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Anthrax is a zoonotic disease characterized by rapid onset with usual fatal outcomes in livestock and wildlife. In Ethiopia, anthrax is a persistent disease; however, there are limited data on the isolation and molecular characterization of Bacillus anthracis strains. This study aimed to characterize B. anthracis isolated from animal anthrax outbreaks between 2019 and 2024, from different localities in Ethiopia. B. anthracis was identified using standard microbiology techniques and confirmed by real-time PCR. For the first time in Ethiopia, the genetic diversity of five Bacillus anthracis strains, isolated from dead cattle and goats, was investigated by Whole Genome Sequencing (WGS) and bioinformatics analyses. The five sequenced strains were compared to one Ethiopian B. anthracis genome and the other 29 B. anthracis genomes available in the global genetic databases to determine their phylogeny. The genomes of the strains were also analyzed to detect the presence of antimicrobial resistance and virulence genes. The whole genome SNP analysis showed that the Ethiopian B. anthracis strains were grouped in the A clade. Three strains (BA2, BA5, and BA6) belonged to the A.Br.034 subgroup (A.Br.005/006), and two strains (BA1 and BA4) belonged to the A.Br.161 (Heroin) clade of the Trans-Eurasian (TEA) group. The findings of this study will contribute to expanding the current understanding of the anthrax hotspots in Ethiopia, and the phylogenetic correlation and/or diversity of the circulating strains.

Anthrax is a zoonotic disease characterized by rapid onset with usual fatal outcomes in livestock and wildlife. In Ethiopia, anthrax is a persistent disease; however, there are limited data on the isolation and molecular characterization of Bacillus anthracis strains. This study aimed to characterize B. anthracis isolated from animal anthrax outbreaks between 2019 and 2024, from different localities in Ethiopia. B. anthracis was identified using standard microbiology techniques and confirmed by real-time PCR. For the first time in Ethiopia, the genetic diversity of five Bacillus anthracis strains, isolated from dead cattle and goats, was investigated by Whole Genome Sequencing (WGS) and bioinformatics analyses. The five sequenced strains were compared to one Ethiopian B. anthracis genome and the other 29 B. anthracis genomes available in the global genetic databases to determine their phylogeny. The genomes of the strains were also analyzed to detect the presence of antimicrobial resistance and virulence genes. The whole genome SNP analysis showed that the Ethiopian B. anthracis strains were grouped in the A clade. Three strains (BA2, BA5, and BA6) belonged to the A.Br.034 subgroup (A.Br.005/006), and two strains (BA1 and BA4) belonged to the A.Br.161 (Heroin) clade of the Trans-Eurasian (TEA) group. The findings of this study will contribute to expanding the current understanding of the anthrax hotspots in Ethiopia, and the phylogenetic correlation and/or diversity of the circulating strains. [ABSTRACT FROM AUTHOR]

Abstract Background Hepatitis E is an enteric and zoonotic disease caused by hepatitis E virus (HEV) that is mainly transmitted via the faecal-oral route through contaminated food or the environment. The virus is an emerging infectious agent causing acute human infection worldwide. A high seroprevalence of the disease was reported in pregnant women in Addis Ababa, Ethiopia, raising significant public health concern. The presence of HEV specific antibodies were also reported in dromedary camels in the country; however, the infectious virus and/or the viral genome have not been demonstrated to date in animal samples. Methods To address this gap, a total of 95 faecal samples collected from both apparently healthy pigs of uncharacterised types (50 samples) in Burayu and Addis Ababa areas and camels (Camelus dromedarius, 45 samples) in west Hararghe were screened for the presence of HEV genome using universal primers in a fully nested reverse transcription polymerase chain reaction (nRT-PCR). The protocol is capable of detecting HEV in faecal samples from both pigs and camels. Results The nRT-PCR detected HEV genes in six (12%) pig faecal samples and one camel sample (2.2%). Therefore, the results indicate that HEV is circulating in both pigs and camels in Ethiopia and these animals and their products could serve as a potential source of infection for humans. Conclusion The detection of HEV in both animals could raise another concern regarding its public health importance as both animals’ meat and camel milk are consumed in the country. Further studies to determine the prevalence and distribution of the virus in different animals and their products, water bodies, food chain, and vegetables are warranted, along with viral gene sequencing for detailed genetic characterisation of the isolates circulating in the country. This information is critically important to design and institute appropriate control and/or preventive measures.

