Publications by authors named "Esayas Gelaye"

31 Publications

Vaccine matching and antigenic variability of foot-and-mouth disease virus serotypes O and A from 2018 Ethiopian isolates.

Int Microbiol 2021 Jul 5. Epub 2021 Jul 5.

National Veterinary Institute, POBox: 19, Bishoftu, Ethiopia.

Foot-and-mouth disease (FMD) is highly infectious, limits live animal trade, and affects ranchers owing to the loss of animal yield. The present study was designed to perform vaccine matching for field FMD virus isolates from clinically diseased cattle and assess the antigenic properties of the field isolates against the current vaccine strains used for vaccine production at the National Veterinary Institute, Ethiopia. Both sequencing and reverse transcription-polymerase chain reactions were used for distinguishing between the viral strains. To evaluate the serological relationship of the vaccine strain with these field isolates (r1 value), in vitro cross-neutralization was performed using ETH/6/2000 and ETH/38/2005 antisera. Infectious field FMD viral samples represented serotypes A and O. Sequence analysis showed that serotype A VP1/1D possessed amino acid variability at positions 28 and 42 to 48, 138, 141, 142, 148, 156, 173, and 197 compared with the ETH/6/2000 vaccine strain, whereas serotype O possessed amino acid variability at positions 45, 48, 138, 139, 140, 141, and 197 compared with the ETH/38/2005 vaccine strain. Based on the one-dimensional virus neutralization test, serotypes A and O demonstrated antigenic matching of up to 13/17 (76.47%) with the vaccine strain, except for the isolates ETH/40/2018, ETH/48/2018, ETH/55/2018, and ETH/61/2018, which had r-values less than 0.3. Therefore, the currently used vaccine strains ETH/38/2005 for serotype O and ETH/6/2000 for serotype A protected against all and most field viruses characterized as serotypes O and A, respectively, and amino acid residue variation was observed in different FMD virus B-C loops, G-H loops, and C-termini of VP1 at sites 1 and 3 in both serotypes.
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http://dx.doi.org/10.1007/s10123-021-00178-wDOI Listing
July 2021

Antigenic and Molecular Characterization of Virulent Newcastle Disease Viruses Circulating in Ethiopia Between 1976 and 2008.

Vet Med (Auckl) 2021 4;12:129-140. Epub 2021 Jun 4.

Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald, Germany.

Introduction: Newcastle disease virus (NDV) cultures held in the isolate collections in Ethiopia between 1976 and 2008 were not characterized using biological and molecular techniques. The already characterized NDV isolates belonged to genotype VI but the genetic nature of previously collected isolates, which could shade light on the history of introduction into the country and their evolutionary relationships, were not established.

Methods: A total of 14 NDVs (11 obtained from outbreak cases in chickens and three commercial vaccinal strains used in the country) were inoculated into specific pathogen free (SPF) embryonated chicken eggs (ECE). Allantoic fluids harvested from grown SPF ECE were tested by heamagglutination (HA) and heamagglutination inhibition (HI) tests. Partial F gene sequences were generated for all samples and molecular evolutionary relationships were reconstructed together with reference sequences freely available online. The pathogenicities of the isolates were assessed in vivo by determining their intracerebral pathogenicity index (ICPI) in day-old chicks and molecularly by determination of F gene cleavage sites.

Results: Of these, 12 viruses (two vaccines and 10 outbreaks) were successfully propagated as evidenced by a positive heamagglutination (HA) test. These 12 propagated viruses were further characterized by heamagglutination inhibition (HI) test, of which only three viruses reacted with monoclonal antibody (MAb 617/616) specific for pigeon paramyxovirus-1. In addition, all 14 viruses were characterized by partial fusion (F) gene sequencing and phylogenetic tree reconstruction. The Ethiopian NDV isolates clustered with genotype VI viruses, forming two clades (groups 1 and 2) that have ancestral relationships with Egypt-1990 and Sudan-1975 like viruses.

Discussion: The characterized genotype VI NDVs were genetically similar to currently circulating NDVs in Ethiopia. The isolates had cleavage sites consistent with mesogenic/velogenic NDV with a mean ICPI value of 1.76, indicating that the isolates were velogenic. Two and four highly virulent viruses were thermostable at 56°C for 2 hours and 1 hour, respectively. To reduce chicken mortality and production losses, proper control of the disease should be instituted using high quality and protective vaccines together with strong biosecurity measures.
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http://dx.doi.org/10.2147/VMRR.S297281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8187085PMC
June 2021

Phenotypic and genetic characterization of MERS coronaviruses from Africa to understand their zoonotic potential.

Proc Natl Acad Sci U S A 2021 06;118(25)

School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong (HKU), Pokfulam, Hong Kong Special Administrative Region, People's Republic of China;

Coronaviruses are pathogens of pandemic potential. Middle East respiratory syndrome coronavirus (MERS-CoV) causes a zoonotic respiratory disease of global public health concern, and dromedary camels are the only proven source of zoonotic infection. More than 70% of MERS-CoV-infected dromedaries are found in East, North, and West Africa, but zoonotic MERS disease is only reported from the Arabian Peninsula. We compared viral replication competence of clade A and B viruses from the Arabian Peninsula with genetically diverse clade C viruses found in East (Egypt, Kenya, and Ethiopia), North (Morocco), and West (Nigeria and Burkina Faso) Africa. Viruses from Africa had lower replication competence in ex vivo cultures of the human lung and in lungs of experimentally infected human-DPP4 (hDPP4) knockin mice. We used lentivirus pseudotypes expressing MERS-CoV spike from Saudi Arabian clade A prototype strain (EMC) or African clade C1.1 viruses and demonstrated that clade C1.1 spike was associated with reduced virus entry into the respiratory epithelial cell line Calu-3. Isogenic EMC viruses with spike protein from EMC or clade C1.1 generated by reverse genetics showed that the clade C1.1 spike was associated with reduced virus replication competence in Calu-3 cells in vitro, in ex vivo human bronchus, and in lungs of hDPP4 knockin mice in vivo. These findings may explain why zoonotic MERS disease has not been reported from Africa so far, despite exposure to and infection with MERS-CoV.
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http://dx.doi.org/10.1073/pnas.2103984118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237650PMC
June 2021

Establishing a Robust Manufacturing Platform for Recombinant Veterinary Vaccines: An Adenovirus-Vector Vaccine to Control Newcastle Disease Virus Infections of Poultry in Sub-Saharan Africa.

Vaccines (Basel) 2020 Jun 26;8(2). Epub 2020 Jun 26.

Viral Vectors and Vaccines Bioprocessing Group, Department of Bioengineering, McGill University, Montreal, QC H3A 0G4, Canada.

