No abstract

Foodborne bacterial diseases are a serious challenge to human and animal health. Salmonella is a zoonotic foodborne pathogen and the etiologic agent of salmonellosis. A cross-sectional study was conducted from January 2016 to April 2016 on small scale and large scale dairy farms in and around Modjo town, Ethiopia. The main objectives of the study were to isolate and identify Salmonella from lactating cows, personnel's' and equipment at farms and to determine the in vitro antimicrobial resistance profiles of the isolates. A total of 266 samples consisting of fresh cow milk, fecal sample, pooled milkers' hand swab, pooled bucket swab, tank swab, and tank milk were collected from 21 dairy farms (n=20 smallholders, n=1 large scale farm). The samples were examined for the presence of Salmonella following standard techniques and procedures outlined by the International Organization for Standardization. Kibry-Bauer disk diffusion test was used for the antimicrobial susceptibility testing. Salmonella was isolated from 28/266 (10.5%) of the total samples. Out of the 28 Salmonella isolates, 18 (64.3%), 3 (10.7%) and 7(25%) were from lactating cows, personnel's', and equipment, respectively. Out of the 28 isolates subjected to antimicrobial susceptibility testing, all isolates were resistant to at least one or more antimicrobials tested. Accordingly, 96.4% (27/28), 82.1% (23/28) and 75.0% (21/28) isolates were resistant to tetracycline, kanamycin and nalidixic acid, respectively. Multiple drug resistance (resistance to two or more antimicrobials) was detected in 27(96.4%) of the isolates. Multiple antimicrobial resistance was observed in 100% (18/18), 7.4% (2/23) and 100% (7/7) of isolates obtained from lactating cows, personnels', and equipment, respectively. High proportion of multiple antimicrobial resistant isolates (96.4%) in 93Fufa Abunna et al., Ethiop. Vet. J., 2017, 21 (2), 92-108 the dairy farms alerts concern for animal and public health as these drugs is used widely for treatment and prophylaxis in animals and humans.

The study was conducted with the objective of isolation and molecular characterization of infectious bursal disease virus (IBDV) circulating in Ethiopia and to assess the immunogenicity of different commercially available live attenuated IBD vaccines and finally to select the appropriate vaccine strain for the existing IBDV. Outbreak samples collected from different poultry farms with IBD infection between 2013 and 2015 were used for the virus isolation and molecular characterization. IBD vaccine immunogenicity test was conducted using four different commercially available live attenuated IBD vaccine strains: namely D78, B2K, LC75, and EXTREM. Day-old Bowman brown chickens purchased from commercial farm in Debre Zeit were used for the experiment. Serum samples were collected at days 14 and 21 and screened for the presence of maternal IBDv antibodies. The screening test result revealed that most of the chickens from vaccinated progeny were positive at the age of day 14 with mean antibody titer of .42, but declined at day 21 to 0.049 below cut-off point (S/P < 0.3). Chickens were divided into five different groups (four vaccinal and one control) and vaccinated at the age of day 21 and boosted after 14 days. Serum samples were collected and all of them were challenged at their 42 days of age with locally isolated very virulent infectious bursal disease virus (vvIBDV). From four of the vaccine strains used for immunogenicity study, the intermediate plus strains (LC75 and EXTREM) found to be superior and efficiently cross protect against the challenge with locally isolated vvIBDV. The development of clinical signs was studied and post-mortem examinations were conducted both on dead and sacrificed birds. From a total of 25 tissue samples processed for virus isolation on chicken fibroblast cell culture, 95% (18/20) of bursa and 80% (4/5) of the spleen samples showed visible cytopathic effect (CPE). The positive samples were tested by PCR and 19 of them had the expected band (643 bp). Further 11 representative samples were sequenced and confirmed that the circulating virus among poultry population in the country is vvIBDV. The study has recommended to produce vaccine using intermediate plus strains to prevent and control currently circulating vvIBDV.

