Browsing by Author "Hagos Ashenafi"

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    Bovine Babesiosis and its Vectors at Kobo and Girana Valleys in Amhara National Regional State of Ethiopia.
    (2007-06) Seyoum Zenebe; Hagos Ashenafi
    A study on bovine babesiosis and its vector was conducted at Kobo and Girana valleys of North Wollo Zone in Amhara National Regional state, Northern Ethiopia. The objective of the study was to determine the prevalence and identify at species level of bovine babesiosis and the vector and indicate the associating risk factor for Boophilus decoloratus tick through longitudinal study. A total of 370 cattle from both valleys were used for a cross sectional study while 60 cattle were also involved in longitudinal study during four consecutive seasons. The longitudinal study was conducted on October, December, January and March that represents late rain, early dry, late dry and early rain seasons respectively. The prevalence of Babesia bigemina in a cross sectional study of age groups <2, 2-4 and >4) was (20.3%, 24.3%, and 16.1%), respectively. The prevalence of B. bigemina among the three age groups was not statistically (p>0.05) significant. Sex (male and female) basis of Babesia bigemina infection rate were (12.7% and 7.6%) respectively and high infection rate (26.5%) were observed in animals with poor body condition than animals with good body condition (15.19%). The prevalence of sex and body condition wise was found statistically (p<0.05) significant. Animals that are found at Kobo valley (22.7%) and Girana valley (17.8%) were surveyed on disease prevalence during a cross sectional study. The prevalence of Babesia bigemina in the valleys was not statistically (p>0.05) significant. The infestation rate of Boophilus decoloratus in age groups (<2, 3-4 and >4) were 73.2%, 82.1% and 91.9%), respectively. And sex (male and female) wise infestation rate were (86.6% and 78.3%), respectively. Age and sex wise prevalence was found statistically (p<0.001 and p<0.05) significant, respectively. Older animals, males and animals with poor body condition were found to carry more ticks than others. Out of the whole Boophilus decoloratus collected, the proportion of females adult ticks were higher in number than males once, that is the ratio male to females was (0.41: 1) and Boophilu decoloratus from the whole tick counts was represent (24.4%), rank third next to Amblyomma cohaerence (24.9%) and Amblyomma variegatum (28.22%). Different tick species have their own preference of attachment sites on their host. Though Boophilus decoloratus has its own preference of predilection feeding sites, but in this study except ano- vulva the tick was collected from all over the host body. Mainly back (shoulder), dewlap, head and ear, but also from venter, tail and hoof. The prevalence of Babesia bigemina during longitudinal study in cattle sub populated by age, sex, and body condition were studied, in general the infection rates were lower, except animals with 3-4 age groups (30%) and sex wise viii prevalence of longitudinal study was found higher than a cross sectional. The difference among age and sex wise were not statistically (p>0.05) significant. Body condition basis prevalence of Babesia bigemina result of longitudinal study was found similar with that of a cross sectional study result and the difference was (p<0.05) significant. The infestation rate of Boophilus decoloratus studied in longitudinal study during four consecutive seasons on animals sub populated by age, sex, body condition, valleys and season was generally lower than that of a cross sectional study and the difference statistically was not (p>0.05) significant except seasons which was found (p<0.05) significant. In all variables studied the prevalence of Boophilus decoloratus was found higher generally during rainy seasons than that of dry seasons. The risk of Boophilus decoloratus infestation was found lower in dry seasons as compared to rainy seasons (OR = 1.56, 95% Cl = 1.43 - 2.39) and the likelihood of acquiring infection was (OR = 3.56, 95% Cl =1.56 - 8.14) 3 times higher in rainy seasons than dry seasons. The main cause of high infestation and infection in the valleys were observed as a result of the unrestricted movement of animals from different part of the country that used to pass via the valleys to the Northern part the country, time less bounded usage of acaricide by different non-ethical individuals, inadequate dosage of acaricide and drought. Restriction of animals' movement, quarantine measures, strong and sustainable extension works should be done to create awareness of the livestock keepers.
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    Bovine Trypanosomosis: Epidemiology and Drug Resistance Study in Selected Sites of Kellem Wollega Zone, Oromia Regional State, Ethiopia
    (2019-08) Efrem Degneh ; Hagos Ashenafi
    African Animal Trypanosomosis remains one of the most important disease constraints to livestock and mixed crop-livestock farming in tropical Africa. Trypanosomosis is responsible for the death of 3 million heads of cattle yearly, with 50 million animals at risk in sub-Saharan Africa. The problem of trypanosomosis is still far from being solved due to the fact that trypanosomes affect multiple hosts, widespread trypanocidal drug resistance and antigenic variation displayed by the trypanosomes. Trypanocidal drugs: Isometamidium chloride (ISM) and Diminazene aceturate (DA) are the most widely used drugs for control of animal trypanosomosis in Ethiopia. In Kellem Wollega, trypanosomosis is one of the main livestock diseases. In the area, a number of brands of trypanocidal drugs from various sources are routinely used by veterinary professionals as well as farmers, which may result in rampant misuse and under-dosage of the medications, actions which might contribute for the emergence of trypanocidal drug resistance. However, study on trypanocidal drug resistance is not yet carried out despite of serious complains of drug failure from professionals and farmers. Therefore, the present study in Gidami and Sayo selected districts of Kellem Wollega Zone of Oromia Regional State; Ethiopia was designed to investigate the problem of bovine trypanosomosis with special emphasis on epidemiology of the disease and assessment of trypanocidal drug resistance. Accordingly, questionnaire survey, cross-sectional studies and field trypanocidal drug resistance trial on naturally infected cattle were used to assess the epidemiological picture of the disease and the utilization of trypanocidal drug practices and evaluate the current status of trypancidal drug resistance trypanosomes. In the questionnaire survey, a total of 100 farmers were interviewed, of which 50 from Gidami and 50 from Sayo districts to assess the knowledge, attitude and practices of farmers towards the control of bovine trypanosomosis. A cross-sectional vector survey was conducted in purposively selected eight villages of Gidami and Sayo districts from November, 2015 to June, 2017 in early dry and early rainy seasons. A total of 160 traps (80 per district) were deployed at approximate intervals of 100 to 200 meters for 48 hours at watering and grazing points of animals in two seasons. For cross-sectional study of bovine trypanosomosis a total of 1790 blood samples were collected from systematically selected cattle and examined by buffy coat blood examination technique during early dry and early rainy seasons in Gidami and Sayo districts. Based on the outcome of the cross-sectional study Kellem and Gry Sonka villages from Gidami district were selected for field trypanocidal drug resistance study. An abbreviated 28-day field prototudycol was used to estimate resistance to 1 mg/kg b.w ISM and 7.0 mg/kg b.w DA trypanosome-positive cattle. For this purpose a total of 100 parasitaemic cattle from Kellem and Giray Sonka villages were selected and treated with Isometamidium chloride and Diminazene aceturate and monitored for trypanosomes and packed cell volume (PCV) levels on days 14 and 28 post treatment. Based on the questionnaire survey, 100% of the respondents from Gidami and Sayo district indicated trypanosomiasis as the major important disease of livestock causing considerable direct and indirect economic losses. Isometamidium chloride and Diminazene aceturate are the commonly used drugs to treat bovine trypanosomosis in both study districts. Sixty percent of respondents from Gidami and only 9% from Sayo districts disclosed that they treat their animals nine to fifteen times per year per animal. Trypanocidal treatment failures were reported by 98% and 76% of the respondents from Gidami and Sayo district, respectively. Among 3289 flies trapped during the study period 1739 (52.88%) were Stomoxys, 1158 (35.21%) Glossina, 252 (7.66%) Tabanus and 140 (4.25%) were Haematopota. The overall apparent fly density was 10.28 flies per trap per days. The apparent density of Glossina, Stomoxys, Tabanus and Haematopota were 3.62, 5.43, 0.79 and 0.44 flies per trap per day, respectively. Four Glossina species: G. tachinoides, G.m.sub-morsitans, G. palidipes and G. fuscipes were recovered in Sayo district. However, only G.m.submorsitans and G. palidipes were caught in Gidami district. Out of the total 1158 tsetse flies caught, 51.81% were G. pallidipes; the remaining 25.65%, 16.58% and 5.96% were G. m. submorsistans, G.fuscipes and G. tachnoides, respectively. The overall prevalence of bovine trypanosomosis was 14.08% (95% CI: 12 -16%) and 11.16 % (95% CI: 9-13%) in Gidami and Sayo districts, respectively. However, there was no statistically significant difference (P > 0.05) between these two districts in the prevalence of bovine trypanosomosis. In the present study, the trypanosome prevalence was higher in low altitude (18.09, 13.80%) compared to mid altitude areas (9.13, 8.5%) in Gidami and Sayo districts respectively. The observed difference was found to be statistically significant (P<0.05). Trypanosoma congolense being the predominant species (57.30%) followed by T. vivax (29.10%), T.b.bruci (9.70%) and mixed infection of T. vivax and T. congolense (3.90%) were the prevailing trypanosome species in the area. The overall bovine trypanosomosis prevalence was siginificantly varied between poor (25.37%) compared to both medium (10.02%) and good (2.66%) body conditioned animals and between adult (14.16%) and young (9.38%) age categories. There was no statistically significant difference (P>0.05) in the prevalence of bovine trypanosomosis between sexes of the examined animals. There was a statistically significant difference (P<0.05) in the mean packed cell volume (PCV) between parasitaemic (21.53%) and aparasitaemic cattle (26.11%) regardless of district and season of sampling. The results of field trypanocidal drug resistance study confirmed the presence of drug resistance to the maximum recommended doses of ISM and DA in Giray Sonka and Kellem villages of Gidami district. From 50 trypanosome positive cattle treated with ISM 2% solution of 1 mg/kg bw, 68% had persistent infections at day 28 post treatment. Similarly, of the 50 trypanosome positive cattle treated with DA 7% solution of 7 mg/kg bw, 36% had persistent trypanosomes at day 14 post treatment. In conclusion, bovine trypanosomosis is a major disease constraint of livestock health and agricultural activity in Gidami and Sayo districts of Kellem Wollega Zone of Oromia Regional State, Ethiopia. Trypanocidal drug resistance is a threat in Kellem Wollega and thus sustainable and integrated tsetse and trypanosomosis control practices should be implemented to ensure productivity of cattle and foster agricultural development. Furthermore, extensive data on trypanocidal drug sensitivity tests using advanced molecular techniques is essential.