Developing vaccine technology platforms to respond to pandemic threats or zoonotic diseases is a worldwide high priority. The risk of infectious diseases transmitted from wildlife and domestic animals to humans makes veterinary vaccination and animal health monitoring highly relevant for the deployment of public health global policies in the context of "one world, one health" principles. Sub-Saharan Africa is frequently impacted by outbreaks of poultry diseases such as avian influenza and Newcastle Disease (ND). Here, an adenovirus-vectored vaccine technology platform is proposed for rapid adaptation to ND or other avian viral threats in the region. Ethiopian isolates of the Newcastle Disease virus (NDV) were subjected to sequence and phylogenetic analyses, enabling the construction of antigenically matched vaccine candidates expressing the fusion (F) and hemagglutinin-neuraminidase (HN) proteins. A cost-effective vaccine production process was developed using HEK293 cells in suspension and serum-free medium. Productive infection in bioreactors (1-3L) at 2 × 10 cells/mL resulted in consistent infectious adenoviral vector titers of approximately 5-6 × 10 TCID/mL (approximately 10VP/mL) in the harvest lysates. Groups of chickens were twice immunized with 1 × 10 TCID of the vectors, and full protection against a lethal NDV challenge was provided by the vector expressing the F antigen. These results consolidate the basis for a streamlined and scalable-vectored vaccine manufacturing process for deployment in low- and medium-income countries.
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http://dx.doi.org/10.3390/vaccines8020338DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7350225PMC
June 2020

Molecular characterization of foot-and-mouth disease viruses circulating in Ethiopia between 2008 and 2019.

Transbound Emerg Dis 2020 Nov 1;67(6):2983-2992. Epub 2020 Jul 1.

The Pirbright Institute, Pirbright, Woking, UK.

One of the constraints to controlling foot-and-mouth disease (FMD) in East Africa is the incomplete knowledge of the specific FMD virus (FMDV) strains circulating and the way in which these viruses move across countries in the region. This retrospective study focuses on Ethiopia, which has one of the largest FMD-susceptible livestock populations in Africa. Analyses of FMDV positive samples collected between 2008 and 2019 demonstrate that serotypes O (n = 175), A (n = 51) and SAT 2 (n = 33) were present in the country. Phylogenetic analysis of the VP1 sequences for these viruses showed that there were at least seven different FMD viral clades circulating during this period: O/EA-3, O/EA-4, A/AFRICA/G-I, A/AFRICA/G-IV, A/AFRICA/G-VII, SAT2/VII and SAT2/XIII. Although these results only represent a snapshot and might not reflect all FMDV lineages that were present, they highlight the importance of serotype O, as well as the complexity and co-existence of FMDV serotypes in Ethiopia and surrounding countries. These sequence data also support the idea that there are two FMDV ecosystems existing in East Africa. Data from retrospective studies, such as these presented here, will be beneficial for vaccine selection and vaccination campaigns to control FMDV within Ethiopia.
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http://dx.doi.org/10.1111/tbed.13675DOI Listing
November 2020

A vaccine-matching assessment of different genetic variants of serotype O foot-and-mouth disease virus isolated in Ethiopia between 2011 and 2014.

Arch Virol 2020 Aug 20;165(8):1749-1757. Epub 2020 May 20.

National Veterinary Institute, P.O.BOX: 19, Bishoftu, Ethiopia.

The aim of this study was to assess the vaccine-matching and antigenic properties of foot-and-mouth disease virus (FMDV) isolates collected from Ethiopia between 2011 and 2014. Samples (n = 51) were collected from cattle and pigs with clinical signs consistent with foot-and-mouth disease (FMD) on farms in Debre-Berhan, Debre-Zeit/Bishoftu, Sidamo, Mekelle, and Addis Ababa. Infectious FMDV was isolated using BHK-21 cell cultures from 38 of the 51 field samples (74.5%). All of these FMDV-positive samples were characterized as serotype O, belonging to two East Africa topotypes (EA-3 and EA-4), and their VP1-encoding sequences demonstrated amino acid sequence variability encompassing 27 positions in comparison to the vaccine strain (O/ETH/38/2005) currently provided by the National Veterinary Institute of Ethiopia. One-dimensional virus neutralization test (1 dm VNT) results showed that O/ETH/38/2005 was antigenically matched to 10 of the 16 serotype O viruses. These findings indicate that the O/ETH/38/2005 vaccine strain can provide protection against outbreaks caused by the O/EA-3 topotype, although poorer vaccine-matching results for the O/EA-4 topotype reinforce the importance of using a good-quality vaccine with high coverage in the susceptible herds with supporting post-vaccination serosurveillance to ensure that sufficient antibody titers are generated in the vaccinated animals.
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http://dx.doi.org/10.1007/s00705-020-04662-yDOI Listing
August 2020

Molecular characterization of foot-and-mouth disease viruses collected from Northern and Central Ethiopia during the 2018 outbreak.

Vet World 2020 Mar 24;13(3):542-548. Epub 2020 Mar 24.

Department of Research and Development, National Veterinary Institute, P.O. Box: 19, Bishoftu, Ethiopia.

Background And Aim: Foot-and-mouth disease (FMD) is endemic in several developing countries and affects poor farmers through loss of production, death of diseased animals, and loss of animal byproducts. Forty-three samples were collected from 12 sites of five geographical located areas from suspected FMD virus (FMDV)-infected cattle during 2018. This study aimed to isolate and characterize the FMDVs using reverse transcription-polymerase chain reaction (RT-PCR) and gene sequencing.

Materials And Methods: Forty-three FMDV-suspected clinical samples cultured on BHK-21 cell were examined, followed by virus serotype identification using RT-PCR and gene sequencing.

Results: Twenty-nine (67.44%) samples were cultured on BHK-21 cell, of which 14 (32.56%) were not isolated; the 43 samples were analyzed using FMDV screening primers and serotype-specific primers. The contribution of the disease-causing serotype was serotype O of 8 (18.60%) samples, serotype A of 20 (46.51%) samples, and mixed infection (O and A) of 1 (2.33%) sample. Serotypes O and A were further characterized by phylogenetic analysis, which grouped them under East Africa 3 and Africa topotypes of genotype IV, respectively. Interestingly, serotype A was isolated for the 1 time from Keyet sub-woreda and Mulo woreda of Ethiopia, and mixed serotypes (O and A) were identified from the purchased animal.

Conclusion: Molecular test result, sequencing, and phylogenetic tree reconstruction analysis revealed that the 2018 FMD outbreak in Ethiopia was caused by FMDV serotypes O and A. FMDV serotype A was the predominant strain circulating in most study areas of the country. Infections in one sample with mixed serotypes of O and A were also reported. The authors recommend a vaccine matching study of those field isolated viruses with the vaccine strain.
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http://dx.doi.org/10.14202/vetworld.2020.542-548DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7183482PMC
March 2020

Sequence-based comparison of field and vaccine strains of infectious bursal disease virus in Ethiopia reveals an amino acid mismatch in the immunodominant VP2 protein.