The aim of the current study was to assess the major animal health problems and their impact on beef cattle production in Doba district of West Harerghe Zone, Ethiopia. The study area was purposively selected, and a simple random sampling method was used to selected households’ fatteners from each kebele and interviewed using structured questionnaires. The present study showed that the overall prevalence of the diseases was internal and external parasite 93.3%, bloat 53.3%, black leg 71.1%, pasteurolosis 71.8%, wound 71.8%, FMD 22.2%, and anthrax 13.33% which affect fattening cattle, respectively, in the study area. All the respondents (100%) involved in the study were experienced with deworming of their animals to protect from parasites. But, only 46.7% and 42.2% of the respondents have accessed veterinary services with limited regularity and vaccination program, respectively, in the study area. Hence, the beef cattle fatting sector should be supported through considering alleviating the major disease affecting this sector and encouraging the farmers’ indigenous knowledge practice with technology.

Rotavirus is a major pathogen responsible for diarrheal disease in calves, resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by rotavirus in calves in the world are inadequately understood, considering that diarrheal disease caused by rotavirus is a vital health problem in calves that interrupts production benefits with reduced weight gain and increased mortality, and its potential for zoonotic spread. The pathological changes made by rotavirus are almost exclusively limited to the small intestine that leads to diarrhea. It is environmentally distributed worldwide and was extensively studied. Reassortment is one of the important mechanisms for generating genetic diversity of rotaviruses and eventually for viral evolution. So, the primary strategy is to reduce the burden of rotavirus infections by practicing early colostrum’s feeding in newborn calves, using vaccine, and improving livestock management. Rotaviruses have a wide host range, infecting many animal species as well as humans. As it was found that certain animal rotavirus strains had antigenic similarities to some human strains, this may be an indication for an animal to play a role as a source of rotavirus infection in humans. Groups A to C have been shown to infect both humans and animals. The most commonly detected strains in both human and animals are G2, G3, G4, and G9, P [6]. Therefore, this review was made to get overview epidemiology status and zoonotic importance of bovine rotavirus.

Lumpy skin disease (LSD) is a viral disease caused by LSD virus and is one of the most economically significant transboundary and emerging diseases of cattle. LSD causes considerable economic losses due to emaciation, damage to hides, infertility, and loss of milk production. In Ethiopia, the disease is distributed almost in all regions and is regarded as one of the most economically important livestock diseases in the country. An outbreak investigation of the disease was monitored from October 2016 to April 2017 in southern pastoral areas of Bale Zone, Oromia, Ethiopia. In December 2016, LSD outbreak occurred in Sawena district of Bale Zone, from which necessary biopsy samples were collected from actively infected animals for the purpose of virus isolation, and characterization using different molecular techniques at National Animal Health and Diagnostic Investigation Center (NAHDIC) of Sebeta, Ethiopia. In addition, clinical examination of infected and in-contact animals was carried out together with a questionnaire survey. Based on the clinical manifestations, LSD was recorded in 18% (94/522) of examined cattle, whereas biopsy samples from 20 clinically positive animals were collected for further laboratory process. The morbidity rate was higher in animals less than two years 28.97% (31/107) than other ages and showed a statistically significant difference with P

Anthrax is a zoonotic disease caused by Bacillus anthracis, a Gram-positive, non-motile, spore-forming bacterium. It is a globally distributed disease, having been reported from all continents that are populated heavily with animals and humans. The objectives were to review general laboratory diagnostic testing methods and reported outbreaks of anthrax in Ethiopia. Anthrax was second top zoonotic priority next to rabies and endemic in Ethiopia that may occur in May and June every year (Anthrax season) in several farming localities. Animal hosts acquire the disease through grazing, usually by ingestion or inhalation while there are three major routs of transmission: ingestion, inhalation and cutaneous. This review indicated that anthrax remains to be major public and animal health problem in Ethiopia. Although suspected cases of anthrax are reported from several districts, they are not well confirmed by laboratories. Prevention and control of anthrax in animals effectively reduces its impact on public health and the national economy. The control of anthrax outbreaks among domestic animals is primarily dependent on rapid identification and treatment of affected animals; enhanced surveillance for additional cases; implementation of control measures including quarantine, prophylaxis, vaccination and the proper disposal of dead animals with decontamination is critical. DOI: http://dx.doi.org/10.5281/zenodo.3773896

