Veterinary Microbiology

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Study on Bacterial Pathogens of Fish in Southern Gulf of Lake Tana with Special Reference to Aeromonas Hydrophila and Edwardsiella Tarda
(2007-06) Anwar Nuru; Bayleyegn Molla
A bacteriological study was conducted from September 2006 to March 2007 to estimate the occurrence and distribution of important Gram-negative bacteria with special reference to Aeromonas hydrophila and Edwardsiella tarda from the kidney and intestine of apparently healthy fish and their aquatic environment in the southern gulf of Lake Tana and carcasses of filleted fish (from commercial enterprises and local dealers) in Bahir Dar, Ethiopia. From a total of 510 swab samples taken from the kidney and intestine of 255 apparently healthy fish, different bacterial species, which belong to the family Aeromonadaceae, Vibrionaceae and Enterobacteriaceae were isolated and identified. Among the isolates Aeromonas (A.) hydrophila (7.1%), Aeromonas (A.) caviae (9.8%), Aeromonas (A.) sobria (15%), Edwardsiella (E.) tarda (2%), Vibrio spp (7.8%), Yersinia (Y.) ruckeri (3.1%), Edwardsiella (E.) ictaluri (1.2%) and atypical strains of Aeromonas (A.) salmonicida (13%) were isolated in both the kidney and intestinal samples. Proteus (P.) mirabilis (5.9%), Enterobacter (E.) aerogenes (5.1%), Plesiomonas (P.) shigelloides (4.3%), Yersinia (Y.) enterocolitica (3.1%), Escherichia (E.) coli (2.4%), Klebsiella (K.) pneumoniae (2.4%), Proteus (P.) vulgaris (1.6%), Shigella (S.) sonnei (0.8%), Citrobacter (C.) diverses (0.4%) and Citrobacter (C.) freundii (0.4%) were isolated only from the intestine of fish. From carcasses of filleted fish A. sobria constituted 13.2% of the total isolates followed by A. caviae (9.6%), atypical strains of A. salmonicida (6.4%), Y. enterocolitica (4.8%), A. hydrophila (3.6%), E. coli (2.4%), P. mirabilis (1.6%), C. diverses (1.2%), P. shigelloides (1.2%) and Vibrio spp (0.8%). Out of 62 water samples, 47 (75.8%) were positive for Aeromonadeceae and Enterobacteriaceae. All the bacterial species, which were isolated from the water samples, were also recovered from fish. Indicators of water pollution bacteria such as A. caviae and E. coli were more frequently isolated from sampling stations found in inshore littoral zone than stations found in sub-littoral and pelagic zones that are situated relatively far from the point source pollutions and hence less likely to be exposed to pollution. XIII From the results of the present study it was concluded that the intestine of fish have been found to be harboring a large group of bacterial species that may be a resident and/or transient microorganism. Isolation of similar types of bacteria from the fish, filleted fish and their aquatic environment has been recorded during the study period. The detection of similar bacterial species both in the fish and the water samples has some implications on the relationship between the fish and their aquatic environment (even though it requires some molecular characterizations of both isolates). Some of the bacterial isolates including Aeromonas hydrophila and Edwardsiella tarda are opportunistic pathogens of fish and may cause mortalities when the fish come under stress. Furthermore, the recovery of various organisms, which are potentially pathogenic to humans, in the kidney and alimentary tract of fish, and/or carcasses of filleted fish suggested that fish either improperly handled, undercooked or consumed raw might cause various diseases to susceptible individuals.
Comparison of Clinical Trials of Bovine Mastitis with the Use of Antibiotics and Honey
(2007-06) Tamrat Tomas; Moorthy
A total of 423 representative randomly selected Holstein, Jersey and local zebu lactating cows located in Wolaita zone at Soddo Zuria Woreda of Southern Nation Nationalities and Peoples Regional State were examined. All the 46 lactating cows of Soddo dairy farm, 11 lactating cows from Soddo Veterinary Clinic, 103 lactating cows from urban dairy holders and the rest 263 were X randomly selected lactating dairy cows from 18 rural Kebeles were included and tested to determine the prevalence of mastitis by using mastitis detecting BOVI-VET (RUUSE, DENMARK), indicator paper and white side test. Milk samples were cultured from 329 cows infected with different grades of mastitis. Examination for mastitis infection in Soddo Zuria Woreda revealed that there were 99 (23.4 %) clinical and 230 (54.3 %) sub clinical cases. Out of 423 cows 99 clinical cases and 230 sub-clinical cases were recorded and grouped into grade I, II, III, IV level of infection and only clinical cases were subjected to antibiotics and honey intramammary infusion treatment. The prime objective of the study is to examine the safety and efficacy of honey compared to a known antibiotic infusion in lactating mastitic cows. Minimum Inhibitory Concentration (MIC) of honey was determined by using different dilutions and different species of bacteria available at the microbiology laboratory of FVM. And it was revealed that minimum concentration of honey that inhibited E. coli was 10 %; L. monocytogenes and K. pneumoniae inhibited at 20 %; Staphylococcus and Streptococcus spp, were inhibited at 30% concentration, where as Micrococcus spp. at 40 % concentration. Salmonella enteritidis was resistant (shown growth in all concentrations). Out of ninety-nine clinical cases, forty-eight cases were treated with antibiotic (Multiject IMM.) infusion and fifty cases were treated with Beza honey. Milk samples from the cows identified and recorded for treatment trial groups were re-cultured within one month post-treatment. Cases included in the analysis had at least one mastitis pathogen isolated from the initial milk samples. Overall bacteriological cure rate of treated cases was 54 % (53 of 98). The effectiveness of honey in clearing bacterial infection in the intramammary infusion for mastitis treatment revealed similar to antibiotic (54.2% (Multiject IMM.) treated cases. Antibiotic and non-antibiotic treatment responses were associated with grade of affection. Honey treatment was more effective 78.1% in grade III type of mastitis when compared to treatment of grade II type of mastitis (11.1%); where as multiject was more effective in grade II type of mastitis (41.9%) and slightly less curative rate (76.4%) for grade III type of mastitis when compared to honey. The present study indicated that honey treatment could be an alternative treatment to antibiotics so that indiscriminate use of antibiotics and emergence of antibiotic resistance strains of microorganisms could be avoided and at the same time financial benefits can be obtained. Treatment with honey is more economical i.e.7-8 times cheaper than the available mastitis treatment drugs in the country. As an alternative to antibiotic treatment for XI mastitis, 10 ml of 40% honey intramammary infusion for each quarter for 3 consecutive days can be tried.