Arch Virol 2020 Jun 13;165(6):1367-1375. Epub 2020 Apr 13.

National Veterinary Institute, P.O. Box 19, Bishoftu, Ethiopia.

Sequencing of the VP2 region was carried out to identify amino acid mismatches between vaccine strains and field isolates of infectious bursal disease virus (IBDV). Viruses were isolated in chicken embryo fibroblast (DF-1) cells using pooled samples of bursa collected from nine outbreaks, which affected 30,250 chickens in five localities, with an overall mortality of 47.87%. Virus strains were identified by comparing the deduced amino acid sequence between positions 232 and 446 of the immunodominant VP2 epitope. All of the pooled samples were positive for IBDV. RT-PCR yielded a 645-bp DNA fragment of the VP2 gene. Phylogenetic analysis of this fragment revealed clustering of these isolates with very virulent IBDV strains. The amino acid sequences of these isolates were identical to those of the European very virulent strains UK 661 and DV 86, except at position 222, but differed from the vaccine strains used in Ethiopia, suggesting the possible introduction of virulent virus strains to Ethiopia from Europe. Our study demonstrates the widespread presence of very virulent strains of IBDV on poultry farms in Ethiopia and demonstrates the need to evaluate the protective level of existing vaccines against circulating field viruses.
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http://dx.doi.org/10.1007/s00705-020-04622-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225184PMC
June 2020

Molecular characterization of Mannheimia haemolytica isolates associated with pneumonic cases of sheep in selected areas of Central Ethiopia.

BMC Microbiol 2018 12 5;18(1):205. Epub 2018 Dec 5.

National Veterinary Institute, P.O. Box 19, Bishoftu, Ethiopia.

Background: Mannheimia haemolytica has been recognized as the principal cause of pneumonic pasteurellosis in sheep and goats. It is one of the important diseases of small ruminants in Ethiopia. While annual vaccination using a monovalent vaccine (inactivated Pasteurella multocida biotype A) is common, respiratory diseases are still reported in various parts of Ethiopia. This suggests the need for further investigation into the species and strains responsible for the disease, which is vital information for development of a multivalent vaccine. The objective of the current study was to isolate M. heamolytica associated with pneumonic cases of sheep in selected areas of Central Ethiopia, determine its role and the strains/genotypes of the bacterium circulating in the study area.

Results: Bacteriological analysis of nasal swab samples collected from a total of 76 pneumonic cases of sheep showed that M. haemolytica was isolated from 26 of them while B.trehalosi from two cases. Further molecular analyses of the isolates using M. haemolytica species-specific and M.haemolytica serotype-1 antigen specific PCR assays revealed, 26 of the isolates were identified as M. haemolytica of which 21 of them were M. haemolytica serotype-1. Both M. haemolytica and B.trehalosi isolates were not detected in a PCR assay targeting capsular biosynthesis gene (capA) of P.multocida despite the non-specific products observed in M. haemolytica isolates. Phylogenetic analysis of M. haemolytica isolates included in this study in comparison with the reference strains with respect to PHSSA and Rpt2 genes revealed that the Ethiopian M. haemolytica isolates constituted three distinct genotypes consistent with site of origin.

Conclusion: The study indicated that M.haemolytica is commonly associated with cases of pneumonia in sheep in the study areas of central Ethiopia although the remaining other pathogens responsible for majority of the cases are yet to be determined. Molecular characterization revealed the existence of three genotypes of M. haemolytica circulating in the study areas consistent to the site of isolation. The findings suggest further extensive work to determine all pathogens associated with sheep pneumonia and the strain distribution of M. heamolytica to understand its molecular epidemiology at national level and design cost effective prevention and control methods.
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http://dx.doi.org/10.1186/s12866-018-1338-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6280500PMC
December 2018

Evaluation of spray and oral delivery of Newcastle disease I2 vaccine in chicken reared by smallholder farmers in central Ethiopia.

BMC Vet Res 2018 Feb 13;14(1):48. Epub 2018 Feb 13.

National Veterinary Institute, Bishoftu, Ethiopia.

Background: Newcastle disease (ND) is a highly infectious disease causing considerable economic losses to poultry farmers worldwide. Conventional vaccine delivery methods are not suitable for smallholder and rural poultry producers, and thus appropriate vaccination methods need to be sought. This study was carried out with the main objective of evaluating the efficacy of ND I2 vaccine delivered via drinking water and spray under smallholder farmers' condition in Minjar-Shenkora district, central Ethiopia. Twenty households were randomly assigned to intervention and control groups. Chickens owned by the selected households were randomly assigned to one of the three intervention groups. Blood samples were collected regularly for antibody assay from individual chicken vaccinated with ND I2 vaccine using different routes.

Results: At baseline, there was no difference in antibody titer among the experimental groups. After the first and booster vaccinations, the three vaccinated groups had significantly higher antibody titer (P < 0.001) than the unvaccinated control group. Interestingly, there was no statistically significant difference in antibody titer among the vaccinated groups. Out of the 40 chicken in the unvaccinated control only 14 had antibody titter≥ log. Similarly 19/37 of chicken in the drinking water group, 19/37 of chicken in the eye drop group and 20/40 chicken in the spray group had antibody titer ≥ log. Two weeks after the first vaccination the proportion of chicken with antibody titer ≥ log rose to 23/37, 30/37 and 29/40 in the group vaccinated via drinking water, eye drop and spray, respectively. The proportion remained low in unvaccinated group. Hundred percent of the vaccinated chicken survived after infection with the virulent ND virus (Alemaya strain); whereas only 40% survived from the unvaccinated control group.

Conclusion: The results of this study showed that ND I2 vaccine administered via drinking water and spray under smallholder farmers' situation provoked protective antibody level similar to the eye drop method. The use of ND I2 vaccine could contribute to food security if used by rural poultry farmers properly.
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http://dx.doi.org/10.1186/s12917-018-1355-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5812036PMC
February 2018

Identification of Clade E Avipoxvirus, Mozambique, 2016.

Emerg Infect Dis 2017 09;23(9):1602-1604

Analysis of scab samples collected from poultry during outbreaks of fowlpox in Mozambique in 2016 revealed the presence of clade E avipoxviruses. Infected poultry were from flocks that had been vaccinated against fowlpox virus. These findings require urgent reevaluation of the vaccine formula and control strategies in this country.
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http://dx.doi.org/10.3201/eid2309.161981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5572868PMC
September 2017

A novel HRM assay for the simultaneous detection and differentiation of eight poxviruses of medical and veterinary importance.

Sci Rep 2017 02 20;7:42892. Epub 2017 Feb 20.

Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, Austria.