Abstract Background Ethiopian livestock production and productivity is still very low due to widespread of diseases. Among the diseases, foot-and-mouth disease (FMD) is an extremely contagious and acute viral disease that causes significant economic problems in the country. A cross sectional study design was conducted from September 2015 to May 2016 to isolate and characterize FMD virus from outbreak cases; determine the sero-prevalence of antibodies against FMD virus (FMDV), and assess potential risk factors associated with sero-prevalence of the disease in selected areas of central Ethiopia. A multistage sampling technique was employed to select the study animals. Isolated viruses were characterized by antigen ELISA (IZLER, Brescia, Italy) and by genetic analysis of the sequence of the viral protein 1 (VP1). Sero-prevalence was determined using an ELISA for antibodies against non-structural proteins of FMDV based on the 3ABC proteins (ID Screen® FMD NSP Competition, ID-VET, Grabels, France). Risk factors for sero-prevalence of antibodies against FMD virus was investigated using logistic regression analysis. Result From outbreak investigation, 28.8% (n = 378) cattle showed signs and lesions suggestive of FMD and 34 samples were subjected to virus isolation. Twenty eight of these cultures exhibited cytopathic effect (CPE) and were serotyped as O, A and SAT 2 FMD viruses. One A and two SAT 2 isolates named A-ETH-19-2015, SAT 2-ETH-18-2015 and SAT 2-ETH-20-2015 were further characterized by phylogenetic analysis. The overall sero-prevalence of antibodies against non-structural proteins of FMDV was 24.2% (n = 574). Cattle herds with crossbreed cattle, with older cattle (> 2 years), and kept together with small ruminants had higher sero-prevalences of antibodies against FMDV (p

Background. Coronavirus and rotavirus are most commonly associated etiologies for calves’ diarrhoea, resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by coronavirus and rotavirus in calves in Ethiopia are inadequately understood. A cross-sectional study was conducted with the aim of isolation and molecular characterization of coronavirus and rotavirus from calves in the central part of Oromia (Bishoftu, Sebata, Holeta, and Addis Ababa), Ethiopia, from November 2018 to May 2019. The four study areas were purposively selected and faecal samples were collected by simple random sampling for diagnosis of coronavirus and rotavirus infection by using the antigen detection enzyme-linked immunosorbent assay (Ag-ELISA) kit. In addition, this study was carried out to have insight in prevalence and associated risk factors of coronavirus and rotavirus infection in calves. Result. During the study, 83 diarrheic and 162 nondiarrheic faecal samples collected from calves less than 4 weeks of age were screened for coronavirus and rotavirus. Of the 83 diarrheic samples, 1 sample (1.2%) was positive for coronavirus antigen and 6 samples (7.2%) were found to be positive for rotavirus antigen by Ag-ELISA. All the nondiarrheic samples were negative for both coronavirus and rotavirus Ag. The overall prevalence of coronavirus and rotavirus infection in calves was estimated at 0.4% (1/245) and 2.45% (6/245), respectively. All samples (7) of ELISA test positive of both coronavirus and rotavirus were propagated in Madin-Darby bovine kidney (MDBK) cells. After 3 subsequent passages, progressive cytopathic effect (CPE), i.e., rounding, detachment, and the destruction of monolayer cell of five samples (1 sample of coronavirus and 4 samples of rotavirus) (71.4%) were observed. At the molecular stage, reverse transcriptase polymerase chain reaction (RT-PCR) technique was used to determine the presence of coronavirus and rotavirus nucleic acid by using specific primers. The 5 samples that were coronavirus and rotavirus antigen positive by ELISA and develop CPE on cell culture were also positive on RT-PCR technique. The prevalence of infection peaked at 1st and 2nd weeks of age in male calves. Conclusion. Diarrheal disease caused by coronavirus and rotavirus has a great health problem in calves that interrupts production benefits with reduced weight gain and increased mortality and its potential for zoonotic spread. So, the present findings show coronavirus and rotavirus infection in calves in Ethiopia that needs to be addressed by practising early colostrum feeding in newborn calves, using vaccine, or improving livestock management.