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    Bovine Trypanosomosis: Parasitological Prevalence, Vectorial Density and Trypanocidal Drug Utilization Practice in Tsetse Suppression and Non-Suppression Areas of South Omo Zone, Ethiopia
    (2019-06) Tegegn Tesfaye; Hagos Ashenafi
    Questionnaire survey to assess knowledge and attitude of trypanocidal drug utilization practices, entomological survey to know apparent cyclical vector density and other mechanical vectors responsible for trypanosome infection transmission and parasitological study to elucidate the prevalence of bovine trypanosome was conducted in tsetse suppression areas and tsetse non-suppression areas of South Omo Zone, Southern Ethiopia from November 2018- May 2019. SPSS version 20 and R- software packages were used to analyze collected field data. For questionnaire survey, 124 cattle owners from tsetse suppression areas and 60 cattle owners from tsetse non-suppression areas were interviewed about their knowledge, attitude and practice (KAP) of trypanocidal drug utilization and constraints of trypanosome infection in the area. Blood samples from 1284 local breed cattle; 642 samples during dry season (344 from tsetse suppression areas and 298 from tsetse non-suppression areas) and 642 during wet season (344 from tsetse suppression areas and 298 from tsetse non-suppression areas) were parasitologically examined by using buffy coat technique and thin blood smear method. For entomological survey, 96 NGU traps were deployed (64 traps in tsetse suppression areas, 32 traps in tsetse non-suppression areas) in suspected Glossina multiplication habitats. The overall prevalence of bovine trypanosome infection in South Omo zone was found to be 11.05% (142/1284). The overall seasonal prevalence of bovine trypanosome infection in South Omo zone was 14.33% (92/642) and 7.78% (50/642) for dry and wet seasons, respectively. There was a statistically significant difference (P <0.05) in disease prevalence between the two seasons. During dry season, only sex and the grazing system were significantly associated with trypanosome infection occurrence but in wet season none of the risk factors were statistically significant. Multiple logistic regression analysis of trypanosome infection prevalence indicated that sex, body condition score (BCS), grazing system and season were significantly associated (P<0.05) with the prevalence of the disease in tsetse suppression areas. However, only sex and season for tsetse non-suppression areas were significantly associated with the prevalence of trypanosome infection. Trypanosoma congolense (T. congolense) was the dominant trypanosome species; 80% and 71.64% respectively from tsetse suppression areas and for tsetse non-suppression areas followed by Trypanosoma vivax (T. vivax). Overall pooled mean packed cell volume (PCV) indicated parasitaemic animals (23.57±3.13) had significantly lower PCV than aparasitaemic animals (27.80±4.95) and animals examined during dry season (26.22±4.37) had lower mean PCV than animals examined during wet season with significant association. Similarly, parasitaemic animals from tsetse suppression areas (PCV= 23.76± 3.07) and tsetse non-suppression areas (PCV= 23.37±3.21) had significantly lower mean PCV than their aparasitaemic counterpart (tsetse suppression areas, PCV= 27.73±5.07 and tsetse non-suppression areas, PCV= 27.88±4.82). However, mean PCV of animals infected with T. congolense (23.59±3.22) was not statistically different (P > 0.05) from those animals infected with T. vivax (23.26±3.31). It was also indicated that the probability of anaemic animals to be parasitaemic was significantly higher (P < 0.05) than non-anaemic animals in both tsetse suppression areas and tsetse non-suppression areas. Entomological survey result revealed that 2.64 F/T/D and 2.03 F/T/D respectively from tsetse suppression areas and tsetse non-suppression areas during dry season and 0.42 F/T/D and 0.56 F/T/D during the wet season. Glossina pallidipes (G. pallidipes) was the only cyclical vector identified from the area along with numerous mechanical vectors of genus Tabanus, Stomoxys and Haematopota. Higher dependency of cattle owners on trypanocidal drugs to treat their sick animals and limited trypanocidal drug availability in the veterinary pharmaceutical market in conjunction with unsustainable and less participatory vector control activities may intensify the threat of the disease in the area. Furthermore, upsetting current prevalence report of the disease in such area with frequent trypanocidal drug usage and drug injection by unskilled herdsmen and owners report on trypanocidal drug treatment failure may point out the issue of trypanocidal drug resistance in the area. Therefore integrated and safe control and prevention effort should be engaged to uphold cattle production and productivity in the area.