Poxviruses belonging to the Orthopoxvirus, Capripoxvirus and Parapoxvirus genera share common host species and create a challenge for diagnosis. Here, we developed a novel multiplex PCR method for the simultaneous detection and differentiation of eight poxviruses, belonging to three genera: cowpox virus (CPXV) and camelpox virus (CMLV) [genus Orthopoxvirus]; goatpox virus (GTPV), sheeppox virus (SPPV) and lumpy skin disease virus (LSDV) [genus Capripoxvirus]; orf virus (ORFV), pseudocowpox virus (PCPV) and bovine papular stomatitis virus (BPSV) [genus Parapoxvirus]. The assay is based on high-resolution melting curve analysis (HRMCA) of PCR amplicons produced using genus specific primer pairs and dsDNA binding dye. Differences in fragment size and GC content were used as discriminating power. The assay generated three well separated melting regions for each genus and provided additional intra-genus genotyping allowing the differentiation of the eight poxviruses based on amplicon melting temperature. Out of 271 poxviral DNA samples tested: seven CPXV, 25 CMLV, 42 GTPV, 20 SPPV, 120 LSDV, 33 ORFV, 20 PCPV and two BPSV were detected; two samples presented co-infection with CMLV and PCPV. The assay provides a rapid, sensitive, specific and cost-effective method for the detection of pox diseases in a broad range of animal species and humans.
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http://dx.doi.org/10.1038/srep42892DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5316968PMC
February 2017

Investigation of Marek's disease virus from chickens in central Ethiopia.

Trop Anim Health Prod 2017 Feb 14;49(2):403-408. Epub 2016 Dec 14.

Research and Development Department, National Veterinary Institute (NVI), P.O. Box 19, Debre zeit, Ethiopia.

Marek's disease (MD) is a lymphoproliferative and neuropathic disease of domestic chickens and less commonly, turkeys and quails, caused by a highly contagious, cell-associated, oncogenic herpesvirus. In Ethiopia, MD is believed to be introduced with importation of exotic and crossbred to improve the poultry production and has been reported to be a potential threat to the poultry sector both in backyard and commercial farming systems. This study was aimed at isolation and molecular analysis of MD virus isolates circulating in chicken population in the central part of Ethiopia where commercial farms are populated. From September 2013 to January 2014, clinical and post-mortem examination were conducted on diseased chickens suspected of MD virus infection. Representative spleen and feather follicle samples were collected following sterile procedure, and infectious virus isolation was performed using primary chicken fibroblast cell culture. Cell culture inoculated with suspension of pathological samples developed characteristic MD virus cytopathic effect of rounding of the cells and small plaques. Further analysis of the virus was conducted by conventional PCR amplifying the ICP4 gene fragment from eleven tissue samples using MD virus specific primers. PCR products were further sequenced and analyzed. Nucleotide sequence similarity search of the local isolates resulted a high degree of sequence similarity with Gallid Herpes virus type 2 strain (Marek's disease virus type 1, JN034558). To our knowledge, the present study is the first report conducted on virus isolation and molecular characterization of MD virus isolates circulated in Ethiopia. Eleven ICP4-like gene fragment (318 bp) sequences generated in the present study were uploaded in the public database (KU842366-76). Further research on virus isolation, genetic characterization, and infection dynamics is recommended targeting chickens of all age groups reared in different agro-ecological zones under different production system.
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http://dx.doi.org/10.1007/s11250-016-1208-1DOI Listing
February 2017

Genetic characterization of poxviruses in Camelus dromedarius in Ethiopia, 2011-2014.

Antiviral Res 2016 10 18;134:17-25. Epub 2016 Aug 18.

Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, Austria. Electronic address:

Camelpox and camel contagious ecthyma are infectious viral diseases of camelids caused by camelpox virus (CMLV) and camel contagious ecthyma virus (CCEV), respectively. Even though, in Ethiopia, pox disease has been creating significant economic losses in camel production, little is known on the responsible pathogens and their genetic diversity. Thus, the present study aimed at isolation, identification and genetic characterization of the causative viruses. Accordingly, clinical case observations, infectious virus isolation, and molecular and phylogenetic analysis of poxviruses infecting camels in three regions and six districts in the country, Afar (Chifra), Oromia (Arero, Miyu and Yabello) and Somali (Gursum and Jijiga) between 2011 and 2014 were undertaken. The full hemagglutinin (HA) and partial A-type inclusion protein (ATIP) genes of CMLV and full major envelope protein (B2L) gene of CCEV of Ethiopian isolates were sequenced, analyzed and compared among each other and to foreign isolates. The viral isolation confirmed the presence of infectious poxviruses. The preliminary screening by PCR showed 27 CMLVs and 20 CCEVs. The sequence analyses showed that the HA and ATIP gene sequences are highly conserved within the local isolates of CMLVs, and formed a single cluster together with isolates from Somalia and Syria. Unlike CMLVs, the B2L gene analysis of Ethiopian CCEV showed few genetic variations. The phylogenetic analysis revealed three clusters of CCEV in Ethiopia with the isolates clustering according to their geographical origins. To our knowledge, this is the first report indicating the existence of CCEV in Ethiopia where camel contagious ecthyma was misdiagnosed as camelpox. Additionally, this study has also disclosed the existence of co-infections with CMLV and CCEV. A comprehensive characterization of poxviruses affecting camels in Ethiopia and the full genome sequencing of representative isolates are recommended to better understand the dynamics of pox diseases of camels and to assist in the implementation of more efficient control measures.
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http://dx.doi.org/10.1016/j.antiviral.2016.08.016DOI Listing
October 2016

One-Step Multiplex RT-qPCR Assay for the Detection of Peste des petits ruminants virus, Capripoxvirus, Pasteurella multocida and Mycoplasma capricolum subspecies (ssp.) capripneumoniae.

PLoS One 2016 28;11(4):e0153688. Epub 2016 Apr 28.

Animal Production and Health Laboratory (APHL), Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna, Austria.

Respiratory infections, although showing common clinical symptoms like pneumonia, are caused by bacterial, viral or parasitic agents. These are often reported in sheep and goats populations and cause huge economic losses to the animal owners in developing countries. Detection of these diseases is routinely done using ELISA or microbiological methods which are being reinforced or replaced by molecular based detection methods including multiplex assays, where detection of different pathogens is carried out in a single reaction. In the present study, a one-step multiplex RT-qPCR assay was developed for simultaneous detection of Capripoxvirus (CaPV), Peste de petits ruminants virus (PPRV), Pasteurella multocida (PM) and Mycoplasma capricolum ssp. capripneumonia (Mccp) in pathological samples collected from small ruminants with respiratory disease symptoms. The test performed efficiently without any cross-amplification. The multiplex PCR efficiency was 98.31%, 95.48%, 102.77% and 91.46% whereas the singleplex efficiency was 93.43%, 98.82%, 102.55% and 92.0% for CaPV, PPRV, PM and Mccp, respectively. The correlation coefficient was greater than 0.99 for all the targets in both multiplex and singleplex. Based on cycle threshold values, intra and inter assay variability, ranged between the limits of 2%-4%, except for lower concentrations of Mccp. The detection limits at 95% confidence interval (CI) were 12, 163, 13 and 23 copies/reaction for CaPV, PPRV, PM and Mccp, respectively. The multiplex assay was able to detect CaPVs from all genotypes, PPRV from the four lineages, PM and Mccp without amplifying the other subspecies of mycoplasmas. The discriminating power of the assay was proven by accurate detection of the targeted pathogen (s) by screening 58 viral and bacterial isolates representing all four targeted pathogens. Furthermore, by screening 81 pathological samples collected from small ruminants showing respiratory disease symptoms, CaPV was detected in 17 samples, PPRV in 45, and PM in six samples. In addition, three samples showed a co-infection of PPRV and PM. Overall, the one-step multiplex RT-qPCR assay developed will be a valuable tool for rapid detection of individual and co-infections of the targeted pathogens with high specificity and sensitivity.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0153688PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4849753PMC
February 2017

