Veterinary Epidemiology

Permanent URI for this collection

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

Browse

Now showing 1 - 7 of 7

Epidemiological and Clinico-pathological Study of Maedi-visna Virus Infectio in Sheep in Selected Districts of the Amhara National Regional State, Ethiopia
(AAU, 2004-06) Tsega Fentie ; Ademe Zerihun
An epidemiological clinical and pathological stud of aedi-Visna virus (MVV) infection in sheep \vas carried out in highland areas of the Amhara ational Regional State (ANRS). The purpose of the stud \ as to estimate the pre alence and distribution of the disease and identi associated risk factors \vith the occurrence of the disease. A total of 2417 serum samples \vere collected from smallholder farms (n = 1491 and sheep breeding ranches (n = 926) from ~oyember 2003 to February 200 . Indirect-Enzyme Linked Immunosorbent Assa i-ELISA) and Agar Gel Immunodiffusion (AGID) tests were employed to determine the presence of antibodies against infection. All sheep sampled \vere clinically investigated \,here as fe\\ seropositive sheep '\ ere slaughtered and examined for gross lesions and histopathological pictures. The apparent seropre alence of infection was found to be different between the management types; 6.6% (95% CI = 5.4 - 7.9) in smallholder farms and 30% (950/0 CI = 27.1 - 33.1) in sheep ranches. The difference in pre alence between the two sheep management types among ranche~ and eredas was statistically significant (P < 0.001). The prevalence of infection increased 'th increasing flock size and found to be higher in ranches (82.6% than in the smallholder farms 18.8% . The breed related seropre alence aried from 16% in indigenous sheep to .6% in Awassi sheep. The age-specific seropre alence increased with the age of sheep from 2.8% in yearlings to 6.5% at 7 years old. F10ck size, breed, age and contact v. ith ranch sheep were significant (p < 0.0001) risk factors associated with the o curren e and transmission of infection. In clinical disease in estigatio~ 31 out of 3 8.3%) seroposi ti e sheep were found to express the clinical disease. Among the seropositi es with 0 ert clinical disease, 96.8% \ ere from sheep ranches \"hile 3 .2% from smallholder farms. There \\ as statistically significant ¥ 8.3' d.f = l ' P < 0.001 association bemeen the clinical disease and the seropositivi . The clinical disease increased \vith age of animals. The large proportion of the clinical disease in ranches and older animals \\ as associated ,vith the flock management and high Ie el of infection. The clinical disease ,vas significantl different among sheep breeds (P<0.05), higher in Indigenous enz breeds than the \yassi and their crosses. C inical manifestations with respiratory symptoms ( 5.2% \\ ere folIo ed b progressi e emaciation (16%). ecrops) VIII examination revealed focal and diffused consolidation of lungs, broncho-interestitial pneumonia. The histopathological investigations with peribronchiolar and perivascular mononuclear cell infiltration, smooth muscle and lymphoid hyperplasia and thickening of the alveolar septa indicated the progressive interstitial pneumonia characteristic of MVV infection. The serological, clinical and pathological findings suggested that MVV infection is a major health problem in highland sheep of the ANRS. The ranch management and husbandry practice consisting o~ large flocks and high proportion of older animals has contributed for the occurrence and spread of MVV in a higher rate in ranches than in smallholder farms. The sheep ranches are considered major sources for the spread of MVV infection to the smallholder farms. The findings of MVV antibodies in areas hypothetically considered free is suggestive for poor knowledge and misdiagnosing of the disease. The serological test agreement between ELISA and AGID found to be almost perfect and this would encourage the use of the two tests in combination for accurate serological diagnostics in the control of MVV infection.
Epidemiological Survey of Contagious Caprine Pleuro-Pneumonia in South OMO and Gamo Goffa Zones, Southern Ethiopia
(2005-06) Solomon Mekuria; Ademe Zerihun