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    Compile Body of Works in Field Epidemiology
    (Addis Abeba University, 2019-06) Gebremedhin Gebreslassie; Negusse Deyessa; Hagos Ashenafi; Abdunnasir Abagaro
    Residents are expected to produce and summit Compile Body of Works as a partial fulfillment for their Masters of public health degree in field epidemiology to school of graduate studies of Addis Ababa University. This Compile Body of Works has six chapters and four annexes. Chapter I: Presents two outbreaks; Cholera and brucellosis investigations. We investigated cholera outbreak in Kafta Humera District Wester Zone of Tigray region. Since August 28, to September 16, 2018 there were139 cases of daily workers those come from different camps to the district. We use them for descriptive analysis without control. Open defecation of farm areas and drinking untreated river water, contact tracing, crowding in one camp room among the identified risk factors. More over weak early contact tracing seasonal flood and distance of farms to health facility furnishes the way to aggravate for long time in controlling. The incidence rate was only male daily workers and new comers that live in camps.We recommended to mobilize ORP sites near to the farms, distribution of water chemicals and should have early contact tracing. We have also an investigation brucellosis outbreak Degua Temben district. We use 50 cases and 150 unmatched controls. From the cases 26(52%) of were males.Here we investigated the abortion case in animals and associated materials was the source of human brucellosis. Human 4(100%), and animal 18(38%) samples taken were confirmed seropositive by RBPT. The odds ratio of having aborted animal and assisting abortions have significant association from risk factors identified. No death at all. We recommended public health education to reduce contact, not to use raw animal products and keeping environmental hygiene. Chapter II: Describes surveillance data analysis on suspected anthrax in Tigray region. We described four year reported data of suspected anthrax cases in human and animals. 404 suspected cases and 6 deaths were recorded (3015-2018) and 1.46 % mortality rate at region level. 55.8% of the cases were recorded in 2016 and 44% case fatality rate was seen in animals (2018). All sex and age groups were affected. Central zone was the highest recorded cases by the two Sectors. We stressed surveillance activities should give attention in general and specially to central zone together. Chapter III: Surveillance system evaluation on suspected anthrax cases in Abi-Adi and Kola Temben districts of Tigray region. We use purposive selection method based the data analysis result we describe in chapter two. Suspected anthrax was under the immediate reportable diseases in human and animals. We showed 83.3% case definition of anthrax in all health facilities, reporting format and daily listed cases by simple chart in two health offices. Surveillance focal persons have a problem data analysis. They couldn‘t take training. Applying the Attributes, core activities in suspected anthrax were well practiced however, as sensitivity of the system, the focal person complains they had additional work load. Ours recommendation training and some logistics such as computers, stationary should be needed to complete by the district and region.Chapter IV: Public health surveillance system in Kola temben. We assessing the public health status of 8 health centers and 28 health posts at district level, Education, water resources supply of power and road access. In representativeness health facility and educational facility were at good level. However, Coverage of water supply (55%), one health center and one separate technical school needs prioritizing and environmental hygiene at woreda level needs attention and so the prioritize diseases. Chapter V. Epidemic research project proposal here we proposed an assessment of brucellosis in southeast zone of Tigray in three districts. Brucellosis is a miss diagnosed and chronic nature; it was not common in our region to see a case of brucellosis in human. The incidence of outbreak in Degua Temben points as, to see the status of knowledge attitude and practice of the community to assess. We will have tried to build community based definitions and mobilizing the professional in diagnosing and the public contact with brucellosis. Chapter VI: Manuscripts prepared for scientific peer received journals for publication from data analysis of suspected anthrax. Chapter VII: Additional works and activities: Abstract of Anthrax for scientific writing. Chapter VIII: Training on capacity building on brucellosis case definition in human and animals, Bulletin‘s week 12 and Consent f
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    Compiled Body of Works in Field Epidemiology
    (Addis Ababa University, 2019-04) Taddie Wondmnew; Hagos Ashenafi; Alemayehu Bekele
    The Ethiopia Field Epidemiology Training Program (EFETP) is 8 years competency based master’s program adapted from the United States Centers for Disease Control and Prevention (CDC) Epidemic Intelligence Service (EIS) Program. The School of Public Health/Addis Ababa University, the Federal Ministry of Health of Ethiopia/Ethiopian Public Health Institute (EPHI),and CDC Ethiopia are running the Program jointly former your years. After all the program extended their coverage to other 8 university to increase field epidemiologist for the country. The field work comprises of 75% of the Program which is called residency; learning by working in public health emergency and other health related priority issues. The Program is designed to assist the Ministry of Health in building or strengthening health systems by recruiting promising health workers and building their competencies through on-the-job mentorship and training.Ethiopia adopted the Field Epidemiology Training Program to help improve leadership within Public Health Emergency Management. The Ethiopian Field Epidemiology Training Program (EFETP) provides residents a Master of Public Health Degree in Field Epidemiology after they complete two years of supervised work in applied or Field Epidemiology. This compiled body of works has 10 main sections or chapters accomplished during the residency time of the Program. The first 7 sections are expected outputs during the residency time; comprising of outbreak investigation, surveillance data analysis, evaluation of the surveillance system, health profile description report, writing of finalized scientific manuscript for peer review journals, abstracts submitted to scientific conferences, summary of disaster situation visited/risk assessment and other additional works. The overall outputs of the two years Field Residency Program will be presented in a summarized way; in the outbreak investigations chapter or section, one unmatched case control outbreak investigation of Pertussis in Sayient Woreda, North west part of Ethiopia, January 2019 was documented. Health profile description report was done in Fogera district in March 2018 and Surveillance system evaluation was also done in Fogera and Dera Districts, Amhara Region, in March 2018. One finalized scientific manuscript was prepared for peer reviewed journal. A report on need assessment (risk assessment) on prioritized Districts of Amhara Regional State was also conducted with other XIII team members from food security center, WHO, UNICEF, ADDPS and Other Regional Bureau. Under other additional works/outputs section (last chapter) activities like provision of training for public health emergency management (PHEM) officers working at different levels (regional to health facility level) in the Amhara Regional Health Bureau were also undertaken. Other activities we developed of Rabies and Anthrax case based and line list and weekly Bulletin,update, summary report of Pertussis outbreak, prepared and present Anthrax outbreak investigation report on Workshops.
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    Epidemiological Study on Hemoprotozoan Parasites of Zebu Cattle in Ambo and Toke Kutaye Districts of West Shewa Zone, Oromia, Ethiopia
    (2017-06) Gudina Mekonnen; Hagos Ashenafi
    A cross sectional study was conducted from October, 2016 to May, 2017 to determine the prevalence of hemoprotozoan parasites, to detect the species of hemoprotozoa parasites, to identify the vectors of hemoprotozoal parasites and risk factors associated with the occurrence of hemoprotozoal parasites in cattle in Ambo and Toke Kutaye districts of West Shewa Zone. A total of 384 blood samples were collected from randomly selected cattle to assess the presence of hemoprotozoan parasites by using buffy coat and thin smear technique and stained using Giemsa stain and identified by using oil immersion objective lens light microscope. The three hemoprotozoan parasites identified in the study area were Babesia bigemina, B. bovis and Trypanosoma vivax. The overall prevalence of hemoprotozoan parasite in the study area was 9.4% (7.6% Babesia bovis, 1% B. bigemina, 0.8% T. vivax). Statistically significant difference was observed between groups of sex, age, body score condition and tick infestation of cattle in presence of hemoprotozoal parasite. Out of the total positive cattle with hemoprotozoal parasite 72% (26/36) of them were anemic (their packed cell volume values less than 25%) and the rest 28% (7/36) of them were not anemic (their packed cell volume value greater or equal to 25%) which is statistically significant. The major tick species identified in the study area include Rhipicephalus spp Amblyomma spp Hylomma spp and Rhipicephalus (Boophilus) spp Tabanus, Stomoxys and Chrysops were the biting fly species identified in the study area.