Molecular characterization of orf virus from sheep and goats in Ethiopia, 2008-2013.

Virol J 2016 Feb 29;13:34. Epub 2016 Feb 29.

Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, A-1400, Vienna, Austria.

Background: Orf is a contagious disease of sheep, goats and wild ungulates caused by orf virus (ORFV) a member of the genus Parapoxvirus, Poxviridae family. Although orf is endemic in Ethiopia, little attention has been given so far as it is not a notifiable disease by the World Organization for Animal Health. In this work, we have investigated orf outbreaks representing five different geographical locations of Ethiopia, in Amba Giorgis, Gondar zuria, Adet, Debre zeit and Adami Tulu, between 2008 and 2013.

Results: The viral isolation and the sequence analysis of the A32L and the B2L genes of eighteen representative isolates confirmed that sampled animals were infected by ORFVs. The phylogenetic study and the comparative analysis of the deduced amino acid profile suggests that there were two main clusters of ORFV isolates which were responsible for the investigated outbreaks. Additionally the analysis of these two genes showed limited variability to ORFVs encountered elsewhere. This is the first report on the genetic characterization of the ORFV isolates from sheep and goats in Ethiopia.

Conclusion: The molecular characterization of Ethiopian ORFV isolates highlighted the circulation of two main clusters causing orf disease in sheep and goats. The use of laboratory based methods and a constant monitoring of Ethiopian ORFV isolates is needed to better understand the dynamic of ORFV circulating in the country and facilitate the implementation of control measures.
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http://dx.doi.org/10.1186/s12985-016-0489-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4770539PMC
February 2016

Capripox disease in Ethiopia: Genetic differences between field isolates and vaccine strain, and implications for vaccination failure.

Antiviral Res 2015 Jul 20;119:28-35. Epub 2015 Apr 20.

Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, Austria. Electronic address:

Sheeppox virus (SPPV), goatpox virus (GTPV) and lumpy skin disease virus (LSDV) of the genus Capripoxvirus (CaPV) cause capripox disease in sheep, goats and cattle, respectively. These viruses are not strictly host-specific and their geographical distribution is complex. In Ethiopia, where sheep, goats and cattle are all affected, a live attenuated vaccine strain (KS1-O180) is used for immunization of both small ruminants and cattle. Although occurrences of the disease in vaccinated cattle are frequently reported, information on the circulating isolates and their relation to the vaccine strain in use are still missing. The present study addressed the parameters associated with vaccination failure in Ethiopia. Retrospective outbreak data were compiled and isolates collected from thirteen outbreaks in small ruminants and cattle at various geographical locations and years were analyzed and compared to the vaccine strain. Isolates of GTPV and LSDV genotypes were responsible for the capripox outbreaks in small ruminants and cattle, respectively, while SPPV was absent. Pathogenic isolates collected from vaccinated cattle were identical to those from the non-vaccinated ones. The vaccine strain, genetically distinct from the outbreak isolates, was not responsible for these outbreaks. This study shows capripox to be highly significant in Ethiopia due to low performance of the local vaccine and insufficient vaccination coverage. The development of new, more efficient vaccine strains, a GTPV strain for small ruminants and a LSDV for cattle, is needed to promote the acceptance by farmers, thus contribute to better control of CaPVs in Ethiopia.
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http://dx.doi.org/10.1016/j.antiviral.2015.04.008DOI Listing
July 2015

Sequence variability in the structural protein-encoding region of foot-and-mouth disease virus serotype A and O of Ethiopian isolates.

Res Vet Sci 2014 Jun 29;96(3):558-66. Epub 2014 Mar 29.

Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Centre for Epidemiology and Biostatistics, P.O. Box 8146, 0033 Oslo, Norway; School of Veterinary Medicine, Hawassa University, P.O. Box 05, Hawassa, Ethiopia.

A total of 13 serotype O and 5 serotype A FMD Ethiopian isolates and some isolates from other countries (six for serotype A and four for serotype O) were sequenced on the structural protein (P1) coding region. The deduced amino acid sequences were aligned and investigated in an attempt to determine the amino acid variation. Differences were observed at 115 (15.6%) and 119 (16.1%) amino acid positions for serotype O and serotype A, respectively. The variation in the derived amino acid sequences is the highest in VP1, while VP4 was highly conserved in both serotypes A and O. In all isolates, hypervariable regions were located at regions corresponding to the highly immunogenic sites, the G-H loop (133-158) and the C-terminus (194-213) of the VP1 gene. The RGD cell attachment site within the G-H loop of the gene was conserved in all isolates. The study revealed the presence of significant amino acid variation at VP2 and VP3 in addition to known VP1 coding region. Hence, determination of amino acid sequence of the whole P1 region provides more information on antigenic variability of FMD virus and could be used in vaccine strain selection in parallel with serological vaccine matching assays.
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http://dx.doi.org/10.1016/j.rvsc.2014.03.010DOI Listing
June 2014

Genetic characterisation of infectious bursal disease virus isolates in Ethiopia.

Acta Trop 2014 Feb 18;130:39-43. Epub 2013 Oct 18.

National Veterinary Institute, Debre-Zeit, Ethiopia; Norwegian School of Veterinary Science, Department of Food Safety and Infection Biology, Centre for Epidemiology and Biostatistics, P.O. Box 8146 Dep., 0033 Oslo, Norway.

