Field Investigation on the Appearance of Drug-Resistant Populations of Trypainosomes in Metekel District, North-West Ethiopia
| dc.contributor.advisor | T., Getachew phD. | |
| dc.contributor.author | Afewerk, Yohannes phD. | |
| dc.date.accessioned | 2021-10-27T08:28:26Z | |
| dc.date.accessioned | 2023-11-08T11:34:28Z | |
| dc.date.available | 2021-10-27T08:28:26Z | |
| dc.date.available | 2023-11-08T11:34:28Z | |
| dc.date.issued | 1998-01 | |
| dc.description.abstract | The objectives of the present study were (1) to determine the prevalence rate of trypnnosome infections in the village cattle populations of Metekel district, North-west Ethiopia, (2) to assess the prophylactic activity of isometnmidium chloride to natural trypanosome infections and (3) to monitor the trypanocidal activity of diminazene acelurate and isometamidium chloride in mice experimentally infected with trypanosome field isolates. In order to obtain information on the prevaknce rate of trypanosome infections in the area and to identify cattle herds highly suspected to be infected with drug resistant trypanosome populations. questionnaire surveys and cross sectional studies were carried out from March to October 1997 in four villages. The results of these studies showed that trypanosomosis is a major constraint to livestock production in the area with an overall prevalence rate of 17.2% (95% CI: 14,20.8). Trypanosoma congolense was the dominant species accounting fo r 47.6% of the overall infections. The overall mean PCV value of the total cattle tested was found to be 4.9 ± 0.20% Parasitaemic cattle had significantly lower mean PCV values(21.6 + 0.47) than aparasitaemic cattle (25.5±0.21 ) (p<0.05) Moreover. there is indiscriminate use of trypanocidal drugs and exposurte of cattle in the area to subcurative doses of trypanocidal drugs and farmers complaine about failure of treatment to cure infections in cattle. Based on the results of the cross sectiona l study and the questionnaire, two villagec were selected for longitudinal field study on the occurrence of drug resistant trypanosome populations. From these villages 50 Zebu cattle naturally infected with trypanosomes. 52.4% of the infections being due to T congolense, were selected and infected with a prophylactic dose (1 mg /kg bw) of isomctamidium chloride (Trypamidium ®. Lot No. U6962 /E. Rhone Merieux). The findings in the field demonslrmed 6 (13% ) relapse/ breakthrough infections. all of them being T. congolensl.within 4 weeks of treatment In the same study 18 (37. 9%) and 25 (50%) relapse/breakthrough infections were recorded within 8 and 12 weeks of treatment, respectively. The result also indicated that 20 cases (80%) of the overall relapse/breakthrough infections were due to T. congolensel. Field isolates were obtained from relapse/ breakthrough infections one. two and three months after treatment and injected in mice. To confirm the field results and to study the therapeutic activity of diminazent.: accturate in experimental animals, three field isolates of T.congole nse were ranuomly selected from the relapse populations. Investigations were conducted on the sensitivity of these isolates to isometamidium chloride Trypamidium ®. Rhone Merieux) and diminazene aceturate ( Bereni l ®, Hoechst). Mice infected and treated with ranges of doses of isomelamidium chloride and diminazene oceturate were followed for relapse injections. isometamidium chloride at doses of 0.5 to -t mg lkg b\\ failed completely 10 cllre T congohmse infections. Similarly, diminazene acelurate at doses of 3.5 to 28 mg /kg bw did not clear the parasites in all or the mice infected. There was a correlation of drug-dosage used and the lime of relapse: mice treated with lower doses showed relapse earlicr than mice treated with higher doses. Based on these studies it is concluded that the duration of prophylactic activity of isometamidium chloride ( 1 mg/kg, bw) to trypanosome populations circulating in the study cattle of Metekel region is less than 1 month. Tryplanosoma cogolense field isolates expressed resistance to both isometamidium chloride and diminazene aceturate in mice. However, it was not known whether this double resistance was expressed by trypanosome populations or by two different populations each of which expressing resistance to one of the drugs. The results indicated that there is an urgent need to extend and inlensif) field and laboratory works to monitor the development of drug resistance of pathogenic trypanosomes and its impact on livestock productivity in Metekel region in particular and across the tsetse infested zone of Ethiopia in general. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/123456789/28349 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa Universty | en_US |
| dc.subject | Trypainosomes in Metekel District, | en_US |
| dc.title | Field Investigation on the Appearance of Drug-Resistant Populations of Trypainosomes in Metekel District, North-West Ethiopia | en_US |
| dc.type | Thesis | en_US |