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    Epidemiology of Cattle ond Sheep Fasciolosis in Selected Abattoirs of Ethiopia and Estimation of the Associataed Economic Losses Due to Lvier Condemnation and Coprological Study in and around Debreberhan and Evaluation of the Immune Response of Sheep Against Primary Experiential Infection with Fasciola Hepatica Metacercariae
    (2021-06) Abebayehu Tadesse ; Hagos Ashenafi
    Fasciolosis is an economically important disease of ruminants which affects mainly sheep and cattle worldwide and causes important economic losses in the animal husbandry. These losses are attributable to mortality, morbidity and condemnation of livers at slaughter. In Ethiopian highlands, sheep and cattle production has remained as an important sector of the country’s agricultural economy. However, their potential has been exploited far less than expected due to several constraints including shortage of forage, poor livestock management and diseases. In Ethiopia, fasciolosis is widespread encompassing the major productive highland plateaus except very limited areas in arid escarpments. The study of liver flukes in live animals depends on the detection of faecal eggs and the use of faecal egg counts. However, these detect only patent infections and their interpretation is constrained by the paucity of information about how they relate to parasite burdens and pathology. Moreover, abattoir-based studies have been used as a component of the study of the liver fluke and to describe various aspects of liver fluke infection. Controlling fasciolosis by vaccination rather than chemotherapy would be a cheaper, more efficient and reliable long term solution for the prevention of infection and eradication of its transmission. Regardless of several attempts, vaccines against Fasciola hepatica were not yet produced to the point of commercialization. A variety of irradiation-attenuated parasite species have been used experimentally to induce protection in various host species. These studies have demonstrated that development of vaccine is potentially feasible. The present study entitled "Epidemiology of cattle and sheep fasciolosis in selected abattoirs of Ethiopia and estimation of the associated economic losses due to liver condemnation and coprological study in and around Debreberhan and evaluation of the immune response of sheep against primary experimental infection with Fasciola hepatica metacercariae" was undertaken in five abattoirs (Debreberhan, Addis Ababa, Bahrdar, HELMIX, ELFORA) while the experimental study was conducted at Aklilu Lemma Institute of Pathobiology. The objectives of the study were to assess the abattoir and coprological prevalence fasciolosis in sheep and cattle and assessment of the associated economic losses in three municipal and two export abattoirs as well as the vaccine trail on immune response of sheep to primary infection with attenuating irradiating dose of Fasciola hepatica metacercariae. The present findings on ruminants at five abattoirs had shown higher prevalence of fasciolosis (46.6% ± 0.059). However, this was much lower that observed in Debreberhan abattoir for sheep (84%) and cattle (77.8%). Overall fasciola infections were only diagnosed in 605 (53.8%) animals coprologically. The highest prevalence was for sheep (60.1%) and followed by cattle (49.2%). The overall herd level infection prevalence, as estimated from the egg-shedding index, was 50.9±29.3. In Debreberhan abattoir, F. hepatica was a dominant (87.9%) species identified followed by F. gigantica (6.3 %). However, this prevalence was much higher than that observed in five of the abattoirs altogether for F. hepatica (70.9%) and F. igantica (21.5%). The overall prevalence of fasciolosis observed in ruminants slaughtered in export abattoirs was 34.6% (877/2530) whereas it was significantly higher in ruminants slaughtered at municipal abattoirs 65.2% (1653/2530) as the whole. The mean annual financial loss recorded altogether in export and municipal abattoirs was 7, 049, 638 ETB / 335, 697.1 USD. The immune response to the infection was proved by the production of specific IgG1 antibodies to irradiated F. hepatica. The parasite viability was severely affected by doses of γ- irradiation of 120 Gy or 240 Gy. In the aforementioned doses relatively low numbers of mature flukes of about 60 (17.1%) and 38 (10.8%) were recovered than the control group, respectively. The sensitized lambs also showed less hepatic damage compared with the controls as indicated by lower liver lesions and lower levels of the serum enzyme glutamate dehydrogenase and γ- glutamyl transferase. The IgG1 antibody titers measured by ELISA vary with the dose of γ- irradiation. Sheep vaccinated with 240 Gy produced the highest antibody titre compared to the non sensitized positive controls. In conclusion, the present study plainly disclosed the high prevalence of fasciolosis both at herd and individual animal level and at abattoir survey. The eggs shedding index seemed to be useful approach in current epidemiological survey than the individual animal coprologic examination. The present findings on ruminants at abattoirs had shown higher prevalence of fasciolosis with significant annual financial loss. Vaccination of sheep with γ-irradiated metacercarae invariably yielded the specific immune response to different treatment groups. Irradiation of F. hepatica had resulted in reduced hepatic damage during migration of juveniles and a strong local immune response, represented by infiltration lymphocytes, eosinophils and macrophages and antifasciola IgG1 titers
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    Experimental Studies on Clinico- Hematology of Trypanosoma Equiperdum Infected Horses and Venereal Transmission in Mice
    (2017-06) Merga Daba ; Hagos Ashenafi
    Dourine is an endemic venereal transmitted trypanosomosis causing a major health problem threatening the life and productivity of the equine population in Ethiopia. The present experimental study was conducted from November 2016 to June 2017 in Bishoftu, central Oromia, Ethiopia. The objective of the study was to evaluating clinico-hematological profile of horses experimentally infected with Trypanosoma equiperdum, assess the effect of cymelarsan treatment on hematological values of horses infected with T. equiperdum and determine the possibility of venereal transmission of T. equiperdum in mice. The study design was conducted on (n=4) mares and (n=4) stallions. Mares were challenged by insemination of semen originated from non-infected stallion after mixed with T. equiperdum at a dose of 100,000 parasite/ml by artificial insemination whereas stallion group were infected with 2ml of blood that drawn from infected mare at dose of 1x106 parasites /ml via intravenous route. Data on parasitaemia, rectal temperature, serology (CATT/T. evansi test) and hematological were determined before and after infection. Furthermore infected horses were divided into two groups designated as treated and non-treated groups. At weeks 6 of post infection treatment group was injected with cymelarsan® at dose of 0.25mg/kg body weight. Changes in clinical sign, parasitemia and hematological values were monitored. Thirty (n=30) female mice and male (n=12) were involved in experiment to check coital transmission. One infected mouse was co-housed with two healthy female mice at low level of parasitemia (1x101-1x103) in six replications and other one infected male mouse co-housed with two healthy female mice at high level of parasitemia (1x104-1x106) in six replications. Other two infected female co-housed with four healthy female as control. Thereafter the appearance of Parasitemia was monitored daily from female mice. The study revealed that, Dodola strain caused a severe change in blood parameter and a clinical sign in both stallion and mare, infection was predominantly characterized by involvement of genital, nervous and corneal signs. There was significant decrease in mean PCV, Hg, RBC, eosinophil, basophil and monocyte count while mean total WBC and neutrophil count had no significant difference (p>0.05) in animals post-infection when compared to pre-infection values. Lymphocyte and MCHC were significantly (p<0.05) higher at post infection as compared to pre-infection. Cymelarsan treatment at dose of 0.25 mg/kg body weight failed to clear the parasite and improve in clinico-hematological values, rather being relapsed after 21days. Treated group had no significant improvement in RBC, Hgb, and differential leukocyte count whereas PCV and WBC which were significantly (p < 0.05) improved as compared to non-treated group. In healthy female mice co-housed with infected male mice using wet smear no trypanosomes were detected in all female mice and their offspring in wet smear throughout study period. In conclusion the current study revealed that dourine resulted in hematological changes that lead to normocytic hypochromic anemia, thus further elucidative investigation recommended on pathogenesis of the disease. In addition, venereal transmission of T. equiperdum in mice was unsuccessful; hence further molecular based test is essential to ascertain this result.
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    Prevalence of Camel Trypanosomosis and Associated Risk Factors in Selected Districts of Bale Zone, Ethiopia
    (2007-06) Esayas Tesema; Hagos Ashenafi
    A cross sectional study was conducted to determine the prevalence of camel trypanosomoses and to identify the risk factors associated with the disease occurrence in Dello-mena and Sawena districts of Bale zone. Blood samples were collected from 619 camels and examined for the presence of T. evansi using card agglutination test for trypanosomiasis (CATT / T. evansi), and a parasite detection test (buffy coat smear – BCS). Clinical examinations as well as questionnaire survey, regarding information about the host and management practices were conducted. Questionnaire survey results indicated that high milk production, bush encroachment as well as the ability to survive drought are the major reasons for camel keeping. Camel trypanosomoses locally known as “Dhukan” is the most important complaint of camel breeders. Respondents clearly described the diseases and ranked it as the most important disease of camel in the study area. The prevalence of the disease was found to be 12.12% using buffy coat smear and 24.88% with CATT. Camels in Dello-mena had a significantly higher prevalence than camels in Sawena district in both BCS and CATT / T. evansi examination results. Thus it was found that camels in riverine areas of Dello-Mena are more at risk of infection than herds in non-riverine areas of Sawena. Age appeared to be a risk factor for individual trypanosomoses serological status and that the highest seroprevalence was observed in camels greater than five years old. Poor body condition was significantly correlated with positive status in both CATT and BCS results. The average PCV of parasitological positive camels was found to be significantly different from the average PCV of parasitological negative camels. However, the average PCV of seropositive but parasitological negative camels did not differ from the average PCV of seronegative camels. From the result of this study it can be inferred that camel trypanosomoses is endemic in dello-mena and Sawena districts with a higher degree of prevalence in Dello-mena than Sawena district. Absence of proper animal health extension and the indiscriminate use of camel trypanocidal drugs often underdosed are major constraints in camel health delivery in the study area. Thus, attention has to be given to provide adequate veterinary service and sensible animal health extension systems. Furthermore, considering the widespread existence of surra and its impact on camel productivity further study on identification of the principal vector species responsible for transmission and investigating the potential for vector control is recommended.