The objective of the investigation was to characterise infectious bursal disease viruses (IBDV) circulating in commercial and breeding poultry farms in Ethiopia between 2009 and 2011. The nucleotide and deduced amino acid sequence for VP2 hypervariable region of ten IBDVs were determined by RT-PCR, sequenced and compared to well characterised IBDV isolates worldwide. IBDV genetic material was amplified directly from bursa or cell passaged material. Phylogenetically, Ethiopian IBDVs represented two genetic lineages: very virulent (vv) IBDVs or variants of the classical attenuated vaccine strain (D78). The nucleotide identity between Ethiopian vvIBDVs ranged between 0% and 2.6%. Ethiopian vvIBDVs are clustered phylogenetically with the African IBDV genetic lineage, independent of the Asian/European lineage. This report demonstrates the circulation of vvIBDV in commercial and breeding poultry farms in Ethiopia.
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http://dx.doi.org/10.1016/j.actatropica.2013.09.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008939PMC
February 2014

Development of a cost-effective method for capripoxvirus genotyping using snapback primer and dsDNA intercalating dye.

PLoS One 2013 7;8(10):e75971. Epub 2013 Oct 7.

Animal Production and Health Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria ; Institute of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria ; Research and Diagnostic Laboratories, National Veterinary Institute, Debre Zeit, Ethiopia.

Sheep pox virus (SPPV), goat pox virus (GTPV) and lumpy skin disease virus (LSDV) are very closely related viruses of the Capripoxvirus (CaPV) genus of the Poxviridae family. They are responsible for sheep pox, goat pox and lumpy skin disease which affect sheep, goat and cattle, respectively. The epidemiology of capripox diseases is complex, as some CaPVs are not strictly host-specific. Additionally, the three forms of the disease co-exist in many sub-Saharan countries which complicates the identification of the virus responsible for an outbreak. Genotyping of CaPVs using a low-cost, rapid, highly specific, and easy to perform method allows a swift and accurate identification of the causative agent and significantly assists in selecting appropriate control and eradication measures, such as the most suitable vaccine against the virus during the outbreaks. The objective of this paper is to describe the design and analytical performances of a new molecular assay for CaPV genotyping using unlabelled snapback primers in the presence of dsDNA intercalating EvaGreen dye. This assay was able to simultaneously detect and genotype CaPVs in 63 samples with a sensitivity and specificity of 100%. The genotyping was achieved by observing the melting temperature of snapback stems of the hairpins and those of the full-length amplicons, respectively. Fourteen CaPVs were genotyped as SPPVs, 25 as GTPVs and 24 as LSDVs. The method is highly pathogen specific and cross platform compatible. It is also cost effective as it does not use fluorescently labelled probes, nor require high-resolution melting curve analysis software. Thus it can be easily performed in diagnostic and research laboratories with limited resources. This genotyping method will contribute significantly to the early detection and genotyping of CaPV infection and to epidemiological studies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0075971PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3792100PMC
June 2014

The first isolation and molecular characterization of camelpox virus in Ethiopia.

Antiviral Res 2013 Jun 8;98(3):417-22. Epub 2013 Apr 8.

National Veterinary Institute, P.O. Box 19, Debre-Zeit, Ethiopia.

A cross-sectional study was conducted from November 2011 to April 2012 in Chifra district of Afar and in Jigjiga Zone of Somali Regional States of Ethiopia with the aims of assessing the epidemiology of camelpox and isolate and molecularly characterize the virus. The study included a questionnaire, active disease search and virus isolation and sequencing. A total of 24 (4.50%) and 12 (3.0%) camels in Afar and Jigjiga respectively were found clinically sick of camelpox during the study period. The questionnaire survey indicated that camelpox is the most common disease in the areas in which 125 (96%) of the respondents reported the frequent occurrence of camelpox in their herds especially during rainy season. The PCR result revealed 12 out of 17 tested samples were positive, of which seven of them collected from Jigjiga zone showed the characteristic PCR positive bands of 881 bp size fragments while five of the Afar samples gave two faint bands. Ethiopian isolates, specially isolated from Somali have very high identity with comparable sequences of CMLV M-96 from Kazakhstan and CMLV CMS from Iran. Out of the total of 780 bp analogous sequences, Ethiopian isolates differ only in two positions, while CMLV-Teheran differed at four nucleotide positions. The successfull isolation and molecular characterization of camelpox virus in Ethiopia, which could help for early diagnosis and control of the disease in the country.
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http://dx.doi.org/10.1016/j.antiviral.2013.04.002DOI Listing
June 2013

Outbreak investigation and molecular characterization of African horse sickness virus circulating in selected areas of Ethiopia.

Acta Trop 2013 Aug 6;127(2):91-6. Epub 2013 Apr 6.

National Veterinary Institute, P.O. Box 19, Debre-zeit, Ethiopia.

The study was conducted from June 2011 to May 2012 in central, northern and western parts of Ethiopia to investigate and identify circulating serotypes of African horse sickness virus (AHSV). The indigenous knowledge of equine owners about AHS in the study areas was assessed and also the retrospective data of AHS outbreaks for 2011 were analyzed. Whole blood samples were collected for virus isolation and serotyping from diseased horses and mules showing typical signs of the AHS. Virus isolation on Vero cell and detection of AHSV genomes using conventional RT-PCR were conducted. Further molecular characterization and serotyping were done on positive isolates. The questionnaire survey revealed that equine owners do recognize AHS clinically and have a local name that varies in different regions. From the 72 equine owners interviewed about their knowhow of AHS, 48 (66.7%) of respondents were not aware of AHS disease mode of transmission. The retrospective disease report data showed that a total of 208 outbreaks were reported and 3036 cases and 1167 deaths were recorded in 2011. AHS outbreaks were more frequently observed from September to December and the highest number of outbreaks was recorded in October. During the study period totally six outbreaks were investigated and a total of 62 horses and 10 mules were found sick and all the four forms of AHS were observed. Cardiac form accounted for 52.8%, followed by African horse sickness fever form 31.9%, pulmonary form 8.4% and mixed form 6.9%. AHSV-9 was the only serotype circulating in the outbreak areas.
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http://dx.doi.org/10.1016/j.actatropica.2013.03.018DOI Listing
August 2013

Lumpy skin disease: preliminary vaccine efficacy assessment and overview on outbreak impact in dairy cattle at Debre Zeit, central Ethiopia.

Antiviral Res 2013 May 19;98(2):261-5. Epub 2013 Feb 19.

National Veterinary Institute, P.O. Box 19, Debre Zeit, Ethiopia.

This study was conducted in and around Debre Zeit town to assess the field efficacy of LSD vaccine in use and overview associated disease impact. The study comprised cross-sectional and retrospective study design which employed active disease follow-up, semi-structured questionnaire survey and molecular techniques. The finding revealed that the Kenyan sheep pox vaccine strain used for the control of LSD did not confer expected protection. From the total of 476 animals observed, 22.9% and 2.31% cattle were found sick and dead due to LSD, respectively. Breed specific morbidity rate was 22.5% in Holstein Friesian-zebu cross and 25.9% in local zebu breed. The disease was observed to be more serious in young animals and also in females. A trend of seasonality was also observed in its occurrence. The study finding urges the need for investigation of vaccine failure including vaccine matching and alternative vaccine development.
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http://dx.doi.org/10.1016/j.antiviral.2013.02.008DOI Listing
May 2013

Molecular evidence of very virulent infectious bursal disease viruses in chickens in Ethiopia.

