Veterinary Microbiology

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Browsing Veterinary Microbiology by Author "Addisu Demeke"

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    Evaluation Of the Immune Response of Newcastle Disease Virus Vaccines, In Layer Chickens
    (2018-06) Abel Sorsa; Addisu Demeke
    This study was undertaken to evaluate the immune responses of NDV vaccines in layer chickens in the National Veterinary Institutes (NVI), Bishoftu, Ethiopia, in the period of February to May 2018.A total of 140 layer day old chicks (Lohmann Brown) were randomly divided into seven groups such as 1, 2, 3, 4, 5, 6, and 7 of which group 1, 2, and 3 were vaccinated primarily with HitchnerB1, LaSota, and Thermos-table I2 vaccine respectively at day 5 of age and secondarily vaccinated using LaSota, LaSota and Thermostable I2; vaccine, respectively at day of 26, again thirdly (second boost) vaccinated using Thermostable I2, Thermostable I2,Thermostable I2; vaccines,at the day of 54 of age, through single eyeinstillationof the same schedules and group 4,5 and 6 were vaccinated with the same vaccines respectively via double eye instillation following the same schedule.Group 7 was kept as unvaccinated control chickens.Sera samples were collected after 10 vaccination days and at day 5, 15, 21, 31 of age from unvaccinated control whereas at day of 15, 36, and 64 of age from vaccinated chickens.Serum sample subjected to Haemagglutination Inhibition (HI) test for the determination of antibody titres. It was observed that after secondary vaccination the geometric mean (GM) titres of vaccinated chickens were induced highest antibody titer than primary vaccinationand third vaccination GMtiter.From the present research it may be concluded that LaSota, LaSota, thermostable I2vaccination schedules was the best combination of which produced highest immune response in single eye instillation whereas HB1LaSota, LaSota, vaccination schedules was the best combination of which produced highest immune response in double eye instillation.The persistence of passive immunity remains in chickens until the age of day 31.
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    Isolation and Molecular Characterization of Lumpy Skin Disease Virus in Central Ethiopia
    (2018-06) Mesay Taye ; Addisu Demeke
    Lumpy skin disease (LSD) is an infectious disease of cattle, caused by a Lumpy Skin Disease Virus. LSD Causes considerable economic losses due to emaciation, damage to hides, infertility and, loss of milk production. In Ethiopia the disease is distributed almost all regions and is regarded as one of the most economically important livestock diseases in the country. Outbreak investigations have been carried out at different regions of the country on different times. The current study focused on the identification of LSDV based on outbreak reports central Ethiopia. Outbreak survey found 8.77% morbidity, 2.12% mortality and 25.61% case fatality rates in the region. Skin lesion samples were collected from clinically sick cattle and virus isolated on cell culture and shown the characteristics CPE of the virus. The virus DNA was identified by amplifying the 172bp DNA fragment using real time and conventional PCR. Phylogenetic analysis of the RPO30 gene sequence revealed that, the present isolates are form matching with previously identified isolates from Ethiopia and also with the KS-1 vaccine strains. The present study also attempt to isolate virus on Vero, ESH-L and LT primary cell cultures and comparing their susceptibility. The study found that lamb testes primary cell was best suited for primary isolation of LSDV. Vero cell however was found to be less sensitive for LSDV primary isolation but isolation can be achieved through continuous passage of the virus.
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    Outbreak Investigation, Isolation and Molecular Characterization of Sheep and Goat Pox Virus in Centeral Ethiopia
    (2018-06) Aberaham Damena; Addisu Demeke
    A cross sectional observational study was conducted from September, 2017 to March, 2018 to outbreak investigation, isolation and molecular characterization of sheep and goat pox virus in different districts of central Ethiopia. Study was engaged different approaches especially questionnaire survey, virus isolation using vero cell line, classical PCR for amplification of the DNA, gel-electrophoresis for identification of the specific band, real time PCR for further genotyping, sequencing the RP030 gene for identification of genetic relationship of sheep and goat pox virus isolate from field with other Capri pox virus (CaPV).The questionnaire survey results indicated that sheep and goat pox was the most common disease in all the study areas and the disease was frequently seen. The disease outbreak more (52.94%) observed in rainy season. Additionally, non vaccinated animals, female and young age shoats were more affected (P< 0.05) by pox virus. A total of 712 sheep and goats (603 sheep and 109 goats) were clinically examined for the presence of pox lesions on their skin and 35.82% sheep and 28.44% goats had pox lesions. Generally, high mortality (9.95%) rate was observed in sheep than goats respectively. The virus was isolated from 16 skin samples (13 sheep and 3 goats) and the cell culture showed a typical characteristic of pox virus induced-cytopathic effect with destruction of monolayer and rounding of the cell. Similarly, the conventional PCR revealed that 16 out of 16 tested samples were positive by developing band size of 172bp (Goat pox virus). Further more real time PCR 16 tested samples were positive for goat pox virus with the melting temperature of (560C/72.50C). Phylogenetic tree analysis revealed that the RP030 gene (606 nucleotides) sequences of the present isolates originated from both sheep and goats were clustered with the goat pox virus group. Even though the existing information suggested that capri pox virus is strictly host specific, but in the current study the PCR and RP030 gene sequencing result confirmed that sheep were infected by goat pox virus similarly to goat pox virus and hence classification of pox virus based on infected host in small ruminant has been found to be inconclusive.