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    Serological and Epasitologlcal Survey of Dourilne (Trypallosoma Equiperdum) in Selelected Sites of Ethiopia
    (Addis Ababa University Faculty of Veterinary Medicine, 2000-06) Hagos Ashenafi; Getachew Abebe
    The present stud} wa~ conducted rrom August 2004 to Apnl 2005 \\ L1h Iht: ObJccll\e~ IIf dctemumng. the prevalence, extent and d istribution 0 dourine III horses and IO\CSlIgaling occurrence of cllmeal cases 3S well 3S carner st:ltes of donkey .. and mules III the Arst- B:llc Illgh la nd s. At the same time a lon g Ltudmal study was conducted to assess the efficacy of the Isomet::mudlUlll chlonde ( IS MM ) Hnd D lITu nazenc acetumte (I)I~ I ) III Iht treatment of ch mcal c ases of dou rine. An IIlvcs ligalion was also conducted encom pa~Slllg cluesttonmure nnd serological survey o n th e presence of dO Urine in adjacent geograph ic"l areas of the Ar<;I- Ha1c highlands and other sclec ted parts o f the country with lugh equlOe population, The stud) methodol ogy was based on quest io nn:lIrc, serological. climeal and pa rasitologica l surve~, The questionnaire survey indi cated th ai do urine, locally known, as " Lappessa" or " D irr C$s a·· is a major health problem of equ ines in th e Arsi-Bale hi g hlands Though, dourine 1<; a common clinical case th rough Qut th e year, it has a seasonal character. \\ hieh most com monly occur" following Ih t' b reeding !;l' aSOIl from Junc to late Septembe r. SOIllC!ltne~ a <;('coml peak IS observcd III Ihe dl) seasons of the ~ car (Marc h to t>. o r any other haemopara~l1c~ could be detected in all cxanll ned Glemsa stained smears (th in blood. gell ital di sc harge and ti~l;uC fluids) as well as In bl ood samples by mil CT. All th e puppIes Inoc ulated \\lth blood samrk~. gellll.tl wa she s and oed cmalOUS nUids remained parasl1ologicall ) Ilegau\e. Diffe rent ch ara ctcri stic clinical signs o f dourinc were observed in clilllcally ~Ic k horses of both sexes . The prominent clinical signs observed as geni tal fo m) o f the di sease mclude vagmal dl:.chargc mallll~ of mucopurulent type "ilh foul odou r. oedema lind presence of deplgmcn ted ..,cars 0\ (' 1' till' o,:)'lerna l genita lia , oc,icmu o f Ihe <;cro ltlm and prepuce aecomp:llllcd by pn:pucl.:t1 ali \\ell .h urethral d Isch arge and ukl'rallon of the gen ita l m ucosae mlllnl~ nf the- pen tie In hoth "'C\l' ~ . lamencs~ in one or both leg ... panml dr;tgg ln g and slIffnc"s of thl' lund Icg~ and Itlcoordtnilth)n \H·r~· lhc dominant sig n .. nbscrv o.!d , I ~ nervous fo rm of lhe dl ~CIl<;C viii Horses with different ehOlc al signs of doun nl! were categonsed Into one of the followi ng fi\e grou[ls based on th e cl llll cal findin gs Apparc llIl y health y (46 81. non -s pccliic s ign s like ema ciat ion ilnd weakne ss (69); ge nital fonn (30); nervou, fonn 01 [15) and bo th gCTll1ul .lnd nervous forms of th e disease (67). Fifty - four horses with hi gh pCrtenl :l ge [lO !.I U\,II)' fOl the md lrec t anllbody ELI SA and mn eleen horses wllh stron g agglullnall un reactlOTlS having end III fe of 1.32 for both CA l-r and LATEX tes ts be longed to th e liw of th ... dlffeT1:nl dUlleal group~ ChI-sq uare analysIs of the di s tributi on of anImals. claSSIfied liS C) tl Wf POS III\ e llr negative 011 Ihe ba sis ofallthi." three teSt s. in th e clull eal grou ps demon st rat ed a s tat l<;tltally slgm fi cn nt d iffe ren ce between gro ups. with s tratum specific prevalence o f po siuvc amma i<; mc rca!'llllg wit h In crc aslIlg severity of clmieal sign .. (p of I SM~1 and Dl:V1 III selected serologically po slI1\·e cli nical cases of Cou nnl.' 111 A<; as<;a dl !'llTh:l of th e Ar !') hlghl.lIlds A lot.11 of 24 adull 10e:11 horses were divided Inl O ~ group, of cq11al number I' CV k\ cl. eos!l1opllll cou nt , bodytemperature, se rologi cal sWt u". unrf\)\emcni of the C'I'tlllg clinical !'Ilgn~ Jnd bod) w ndition ~Cl)rc \\ en: moni tored tWIce m 10 d):" 1I1Ienal fClr a penod til 40 dll) ~ rhe res ults IIldu:ated th at mean ]l eV, eosinophil counts and t>"dy Icmperaturl' impw\ ed in bo th J S\ I~I and D I ~I treated group during th e 40 day s pO St tr(';ll meni penod A ~ Ia nsth:,ill ~ sig nifi can t Increase in PCV and body temperature was observed ~1.lrIlIIg frOlll th e day 10 ( P kilO .... n ende mi C fOCI of the ArSI-Ualc hIghlands of I:thIOPI:l ,\llhough thcre wa~ no d,rect detection of T C'qU/f)('rdllfll, there IS 'mong eVidence Ihal dounne IS highly pre\:llclll, mo,t Important problem LIl th e Arsi- llaic hIghlands. whe re the Sllua tlon IS gellmg .... orse \\ Llh the preo;cOI spreading trend to areas previously known as free of the disease. neces,"alC~ urgent nall onal control intrevtion
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    Serologlcal and Parasltologlcal Survey of Dourlne (Trypallosoma Equiperdum) in Selected Sites of Ethiopia
    (Addis Ababa University Faculty of Veterinary Medicine, 2005-06) Hagos Ashenafi; Getachew Abebe
    The present stud} wa~ conducted rrom August 2004 to Apnl 2005 \\ L1h Iht: ObJccll\e~ IIf dctemumng. the prevalence, extent and d istribution 0 dourine III horses and IO\CSlIgaling occurrence of cllmeal cases 3S well 3S carner st:ltes of donkey .. and mules III the Arst- B:llc Illghla nds. At the same time a longLtudmal study was conducted to assess the efficacy of the Isomer::medulla chlonde ( ISMM) Hnd DlITu nazenc acetumte (I)I~ I ) III Iht treatment of chmcal cases of dou rine. An IIlvcs ligalion was also conducted encom p a~Slllg cluesttonmure nnd serological survey on the presence of dOUrine in adjacent geographic"l areas of the Ar<;I-Ha1c highlands and other sclected parts of the country with lugh equlOe population, The stud) methodology was based on quest ionn:lIrc, serological. climeal and pa rasitological s urve~, The questionnaire survey indicated thai dourine, locally known, as " Lappessa" or "DirrC$sa·· is a major health problem of equines in the Arsi-Bale highlands Though, dourine 1<; a common clinical case through Qut the year, it has a seasonal character. \\ hieh most commonly occur" following Ih t' breeding !;l'aSOIl from Junc to late September. SOIllC!ltne~ a <;('coml peak IS observcd III Ihe dl) seasons of the ~ car (March to t>. or any other haemopara~l1c~could be detected in all cxanllned Glemsa stained smears (th in blood. gell ital di sc harge and ti~l;uC fluids) as well as In blood samples by mil CT. All the puppIes Inoculated \\lth blood samrk~. gellll.tl washes and oedcmalOUS nUids remained parasl1ologicall) Ilegau\e. Diffe rent charactcri stic clinical signs of dourinc were observed in clilllcally ~Ic k horses of both sexes.The prominent clinical signs observed as genital fom) of the disease mclude vagmal dl:.chargc mallll~ of mucopurulent type "ilh foul odour. oedema lind presence of deplgmcn ted ..,cars 0\ ('1' till' o,:)'lernal genita lia, oc,icmu of Ihe <;cro ltlm and prepuce aecomp:llllcd by pn:pucl.:t1 ali \\ell .h urethral dIscharge and