Avian Dis 2012 Sep;56(3):605-10

Clinic for Poultry, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany.

Infectious bursal disease virus (IBDV) is an important immunosuppressive pathogen of chickens worldwide. The introduction and evolution of IBDV in most African countries, especially in Ethiopia, remains unclear. We have investigated IBDV isolates obtained from commercial broilers, indigenous chickens, and pullets. The hypervariable region of the virus protein (VP) 2 and the 5' two-thirds of VP1 of 11 IBDV isolates were characterized by RT-PCR and further sequencing. All isolates were identified as very virulent (vv) IBDV based on the predicted amino acid (aa) sequences of the VP2 protein. Interestingly, the sequence analysis of the 5' two-thirds of VP1 indicated that the Ethiopian IBDV strains have aa residues typical for vvIBDV and for attenuated IBDV strains. Among all IBDV strains included in this study for phylogenetic comparison of VP2 nucleotide sequences, Ethiopian strains form a cluster within the vvIBDV lineage. We have also shown that Ethiopian IBDV strains have mutations in the VP1 region. Their roles in IBDV virulence may require further in vivo studies. As depicted in this study, the nucleotide and aa sequence analysis of VP1 in addition to VP2 is necessary to obtain a clear picture of the molecular evolution of IBDV.
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http://dx.doi.org/10.1637/10086-022012-ResNote.1DOI Listing
September 2012

A study on seroprevalence of caprine brucellosis under three livestock production systems in southern and central Ethiopia.

Trop Anim Health Prod 2013 Feb 8;45(2):555-60. Epub 2012 Sep 8.

School of Veterinary Medicine, Hawassa University, P.O. Box 05, Hawassa, Ethiopia.

Caprine brucellosis in Ethiopia is less commonly reported with limited information on the disease status in the country. The objective of this study was therefore to highlight the status of goat brucellosis in three distinctly different livestock production systems of southern and central Ethiopia. A total 3,315 goats of different age and sex, living with other animals in variable flock size, were sampled from 448 flocks raised in sedentary, pastoral and agro-pastoral production systems. Goats were bled aseptically and sera were collected for serial testing using Rose Bengal Plate Test as screening test and subsequently complement fixation test as confirmatory test. Questionnaire and laboratory data were analysed for descriptive, univariable and multivariable logistic regression analysis both at individual and flock level (STATA 11). The study revealed an overall animal level seroprevalence of 1.9 % (95 % CI 1.5, 2.4). In sedentary production system, the observed seroprevalence was 0.6 % (95 % CI 0.2, 0.9) while 1.9 % (95 % CI 1.1, 2.7) and 7.6 % (95 % CI 5.1, 10.1) were the proportion of seroreactors for agro-pastoral and pastoral production systems, respectively. The observed prevalence difference between the three production systems was statistically significant (P < 0.05). At the flock level analysis, 11.2 % (95 % CI 8.2, 14.1) of the flocks sampled had at least one seropositive goat among themselves. Like individual level analysis, the highest prevalence of 32.5 % (95 % CI 21.9, 43.0) was recorded for pastoral production system, followed by agro-pastoral, 13.0 % (95 % CI 7.0, 19.0) and sedentary production system, 3.6 % (95% CI 1.3, 6.0). Accordingly, the odds of Brucella seropositivity were higher (OR = 12.8) in pastoral followed by agro-pastoral (OR = 4.0) in relation to sedentary production system. Large numbers of seroreactors were observed in adult age living in larger flocks with other livestock species. However, no difference was noted between male and female goats. Finally, the need for nationwide survey and subsequent designing and implementation of appropriate control measure is suggested.
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http://dx.doi.org/10.1007/s11250-012-0258-2DOI Listing
February 2013

Infectious bursal disease: seroprevalence and associated risk factors in major poultry rearing areas of Ethiopia.

Trop Anim Health Prod 2013 Jan 26;45(1):75-9. Epub 2012 May 26.

National Veterinary Institute, P. O. Box 19, Debre Zeit, Ethiopia.

The study was conducted in eight districts of Ethiopia with the objectives of determining the seroprevalence and associated risk factors of infectious bursal disease (IBD). From the total of 2,597 chicken serum samples examined using ELISA, 83.1 % were found positive. The highest seroprevalence was found at Mekele (90.3 %) while the lowest was recorded at Gondar district (69.8 %). These differences among the study areas were statistically significant (p < 0.05). Highest seroprevalence was found in crossbreed of chicken (91.4 %) while the lowest was recorded in indigenous breed of chicken (81.4 %). This difference was statistically significant (p < 0.05) among the three breeds of chickens, but sex was not statistically significant (p > 0.05). The seroprevalence of the disease was found high in young (≤ 8 weeks) age group (86.6 %) while the lowest prevalence was recorded in adults (>8 weeks) (72 %). This is also statistically significant (p < 0.05) between young and adult age groups. The prevalence of IBD in different production system indicated that higher seroprevalence was recorded in intensive production system (85.9 %) while the lowest was recorded in extensive production system (81.6 %). This difference is also statistically significant (p < 0.05).
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http://dx.doi.org/10.1007/s11250-012-0176-3DOI Listing
January 2013

Gross and histopathological studies on pulmonary lesions of camel (Camelus dromedarius) slaughtered at Addis Ababa abattoir, Ethiopia.

Trop Anim Health Prod 2012 Apr 11;44(4):849-54. Epub 2011 Sep 11.

National Veterinary Institute, P. O. Box 19, Debre Zeit, Ethiopia.

This study was carried out with the aim of identifying types of gross and histopathological lesions in lungs of camels slaughtered between October 2009 and April 2010 at Addis Ababa abattoir enterprise, Ethiopia. All camels were originated from Borana and Kereyu areas. A total of 387 slaughtered camel lungs were inspected during the study period. Of which, one or more gross lesions were encountered on 300 lungs. Lesions were further subjected for detail gross and histopathological examinations. The occurrence of pulmonary lesions was 77.5%. The gross and histopathological examination of these lesions had revealed 60.2% emphysema, 21.2% hydatidosis, 18.6% pneumonia, 10.6% atelectasis, 4.9% aspiration of blood, 3.9% pneumoconiosis, 2.6% pulmonary edema and congestion, 1.6% abscess, 1% pleurisy, and 0.8% granulomatous pneumonia. Most camels had one or more pulmonary lesions on postmortem examination, but they were apparently healthy during antemortem inspection. Therefore, the prevailing stressful environmental condition coupled with the existing poor level of veterinary service in camel-rearing areas of the country might reverse these hidden inactive lesions and thereby contributed for the higher occurrence of respiratory diseases in camels.
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http://dx.doi.org/10.1007/s11250-011-9977-zDOI Listing
April 2012

Serological survey of African horse sickness in selected districts of Jimma zone, Southwestern Ethiopia.

