Tropical Veterinary Medicine

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Browsing Tropical Veterinary Medicine by Author "Ademe Zerihun"

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    Across- Sectional Study of Bovine Mastitis in and around Bahirdar and Antibiotic Resistance Patterns of Major Pathogens
    (Addis Ababa University Faculty Of Veterinary Medicine, 2004-06) Gizat Almaw; Ademe Zerihun
    Three hundred fi fty one (J 95 local zebu and 156 Holstein x Local Zebu) lactating cows of smallholder private farms in Bahir Dar milk shed were examined from September, 2003 to March, 2004 (0 determine mastitis prevalence, isolate pathogens involved, evaluate the antibiotic susceptibility profi les and [0 evaluate somatic cell count in identifying intramammary infections. Clinical prevalence was detemlined through examination of abnomlalities of milk, udder or cow. Cal ifornia mastitis test (CMT) and culture were used for subclinical mastitis determ ination. Agar disc di ffusion was used for antibiotic susceptibility test. Somatic cell count was conducted following standard procedures described In International Dairy Federdtion for enumeration of cells with direct Microscopic method. Clinical prevalence at cow level was 3.9% in crossbreds and nonc in local zebu breeds. Subclinical mastitis at cow level based on CMT was high (34.4%) in crossbreds compared to indigenous zebu (17.9%) (p < 0.05). Quarter subclinical prevalence based on eMT was 17.90% and 4.95% for crossbreds and local zebu. respectively. Among potential risk factors considered, stage of lactation, parity and breed were found 10 afTecI the occurrence of mastitis significantly (p < 0.05). The pathogens isolated from mastitic milk were coagulase negalive staphylococci (eNS), s. aureus. Srr. agalacliae. Sir dysgalactiae. Srr. uberis. Micrococcus species, C. bovls. A. pyogefls, B. cereus, and S. illtermedius. Among these, the most frequent isolates were eNS (49.6% of the 10lal isolates). S. alirellS (17.9%), Srr. agalacliae (8.2%) and SIr dysgalacliae (6:7%). Seven antibiotics including sulfi soxazole. tetracycline, erythromycin. oxacillin, chloramphenicol, cJindamycin, and streptomycin were tested on 81 isolates. Except for streptomycin, all isolates \\ere sensitive to all antibiotics. All isolates were most sensitive 10 sulfisoxazole. Staphylococcw; allreus was susceptible to all drugs except streptomycin. SllIphylococcus Ollreus was 91.7% susceptible to oxacillin, however, CNS were less susceptible (68.2%) ill vilro. To evaluate somatic cell count (SeC) in identifying imramamary infection for crossbreds. 10 cutoff poims between 100000 cellsl ml and 300000 celJSJml were evaluated for their sensllivity and speci-ficity in comparison with cultural results. Similarly, cutoff points between 80000 cell ml and "250000 cell ml were taken for local zebu breeds. The sensitivity for
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    Retrospecitve and Cross-Sectional Investigation of Rift Valley Fever in Small Ruminants in Pastoral Areas of Ethiopia
    (Addis Ababauniversity, 2004-06) Melesse Balcha; Ademe Zerihun
    Rift Valley Fever Disease is a peracute or acute, febrile, mosquito-borne, zoonotic disease characterized by high rates of abortion and neonatal mortality. It occurs primarily in sheep, goats and cattle. It is a zoonotic disease causing an unexpectedly very high numbers of cases and deaths. It is caused by Rift Valley Fever Virus of the Bunyaviridae family and genus Phlebovirus. Due to the epidemics in Saudi Arabia and Yemen, in September, 2000 export trade of live animals from east African countries, including Ethiopia, was banned by the Gulf countries due to fear of importing risk of Rift Valley Fever. In some of the countries the disease was identified but in others like Ethiopia there was no evidence of the disease, except suspicion and inability of the country to prepare scientific evidence on the situation of the disease. In response to this and to safe guard its population a National surveillance strategy had been launched in 2001 and is being implemented, though it hadn’t generated an official report. The ban affected the country as a whole but there were parts of the community affected more, the pastoralists and investors in the sector. The pastoralists provide about90% of the export animals particularly small ruminants. Therefore this survey was proposed in September 2003, with the aim to support the surveillance programme by generating a scientific report from the pastoral areas through determining the sero-prevalence of RVF in the small ruminants and detecting the risk factors associated with. Across-sectional and retrospective survey was conducted on 1176 sheep