of assessing the impact of a strategic treatment intervention on ruminant fasciolosis. The study was conducted using questionnaire survey, cross sectional prevalence study and experimental study involving naturally infected animals with Fasciola spp. and treatment with triclabendazole at a dose rate of 10mg/kg bodyweight orally. A total of 384 cattle from Fogera woreda and 368 sheep from Mecha wereda were involved in cross section prevalence study. 167 animals (80 cattle and 87 sheep) were selected from the study population and grouped into three (group I, one- time treated group, group II two-times treated group and group III, positive control) to serve as experimental animals. Out of the 752 faecal samples collected from cattle and sheep for cross sectional study, 283 (37.6%) were found positive for fasciolosis with a specific prevalence of 37.2% in cattle and 38% in sheep. Analysis of the findings among different age groups indicated the existence of a significant difference in prevalence of fasciolosis both in cattle and sheep (P<0.05). Sheep with poor body condition are more affected with fasciolosis than sheep of good body condition (P<0.05), while no significant difference was noted in cattle. The experimental study in its turn indicated a significant reduction in the prevalence of fasciolosis both in group I and group II animals following the October treatment and the overall prevalence of infection was reduced significantly after the end of the experiment in group II (P<0.05). Statistically, there was a significant difference (P<0.05) in infection rate between the three groups. The results of PCV in sheep showed that group II animals had the highest PCV (36.28±5.54) followed by group I (27.18±4.15) and group III (26.46±3.17). The progress of PCV value in group II was significantly greater (P<0.05) than those of group I and III from December to March. Analysis of live weight change between the three groups of sheep showed significant differences (P<0.05) whereby group II had better weight gain (28.84±4.64) than group III (21.53±6.55) and group I (19.92±4.98). Mean total weight gain per animal after the end of trial for group I, group II and group III was –2.11kg, 5.09kg and -3.11kg, respectively. In cattle, the mean body condition score for group I, group II and group III was 2.29±0.71, 3.7±0.7 and 1.97±0.69 at the end of the trial, respectively. Analysis of variance indicated that there was a significant difference in body condition score (P<0.05) between group II and group III while no difference (P>0.05) was observed between groups I and III at the end of the experimental trial indicating improvement in animals’ body condition in twice treated cattle. At the start of the experiment (October) there were no significant differences in enzyme ix concentration level of aspartate aminotransferase (AST) among the 3 groups of sheep. Thereafter (March), the enzyme level in all experimental groups has increased, however, group III had higher AST values than group II and I indicating the comparatively more liver tissue damage in untreated control groups (P<0.05). This study has found the previously recommended Fasciola control methods and treatment intervention schedules appropriate to the Ethiopian northwestern highland areas. Nonetheless, the study indicated that the time span between the recommended intervention periods appears to be long enough so that fasciolosis buys time to highly prevail in the form of re-infestation in the study areas. Hence, additional treatment intervention in mid-dry season (December-January) has important impact in the reduction of the prevalence of liver fluke in the study areas.
  • No Thumbnail Available
    Item
    An Epidemiological Study on Major Protozoal Causes of Calf Diarrhea on Selected Dairy Farms of Central Ethiopia
    (2005-06) Rahmeto Abebe; Abebe Wosene
    A cross-sectional study was undertaken from September 2004 to March 2005 on selected 40 dairy farms located in Central Ethiopia to determine the prevalence and species of the major protozoal causes of calf diarrhea, and the factors associated with their occurrence. Fecal samples were collected once from a total of 580 calves 0-345 days old and examined for the oocysts of Cryptosporidium and Eimeria spp. by centrifugal fecal flotation technique using concentrated sucrose solution. Accordingly, an overall point prevalence of 17.6% and 68.1% was recorded for Cryptosporidium and Eimeria spp., respectively. Of the 40 dairies sampled, 26 (65%) had one or more calves shedding Cryptosporidium oocysts whereas all of the farms had calves shedding Eimeria oocysts. In this study the species of Cryptosporidium circulating in the farms was presumed to be Cryptosporidium andersoni (formerly known as Cryptosporidium muris) based on morphology of the oocysts and certain epidemiological features of the parasite. With regard to the species of Eimeria, a total of 11 species were identified namely Eimeria bovis, Eimeria zuernii, Eimeria auburnensis, Eimeria canadensis, Eimeria ellipsoidalis, Eimeria subspherica, Eimeria cylindrica, Eimeria alabamensis, Eimeria wyomingensis, Eimeria bukidnonensis, and Eimeria brasilensis in descending order of their relative prevalence. Neither Cryptosporidium nor Eimeria spp. were found to be statistically associated with diarrhea (P>0.05). Both parasites were detected in a wide age range of calves: Cryptosporidium in 21-345-day old calves and Eimeria spp. in 15-345-day old calves. Among the risk factors studied, the frequency of cleaning the calf rearing houses was the most important factor associated with the likelihood of infection with Cryptosporidium spp. whereas geographical zone where samples were taken from and age of the calves were the most important factors associated with the likelihood of infection with Eimeria spp. The mean and maximum Eimeria oocysts per gram of feces (OPG) determined by using McMaster technique was 5109 and 267,000, respectively. There was a strong association between OPG and age of the calves (P<0.001) and consistency of the feces (P<0.001), the mean OPG was significantly higher in younger and diarrheic calves.