Contagious caprine pleuropneumonia (CCPP) is a fatal disease of goats occurring in many countries ofAfrica and Asia where the total goat population is more than 500 million. Vaccination is the most cost effective technique in the control of CCPP than any other control measures. In National Veterinary Institute (NVI) inactivated mycoplasma protein based vaccine obtained by centrifugation has been in use since many years. This study focuses on evaluating the safety and immunogenicity of inactivated whole culture CCPP vaccine currently developed in the NVI. Twenty six Mycoplasma capricolum subspecies capripneumoniae (Mccp) antibody free goats were used to evaluate the safety and immunogenicity of inactivated whole culture CCPP trial vaccine. The trial vaccine was prepared from culture of Mccp vaccinal seed grown in Mycoplasma specific hayflick media using spinner bottle. The protein content for one milliliter of whole culture was checked and found to be more than the minimum recommended dose (0.15 mg per dose). The culture was inactivated by 37% formalin at proportion of 0.5% of whole culture and adjuvanted by saponin at final concentration of 0.3%. The experimental animals were distributed into four groups: The group A consist of five goats for safety and all the other groups consists of seven animals each with group B for trial vaccine, group C for positive control and group D for negative control for immunogenicity trials. The goats were observed for two months for safety and immunogenicity evaluation during which serum samples were collected for immunogenicity and tested by using competitive Enzyme Linked immunosorbent Assay (cELISA) test. The results indicated that out of 7 goats vaccinated with trial vaccine, the mean sero-positivity was 60.71% while 7 goats vaccinated with the positive control showed mean sero-positivity of 58.86%. The analysis showed no significant difference between mean sero positivity of trial vaccine and positive control (P>0.05) as indicated by sero-conversion. The mean percent inhibition (PI) of trial inactivated whole culture CCPP vaccine vaccinated goats was 61.52% while the mean PI for positive control vaccine vaccinated group was 51.86%. In contrast the non-vaccinated controls showed mean PI of 40.65% which is significantly less than percent inhibition of the vaccinated groups (p=0.000). The body temperature and clinical observation of safety tested animals and other immunogenicity tested goats showed absence of any abnormality after vaccination both in vaccinated and controls. This study which was novel in its nature concluded that the trial inactivated whole culture ccpp vaccine is equally immunogenic as that vaccine already in use, the non-whole culture concentrated CCPP vaccine, and could be used for mass vaccination after conducting field immunogenicity trial.

Background: Foot-and-mouth disease (FMD) is one of the contagious and the most economically devastating viral diseases caused by the FMD virus. The present study was conducted with the aim of molecular characterization of the FMD virus isolated from outbreaks that occurred in cattle in two different districts of Amhara regional state of Ethiopia. Samples collected from outbreaks were isolated on BHK-21 cell and serotype were detected using antigen detection ELISA. Phylogenetic and amino acid variability analyses of isolated viruses were undertaken after sequencing the VP1 gene in World Reference Laboratory, Pirbright, UK.Result: In the present study only serotypes O was found in the samples analysed using antigen detection ELISA and in 10 out of 13 (76.9%) cultured samples, virus were isolated on BHK-21 cells. Phylogenetic analysis of these isolates revealed that, they belonged to East Africa topotype-3 (EA-3) and shared 96.6% nucleotide similarity with Sudan’s isolates. A total of 10.3% amino acid variations were recorded between VP1 gene sequences of the field isolates of serotype O FMDV and vaccine strain (O/ETH/38/2005) used in Ethiopia for vacccine production.Conclusion: The phylogenetic analysis serotype O detected in this study revealed that the virus was clustered with East African topotype-3 (EA-3) and exhibited high genetic similarity with isolates from Sudan. A number of amino acid variations were also noted at different sites of VP1 gene when comparing field isolates with the vaccine strain. Thus, to enhance control of FMD in Ethiopia, detailed molecular analysis of the field isolates along with in-vitro vaccine matching tests need to be undertaken at frequent intervals to assess the protective potential of the vaccine strain in use.