Cross-sectional study was conducted in South Omo and Gamo Goffa zones of Southern Nations Nationalities and People Regional State from September 2004 to February 2005 to determine seroprevalence and associated risk factors, isolate the causative agent, evaluate test agreement, and validate community perception. A multistage sampling was used in pastoral and mixed production systems. A total of 1033 goats’ and 80 sheep’s sera were collected for serological study. Additionally nasal swabs, lung tissue and thoracic fluid were collected from sick goats and all samples were submitted to National Veterinary Institute for isolation. Participatory disease search in pastoral area and questionnaire survey in mixed farming area were conducted. Proportional piling and matrix scoring were used to characterize major diseases of goats including their causes and signs. Based on the CFT results seroprevalence was vary among selected woreda. In Hammer and Benna tsemay woreda it was almost equal 15.5%, whereas in Boreda (32%) and Arbaminch (23%) was observed. The overall mean seroprevalence in study area was16.5%. There was no significant difference observed in seroprevalence among age groups, even though seroprevalence increases as the age increases. Pastoral and mixed farming area showed 15.5 and 18.4% seroprevalence, respectively. However, seroprevalence obtained using cELISA showed significant difference between production systems, age category and flock size category by univariate analysis (p<0.05). The overall mean seroprevalence was 57.3%. Based on cELISA the mean seroprevalence at flock level was 90.3 %( n=58) in mixed and 100% (n=15) in pastoral production systems. Compliment fixation test result, using Mycoplasma capricolum sub sp. Capripneumoniae and Mycoplasma mycoides sub sp. mycoides Small colony antigens, showed substantial agreement with Kappa value of 0.62 and 0.78, in goats and sheep, respectively. The test agreement between CFT and competitive Enzyme Linked Immuno Sorbant Assay was negative with Kappa value -0.014 in goats and -0.005 in sheep. Using multivariate analysis production systems were not statistically associated (P>0.05) with seroprevalence except flock size and age category greater than 4years (P<0.05). Mycoplasma capricolum sub sp. capripneumoniae was isolated from specimen submitted to the laboratory. Contagious Caprine Pleuropneumonia (Sompo) was ranked as the first disease of goats in pastoral area. Local perception of disease causes, disease signs, and seasonal calendar were described. Matrix xii scoring between groups (n = 12) and individuals (n = 44) revealed that disease signs and disease causes showed weak, moderate and good agreement by Kendall’s coefficient concordance (W=0.21-0.99). Questionnaire survey in mixed farming area revealed that Contagious Caprine Pleuropneumonia was ranked first and introduction of sick goat into the flock considered as main source of infection. In this study participatory disease search, questionnaire survey, bacteriological, serological and postmortem findings substantiated each other and it is possible to conclude that Contagious Caprine Pleuropneumonia is a major disease of goats in the area. Participatory disease search shows indigenous knowledge used to generate more information with minimum cost, local materials and within short period of time. High seroprevalence result in sheep indicates that this species is a potential carrier of the causative agent. Therefore, appropriate control measures have to be implemented to mitigate the problem in the area. At a time of control measure attention must be given for sheep as itcould be a source of infection. Detailed study need to be conducted as to the role of risk factors for prevailing of the disease. Diagnostic kits need to be evaluated further based on this study finding.
Epidmiology and Zoonotic Importance of Bovine Tuberculosis in Selected Sites of Eastern shoa Ethiopia
(Addis Ababa University Faculty Of Veterinary Medicine, 1998-01) Tade!e Kiros; Ademe Zerihun
A. survey was conducted In De bre Zeit and .-\ddis Ababa. from Jo.nu:!ry to October. 1997 in canle and human tuberculosis patients to study thl;! epidemiology or bO\Jne tuberculosis and to assess the role of J! hOlliS in human T8 cases re spectively. The methods applied wefe comparative intradermal tuberculin te st. postmortem diagnosis. cul tural examination. biochemical te:m and questionnaire su rve::v on human TB p:ltients and 'Jlry farm \\"o rkers. A to tal of 788 anim:tls \\ere subjected to the comparatj\e intradermal :uberculin test (C lOT) resulting In 2.3Qo o pOSHl\e and 5.81)'0 doubtful reacWrs. Th ere \\as a slgmricant difference In pre\ alenee between tiums sites ranging fr om -J. .2° 0 to 90.8°0 mcludin.,; the doubtful reactors , I,Z~ test. p
Oral Newcastle Disease Vaccination Trials and Studies of Newcastle disease In Ethiopia
(AAU, 1998-01) Mohammed Nasser; Ademe Zerihun