Pneumonic pasteurellosis is the leading cause of recurrent morbidity and mortality in ruminant livestock in Ethiopia. Its control is mainly done using an annual vaccination with a monovalent whole broth culture of Pasteurella (P.) multocida. However, the multiplicity of the serotypes circulating in the field and the lack of cross-protective immunity hinder the effectiveness of the vaccination program warranting the development of a vaccine with better efficacy. To this effect, the identification, and characterization of the strains from different regions of the country is necessary. In this paper, Pasteurella organisms collected from camels, cattle, goats, and sheep with respiratory signs suggestive of pasteurellosis in the Afar, Tigray, and Benishangul Gumuz regional states were isolated, and characterized. From clinically pneumonic cases, 793 nasal swabs (286 goats, 276 sheep, 168 camels, and 63 cattle) were collected aseptically and cultured on Blood Agar. Bacteria pathogens were identified at the species level by biochemical tests. Culture positivity was 29.3% (243/793). The isolation frequencies of B. trehalosi, M. haemolytica, and P.multocida were 47.7% (116/243), 43.2% (105/243), and 9.1% (22/243), respectively. A higher isolation rate was observed in sheep (37.4%), and the lowest in cattle (6.2%). Mixed infection with B. trehalosi and M. haemolytica was observed in sheep, goats, and camels. Despite the higher frequencies of isolation of B. trehalosi and M. haemolytica from all host species, the vaccine currently being used in Ethiopia consists of only P. multocida biotypes A for sheep and goats and biotype B for cattle. Moreover, camels are not considered in the pasteurellosis vaccination program in the country. Therefore, the result of the study suggests the need to include B. trehalosi and M. haemolytica in the vaccine preparation as well as underlines the relevance of considering camels in the vaccination program. [ABSTRACT FROM AUTHOR]

We found serologic evidence for the circulation of Middle East respiratory syndrome coronavirus among dromedary camels in Nigeria, Tunisia, and Ethiopia. Circulation of the virus among dromedaries across broad areas of Africa may indicate that this disease is currently underdiagnosed in humans outside the Arabian Peninsula.

Across-sectional questionnaire survey and focused group discussions were conducted to characterize camel production systems and to evaluate reproductive performances of camels at their natural pastoralist management systems of Somali region. A total of 100 households were included in the study during the period of October 2012 to March 2013. About 98% of Somali pastoralists preferred camels as their first choice over other livestock species and mainly kept in the society for milk and meat production. The camel management dominating in the study areas of Somali region is traditional nomadic. Camel is one of the most important livestock for Somali pastoralists’ livelihood as a source of milk, meat and draught power. Mature female camels were dominant (54.87%) in the camel herd. The ratio of male to female camel was 1:13. Mean age at first calving and calving interval were 62.16±10.44 and 23.28±3.36 months respectively. Age at first calving and calving interval can be minimized to 57±5.52 and 21.84±4.8 months by proper husbandry and health care. The mean lactation length was 11.51±1.91 months. Diseases and predators were reported as the main causes of calf mortality. In the herd dynamic simulation calf mortality rate can be reduced at least to 7% only by preventing predators attack. Diseases (66%), lack of pasture (59%) and security (47%) were the main constraints in camel production of the study areas. For the better productivity of camels, the major constraints such as disease problems, lack of pasture and tribal conflicts should be mitigated. Proper husbandry and health services can play significant roles in the long term improvement of camel production and productivity of the region.

The aim of the current study was to assess the major animal health problems and their impact on beef cattle production in Doba district of West Harerghe Zone, Ethiopia. The study area was purposively selected, and a simple random sampling method was used to selected households' fatteners from each kebele and interviewed using structured questionnaires. The present study showed that the overall prevalence of the diseases was internal and external parasite 93.3%, bloat 53.3%, black leg 71.1%, pasteurolosis 71.8%, wound 71.8%, FMD 22.2%, and anthrax 13.33% which affect fattening cattle, respectively, in the study area. All the respondents (100%) involved in the study were experienced with deworming of their animals to protect from parasites. But, only 46.7% and 42.2% of the respondents have accessed veterinary services with limited regularity and vaccination program, respectively, in the study area. Hence, the beef cattle fatting sector should be supported through considering alleviating the major disease affecting this sector and encouraging the farmers' indigenous knowledge practice with technology. [ABSTRACT FROM AUTHOR]