and goats sera to detect anti-Rift Valley Fever Virus IgG and IgM antibodies using indirect ELISA. All the samples were collected in 1999 and the year 2003/2004 from Afar regional state and Borana zone. Of the total 900 sera tested, for cross-sectional survey, 29 (3.22%) were found positive to IgG antibodies; but 30 samples including the 29 IgG positives, tested for the detection of IgM were with no any positive. Because the serum samples used for the retrospective survey were tested in the year 2000 with an ELISA kit that have many limitations that resulted in high false positives; therefore, a retest of 246 sera including 142 previously positives resulted in only 32 (22%) positives reducing the previous prevalences of the total sera from 17.9% (142/820) to 3. 9% (32/820). The recalculated respective prevalence of Afar and Borana was 2.6% (13/500) and 5.9% (19/320). The respective prevalence by the previous kits was 12.8% and 24.4%. XI The cross-sectional survey prevalence is 3.2%, 4% and 2% for the total sero, Afar region and Borana zone, respectively. Prevalence showed increase in Afar while there was a decrease in Borana. The risk factors found significantly with sero-positivity were species of animal, living in irrigated land and areas found near permanent water sources and with flooding problems by univariate analysis of risk factors but only animal species, distance from permanent water sources and flooding. The age-specific sero-prevalences analyzed based on positives predictive value of the test revealed that there was no any indication of viral activites within the last four years. The geographic distribution of the sero-positives was mapped using a georeferenced data and the sero-prevalence data. The predicative value of the test was less than 50%, ranging form 33.4% to 50%, therefore, it will be erroneous to give any conclusion on the situation of the infection or disease in the country based on this serology with out any supportive confirmatory diagnosis of the causal agent either from vector or vertebrate host .
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    Serological, Pathological and Bacteriological Investigation of Mycoplasma Infection in Goats Slaughtered at Elfora Export Abattoir, Debre Zeit
    (2006-06) Daniel Gizaw; Ademe Zerihun
    A cross sectional study of contagious caprine pleuropneumonia in goats was conducted from October 2005 to March 2006; to determine seroprevalence, pathology and Mycoplasma species involved in pneumonic lungs of goats slaughtered at ELFRA export abattoir. Laboratory work was carried out at National Veterinary Institute (NVI). A total of 704 sera were collected from goats that purchased from Awash (n= 224), Dire Dawa (n =200) and Borana (n =280). Using the Complement Fixation Test (CFT) an overall prevalence of 48.3% (95% CI 47.4 -52.1%) was obtained. The prevalence in Awash, Dire Dawa and Barana were 47.3% (95% CI 41.2- 54.3%), 44.5% (95% CI 38.1-51.9%) and 51.8% (95% CI 46-58%) respectively. There was no significant difference (p>0.05) in seroprevalence among three origins, as well as no statistical significance (p>0.05) among individual ages of goats. A serial c-ELISA was also conducted on CFT positive sera; accordingly an overall prevalence of 11.8% (95% CI 8.8 - 15.7%) was recorded. Seroprevalence in Awash, Dire Dawa and Borana were 17% (95% CI 11.1 - 25.9%), 5.6% (95% CI 2.4 - 13.2%) and 11.7% (95% CI 7.5 - 18.3) respectively. There was significant difference (p<0.05) in individual age of goats using c-ELISA. Further more, there was marginally significant difference (p<0.05) among the three origins. Lower seroprevalence was recorded in both tests in goats of Dire Dawa origin. Of the 704 lungs of goat examined for gross pathological lesions 94 (13.4%) had lung lesions of which 33 (14.7%), 18 (9.0%) and 43 (15.5%) were from goats that originated from Awash, Dire Dawa and Borana respectively. The prevalence of lung lesions didn’t various significantly (p>0.05) among their origins. However, prevalence of lung lesions within individual ages of goats was significantly different (p<0.01). Of total 94 pneumonic lungs and 4 thoracic fluids cultured on Hayflik’s solid and liquid media, Mycoplasma was isolated from 15 (16%) pneumonic lung lesions. The Mycoplasma species identified includes: - M. mycoides subsp. mycoides Large colony (MmmLC), M. agalactiae, M. capricolum subsp. capricolum (Mcc), M. capricolum subsp. capripneumoniae (Mccp), M. ovipneumoniae and M. arginini. The isolation of pathogenic Mycoplasma species of Mccp and M. agalactiae from apparently healthy slaughtered goats could be an indication of chronic carrier, which might have spread the organisms throughout their way to the slaughterhouse.