Establishment of an Efficient and Flexible Genetic Manipulation Platform Based on a Fosmid Library for Rapid Generation of Recombinant Pseudorabies Virus

Conventional genetic engineering of pseudorabies virus (PRV) is essentially based on homologous recombination or bacterial artificial chromosome. However, these techniques require multiple plaque purification, which is labor-intensive and time-consuming. The aim of the present study was to develop an efficient, direct, and flexible genetic manipulation platform for PRV. To this end, the PRV genomic DNA was extracted from purified PRV virions and sheared into approximately 30–45-kb DNA fragments. After end-blunting and phosphorylation, the DNA fragments were separated by pulsed-field gel electrophoresis, the recovered DNA fragments were inserted into the cloning-ready fosmids. The fosmids were then transformed into Escherichia coli and selected clones were end-sequenced for full-length genome assembly. Overlapping fosmid combinations that cover the complete genome of PRV were directly transfected into Vero cells and PRV was rescued. The morphology and one-step growth curve of the rescued virus were indistinguishable from those of the parent virus. Based on this system, a recombinant PRV expressing enhanced green fluorescent protein fused with the VP26 gene was generated within 2 weeks, and this recombinant virus can be used to observe the capsid transport in axons. The new genetic manipulation platform developed in the present study is an efficient, flexible, and stable method for the study of the PRV life cycle and development of novel vaccines

Foot and mouth disease vaccine efficacy in Africa: a systematic review and meta-analysis

BackgroundSeveral factors, such as diverse serotypes, vaccination methods, weak biosecurity, and animal movements, contribute to recurrent Foot-and-Mouth Disease Virus (FMDV) outbreaks in Africa, establishing endemicity. These outbreaks cost over $2 billion annually, prompting a high-priority focus on FMDV vaccination. Despite extensive efforts, vaccine efficacy varies. This study aims to evaluate routine foot and mouth disease (FMD) vaccines in Africa via systematic review and meta-analysis.MethodsA systematic review and meta-analysis were carried out following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Meta-analysis was conducted to assess the efficacy of FMDV vaccination using the meta for package of R.ResultsVaccinated animals have roughly a 69.3% lower chance of FMDV infection compared to unvaccinated animals, as indicated by the pooled results from the random-effects model, which showed a risk ratio (RR) of 0.3073. There was a statistically significant heterogeneity (p < 0.05) across all of the included articles.ConclusionOverall findings suggest that if properly planned and implemented, FMDV vaccination programs and strategies in Africa could help control the spread of the disease throughout the continent and beyond

Brucellosis in Sub-Saharan Africa:Current challenges for management, diagnosis and control

Brucellosis is a highly contagious zoonosis caused by bacteria of the genus Brucella and affecting domestic and wild mammals. In this paper, the bacteriological and serological evidence of brucellosis in Sub-Saharan Africa (SSA) and its epidemiological characteristics are discussed. The tools available for the diagnosis and treatment of human brucellosis and for the diagnosis and control of animal brucellosis and their applicability in the context of SSA are presented and gaps identified. These gaps concern mostly the need for simpler and more affordable antimicrobial treatments against human brucellosis, the development of a B. melitensis vaccine that could circumvent the drawbacks of the currently available Rev 1 vaccine, and the investigation of serological diagnostic tests for camel brucellosis and wildlife. Strategies for the implementation of animal vaccination are also discussed.Publishe

Study on common phenotypic traits for purchasing sheep and their association with price and purpose of purchase in four markets of East Showa Zone

A study was conducted in 2008 to assess the relationship between common phenotypic traits most considered for marketing sheep and the body weight and price of sheep at markets of four towns in East Showa zone. Six hundred randomly selected sheep purchased for various purposes were studied. The study methods include questionnaire surveys with 600 sheep buyers, color observations and five morphometric measurements on purchased animals. Questionnaire survey responses showed that sheep were commonly bought for slaughter. Almost all respondents consider in order of importance, chest size, lumbar width and tail width as criteria for selecting sheep of their choice. Brownish coat color followed by whitish predominates among the sheep purchased. The mean heart girth, chest size, lumbar width and tail width values of sheep bought for slaughter was significantly higher than for those bought for breeding and other purposes. Animals bought for slaughter and resale earned significantly higher price than those purchased for breeding and fattening. Linear measurement values except tail length and price had strong positive correlations (P<0.01). During sheep marketing, call price to selling price ratio shows that after an intense negotiation, sheep owners accepted 84±7.3% of the call price. In conclusion, sheep market customers’ criteria to select sheep of their preference had strong association with the purpose of buying and the price paid after negotiation

Generation and Evaluation of an African Swine Fever Virus Mutant with Deletion of the CD2v and UK Genes