Trop Anim Health Prod 2011 Dec 5;43(8):1543-7. Epub 2011 Apr 5.

College of Agriculture and Veterinary Medicine, Jimma University, P.O. Box 307, Jimma, Ethiopia,

A cross-sectional serological survey was undertaken in selected districts of different agro-ecology of Jimma zone (Dedo, Yebu, Seka, Serbo, and Jimma town) from November 2009 to February 2010 to determine the seroprevalence of African horse sickness virus and associated risk factors of the disease. Two hundred seventy-four equids (189 horses, 43 mules, and 47 donkeys) with a history of non-vaccination for at least 2 years were selected randomly from the above areas. Sera samples were collected and assayed for the presence of specific antibody against African horse sickness virus using blocking ELISA. An overall seroprevalence of 89 (32.5%) was found and it was 24 (51.1%) for donkeys, 13 (30.2%) for mules, and 52(28.3%) for horses. Seroprevalence was significantly (X(2) = 11.05, P < 0.05) different among the different species of equids. Seroprevalence was also significantly (X(2) = 11.43, P < 0.05) different among the different agro-ecological areas being higher in highlands 47 (40.5%) followed by midland 30 (34.5%) and lowland 12 (16.9%). Age and sex were not significantly (X(2) = 3.15, P > 0.05 and X(2) = 3.38, P > 0.05, respectively) associated with seroprevalence of AHSV. The present study showed that African horse sickness (AHS) is highly prevalent disease for the horses followed by mules and then donkeys in Jimma zone explained by lower seroconversion rate. Therefore, control strategy against AHS should target at high risk species of all age and sex in their locality in the initial stage for better containment of the disease.
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http://dx.doi.org/10.1007/s11250-011-9839-8DOI Listing
December 2011

Study on seroprevalence, risk factors, and economic impact of foot-and-mouth disease in Borena pastoral and agro-pastoral system, southern Ethiopia.

Trop Anim Health Prod 2011 Apr 20;43(4):759-66. Epub 2011 Jan 20.

Faculty of Veterinary Medicine, Addis Ababa University, P.O. Box 34, Debre zeit, Ethiopia.

Cross-sectional serological study and questionnaire survey were conducted in Borana pastoral and agro-pastoral area to determine seroprevalence and risk factors associated with foot-and-mouth disease (FMD) infection and to assess community perceptions as to importance of the disease. A multistage random sampling was carried out to select cattle for seroprevalence and households for interviews. Totally, 768 sera were collected from 111 herds. The overall individual level seroprevalence of 23.0% (n = 177) and herd level seroprevalence of 58.6% (n = 65) were recorded using 3ABC ELISA test. The variation of individual level seroprevalence in districts were statistically significant (P < 0.05) which was 29.9% in Arero, 24.0% in Yabello, and 15.7% in Teltele. From multivariate logistic regression analysis, herd size and age were seen to be significantly (P < 0.05) associated with FMD seroprevalence. The result of the questionnaire survey based on 120 respondents indicated that, the daily milk yield of cows infected with FMD during outbreaks is reduced to an average of 0.5 L for 25.5 days while cows developing heat-intolerance syndrome after acute infection gave an average 0.67 L for 3.8 months and their calving interval prolonged about 12 months. The questionnaire survey in agro-pastoral area of Borena also indicated that FMD-infected oxen remained off-plough for one season when outbreaks occur in cropping time, whereas heat-intolerant oxen were no longer used for traction. These findings of the present study indicated that FMD is a highly prevalent and economically important disease in the Borana pastoral and agro-pastoral production systems which need effective control strategy for the disease.
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http://dx.doi.org/10.1007/s11250-010-9728-6DOI Listing
April 2011

Evaluation of Deltamethrin applications in the control of tsetse and trypanosomosis in the southern rift valley areas of Ethiopia.

Vet Parasitol 2010 Mar 16;168(3-4):177-84. Epub 2009 Dec 16.

Hawassa University, Faculty of Veterinary Medicine, Awassa, Ethiopia.

A study aimed at evaluating the efficacy of Deltamethrin (0.4% impregnated targets and 1% pour-on formulation) in controlling tsetse and trypanosomosis was carried out in two selected 10km x 10km Universal Transverse Mercator Grids of the Southern Tsetse Eradication Project (STEP) area in the southern rift valley of Ethiopia. The Grids selected were H3 (site I) and G5 (site II) in two districts of the Wolaita Zone. The trial was underway from September 2003 to April 2004. The strategy followed to accomplish the trial was a pre-intervention phase (entomology and parasitology) and an intervention phase with insecticide (Deltamethrin 0.4%)-impregnated odour-baited targets in site I and Deltamethrin 1% 'pour-on' application to cattle in site II. The intervention phase was monitored on a monthly basis. Following the deployment of 460 targets at a density of 4 targets per km(2) in trial site I, the relative abundance of tsetse fly (Glossina pallidipes) declined from a pre-intervention mean catch of 1.35 flies per trap per day to 0.05 flies per trap per day at final monitoring. These resulted in an 88.9% overall reduction. Similarly, an 83.25% reduction was recorded in the incidence of trypanosomosis in sentinel cattle as it dropped from 10.75% (first monitoring) to 1.8% (last monitoring). The corresponding measures of packed cell volume (PCV) have shown a significant improvement from a mean of 21.8% (95% confidence interval (CI): 20.7-22.9) at first monitoring to 25.5% (95% CI: 24.3-26.7) of last monitoring (P<0.01). In site II, the trial was started by spraying Deltamethrin 1% pour-on to 409 cattle at a rate of 1ml/10kg body weight. Pour-on treatment was repeated every month throughout the trial period. A sharp drop in the relative abundance of tsetse fly was revealed soon after. The catch was nil at fourth monitoring as it declined from 0.91 flies per trap per day of pre-intervention (P<0.01). A 94.9% overall reduction was achieved. The incidence of trypanosomosis in sentinel cattle also declined from 10% (first monitoring) to 0.95% (last monitoring) with about 90.5% decline. An improvement in the overall mean PCV was seen as it rose from a mean of 24.1% (95% CI: 22.9-25.3) at first monitoring to 27.2% (95% CI: 26.2-28.1) at last monitoring which revealed a significant increase (P<0.01) until the third monitoring and maintained a stable state thereafter. This work finally disclosed that a relatively better efficacy was attained by using Deltamethrin pour-on formulation than targets in controlling tsetse and trypanosomiosis. However, this difference did not prove an apparent significance (P>0.05). So it is recommended to continue the current tsetse suppression by using the integrated approach of both techniques under consideration.
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http://dx.doi.org/10.1016/j.vetpar.2009.11.028DOI Listing
March 2010