Browsing by Author "Hagos Ashenafi"
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Item Bovine Babesiosis and Its Vectors at Kobo and Girana Valleys in Amhara National Regional State of Ethiopia.(2007-06) Seyoum Zenebe; Hagos AshenafiA 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.Item Compile Body of Works in Field Epidemiology(Addis Abeba University, 2019-06) Gebremedhin Gebreslassie; Negusse Deyessa; Hagos Ashenafi; Abdunnasir AbagaroResidents 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 fItem Compiled Body of Works in Field Epidemiology(Addis Ababa University, 2019-04) Taddie Wondmnew; Hagos Ashenafi; Alemayehu BekeleThe 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.Item 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 AbebeThe 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 intrevtionItem 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 AbebeThe 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 controllntcnCnllonItem Studies on prevalence of trypanosomosis and drug sensitivity on trypanosome congolenes in Wolayita and Dawero zone of Southern Ethiopia(2007-06) Miruk Assefa; Hagos AshenafiThe 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.Item Study on Concurrent T. Congolense and H. Contortus Experimental Infection in Goats: Interaction and Pathogenic Effects(AAU, 2006-06) Abebayehu Tadesse Wazza; Hagos AshenafiStudy 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.Item 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 AshenafiBackground: 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.Item Trypanosoma Equiperdum: Venereal Transmission and Pathogenesis(2019-08) Ahmed Yasine; Hagos AshenafiDourine, 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