Background: Hepatitis E is an enteric and zoonotic disease caused by hepatitis E virus (HEV) that is mainly transmitted via the faecal-oral route through contaminated food or the environment. The virus is an emerging infectious agent causing acute human infection worldwide. A high seroprevalence of the disease was reported in pregnant women in Addis Ababa, Ethiopia, raising significant public health concern. The presence of HEV specific antibodies were also reported in dromedary camels in the country; however, the infectious virus and/or the viral genome have not been demonstrated to date in animal samples. Methods: To address this gap, a total of 95 faecal samples collected from both apparently healthy pigs of uncharacterised types (50 samples) in Burayu and Addis Ababa areas and camels (Camelus dromedarius, 45 samples) in west Hararghe were screened for the presence of HEV genome using universal primers in a fully nested reverse transcription polymerase chain reaction (nRT-PCR). The protocol is capable of detecting HEV in faecal samples from both pigs and camels. Results: The nRT-PCR detected HEV genes in six (12%) pig faecal samples and one camel sample (2.2%). Therefore, the results indicate that HEV is circulating in both pigs and camels in Ethiopia and these animals and their products could serve as a potential source of infection for humans. Conclusion: The detection of HEV in both animals could raise another concern regarding its public health importance as both animals' meat and camel milk are consumed in the country. Further studies to determine the prevalence and distribution of the virus in different animals and their products, water bodies, food chain, and vegetables are warranted, along with viral gene sequencing for detailed genetic characterisation of the isolates circulating in the country. This information is critically important to design and institute appropriate control and/or preventive measures. [ABSTRACT FROM AUTHOR]

Rotavirus is a major pathogen responsible for diarrheal disease in calves, resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by rotavirus in calves in the world are inadequately understood, considering that diarrheal disease caused by rotavirus is a vital health problem in calves that interrupts production benefits with reduced weight gain and increased mortality, and its potential for zoonotic spread. The pathological changes made by rotavirus are almost exclusively limited to the small intestine that leads to diarrhea. It is environmentally distributed worldwide and was extensively studied. Reassortment is one of the important mechanisms for generating genetic diversity of rotaviruses and eventually for viral evolution. So, the primary strategy is to reduce the burden of rotavirus infections by practicing early colostrum's feeding in newborn calves, using vaccine, and improving livestock management. Rotaviruses have a wide host range, infecting many animal species as well as humans. As it was found that certain animal rotavirus strains had antigenic similarities to some human strains, this may be an indication for an animal to play a role as a source of rotavirus infection in humans. Groups A to C have been shown to infect both humans and animals. The most commonly detected strains in both human and animals are G2, G3, G4, and G9, P [6]. Therefore, this review was made to get overview epidemiology status and zoonotic importance of bovine rotavirus. [ABSTRACT FROM AUTHOR]

Lumpy skin disease (LSD) is a viral disease caused by LSD virus and is one of the most economically significant transboundary and emerging diseases of cattle. LSD causes considerable economic losses due to emaciation, damage to hides, infertility, and loss of milk production. In Ethiopia, the disease is distributed almost in all regions and is regarded as one of the most economically important livestock diseases in the country. An outbreak investigation of the disease was monitored from October 2016 to April 2017 in southern pastoral areas of Bale Zone, Oromia, Ethiopia. In December 2016, LSD outbreak occurred in Sawena district of Bale Zone, from which necessary biopsy samples were collected from actively infected animals for the purpose of virus isolation, and characterization using different molecular techniques at National Animal Health and Diagnostic Investigation Center (NAHDIC) of Sebeta, Ethiopia. In addition, clinical examination of infected and in-contact animals was carried out together with a questionnaire survey. Based on the clinical manifestations, LSD was recorded in 18% (94/522) of examined cattle, whereas biopsy samples from 20 clinically positive animals were collected for further laboratory process. The morbidity rate was higher in animals less than two years 28.97% (31/107) than other ages and showed a statistically significant difference with P < 0.05. Female animals showed higher morbidity rate of 20.59% (76/369) than male animals (11.76%) (18/153) with a significant difference at P ≤ 0.003. Mortality rate and case fatality were also significantly higher in young animals than other age groups. Viruses were isolated from both skin biopsies and nasal swabs on Vero cell line. From both skin biopsies and nasal swabs, the virus DNA was identified by amplifying the 172 bp DNA fragment using real-time and conventional PCR. Providing adequate diagnostic facilities, establishing strategic policies for effective control and eradication and awareness creations for communities for early identification or reporting were recommendations made to minimize economic losses of the disease. [ABSTRACT FROM AUTHOR]