ukl'rallon of the genital mucosae mlllnl~ nf the- pen tie In hoth "'C\l' ~ .lamencs~ in one or both leg ... panml dr;tgglng and slIffnc"s of thl'lund Icg~ and Itlcoordtnilth)n \H·r~· lhc dominant sign .. nbscrvo.!d ,I ~ nervous form of lhe dl ~CIl<; C viii Horses with different ehOlcal signs of doun nl! were categonsed Into one of the followi ng fi\e grou[ls based on the cl llllcal findings ApparcllIly healthy (4681. non-spccliic signs like emaciat ion ilnd weakness (69); genital fonn (30); nervou, fonn 01 [15) and both gCTll1ul .lnd nervous forms of the disease (67). Fifty-four horses with hi gh pCrtenl:lge [lO!.I U\,II)' fOl the mdlrect anllbody ELISA and mneleen horses wllh strong agglullnallun reactlOTlS having end IIIfe of 1.32 for both CA l-r and LATEX tests belonged to the liw of th ... dlffeT1:nl dUlleal group~ ChI-square analysIs of the distributi on of anImals. claSSIfied liS C) tlWf POSIII\ e llr negative 011 Ihe basis ofallthi." three teSts. in the clull eal grou ps demonst rated a stat l<;tltally slgm fi cn nt difference between groups. with stratum specific prevalence of posiuvc ammai<; mcrca!'llllg with IncrcaslIlg severity of clmieal sign .. (p of I SM~1 and Dl:V1 III selected serologically poslI1\·e clinical cases of Cou nnl.' 111 A<;as<;a dl !'llTh:l of the Ar!') hlghl.lIlds A lot.11 of 24 adull 10e:11 horses were divided InlO ~ group, of cq11al number I'CV k\ cl. eos!l1opllll cou nt, body temperature, serological sWt u". unrf\)\emcni of the C'I' tlllg clinical !'Ilgn~ Jnd bod) w ndition ~Cl)rc \\ en: moni tored tWIce m 10 d):" 1I1Ienal fClr a penod til40 dll) ~ rhe results IIldu:ated that mean ]leV, eosinophil counts and t>"dy Icmperaturl' impw\ ed in both J S\ I~I and D I ~I treated group during the 40 days pOSt tr(';ll meni penod A ~ Ia nsth:,ill ~ significant Increase in PCV and body temperature was observed ~1.lrIlIIg frOlll the day 10 (P kilO .... n ende miC fOCI of the ArSI-Ualc hIghlands of I:thIOPI:l ,\llhough thcre wa~ no d,rect detection of TC'qU/f)('rdllfll, there IS 'mong eVidence Ihal dounne IS highly pre\:llclll, mo,t Important problem LIl the Arsi- llaic hIghlands. where the Slluatlon IS gellorse \\ Llh the preo;cOI spreading trend to areas previously known as free of the disease. neces,"alC~ urgent nallonal controllntcnCnllon
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    Studies on Bovine Trypanosomosis and Efficacy of Selected Trypanocidal Drugs in Konso District, Southern Ethiopia
    (2008-06) Gewado Ayledo; Hagos Ashenafi
    Field and experimental investigations on bovine trypanosomosis and efficacy of selected trypanocidal drugs were undertaken in Konso district, southern Ethiopia, from September 2007 to April 2008, with major views to determine the prevalence and socioeconomic impacts of bovine trypanosomosis; assess the efficacies of selected trypanocidal drugs; and evaluate the propensity of Konso community to devote public resources to integrated tsetse/trypanosomosis control approaches. Questionnaire interviews, cross-sectional and experimental study designs were applied to collect relevant information. A structured questionnaire was designed and posed to randomly selected households and key informants to identify areas with high suspicion of drug resistance. Questions addressed main issues like herd structure and major livestock health problems; socioeconomic impacts of trypanosomosis; the sources, usage pattern and suspected failure of trypanocidal drugs, etc. Open-ended and close-ended questionnaire interviews were administered to randomly selected households to evaluate the propensity of the community to a holistic, integrated disease control. In order to identify areas with high trypanosome infection pressure and risk of drug resistance, initial cross-sectional study was undertaken on randomly selected cattle heads the monthly blood samples of which were examined through micro- haematocrit centrifugation and Buffy coat methods. Linear regression model was employed to assess the relationship between parasitological prevalence of trypanosomal infections and herd average PCV. In order to assess the therapeutic and prophylactic efficacies of the common trypanocidal drugs, ten zebu calves (Bos indicus) were experimentally infected with randomly selected field isolates of T. congolense, and treated with Diminazene aceturate (3.5 mg/kg BW) when the first peak of trypanosomal parasitaemia appeared. Based on deterioration in clinical and haematological parameters, relapsed calves were re-treated with Isometamidium chloride (0.5 mg/kg BW). Experimental animals were monitored for clinical as well as parasitological parameters on regular basis for over three months. The study results revealed trypanosomosis to be a major threat to livestock production with contrasting arrays of socioeconomic impacts; significant reductions in cattle production losses after tsetse control and a corresponding rise in mean holdings of draft oxen and use of animal traction over the same period; an indiscriminate use and increasing tendencies in mean annual expenditure on trypanocidal drugs at the household level. Contingent valuation study disclosed animus propensity of Konso community to devote VII both labour and monetary resources to support integrated tsetse/trypanosomosis control; household size, wealth status and educational background of household heads to be the major determinants influencing willingness to support integrated disease control. Cross-sectional study on bovine trypanosomosis indicated an overall parasitological prevalence of 17.0 % and 13.4 % during rainy and dry season, respectively, reflecting its significant temporal and spatial variation (p< 0.001); and T. congolense to be a dominant trypanosome species hampering livestock sub-sector in Konso district. Regression analyses on haematological findings disclosed a significant reduction (p<0.05) in the herd mean PCV with an increase in the prevalence of trypanosomosis; and that the reduction in herd PCV was significantly higher during dry season than in rainy season (p<0.001), suggesting that trypanosomosis is less-well tolerated during dry months. Results of drug sensitivity testing revealed the presence of T. congolense populations exhibiting resistance to Diminazene aceturate. In conclusion, the absence of improved veterinary service and indiscriminate use of poor-quality trypanocidal drugs have proven to boost the risk of drug resistance in Konso district. In light of the high likelihood of trypanocidal drug resistance in Ethiopia, the present findings could be a useful tool to improve trypanocidal drug usage strategies in the field, and could form baseline information to undertake holistic assessments of drug resistance across tsetse-infested areas of Ethiopia. It is recommended that integrated disease control approaches be adopted with chemotherapy restricted to clinically sick animals, and legislations be devised and harmonized to ensure the quality of trypanocidal drugs.