Study on Sheep Brucellosis in Selected Woredas often Eastern Amhara Regional State, Northeastern Ethiopia
(2008-06) Shimeles Abegaz; Muniyappa
A cross-sectional study was conducted in South Wollo, North Wollo and North Showa Zones of the Amhara Regional state, between octobrr, 10, 2007 to march 1, 2008,with the objectives of determining the seroprevalence distribution and magnitude of brucellosis in sheep and identifying the potential risk factors associated with diseases. Two strata sampling methods were employing, sheep flock in extensive production (n=1838) and sheep flock in intensive production system (n=571) , with an overall serum sample of 2409, collected from sheep above 06 months of age without previous history of vaccination. The overall seroprevalence obtained by Rose Bengal Test was 4.98% (n=120), the 120 positive sera by RBPT was subjected to the Complement fixation (CFT) and 118 (4.89%) sera become positive for antibodies to brucella infection.. The subsequent analysis were based on the 4.89% (n=118) sera that were positive to both the RBPT and CFT (serial interpretation) test results. In the current study, a flock and individual level seroprevalence for brucella antibodies were conducted. A flock was said to be positive if at least one animal reacted positively by the test. The overall individual and flock level seroprevalence for brucella antibodies in sheep were 4.89% (n=118) and 22.26% (n=274) respectively. Analysis of the findings among the two production system indicated significant difference in both individual (p<0.05) and flock level (p< 0.05) seroprevalence. Brucella seroreactor female and male sheep vary significantly in the extensive production system (p<0.05) compared with intensive production system (p>0.05%). Analysis of the findings among different age groups indicated the existence of a significant difference (p<0.05) in extensive production, whereas in intensive production statistically no significant difference (p>0.05). The existence of seroprevalence in the three flock categories shows significant difference (p<0.05) in extensive production, while no difference (p>0.05) in intensive production system. Concerning breed level seroprevalence for brucella antibody in both production system reveal significant association (p>0.05). Moreover, this study was also assessed the association of reproduction and production performance in relation to brucella infection. Generally the present study disclosed the importance of brucella seroreactor sheep in the study areas, hence, care should be taken and warranting more focused investigation, so as to support intervention efforts in the region.
A Study on Bovine and Human Brucellosis in Urban Areas and in Cattle Breeding Centers, Northwestern Amhara Region, Ethiopia
(2008-06) Taddesse Yayeh; Girma Zewde
A cross-sectional study was conducted from October 2007 to March 2008 in urban areas (Bahir Dar and Chagni towns) and in cattle breeding centers (Andassa Livestock Research Center and Metekel Cattle Breeding and Improvement Center) to determine the seroprevalence and to identify potential risk factors associated with bovine brucellosis, to find out its association with reproductive disorders and to assess the public health hazard. Sampling units were selected by one-stage cluster sampling method. Samples were tested serologically for brucellosis and questionnaire data was collected. In cattle breeding centers, all eligible cattle were sampled. Sera of 2,224 cattle from 183 herds were subjected to Rose Bengal Plate Test and those positives were further tested by Complement Fixation Test. An overall individual and herd level seroprevalences of 0.49% (11 of 2,224) and 4.9% (9 of 183), respectively were found. Statistically significant difference in seroprevalence was found between urban areas 1.1% (5 of 443) and cattle breeding centers 0.3% (6 of 1,781) (P< 0.05). The potential risk factors such as sex, age, breed, parity, herd size, pregnancy status and source of replacement stock were not significantly associated with brucellosis seroprevalence. Among the reproductive disorders, abortion was significantly associated with seroprevalence of brucellosis (P<0.05). Furthermore, management and husbandry risk factors were not significantly associated with brucellosis seropositivity. Out of 79 individuals tested for human brucellosis, 6.3% (5) were positive seroreactors. However, there were no statistical associations between brucellosis and potential risk factors (occupation, sex, age, consumption of raw milk and raw meat as well as contact with fetal membrane). In conclusion, the seroprevalence of bovine brucellosis in urban areas and in cattle breeding centers was very low. Thus, slaughter of positive reactors and enhancing the management and husbandry practices were recommended.