Introduction: Lumpy skin disease (LSD) is viral disease affecting cattle production and productivity in Ethiopia. As a prevention method, vaccinations have been used for a long period with a questionable output due to the existence of LSD outbreaks in vaccinated herds in different parts of Ethiopia., Methods: A longitudinal study was performed from October 2019 to April 2020 with the objective of assessing the humoral immune response of cattle with a serum neutralization test (SNT) from different management systems in central Ethiopia. In this study, theserum was collected from 113 cattle (extensive (60/113) and intensive (53/113) management systems) before and after vaccination., Results and Discussion: From collected sera, a limited number of cattle had seroconversion before vaccination (7.08%). On the other hand, it is obvious the seroconversion rises post vaccination. Accordingly, seroconversion starts to increase after a week (8.85% at 7 dpv) post-vaccination which proceeds to significantly increase at 30 days post vaccination (dpv) (41.65% (25/60)). Furthermore, the risk factor study before and after vaccination showed intensively managed cattle with significantly higher levels of antibody titer at 7 dpv (OR = 1.17; 95% CI = 0.22, 6.2; p = 0.016) and 30 dpv (OR = 3.67; 95% CI = 1.1, 12.29; p = 0.035) compared with that of extensively managed cattle. The other animal-related risk factor that showed a significant difference was breeds and a specific age group ([4½, 7] years) at 15 dpv (OR = 6.69; 95% CI = 2.02, 22.08; p = 0.002) and 30 dpv (OR = 4.24; 95% CI = 1.22, 14.71; p = 0.023); respectively., Conclusion: This study showed an overall lower antibody detection across the study, posing a question on the current LSD-vaccine efficacy. Therefore, a circulating strain of LSDV should be cross-checked with the vaccine strain and adaptations should be made from it., Competing Interests: The authors declare that they have no competing interests., (© 2023 Moje et al.)

Introduction: Foot-and-mouth disease is globally one of the most economically important viral diseases of cloven-hoofed animals that can be controlled by different strategies, where vaccination plays an important role. Selection of adjuvant added to vaccine preparation is crucial in ensuring the protective effect of the vaccine. Aluminum hydroxide gel mixed with saponin (AS) is widely used adjuvant, with its suboptimal immune response in FMD vaccine. The present study was undertaken to evaluate different ingredients of adjuvants for inactivated trivalent (A, O and SAT 2) FMD vaccine and to demonstrate the effect of booster dose in cattle., Methods: Cattle were grouped into five; four experimental and one control, with six animals in each group and immunized with trivalent vaccine with various formulations of adjuvants. Immune response was measured using Solid Phase Competitive Enzyme Linked Immune Sorbent Assay (SPCE)., Results: The antibody level in cattle immunised with a vaccine formulation containing a mixture of aluminum hydroxide gel and saponin (AS) were significantly lower than AS boosted group for the three serotypes (p<0.05, t -test), which directs the need for booster dose. Whereas the antibody response in the AS + oil group was higher followed by oil alone. The AS preparation with a booster dose has shown better immune response compared to the group without., Conclusion: The findings of this study could suggest that oil based and AS with oil could replace the conventional aluminum hydroxide gel and saponin adjuvants in FMD vaccine preparations. Challenge test was not successful indicating the need for further research on the virus infectivity., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (© 2023 Ayele et al.)