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    Studies on prevalence of trypanosomosis and drug sensitivity on trypanosome congolenes in Wolayita and Dawero zone of Southern Ethiopia
    (2007-06) Miruk Assefa; Hagos Ashenafi
    The current study was conducted in tsetse and non tsetse controlled areas of the Southern Nation Nationalities and Peoples Regional State (SNNPRS) of Ethiopia. A cross sectional study to determine the prevalence of bovine trypanosomosis as well as a drug sensitivity tests on T. congolense in both naturally and experimentally infected cattle and mice, respectively were carried out. In the first study area, Humbo district, a total trypanosome prevalence of 4.8% (95% CI: 1.8–7.5) was recorded. In the second study area, Mareka district, a total prevalence of 20.4 (95% CI: 14–26.8) was recorded. There was statistically significant difference in the mean prevalence of trypanosomosis between the two areas (P<0.001). The mean PCV value for Humbo and Mareka was 26.2 (95%: 25.7-26.7) and 22.7 (95% CI: 22.1- 23.3), respectively. There was statistically significant difference in the mean PCV value between the two study areas (P<0.001). To assess the prophylactic activity of isometamidium chloride a field trial was conducted in Humbo on nine parasitological positive zebu cattle. A breakthrough case of 66.7% (6/9) was recorded in less than five weeks. A qualitative mice assay was conducted on two T. congolense isolates obtained from the break through cases with ranges of doses of isometamidium chloride and diminazene diaceturate. Thereafter the mice were followed for relapse infection. Isometamidium at doses 0.5-4mg/kg b.w and diminazene at doses of 3.5-28mg/kg b.w failed completely to cure T. congolense infections in any of the mice. A quantitative mice assay was conducted on four T. congolense isolates obtained from Mareka. The four isolates were pooled into two pools (Pool-1 and Pool-2) for the quantitative mice assay. The pooled isolates were tested with the same trypanocidal drugs and ranges of doses as it was used for the qualitative mice assay. The minimum curative dose (MCD) of isometamidium chloride and diminazene diaceturate that cleared the trypanosome from mice infected with Pool-1 was found to be 4mg/kg b.w and 28mg/kg b.w, respectively. For mice infected with Pool-2 the MCD of isometamidium chloride and diminazene diaceturate that cleared the trypanosme was found to be 2mg/kg b.w and 14mg/kg b.w, respectively. Even though cloned populations were not used to proof the observed resistance was at the individual level or not the result indicated that there is the possibility of failure of “sanative pair” between the two drugs.
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    Study on Concurrent T. Congolense and H. Contortus Experimental Infection in Goats: Interaction and Pathogenic Effects
    (AAU, 2006-06) Abebayehu Tadesse Wazza; Hagos Ashenafi
    Study on concurrent Trypanosoma cOllgo/ellse and Haemonchus COllrortliS infections to assess the interaction and pathogenic effect of single and mixed experimentally induced infection were conducted in goals. A total of 25 goats of approximately one year old were divided into five groups and each group was infected either with H. COlltorWs one week after a preceding infection with T. congo/elise or with primary H. conlOrlus infection one week prior to T. cOllgo/ellse or infection with either the nematode or trypanosome alone, and the fifth group was served as non infected control. For experimental purpose each experimental animals were infected with T. congo/elise. derived from the donor goat after one passage in mice with total intravenous inoculation of 5x I 4 T. congo/elIse. The tOlal infective dose of H. cOl/torll/S, which was given orally to each animals was, 10,000 3rd stage larvae. Parasitological observations such as prepatent period, faecal egg count, woml burden and trypanosome parasitaemia; and hematological parameters like packed cell volume, haemoglobin concentration. mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC), red blood cell counts, white blood cell coul1ls. differential leukocyte counts (eosinophil, lymphocyte and neutrophils), total protein and also clinical parameters including body weight change, mortality rates among various treatment groups were made in mixed infected groups and in animals singly infected with ei ther parasites. It was revealed that the order of infection in the preceding or subsequent infection was very important in which the most hannful combination was a primary T. cOllgo/eflse infection one week prior to Ii. COllforllls super Infection. that resulted in progressive and sever anaemia accompanied by leucopenia, hypoprOleinemia, loss of weight and short prepatem period of H. COlftorlllS. Except animals mono infected with H. COnforms, which have shown macrocytic hypochromic anaemia, all other treatmem groups have revealed nomlocytic nonnochromic anaemia throughout the whole observation period. The result also showed that animals with concurrent T. cOllgo/ellse and Ii. COI/lortus run high risk of succumbing during the infection period. Higher rate of mortality and more pronounced pathological effects were observed in combined infections than single ones. It was concluded that the increased I/. cOlllortus egg excretion observed in animals infected with both parasites might signi fi cantly increase the risk of nematode infections. The interaction between these two highly potent anaemia causing pathogens should be considered whenever attempts are made to control these two diseases.
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    Study on Molecular Characterization and Pathogenesis of Peste des Petits Ruminants Virus (PPRV) in selected sites of Ethiopia
    (Addis Abeba University, 2025) Fasil Aklilu; Hagos Ashenafi
    Background: PPR has emerged as a significant and high-priority livestock disease in Ethiopia. A relatively recent study indicated that the disease leads to economic losses amounting to 14% of the yearly household income, posing a serious threat to the livelihoods of livestock owners. In connection to the worldwide significance of PPR, the FAO and WOAH developed a global strategy in 2015 to eradicate the disease by 2030. In alignment with this framework, countries such as Ethiopia have devised their own plans to achieve eradication by setting the same target year. However, over five years of control efforts, PPR outbreaks persist in Ethiopia and continue to expand into regions that were previously unaffected. This phenomenon coupled with others necessaitates to the need and urgency of investgating the factors that influence the continued presence of the virus in the field. One of the potential factors is the involvement of non-target host species, such as cattle, which may play a significant role in the epidemiology of PPR. Furthermore, much of the current understanding of PPR pathology and pathogenesis is derived from research on closely related viruses, such as the rinderpest (RP) virus signifying knowledge gap in the area. oreover, updated knowledge of circulating PPRV lineages/strains and their virulence profiles is essential for targeted and effective PPR control and eradication efforts in Ethiopia. Objectives: This study aimed to identify factors hindering the success of ongoing PPR control and eradication efforts in Ethiopia and beyond. The first study addressed whether infected cattle shed enough PPRV to transmit the virus to seronegative small ruminants or other seronegative cattle while also evaluating the role of cattle in PPR epidemiology. The second study aimed to investigate PPRV tissue tropism, shedding patterns, pathogenesis, clinical progression, and comparative pathology in goats and cattle to support the development of more effective surveillance and control strategies. The third study aimed to identify circulating strains and compare their virulence in an experimental setting. Such insights could aid in strategic planning for more effective disease control. Methodology: The first experimental study aimed to investigate the role of cattle in PPR epidemiology by using both empirical and model-based approaches. The trial was conducted at the Animal Health Institute (AHI) experimental facility. Local virus strains, lineage IV isolate Ethiopia/Habru/2014) and animal breeds were used in the study. The first experiment consisted of five consecutive trials involving 15 sheep, 66 goats, and 37 cattle, with a total of 118 animals. To simulate natural transmission, sheep and goats were administered 1 ml of viral suspension, while cattle received 2 ml, all via the intranasal inoculation route. Similarly, the second experimental study was conducted using local breeds of goats and cattle, along with a locally circulating PPRV strain. A total of 32 animals, with 16 from each species, were included. Samples were collected from live animals, as well as postmortem samples from purposivelly sacrificed goats and cattle. In goats, sampling was performed daily, while in cattle, it was conducted at predetermined intervals. Finally, an experimental study was conducted on 21 goats, including both experimental and control groups, to assess the virulence of six PPRV strains circulating in specific regions of Ethiopia. Samples were collected from both live and sacrificed goats at predetermined intervals for further analysis. All animals used in the experiments were serologically negative for PPR, allowed to acclimatize for 10–15 days, randomly assigned to experimental barns, and analyzed using various diagnostic techniques. Results: Studies on the role of cattle in the epidemiology of PPR demonstrated that the animals can naturally contract the virus through contact with infected goats, though they typically exhibited only mild and short-lived clinical symptoms. This indicates that cattle play a limited role in PPRV transmission due to the fact, cattle-to-goat transmission being rare, even when the animals share the same space for extended periods. While qRT-PCR detected PPRV RNA in a virusinfected sentinel calf, attempts to isolate the virus were unsuccessful. Additionally, cattle that were experimentally inoculated or housed with PPRV-infected goats did seroconvert. These findings underscore the need for further investigation into the mechanisms that may restrict disease development and viral shedding in this species. A comparative pathology study of PPRV in goats and cattle revealed moderate level of clinical signs in goats while, no obvious symptoms among cattle. Instead, cattle experienced a subclinical infection, suggesting they could act as silent carriers of the virus. The significant difference in clinical manifestations between the two species (P-value = 0.0070) underscores the variation in host responses to PPRV infection. Although the successful isolation of live PPRV from cattle samples was limited, it raises the need to reassess the epidemiological role of cattle in PPRV transmission. These findings indicate that under certain conditions, cattle could serve as potential reservoirs or silent spreaders of the virus. However, further research is needed before applying these results to other PPRV lineages or regions beyond the currently circulating lineage-IV PPRV in Ethiopia. Investigation of comparative virulence of locally circulating PPRV strains in indigenous goats, demonstrated that five out of six strains displayed typical PPR clinical signs, with the exception of one lineage-IV strain (designated as 38920/19), which only caused a mild nasal discharge. Goats inoculated with viruses from two different lineages, lineage-IV and lineage-III, exhibited nearly identical clinical outcomes, indicating that lineage classification alone may not be a reliable predictor of disease severity. The observed reduction in virulence in one strain may be attributed to inherent biological differences or technical factors related to laboratory procedures. Conclusions: The present study considered in-depth examination of various factors and insights that could potentially affect theongoing PPR control and eradication efforts, highlighting key areas for further research and consideration. The study on the role of cattle in PPRV epidemiology suggests that local breed (zebu) in mixed-species environments play a limited role in transmitting PPRV to sheep and goats. The detection of PPRV RNA in a naturally infected sentinel calf, despite failed virus isolation attempts, highlights the need for further comparative studies on both cattle and goats. A comparative pathology study of PPRV in goats and cattle provides evidence of subclinical infections and live virus shedding in cattle, suggesting that under certain conditions, cattle may play a more active role in PPRV epidemiology than previously recognized. However, the current study relied on a single local lineage (L-IV) limits the broader applicability of the findings to other strains and regions. To enhance understanding of PPRV, further research should investigate additional virus strains and their virulence characteristics. The comparative virulence study of Ethiopian PPRV strains reveals similar virulence profiles across lineages (L-III and L-IV) in local goats, indicating that lineage classification alone may not reliably predict clinical outcomes. This finding is essential for informing regional disease control strategies.