Epidemiological and Microbiological Studies on Calf Diarrhoea and Pneumonia in Debre Zeit, Holeta and Muke Turi Dairy Farms, Ethiopia
(2008-06) Yenehiwot Berhanu; Moses N Kyule
A six-month prospective study was conducted in Holeta, Debre Zeit and Muke Turi dairy farms between November, 2007 and April, 2008 with the major objective of determining both the cumulative incidences of neonatal calf diarrhoea (NCD) and pneumonia. In addition, determination of calf mortality rates, identification of agents of NCD, pneumonia and potential risk factors as well as determinations of the antibiotic sensitivity patterns of the bacterial pathogens. Cluster sampling was used. A total of 429 calves, from seven intensive dairy farms were followed up. The farms were described using a pre-tested questionnaire and personal observations. Study calves in each farm were visited weekly and appropriate test samples collected from diarrhoeic and pneumonic cases. Antigenic ELISA test was utilized to identify four major enteropathogens (rotavirus, coronavirus, Cryptosporidium parvum and E. coli K 99). Standard isolation techniques were used to identify Salmonella and other strains of E. coli from diarrhoiec cases (n=112) and Pasteurella species, Mannheimia species and Haemophilus somnus from pneumonic cases (n=28). In addition, the antimicrobial susceptibility pattern of the bacterial isolates was performed. The cumulative incidences (CI) of NCD in Holeta, Muke Turi and Debre Zeit dairy farms were 0.41, 0.63 and 0.37, respectively. While for pneumonia, they were 0.12, 0.09 and 0.07, respectively. Higher CI of NCD was recorded from Farm 1 with 0.65 followed by Farm 3 with 0.63. The least CI was observed in Farm 2 of 0.11. Highest calf pneumonia was observed in Farm 6 followed by Farm 1. No calf pneumonia was observed in Farm 5. Associations of the potential risk factors for NCD and pneumonia revealed significant results with young ages. Significant positive hazard rates of both diseases were recorded in young age-groups. Other risk factors (sex of calves, breed, etc) were not significantly associated with these diseases. The ELISA results showed that, C. parvum was prevalent in the majority of calves with diarrhoea followed by rotavirus, coronavirus and E. coli K 99. The bacterial isolates were 91.96 % of E. X coli other than the strain K 99 and 24.11 % of Salmonella species. Nasal swab samples taken for isolation of Pasteurella and Mannheimia species revealed 42.85 % positive reactors for Pasteurella and Mannheimia species. No Haemophilus somnus was isolated. Antimicrobial sensitivity test was performed for all the bacterial isolates. Norfloxacillin and gentamycin were highly sensitive and clindamycin the least sensitive. The susceptibility to other antimicrobial agents varied by different bacterial isolates, but resistance to all antimicrobials used were observed in most of the isolates. In conclusion, NCD is a serious problem among dairy calves followed by pneumonia. Both of them were influenced by the age of calves. These diseases have complex etiopathogenesis. Therefore, further epidemiological and microbiological studies of NCD and pneumonia with aims of designing and implementing appropriate prevention and control strategies are strongly recommended. In addition, the higher rate of antimicrobial resistance necessitates the strategic use of the drugs.
Study on Mycobacterium Bovis Using Conventional and Molecular Methods in Cattle Slaughtered in Kombolcha Elfora Meat Processing Plant
(2008-06) Desta Fekadu; Yilkal Asfaw
A cross-sectional study was conducted on 1138 heads of cattle at Kombolcha ELFORA meat processing plant, South-Wello Administrative Zone, Amarha Regional State from November 2007 to May 2008. The objectives of the study were to estimate the prevalence of bovine tuberculosis in cattle slaughtered at Kombolcha ELFORA meat processing plant, and to isolate and characterize the strains of mycobacteria from tuberculousis suspicious lesions. Detailed post mortem examination, bacteriological culturing, regions of difference-bases polymerase chain reaction and spoligotyping were used. The prevalence of bovine tuberculosis was 5.0 % (57/1138) in cattle slaughtered at Kombolcha ELFORA meat processing plant on the basis of detailed post-mortem examination. There was no significance difference in prevalence between male and female (P > 0.05), as well as among the age groups (P > 0.05). Mycobacteria were able to be isolated from 28 of the 57 cattle with gross lesion. A total of 49 isolates were recovered from the different tissues of these 28 cattle, and 20 isolates showed signal for M. tuberculosis complex species of which 19 were M. bovis while one isolate was M. tuberculosis. Further characterization of the strains of M. bovis using spoligotyping revealed the presence of five different cluster of spoligotyping pattern, which include Ethiopian M. bovis train 1, SB1176, SB0134, SB0133 and new strain. The binary number representation of the new strain is 1100000101010110111111111111111101111100000 where 1 indicates the presence of a spacer and 0 indicates a loss. The new spoligotyping was not reported previously from elsewhere to the M. bovis database (www.mbovis.org). The findings of this study indicated that tuberculous lesions were common in cattle slaughtered at Kombolcha ELFORA meat processing plant, and hence detailed post mortem meat inspection procedures are required to minimize the risk of its transmission to the public through meat consumption. In addition, appropriate cooking of meat is required before consumption.