Introduction: Infectious bursal disease virus (IBDV) is an avian viral pathogen that causes infectious bursal disease (IBD) of chickens. The disease has been endemic in Ethiopia since 2002, and vaccination has been practiced as the major means of disease prevention and control. An IBD vaccine is produced in Ethiopia using primary chicken embryo fibroblast (CEF) cell, which is time-consuming, laborious, and uneconomical. The present study was carried out to develop cell-based IBDV LC-75 vaccine using Vero cells and to evaluate the safety, immunogenicity and protection level., Methods: Identity of the vaccine seed was confirmed with gene-specific primers using reverse transcription polymerase chain reaction (RT-PCR). Confluent monolayer of Vero cells was infected with vaccine virus and serial passage continued till passage 10. A characteristic virus-induced cytopathic effect (CPE) was observed starting from passage 2 on the third day post-infection. The infectious titer of adapted virus showed a linear increment along the passage level. The virus-induced specific antibody was determined using indirect ELISA after vaccination of chicks through ocular route., Results: The antibody titer measured from Vero cells vaccinated chicks revealed similar level with the currently available CEF cell-based vaccine, hence no significant difference. Chicks vaccinated with Vero cell adapted virus showed complete protection against very virulent IBDV, while unvaccinated group had 60% morbidity and 25% mortality., Conclusion: It is concluded that the IBDV vaccine strain well adapted on Vero cells and found to be immunogenic induces antibody development and successfully protects chicks against challenge with the circulating field IBDV isolate. Hence, it is recommended to produce IBD vaccine using Vero cell culture at the industrial scale to conquer the limitations caused by using CEF cells and thus to vaccinate chicks population to protect against the circulating IBDV infection., Competing Interests: The authors report no conflicts of interest in this work., (© 2021 Kebede et al.)

Introduction: In 2017 infectious bursal disease viruses (IBDVs) were reclassified into genogroups based on nature of clustering on a phylogenetic tree constructed using VP2 gene sequence data rather than according to their pathotype and/or antigenic types. Ethiopian IBD viruses were not reclassified according to the proposed genogrouping., Methods: In order to genogroup the Ethiopian IBDVs, available VP2 gene sequences data together with reference strain sequences were retrieved from GenBank and genogrouped as recently recommended based on evolutionary tree reconstruction and determination of their clustering on the phylogenetic tree., Results: The Ethiopian IBDVs were grouped into genogroups 1 and 3 that antigenically represent classically virulent and very virulent IBDVs, respectively. The genogroup 1 IBDVs were clustered with the vaccine strain while the genogroup 3 viruses were clustered with four known viruses belonging to sub-genogroup 3a and sub-genogroup 3b. Almost half of the Ethiopian IBDVs reported did not cluster with the specific sub-groups of genogroup 3; rather, the isolates were clustered differently suggesting they deserve a different sub-genogroup tentatively proposed as 3d. The two genogroups observed based on clustering on a phylogenetic tree were supported by corresponding deduced amino acid changes in similar positions in VP2 sequences. In addition, virulence marker amino acid genes coupled with second major hydrophilic region (amino acid positions 314-325) were predicted in these sequences that could be responsible for the occurrence of IBD outbreaks., Conclusion: A new sub-genogroup of IBDVs, 3d, were observed in the sequences that could be one of the reasons for the frequent occurrence of IBD outbreaks and questions the protective potential of the existing vaccine. To institute disease control in the country, the effectiveness of the vaccine in use needs to be assessed in vivo against both genogroups 1 and 3 viruses and all three sub-genogroup 3 viruses circulating in the country., Competing Interests: The author reports no conflicts of interest in this work., (© 2021 Bari.)

Epitopes on the surface of the foot-and-mouth disease virus (FMDV) capsid have been identified by monoclonal antibody (mAb) escape mutant studies leading to the designation of four antigenic sites in serotype A FMDV. Previous work focused on viruses isolated mainly from Asia, Europe and Latin America. In this study we report on the prediction of epitopes in African serotype A FMDVs and testing of selected epitopes using reverse genetics. Twenty-four capsid amino acid residues were predicted to be of antigenic significance by analysing the capsid sequences (n = 56) using in silico methods, and six residues by correlating capsid sequence with serum-virus neutralization data. The predicted residues were distributed on the surface-exposed capsid regions, VP1-VP3. The significance of residue changes at eight of the predicted epitopes was tested by site-directed mutagenesis using a cDNA clone resulting in the generation of 12 mutant viruses involving seven sites. The effect of the amino acid substitutions on the antigenic nature of the virus was assessed by virus neutralization (VN) test. Mutations at four different positions, namely VP1-43, VP1-45, VP2-191 and VP3-132, led to significant reduction in VN titre (P value = 0.05, 0.05, 0.001 and 0.05, respectively). This is the first time, to our knowledge, that the antigenic regions encompassing amino acids VP1-43 to -45 (equivalent to antigenic site 3 in serotype O), VP2-191 and VP3-132 have been predicted as epitopes and evaluated serologically for serotype A FMDVs. This identifies novel capsid epitopes of recently circulating serotype A FMDVs in East Africa., (© 2015 The Authors.)