African swine fever (ASF) is a highly contagious and often lethal disease caused by African swine fever virus (ASFV). ASF emerged in China in August 2018 and has since rapidly spread into many areas of the country. The disease has caused a significant impact on China’s pig and related industries. A safe and effective vaccine is needed to prevent and control the disease. Several gene-deleted ASFVs have been reported; however, none of them is safe enough and commercially available. In this study, we report the generation of a double gene-deleted ASFV mutant, ASFV-SY18-∆CD2v/UK, from a highly virulent field strain ASFV-SY18 isolated in China. The results showed that ASFV-SY18-∆CD2v/UK lost hemadsorption properties, and the simultaneous deletion of the two genes did not significantly affect the in vitro replication of the virus in primary porcine alveolar macrophages. Furthermore, ASFV-SY18-∆CD2v/UK was attenuated in pigs. All the ASFV-SY18-∆CD2v/UK-inoculated pigs remained healthy, and none of them developed ASF-associated clinical signs. Additionally, the ASFV-SY18-∆CD2v/UK-infected pigs developed ASFV-specific antibodies, and no virus genome was detected in blood and nasal discharges at 21 and 28 days post-inoculation. More importantly, we found that all the pigs inoculated with 104 TCID50 of ASFV-SY18-∆CD2v/UK were protected against the challenge with the parental ASFV-SY18. However, low-level ASFV DNA was detected in blood, nasal swabs, and lymphoid tissue after the challenge. The results demonstrate that ASFV-SY18-∆CD2v/UK is safe and able to elicit protective immune response in pigs and can be a potential vaccine candidate to control ASF

Prevalence and Risk Factors of Bovine Mastitis in Southern Zone of Tigray, Northern Ethiopia

Mastitis is the most common disease of adult dairy cattle. The disease continues to be one of the most perplexing and costly diseases of dairy cattle. The present study was conducted to detect bovine mastitis cows and identify potential risk factors for the distribution of bovine mastitis of smallholder dairy farmers using the California mastitis test. A cross-sectional study was conducted from September 2013 to May 2015 in the southern zone of Tigray, Northern Ethiopia, on 146 head of randomly selected cattle, of which 99 (67.8%) were crossed zebu and 47 (32.2%) pure local zebu using the California mastitis test and questionnaire. The overall prevalence was 65 (45.5%), of which 72.3% of crossed local and 27.69% of local zebu were found positive for the CMT test. The investigated risk factors were the season of lactation (OR = 0.510, CI = 0.208–1.247, P=0.140), washing hands between consecutive milking events (OR = 0.354, CI = 0.146–0.856, P=0.021), and history of previous mastitis (OR = 0.441, CI = 0.226–0.858, P=0.016), which had significant (P<0.05) effect on the present prevalence of bovine mastitis in the study area. A high prevalence of bovine mastitis was observed in the southern zone of Tigray. The summer season of lactation and not washing hands between consecutive milking of cows were significant mastitis causation risk factors in addition to the history of previous mastitis disease history

Foot and mouth disease in selected districts of western Ethiopia: seroprevalence and associated risk factors

A study was conducted in western Ethiopia in two districts of Oromia state and four districts of Beneshangul Gumuz state to determine the seroprevalence of foot and mouth disease and the associated risk factors, using multistage random sampling. A 3ABC blocking enzyme-linked immunosorbent assay was used to measure antibody against the non-structural protein of foot and mouth disease virusto differentiate between vaccinated and infected animals. Atotal of 1,144 sera from 181 herds were collected and examined. The overall seroprevalence at animal level and herd level was 9% (95% C17.2-10.6) and 38.1% (95% CI 29.1-47.1), respectively. Statistically significant differences (p < 0.05) were recorded among different species, with 13%, 5% and 3% seropositivity in cattle, sheep and goats, respectively. Statistically significant differences (p < 0.05) in herd seroprevalence were observed among districts, with 52%, 50%, 50%, 44%, 21% and 11% in Gidami, Begi, Tongo, Bambasi, Mange and Asosa districts, respectively. In univariable and multivariable logistic regression, the variables that had a positive relationship with seroprevalence at herd level (p < 0.05) were herd size, contact of livestock with ungulate wildlife, and contact of animals with animals/herds of a different peasant association. Univariable and multivariable logistic regression analysis indicated that, at the animal level, age and species had a statistically significant association (p < 0.05) with seropositivity. In conclusion, herd size, contact of livestock with ungulate wildlife, contact between herds from different peasant associations, and the age and species of the animals were the main risk factors for virus circulation in the study area

Prevalence and Risk Factors of Bovine Mastitis in Southern Zone of Tigray, Northern Ethiopia

Mastitis is the most common disease of adult dairy cattle. The disease continues to be one of the most perplexing and costly diseases of dairy cattle. The present study was conducted to detect bovine mastitis cows and identify potential risk factors for the distribution of bovine mastitis of smallholder dairy farmers using the California mastitis test. A cross-sectional study was conducted from September 2013 to May 2015 in the southern zone of Tigray, Northern Ethiopia, on 146 head of randomly selected cattle, of which 99 (67.8%) were crossed zebu and 47 (32.2%) pure local zebu using the California mastitis test and questionnaire. The overall prevalence was 65 (45.5%), of which 72.3% of crossed local and 27.69% of local zebu were found positive for the CMT test. The investigated risk factors were the season of lactation (OR = 0.510, CI = 0.208–1.247, P = 0.140 ), washing hands between consecutive milking events (OR = 0.354, CI = 0.146–0.856, P = 0.021 ), and history of previous mastitis (OR = 0.441, CI = 0.226–0.858, P = 0.016 ), which had significant ( P &lt; 0.05 ) effect on the present prevalence of bovine mastitis in the study area. A high prevalence of bovine mastitis was observed in the southern zone of Tigray. The summer season of lactation and not washing hands between consecutive milking of cows were significant mastitis causation risk factors in addition to the history of previous mastitis disease history.</jats:p