Microbiological Study of Bacterial Cause Bovine Mastitis and its Antibiotics Suscebtibility Patterns in East Shoa Zone Oromia Regional State
(2009-06) Redeat Belayneh; Mniyyaapa
Mastitis is inflammation of mammary gland and primarily results from invasion of pathogenic microorganisms through teat canal. Mastitis has great effect on milk quality, production, composition and economy, and public health significance. Mastitic milk losses its appearance, flavor, maintenance of original nutritional qualities and has no long shelf life. Factors that influence infection rate with mastitic organisms are host factor, environmental factor and pathogenic factor. Mastitis can be classified as contagious and environmental depending on the source of infection. A variety of diagnostic tests can be employed to screen and detect mastitis, as well as to isolate and identify the causative agents. The study was conducted in east shoa zone Adama and Akaki woredas with the objectives of determining the prevalence of clinical and subclinical mastitis to identify risk factor of bovine mastitis, to isolate and identify the bacterial causes of bovine mastitis and to conduct in-vitro antimicrobial susceptibility test of isolated pathogens from September 2008 to 2009. For this study, 102 and 46 small holder dairy farms and 303 and 200 dairy cows were selected .by one stage cluster sampling in Adama and Akaki woredas respectively. Questionnaire survey was administered to the small holder dairy farm owners to collect data on clinical examination of animal and farm attribute. Farms inspection and clinical examination of cow was performed to associated mastitis with farm based factors and animal factors. California mastitis test (CMT) was used as screening for selection of culture samples for the cow under study. Strict aseptic producers were used when collected milk samples in order to prevent contamination with microorganism. The bacteriological culture was performed following the standard microbiological technique to diagnose the occurrence of clinical and sub clinical mastitis. All collected data analyzed by using descriptive statistics SPSS and Stata. In both the study farms the prevalence of clinical and sub-clinical mastitis were made at herd, caw and quarter level. Based on clinical manifestation for clinical mastitis prevalence and on California mastitis test for sub-clinical mastitis prevalence infections. In the result revealed that the prevalence of clinical mastitis at herd, cow and quarter level (15.6%, 5, 9% and 2.9%) and (17.3%, 3.0% and 1.5%) in Adama and Akaki respectively. X The prevalence of subclinical mastitis at herd, cow and quarter level (57.8%, 33.6%and 20.8%) and (60.8%, 25.0 % and12.7%) in Adama and Akaki respectively. The major isolates of pathogen in both areas from subclinical mastitis cases were S.aureus (26.8% and 34.8%), S.intermidiua (2.48% and 0.49%) ,CNS (18.7% and 20.9%) , St. agalactiae (5.77%and5.8%), St dysgalactaie (1.99% and1.16%), St uberis (4.47% and 1.16%) ,Bacillus Species (7.96% and9.3%), E.coli (6.46% and 6.98% ).and from clinical mastitis S.aureus (2.48% and 2.38% ), St agalactiae (_3.84% and 3.48%) in Adama and Akaki woredas respectivly . Regarding to association risk factor with prevalence of mastitis, the univariate logistic regression in cow level showed that among the risk factor considered, stage of lactation (p< 0.05), parity number (p< 0.05) and presence of teat lesion (p<0.05) significant effect of sub clinical mastitis in both woredas, milking mastitis cow last (p<0.05) in both woredas in herd level was significant effect .In considering multivariate logistic regression only stage of lactation had significant on sub clinical mastitis in both woredas in cow level. Regarding the antimicrobial tests comparing the over all efficiency (on all isolates) Gentamycine, Kanamycine, Chloramphenicol and Vancomycine were the most effective antibiotics were found susceptible in both woredas. Fallowing that Streptomycin and penicilline were effecective. The least effective drug was Bacitracine. Amoxaciline was also with relatively weak efficacy.
Isolation and Molecular Characterization of Mycobacteria From Infected Cattle in and Around Bako, Western Oromia, Ethiopia
(Addis Ababa University, 2010-06) Temesgen Ayana; Tesfaye Sisay; Gobena Ameni
A cross-sectional study was conducted on 858 heads of cattle (371 recruited from Bako Agricultural Research Center, BARC and 487 from Bako municipal abattoir) from October 2009 to April 2010 to estimate the prevalence of bovine tuberculosis (BTB) and characterize its causative agents. To this effect, comparative intradermal tuberculin (ClOT) test, post mortem examination, bacteriological culturing, genus typing using multiplex polymerase chain reaction (PCR) were applied. At the cut-off point of ~4mm (recommendation of the Office des International Epizooties, OlE), animal prevalence of BTB was 1.3%. Re-analysis of the same data using the newly defined cut-off point of >2mm gave a prevalence of 4.6%. There was a highly significant difference (P=O.OOO) in prevalence estimated using the two cut-off points in zebu cattle. The prevalence was significantly associated with age (P=0.012) and origin (P=0.04) of the animal. On the other hand, the prevalence was 9.3% (46/492) in cattle slaughtered at Bako abattoir. Lesions were more frequent and severe in the mesenteric (60.9%), retropharyngeal (17.4%), and bronchial (17.4%) lymph nodes of slaughtered cattle. Culture positivity in suspicious tissues was 32.6% (29/89) although only 69% (20/29) were confirmed to be acid-last bacilli (AFB) by Ziehl Neelsen staining. Of the 20 AFB positive isolates, 17 were characterized by multiplex PCR and almost all (94%) of the isolates showed signal for the Genus Mycobacterium. Nevertheless, none of these isolates showed signal for the Mycobacterium Tuberculosis complex as revealed by multiplexer. Therefore, further identification and characterization of these isolates should be done. Furthermore, the pathogenicity of these mycobacteria in livestock requires further investigation. Key words: Bovine tuberculosis, Prevalence, Pathology, Culturing, Molecular typing, Mycobacteria, Balm, Ethiopia.
Virological Investigation of Emerging Camel Disease in Ethiopia
(Addis Ababa University, 2010-06) Dejene Milkessa; Fufa Dawo; Tesfaye Sisay; Gelagay Ayelet
The dromedary of East Africa particularly, Ethiopia has been suffering from different diseases for the past so many years. Of the many diseases of camels that are rampant in the region, the recently emerged camel disease with still unknown causes is the single most important disease. This camel disease is the leading problem inflicting high morbidity and mortality among the camel population. To this effect, isolation and characterization of the causative agent has of paramount importance. This study was undertaken in the National Veterinary Institute laboratory, Debre Zeit, Ethiopia from October 2009 - June 2010 to isolate and characterize the viral agent from camel postmortem tissues collected during the outbreak of 2007 in Ethiopia. The study was conducted on the basis of cell culture, degenerate oligonucleotide primed polymerase chain reaction (PCR) and laboratory animal assay. Virus isolation was attempted for virus in Vero and Dubca cells; four specimens yielded cytopathic virus when inoculated onto the Vero cell culture. The cytopathic effect (CPE) consisted of round floating cells, giant cells, rounded refractive cells, ballooning of cells, sloughing, and some syncytia formation were observed from day two to day seven post inoculation. The appearance of the CPE was looking uniform among different purified tissue samples used for cell infection. The growth of virus was confirmed by degenerate oligonucleotide primed PCR in which amplification was recorded particularly, where extracted RNA was amplified, both from tissue and cell culture. The growth of the virus after storage in -20 DC for days was lost while it can grow from +4 DC and -85 DC in Vero cells. The cell culture suspension was injected to laboratory guinea pigs in which the animals were observed to develop abnormal clinical signs that resulted in death. Although many scientists suspected different known viruses for the cause of outbreak, the isolated virus was confirmed to be out of adenovirus, morbillivirus, parainfluenza 1-3 and respiratory syncytial virus groups. However, although the above known viruses were excluded, a variant of the above viruses that can skip detection using previously known primers and other emerging viruses might not be excluded. Key words: Came l, Cell culture, Emerging disease, Molecular diagnosis, Viral etiologies, Virus isolation.