Oral Newcastle Disease Vaccination Trials and Studies of Newcastle disease In Ethiopia ==Three laboratory trials Wert: conducted in commercial broiler chickenst to determine efficacy of the heat-resistant NDV-12 vaccine (similar to V4 vaccine). and to compare the NDV-I~ vaccine with conventional vaccines (HBI and LaSola). Sorghum and barley were tested for their suilabiJity as vaccine carriers for oral administration. Further one eight field isolates of NOV were tested for their pathogenicity and nine ND outbreaks between 1983 and 1995 in state poultry farms in Ethiopia were studied retrospectively. In the vaccination Trials, chickens were vaccinntcd twice or three timcs with NDV-i2 and conventional vaccines via the ocular and/or the drinking water route, and via feed with parboiled and untreated barley and sorghum as carriers. Sera were collected al wekly intervals up 10 the end of the triias and were tested for haenugglutinatioll.inhibition (Hi) activity. The protcection level was assesse'-lebratu d by challenging the chickens intramuscularly by a locatly isolated velogenic strain of NDV
The Status of Bovine Tuberculosis in Selected Areas of North Gondar Administrative Zone, Ethiopia
(2006-06) Mohammed Ali; Ademe Zerihun
Mycobacterium bovis (M. bovis) is one of the members of Mycobacterium tuberculosis complex, which infects both animals and man causing mammalian tuberculosis. A cross sectional and case control studies were conducted in Dembia and Gondar districts of North Gondar from September 2005 to April 2006 to determine the prevalence of bovine tuberculosis (BTB) and associated risk factors and assess the sources of infection of human tuberculosis (HTB). In the cross sectional study, cattle from extensive (310) and semi intensive (315) production systems were tested with the comparative intradermal tuberculin test (CID). In the case control study design, 50 human tuberculous patients (cases) and a similar number of patients visiting the hospital for some other health problems other than tuberculosis were interviewed about their hygienic practices, feeding habits and cattle management practices that would contribute to the transmission and maintenance of the disease. From each of the cases and control groups, 200 cattle owned or attended by them were tested with the CID test. Of all 1025 animals examined, 21% were positive. In the cross sectional study, assuming doubtful reactors as negative, prevalence was higher (16.8%) in semi-intensive production system than extensive (11.6%) and this difference was significant (p<0.05). Herd level prevalence was 37.7% and 56.3% in extensive and semi intensive production systems, respectively. It was also significant (p<0.001) between poor and good cattle management practices; cattle under poor management were 3.4 times more likely to be infected with BTB than those under good management. Other factors which were significantly (p<0.05) associated with prevalence were production system, breed, age, sex and body condition. In the multivariate logistic regression analysis, production system and management were significant (p<0.05). In the case-control study, out of the 200 animals tested that are owned by tuberculous human patients, 40 (20%) and from the same number of animals owned by non-tuberculous control groups, 22 (11%) were positive for the tuberculin test. The differences in prevalence of BTB in cattle owned by human TB cases and control group were significant (2=98.90, p<0.001). Of 50 TB cases, 66% and 34% were diagnosed as pulmonary and extra pulmonary tuberculosis, respectively. About 86% of the patients consume raw milk and milk products. The majority (58%) of HTB patients are between the ages 15 and 45 while 24% and 18% were below 15 and above 45 years, respectively. Cattle owners who consumed raw milk were at higher risk (OR = 14.33) of being infected with tuberculosis than those who consumed boiled milk. From the questionnaire survey, significant associations (p<0.05) with VIII cases were found when patients had physical contact with other clinical cases, drinks raw milk (2 =32.18; P<0.001) and are farmers compared to similar variables in the control group (2=25.01; P<0.001). In the bacteriological examination, Mycobacterium species were isolated from 26 (47.3%) sputum, 2 (15.4%) fine-needle aspirates (FNA) and 1(14.3%) peritoneal fluid of humans and 7 (7.1%) of 99 milk samples. The majority (88.5%) of sputum isolates were M. tuberculosis, and only one isolate (3.8%) was M. bovis while