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    Trypanosoma Equiperdum: Venereal Transmission and Pathogenesis
    (2019-08) Ahmed Yasine; Hagos Ashenafi
    Dourine, a venereal transmitted trypanosomosis caused by Trypanosoma equiperdum, has different clinical signs related to the reproductive and nervous system. It is one of the life-threatening venereal diseases in equidae. So far, there is no clear evidence on how and when stallions become infectious, nor which tissues are affected by the parasite in diseased animals. Post-infection, after a transient, temporary phase of parasitaemia, the parasite disperses to different tissues in an unknown distribution pattern. A review of the available literature was performed and knowledge of previous reports concerning dourine and T. equiperdum was gathered (Chapter 1).T.equiperdum is very closely related to T.evansi (the causative agent of surra) in morphology, biochemical and molecular characteristics. Differentiation is possible by use of PCR targeting the kinetoplast DNA gene more specifically,the maxicircle and minicircle genes. Pathologic tissue changes associated with the disease are poorly described so far. The necessity to impose management strategies for the control and eradication of dourine from endemic areas is in demand of more evidence-based data about more accurate feasible diagnostic measures and a better understanding of possible pathways of disease transmission. The aim of this thesis was to get more insights into the pathogenesis and venereal transmission of T. equiperdum (chapter 2).Histopathological lesions in four naturally T. equiperdum-infected horses in the chronical stage of dourine from Arsi-Bale highland of Ethiopia, exhibiting obvious clinical signs of dourine, were examined. Tissues collected at necropsy revealed on PCR test characteristics of T. equiperdum. A full post-mortem examination on the horses did not reveal typical gross lesions in the organs that were assumed to be responsible for the symptomatology. On histopathology, genital organs (especially testicles, uterus and vagina) were affected with mononuclear cell infiltration and erosions leading to degeneration of seminiferous tubules and perivascular lymphoplasmacytic cuffing in the uterus. In the nervous system, mononuclear cell infiltration was located in peripheral nerves and ganglia and in the white matter of the spinal cord, leading to axonal degeneration and fragmentation. Starting from tissue samples from the predilection sites of the parasite, real-time and conventional PCRs, . Clinical and haematological parameters were recorded and finally the effect of Cymelarsan® treatment given at the chronic stage of the disease, was assessed. At the same time we looked whether this treatment could alleviate the clinical signs and health status of the animal and induces differences in the pathology and tissue distribution of the parasite or not (chapter 4).Mares were artificially inseminated with T. equiperdum Dodola 943 spiked semen whereas stallions were infected by blood transfusion of the same strain. The course of the disease was monitored by parasitological (Woo), serological (CATT/T. evansi) and molecular (PCR) tests and clinical signs and haematological parameters were recorded. At 120 days post infection, they had a full necropsy for histopathology and PCR. A similar pattern of parasitaemia, disease progression and tissue distribution were seen in all horses with different routes of infection. Ejaculated semen in the preclinical stage and epididymal semen in the chronic stage of the disease was positive for T. equiperdum on PCR and caused infection in mice. Cymelarsan® treatment in the chronic stage did not result in a clinico-haematological or histopathological improvement. At necropsy, lesions were observed in the nervous and reproductive system. Histopathological lesions were most severe in the peripheral nerves and associated ganglia, the testicles and genital mucosae with multifocal infiltration of lymphocytes, plasma cells and histocytes. The parasites disseminated to several tissues including the nervous system, testicles and semen.ther measures should be taken into account in an attempt to eliminate dourine in endemic areas. Dourine is dealt with international legislative measures imposed by the World Organization for Animal Health (OIE) aimed at isolation, castration or slaughtering of positive horses. In developing countries like Ethiopia, it is economically and morally not feasible to impose strict slaughter policies to control dourine. When dealing with a disorder that is transmitted by venereal routes, it seems obvious that in an attempt to eliminate such a condition or even to diminish the morbidity of the disease, life cover should be replaced by artificial insemination. Purification of semen by single layer centrifugation (SLC) was attempted to remove trypanosomes from semen (Chapter 5).SLC has been proven to be successful in reducing venereal transmitted diseases when dealing with other pathogens. For this hypothesis semen was spiked using cryopreserved T. equiperdum stabilates (Dodola 943) in varying concentrations, from 102 to >5x106 trypanosomes/ml. Subsequently, SLC was performed following standard procedures. The presence of the parasite in the purified semen was checked by wet smear examination, ITS1 PCR and in vivo inoculation in mice. Before SLC, all spiked semen samples, except the negative controls, were positive on PCR analysis. After SLC, all the pellets were found to be negative for T. equiperdum on microscopic examinations. PCR analysis also could not detect any parasite-DNA in the SLC-pellet of semen spiked with the lower concentration (102 to 104 trypanosomes/ml). However, in the SLC pellets spiked with higher concentrations (104 - 5x104 trypanosomes/ml), only 1 out of the 4 replicates was negative for parasite DNA. All groups spiked with >5x104 trypanosomes were found to be positive on PCR. All mice in the positive controls exhibited parasitemia (5/5). Mice inoculated with SLC-purified semen that was spiked with lower than 5x104 trypanosomes remained free of parasitemia, similar to the negative controls. However, inoculation with SLC-pellets from samples with a higher number of trypanosomes (> 5x104 - 5x106 and > 5x106 /ml), induced parasitaemia in 2 out of 5 and 3 out of 5 mice, respectively. This study indicates that single layer centrifugation can be used to lear T. equiperdum infected semen but that the success is dependent on the concentration of the trypanosomes in the semen.Finally, all the obtained results were summarized and compared with the current knowledge and opinions and discussed in chapter 6.In conclusion, our results indicate that transmission of T. equiperdum is possible through semen and semen from symptomless stallions, in the preclinical-, clinical- and in the post-treatment periods. The results of the treatment trial to manage dourine especially at the chronic stage discourages the use of Cymelarsan®. The observed histopathological lesions in the reproductive organs, distal spinal cord and peripheral nerves might give an explanation to the diagnostic clinical incoordination of the hind legs in T. equiperdum-infected horses and its presence in the reproductive tract can exemplify the venereal transmission.Finally, our findings confirmed some of the assumptions about the pathogenesis and transmission of T. equiperdum and attributed to the growing knowledge about dourine in equines and trypanosomosis in general. When aiming to develop an all-encompassing eradication program, these insights may lead to a more efficient approach of dourine and thus add value to the agricultural and socio-economic situation in endemic areas
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