Isolation and Characterization of Mycobacterial Species Causing Tuberculosis Lesions in Slaughtered Camels in Eastern Ethiopia
(Addis Ababa University, 2011-06) Kaleab Zerom; Tesfaye Sisay; Gobena Ameni; Gezahaegne Mamo
A cross sectional study was conducted on 293 apparently healthy camels slaughtered at Jigjiga. Harar, Aweday and Dire Dawa abattoirs between December 2010 and April 20 11, The objective of the study was to isolate and characterize Mycobacterial species causing tuberculous lesions III slaughtered camels through postmortem examination. mycobacteria logical culturing. and multiplex polymerase chain reaction (PCR). A prevalence or 12.3% (36 /293) was recorded on the basis of postmortem examination and the di afference was statistically significant in females (X'=7.474. 1'=0.006) and in poor body condition (X'~ 7.323, 1'=0.025) camels when compared to their counter parts. About 79.5% of tuberculous lesions were found in lungs and associated lymph nodes in thoracic cavity and 15.9% in the lymph nodes of the head indicating inhalation as principal route of infection .Of the 36 camels with gross suspicious TB lesion organs and tissues cultured mica bacterial growth was observed in 66.7% (24 /3 6). Genotyping of the 17 isolates using multiplex polymerase chain reaction identified 88.2% (15/ 17) of them as member of mycobacteria other than Mycobacterium liber calliopsis complex and only once as member of M)lcobaCleriul1l ,tuberculosis complex. The relatively higher isolate ion of nontuberculous mycobacteria from most of camel 1'B lesions in this study could indicate their pathogenic or opportunistic role in the pathology or camel 1'13 signifying the need to further examine these species as cause of came l 'I'll so as to c1kctively elucidate its pathology. and enhance the effort in the control 01' the disease. Key words: Camels, Genotyping, Mycobacterium tuberculosis complex. Nontuberculous mycobacteria, Prevalence, Tuberculosis
Investigation of Respiratory Viruses in Camels Slaughtered at Addis Ababa Akaki Abattoir
(Addis Ababa University, 2011-06) Wossene Negash; Tesfaye Sissay; GeJagay AyeJet
This study was conducted from September 20 10- June 20 11 at Debre Zeit National Veterinary Institute (NVI) with an attempt to isolate and characterize respiratory viruses from pneumonic lungs of camels slaughtered at Addis Ababa Akaki abattoir. Accordingly, pneumonic camel lung tissues were collected and transported in ice box to NVI virology laboratory and temporarily stored at -85°C and then processed and inoculated on confluent vero cells mono layers, incubated at 37°C and followed for the development of CPE for 4-15 days. All CPEs observed developed between 4-14 days. Thirty five (35) pneumonic camel lungs were cultured among which 27 of them were CPE positive characterized majorly by initial rounding of vero cells, elongation, syncytia formation, swelling and rounding, floating and sloughing of cells. Some of the supernatant suspensions of those samples exhibiting CPEs were taken and extracted both for DNA and RNA viral genomes. cDNAs were synthesized from RNA extracted samples. The DNAs and cDNAs were used to test both DNA and RNA viruses, respectively using universal (DOP- PCR) and conventional PCR techniques. Respiratory syncytial virus, Adenovirus, Pest des polities ruminants virus, Parainfluenza I virus, Parainfluenza 2 virus and Parainfluenza 3 virus were tested. All six samples tested were negative for PPRV and Parainfluenza virusesl-3. But nine of ten samples tested were positive for Respiratory syncytial virus and two of six samples tested were positive for Adenovirus. Finally, further investigative, epidemiological and molecular characterization studies were forwarded . Key words: Abattoir, Camel, Polymerase chain reaction, Respiratory viruses, Virus isolation
Sero-Prevalence and Participatory Study of Contagious Caprine Plueropneumonia in Gulina Wereda, Afar National Regional State, Ethiopia
(Addis Ababa University, 2012-04-10) Amare Getu; Tesfaye Sisay
A cross sectional study of Contagious Caprine Pleuro pneumoma (CCPP) in goats was conducted from October 2007 to April 2008 to determine sero prevalence in Gulina district of Afar National Regional State. A total of 446 sera were collected from goats. Complement Fixation Test (CFT) was carried out at National Veterinary Institute. The Participatory approaches are holistic in nature where by all aspects of the phenomenon questions are studied by the use of multiple methods in a process referred to as triangulation. Camels had the highest proportion (44.6%) followed by 30.6% of goats to the relative importance of livestock species to pastoralists. The possible source of CCPP is watering followed by grazing (31.9%) due to goats gathered from different sites for the search of feed and water. The main control tactic for CCPP is Isolation of the affected goat(s). Among the cases in the area 34.7% were pasteurellosis followed by CCPP. Significant numbers of goat were lost due to CCPP (32.6%) next to PPR (38.7%). Drought (65%) is a major challenge to their livestock. The overall sero prevalence was 42.8% (n = 191). The age group sero prevalences were 42.4, 36.8 and 49% in age group less than 1, 1-3 years and >3 years older respectively. Sex specific sero prevalence observed was 40.9% in males and 43.7% in females. Because of few male goats compared to females in each flock, the contribution of males to the total sero positivity was only 32.9%. High significance association was found between Flock size 51-150 and greater than 150 (OR=25.6, P=O.OOO) to CFT test. Goats ofless than 1 year were found to be safer (OR=0.974, P=0.324).