one isolate from milk was M. tuberculosis. Atypical mycobacteria were isolated from sputum (2), FNA (1) and milk (2). Among the isolates, 79.4% (23/29) and 10,3% (3/29) of the human isolates were M. tuberculosis and M. bovis, respectively. The rest 10.3% (3/29) were other mycobacterial species. On the other hand, 14.3% (1/7) and 57.1% (4/7) of the cattle isolates indicates were M. tuberculosis and M. bovis, respectively. The rest 28.6% (2/7) were other mycobacterial species. The findings in this study demonstrate the importance of BTB as a major health risk and cattle being one of the most important sources of infection. The findings of the present study using comparative intradermal tuberculin test and cultural examination of samples from humans and animals have shown that cattle may be important sources of infection to humans particularly of M. bovis infection.
Status of Dermatophilosis in Urban and Periurban Indigenous and Crossbreed Cattle in Bahir Dar and Debre Berhan Towns
(2005-06) Meseret Admassu; Ademe Zerihun
A cross sectional study of bovine dermatophilosis was undertaken on a total of 2284 cross-bred and 4628 indigenous cattle in urban and periurban areas of Bahir Dar town (mid altitude) and Debre Berhan town (high altitude). The majority (1590 local and 138 cross-bred) animals were found in mid-altitude while 724 local and 1004 crossbreed were found in high altitude representing Bahir Dar and Debre Berhan, respectively. Skin lesions were found in 2.4 % of animals examined out of which Dermatopholus congolensis was isolated from 22.6 (%). There was a higher prevalence (1.62%) in wet period than (0.46%) in dry period; (5.4 %) in cross-bred than (0.66) local breed cattle; (2.65) A. variegatum infested cattle than (0.44%) in A. variegatum none infested cattle, and (1.24%) in adult than (0.79 %) in young cattle with statistical significant (P< 0.05) difference between them in mid-altitude. There was also high prevalence (1.04%) in mid-altitude than (0.03%) in high altitude of the two seasons with a statistical significant (p < 0.05) difference, but a high prevalence (1.74%) in male than (0.77%) female with none statistical significant (p> 0.05) difference. According to the result obtained significantly associated risk factors with dermatophilosis have a high influencing contribution on the occurrence of the disease in the studied area (urban and periurban of Bahir Dar town).
Study on Mycobacterium Bovis Infection in Umans and Animials in North West Shoa Zone, Oromia National Regional State
(AAU, 2005-06) Alemayehu Regassa; Ademe Zerihun
A case control study was conducted between October 2005 and April 2005 to assess the My cobactium bovis and other Mycobacterium complex infection In callie and Their respective owners in selected districts of North Shoa Zone of Oromia National Regional State. Central Elhiopa. A total of 174 cattle owners (87 tuberculosis cases and 87 controls). And 1041 heads ofeanlc (506 owned by cases while 535 owned by controls) were included In the Study. The methods used were comparative interademlal cervcal tuberculin test (CIDT). Mycobacteriology. Acid fast staining. Chest x-ray, biochemical tests and drug suscepllbility Test. The prevalence of tuberculosis was significantly (x2=48.4, P<0.001) higher In cattle Owned by tuberculosis p atjems (24.3%) than in cattle owned by controls (8.6%), and thus. Cattle owned by a tuberculosis patient was about four times more hkeily to be infected (Odds Ratio. OR=4.2 ,95% CI= 2.79.6.2)with tuberculosis than cattle owned by a tuberculosis free Owvner. Funher. Cattle owners who consumed raw milk were at higher risk (x2=14.12, P<0.001,OR=3.34)Of acquiring tuberculosis than those who consumed boiled milk. The Prevalence of Tuberculosis in canle was significantly higher in exotic breeds( x2=101.3, P<0.05,OR =74) Animals older than 4 years (x2=39.2, P<0.001, OR = 5), and animals in poor physical condition (x2-15.3, P<0.003, OR = 2.S). Of the 42 human isolates, 31(73.8%) were ,Mycobaclerlunt Tuberculosis. 7 (16.28%) were Mycobacterium bovis while 4 (9.S%) \were atypical Mycobacteria as demonstrated by biochemical and drug se nsitivity tests. On the other band. Of The II cattle Isolates, 2 (18.1%) were M. Tuberculosis. 5 (45.5%)M bovis and 4(36A%) were Atypical mycobacteria. In conclusion. The results of the present study showed the transm ission Of mycobacterial species between cattle and their Owners.

Browse

Browsing Veterinary Epidemiology by Author "Ademe Zerihun"

Results Per Page

Sort Options