Infectious Bursal Disease Viru : Outbreaks Investigation, Molecular Characterization and Development of Live Attenuated Vaccine Using Local Isolates
(Addis ababa Universty, 2012-04-15) Senait Belete; Tesfaye Sisay
This study was conducted on sample collected from different regions of the country, where infectious bursal disease (IDB) outbreaks were reported. Samples were processed both at National Veterinary Institute and University of Liverpool, United Kingdom, with the aims of molecular characterization of local isolates, analyzing genetic relatedness of IDB virus circulating in the country with currently produced vaccine and development of vaccine from local isolates. The nucleotide and deduced amino acid sequence for VP2 hypervariable region (HVR) of ten IBDV isolates collected from 2009 until 2011 was also determined by RT-PCR and sequencing, and compared with well characterised IBDV isolates worldwide. A total of 136 bursa sample were pulled into 44 samples. Bursa samples were processed and cultured onto both confluent primary CEF cell cultures as well as fully confluent established cell line (Vero). Viruses were isolated from 41 (93 .2%) samples out of the 44 pulled samples. All the (Vero). Viruses were isolated from 41 (93 .2%) samples out of the 44 pulled samples. All the isolates were grown and able to demonstrate CPEs on CEF cell cultures on the first passage Phylogenetically, Ethiopian IBDV isolates were from one of two genetic lineages: very virulent lBDV and variants of the classical attenuated vaccine strain (078). Nucleotide identity between Ethiopian vvIBDVs range between 0% to 2.6% over VP2 HVR. isolate was superior to the current commercially available vaccine. The adapted trial vaccine isolate was superior to the current commercially available vaccine. The adapted trial vaccineEthiopian vvIBDVs clustered phylogenetically with the African IBDV genetic lineage, independent of the Asian/European genetic. This indicates the circulating of vvIBDV among Ethiopian chickens. Classical variant strain (IBDV 06/10) was selected for adaptation trial using Vero cells. The 9th Vero passage local isolate was evaluated with the current NVI vaccine for immunogenicity and pathogenesity on chicken. The result showed that the adapted local isolate was superior to the current commercially available vaccine. The adapted trial vaccine induced significantly (P<0.05) higher mean antibody titre (3281.35± 101.43) compared to the cun'ently used vaccine strain (2784.12±92.34). The mean bursa weight from the unvaccinated control groups was 20.8±1.2 g while it was 3.6±O.l6g and 2.8±0.07g, respectively, for commercial vaccine and 9th passaged local isolate. Although the difference in the mean bursa weight between the vaccinated groups was not statistically significant (P>0.05), the difference in the mean bursal weight between control and vaccinated groups was statistically significant (P<0.05).
Study on Foot and Mouth Disease Virus Vaccine Strain Selection of Ethiopian Isolates
(Addis Ababa University, 2012-04-30) Mekonnen sorsa; Tesfaye Sisay
This study was conducted at National Veterinary Institute (NVI) on foot and mouth disease viruses of known serotypes and topotypes identified and characterized ./i•om samples collected from cattle and swine, at different times from different parts of Ethiopia. The study was designed with the aim of selecting appropriate vaccine strains that can provide a broad spectrum cross protection against the circulating serotypes or strains by assessing the serological or antigenic match between the candidate vaccine strains and field isolates of 0, A, and SAT2. The study was done by two-dimensional virus neutralization assay to determine the serological or antigenic relationship 'rl' value between the candidate vaccine strains and field isolates. A total of 21 serotype 0 , 7 serotype A, and 8 serotype SAT2 FMD viruses were used for the study including candidate vaccine strains. The study findings revealed that out of 19 serotype 0 field isolates tested for vaccine match with antisera raised against candidate vaccine strains, 0-ETH/58/2005 and 0-ETHl38/2005, all (J 00%) were found to be antigenically similar with vaccine viruses with 'rl' values above the cut-off point (0.3)(with mean 'rl' value of 0.83 and 0.84, respectively), indicating that both these vaccine strain candidates can confer protection for serotype 0 field viruses circulating in the country. Of the 5 serotype A field strains tested, 4 (80%) match serologically with antisera raised against candidate vaccine strains, A-ETHl6/2000 and AETHl7/2008 with 'rl ' value greater than the cut-off point (mean 'r1 ' value of 0.58 and 0.70, respectively). But 1 serotype A field virus, A-ETHI13/1981 showed significant antigenic variation with vaccine strains with 'r 1' value below the cut-off point (r 1 value: 0.14 and 0.25 for AETHl6/2000 and A-ETHl7/2008, respectively). Furthermore, the 'r1' value obtained by serological matching between 6 SAT2 serotype field isolates and two vaccine strain candidates, SAT2-ETHl64/2009 and SAT2-ETHI76/2009, revealed that the vaccine strains can protect field viruses circulating in the country (Mean 'r1' value: 0.70 and 0.76, respectively). In general, the overall assessment of antigenic relations between the candidate vaccine strains and circulating field isolates tested showed better matching. The protection level of the selected vaccine strains against the challenge by field viruses should be supported by potency testing or animal challenge.
Sero-Prevalence and Participatory Study of Contagious Caprine Plueropneumonia in Gulina Wereda, Afar National Regional State, Ethiopia
(2012-06) Amare Getu; Tesfaye Sisay
A cross sectional study of Contagious Caprine Pleuro pneumonia (CCPP) in goats was conducted from October 2007 to April 2008 to determine sero prevalence in Gulina district of Afar National Regional State. A total of 446 sera were collected from goats. Complement Fixation Test (CFT) was carried out at National Veterinary Institute. The Participatory approaches are holistic in nature where by all aspects of the phenomenon questions are studied by the use of multiple methods in a process referred to as triangulation. Camels had the highest proportion (44.6%) followed by 30.6% of goats to the relative importance of livestock species to pastoralists. The possible source of CCPP is watering followed by grazing (31.9%) due to goats gathered from different sites for the search of feed and water. The main control tactic for CCPP is Isolation of the affected goat(s). Among the cases in the area 34.7% were pasteurellosis followed by CCPP. Significant numbers of goat were lost due to CCPP (32.6%) next to PPR (38.7%). Drought (65%) is a major challenge to their livestock. The overall sero prevalence was 42.8% (n = 191). The age group sero prevalences were 42.4, 36.8 and 49% in age group less than 1, 1-3 years and >3 years older respectively. Sex specific sero prevalence observed was 40.9% in males and 43.7% in females. Because of few male goats compared to females in each flock, the contribution of males to the total sero positivity was only 32.9%. High significance association was found between Flock size 51-150 and greater than 150 (OR=25.6, P=0.000) to CFT test. Goats of less than 1 year were found to be safer (OR=0.974, P=0.324).
Study on the Prevalence of Bacillus Cereus and Associated Risk Factors in Bovine Raw Milk in Debre Zeit, Ethiopia
(2012-06) Alemneh Kassa; Girma Zewde
The objectives of this study were to determine the prevalence of B. cereus, evaluate the load of B. cereus and assess risk factors associated with B. cereus load and its public health implication in raw milk samples collected from dairy farms in Debre Zeit, Ethiopia. A total of 384 raw milk samples were collected from eleven randomly selected dairy farms. The overall prevalence of B. cereus in raw milk sample was 15.4% (59). The B. cereus count ranges from 2.3 x 104 - 5.4 x 105 CFU/ml. From positive samples, 58 (15.1%) of total samples have significant counts (> 105 CFU/ml) which was above legal limit in raw milk intended for human consumption. The mean of B. cereus counts differed significantly between farms and within parities (p < 0.05). An attempt was made to assess hygienic keeping quality of milk at farm level by using semi structured questionnaire survey. Our study results indicated that raw milk samples collected from both zero-grazing and semi-intensive farm management systems were highly contaminated with B. cereus, exceeding the legal limit set for raw milk (> 105 CFU/ml), suggesting effective hygienic measures should be introduced in milk value chains during milk production, distribution and processing and food service establishments to avoid public health hazards.
Isolation and Identification of Corynebacterium Pseudotuberculosis from Superficial Lymphlinodes of Sheep and Goat at Organic Export Abbatoir, Modjo Ethiopia
(Addis Ababa University, 2012-06) Daniel Abebe; Tesfaye Sisay
Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CL.J\), a disease characterized by the formation of suppurative abscesses, particularly in superficial and internal lymph nodes, and in internal organs in small ruminants. The present study was conducted from November to April 201 1/ 2012 only on the superficial lymph nodes and carcass of small ruminants. Out of 768 small ruminants slaughtered at Organic slaughterhouse during the study period, 82 (68 in goats and 14 in sheep) were found to have gross evidence of abscess or caseous lymphadenitis. The typical gross lesion is a discrete abscess distended by thick and often dry, greenish yellow or white, purulent exudates. The most frequent sites of abscesses in goats occurred in the periscapular, pretemporal and popliteal lymph node and carcass 34(5.5'10/0). 24(3.91 %),2(0.33%) and 8(1.30%) respectively. In sheep 7(4.54%) in the periscapular, 5(3.25%) in pretemporal and 0% in popliteal lymph node and 2(1.23%) abscess on carcass were found. The study indicated that in both species young animals are more in number than adult, however, caseous lymphadenitis was found to be higher in ad ult than young animals in both species. There was statistically significant difference in the occurrence of CLA between age groups (P<0.05 J. Out of 68 bacterial cutes from goats 18 and 50, pure and mixed colonies, respectively. livre obtained; while out of 14 bacterial cultures boom sheep 4 and 10, pure and mixed colonies, respectively, were obtained. Corynebacterium pseudotuberculosis isolates were obtained from S9 out of 82 collected abscessed lymph nodes and carcass. Bacterial colonies were identified on the basis of morphological characteristics, primary and secondary biochemical tests, i.e cablese, urease, trehalas, xylose, maltose, and glucose fermentation tests and reverse CAMP test (antagonistic hemolysis between C. pseudotuberculosis and Staphylococcus aureus). Isolates positive for catalase, urease, maltose, and glucose, but with inhibiting hemolysin of Soured' by phospholipase D of C. pseudotuberculosis and negative for trehalas, and xylose "ere considered as C. pseudotuberculosis. The susceptibility pattern of C. pseudotuberculosis to antimicrobial agents varied among isolates. Out of 59 isolates of C. pseudotuberculosis isolated from lesions of caseous lymphadenitis in goats and sheep were susceptible to the antibi optics norfloxacin, tetracycline, doxycycline HCl and kanamycin. Keywords: Antimicrobial agents; Caseous lymphadenitis; Corynebacterium pseudotuberculosis; Goat; Lymph nodes; Mixed colonies; Pure colonies; Sheep.
Lumpy Skin Disease (Lsd): Outbreak Investigation, Isolation and Molecular Detection of Lsdv in Selected Areas of Eastern Shewa, Ethiopia
(2012-06) Rgbe Haftu; Tesfaye Sisay
The study was undertaken to investigate outbreaks of lumpy skin disease (LSD), isolate and identify LSDV at molecular level, to asses the economic significance of lumpy skin disease in the study area, and to asses the protection of the vaccine for lumpy skin disease given at field condition. The study was conducted from September 2011-April 2012 in selected areas of eastern Shewa. LSD Outbreaks were reported from 4 different areas of Eastern Shewa; Adama (5 intensive fattening farms), Wenji (4 intensive fattening farms), Mojo (small holders) and Welenchit (small holders). In total 2174 local Zebu breed cattle, the majority composed of males (98.8%), were visited and clinically diagnosed. From the total of visited cattle 296 (13.78%), 108 (5.03%) and 1 (3.84%) morbidity, mortality and abortion rates were recorded respectively. Analysis of the outbreak statistics revealed a relatively consistent morbidity rate with highest value in Adama (15.67%) followed by Wenji (10.26%), Wolenchit (8.8%), and Mojo (7.01%) was recorded respectivly. Highest mortality rate was observed in Adama (5.99%) followed by Wenji (3.42%), Welenchit (2.4%) and Mojo (0%) respectively. Isolation and identification of the agent was conducted based on cell culture and PCR results. LSDV genome was extracted and identified in all 22 skin nodules by PCR. Furthermore, LSD causes a great economic loss in the study area. Questionnaire survey based assessment on protection of the vaccine showed that the current vaccine (KSGPV) used in the area was not protective and high percentage of morbidity (15.1%) and mortality (5.37%) rates were reported among vaccinated animals but efficacy test of the vaccine under laboratory protocol in six seronegative calves showed that the vaccine was immunologically protective.
Isolation and Identification of Corynebacterium Pseudotuberculosis from Superficial Lymphnodes of Sheep and Goat at Organic Export Abbatoir, Modjo Ethiopia
(2012-06) Daniel Abebe; Tesfaye Sisay
Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), a disease characterized by the formation of suppurative abscesses, particularly in superficial and internal lymph nodes, and in internal organs in small ruminants. The present study was conducted from November to April 2011/ 2012 only on the superficial lymph nodes and carcass of small ruminants. Out of 768 small ruminants slaughtered at Organic slaughterhouse during the study period, 82 (68 in goats and 14 in sheep) were found to have gross evidence of abscess or caseous lymphadenitis. The typical gross lesion is a discrete abscess distended by thick and often dry, greenish yellow or white, purulent exudates. The most frequent sites of abscesses in goats occurred in the prescapular, prefemoral and poplitial lymph node and carcass 34(5.54%), 24(3.91%), 2(0.33%) and 8(1.30%) respectively. In sheep 7(4.54%) in the prescapular , 5(3.25%) in prefemoral and 0% in poplitial lymph node and 2(1.23%) abscess on carcass were found. The study indicated that in both species young animals are more in number than adult, however, caseous lymphadenitis was found to be higher in adult than young animals in both species. There was statistically significant difference in the occurrence of CLA between age groups (P<0.05). Out of 68 bacterial cultures from goats 18 and 50, pure and mixed colonies, respectively, were obtained; while out of 14 bacterial cultures from sheep 4 and 10, pure and mixed colonies, respectively, were obtained. Corynebacterium pseudotubrculosis isolates were obtained from 59 out of 82 collected abscessed lymph nodes and carcass. Bacterial colonies were identified on the basis of morphological characteristics, primary and secondary biochemical tests, i.e. catalase, urease, trehalose, xylose, maltose, and glucose fermentation tests and reverse CAMP test (antagonistic haemolysis between C. pseudotuberculosis and Staphylococcus aureus). Isolates positive for catalase, urease, maltose, and glucose, but with inhibiting β- haemolysin of S. aureus by pospholipase D of C. pseudotuberculosis and negative for trehalose, and xylose were considered as C. pseudotuberculosis. The susceptibility pattern of C. pseudotuberculosis to antimicrobial agents varied among isolates. Out of 59 isolates of C. pseudotuberculosis isolated from lesions of caseous lymphadenitis in goats and sheep were susceptible to the antibiotics norfloxacin, tetracycline, doxycyline HCl and kanamycine.
Bacteriological Studies on The Respiratory Tracts of Apparently Healthy and Pneumonic Camels (Camelus Dromedaries) In Selected Districts of Afar Region, Ethiopia
(2012-06) Mu’uz Gebru; Tesfaye Sisay
A cross-sectional study was conducted to isolate and characterize the normal bacterial flora and bacterial agents implicated in pneumonia from the respiratory tract of the apparently healthy and pneumonic camels in the selected districts of Asayita and Dubti woredas of Afar Region. A total of 532 samples including 384 nasal swabs, 74 lung tissues and the same number of corresponding tracheal swabs were collected for bacteriological examination from September 2011 to May 2012. Generally, 903 bacterial isolates that constituted 14 different genera were identified from both the field and abattoir based study. The 384 nasal specimens collected yielded a total of 641 bacterial isolates. CNS, 28.6%, Bacillus, 13.5%, S. aureus, 13.3% and E. coli, 7.8% were the leading bacterial species isolated from the nasal tracts of apparently healthy camels. Nasal swabs collected from the pneumonic camels revealed S. aureus, CNS, Bacillus species and K. pneumoniae at a rate of 28.0%, 11.7%, 11.3% and 7.0%, respectively. E. coli, 12.7%, Proteus species, 10.9%, and K. pneumoniae, 9.1% were recognized at higher proportions among the 55 bacteria identified from the normal lungs. On the other side, S. aureus, S. equi subsp. equi and P. multocida were the frequently encountered species in the pneumonic lungs with the incidence of 16.3%, 13.0% and 10.9%, respectively. The majority of the isolates colonized all the anatomical sites investigated. However, a general decrease in the isolation rate was observed as one goes down the respiratory passageways. There was a statistically significant difference between the health status of the camels as well as along the anatomical sites studied with the isolation rates of the major camel respiratory pathogens (p<0.05). Streptococcus equi subsp. equi, S. equi subsp. zooepidemicus and S. pneumoniae were identified using the Omnilog®-Biolog identification system at the Institute of Biodiversity Conservation, Addis Ababa. The majority of the strains of the camel respiratory pathogens were found susceptible to norfloxacin, streptomycin and gentamicin but resistant to the action of ampicillin and tetracycline on the invitro test. Further studies on the demonstration of the role of other microorganisms, the pathogenicity of S. equi subsp. equi, identification of the serotypes involved and development of polyvalent vaccine are recommended to allow the progress of preventive methods.

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