Wondwossen A. Gebreyes

DVM, PhD Diplomate ACVPM

Executive Director of Global One Health Initiative; Professor


gebreyes.1@osu.edu (614) 292-9559 Sisson Hall
1920 Coffee Road
Columbus, OH 43210
Map Link


Veterinary Preventive Medicine

Professional Training and experience

  • Diplomate, American College of Veterinary Preventive Medicine, ACVPM, 2002
  • Ph.D., North Carolina State University, Comparative Biomedical Sciences, 2001
  • DVM, Addis Ababa University, Veterinary Medicine, 1990

Research Interests

  • Antimicrobial resistance
  • Food safety
  • Infectious disease molecular epidemiology

Research Summary

The major areas that my research is particularly focused are antimicrobial resistance, genotypic diversity and detection methods development of foodborne zoonotic pathogens. Specific activities in my laboratory include molecular characterization of genetic elements such as antimicrobial resistance genes, class-I integrons, and plasmids in strains of leading food safety problems such as multi-drug resistant ones.

The work in our laboratory mainly focuses on swine. Therefore, results generated from our studies have direct relevance to the Pork industry. In addition, as we are dealing with foodborne pathogens that are capable of infecting multiple host specieis, thefindings have significant impact on human health as well as food safety in other animal hosts.

In addition I collaborate with other experts in viral foodborne pathogens (mainly norovirus) and parasitic foodborne hazards (Ascaris, Trichinella and Toxoplamsa).

Other expertise in our laboratory include evaluation of DNA fingerprinting method for foodborne pathogens and comparative anlysis of antimicrobial resistance among Salmonella isolates from humans and swine.
Future Research

Development of molecular diagnostic/ detection methods using real-time PCR and microarray systems that enable accurate and rapid detection of multiple bacterial and viral foodborne pathogens simultaneously.


Professional Memberships

  • American Association of Swine Veterinarians
  • American College of Veterinary Preventive Medicine
  • American Society for Microbiology
  • International Association for Food Protection
  • Phi Zeta, Honor Society of Veterinary Medicine
  • Sigma Xi, The Scientific Research Society
  • Society for Tropical Veterinary Medicine

Professional Service


  • Lim, K.; Pennell, M.; Lewis S.; El-Gazzar, M.; Gebreyes, W. (2021). Effects of flavophospholipol on conjugation and plasmid curing of multidrug-resistant Salmonella Enteritidis in broiler chickens. JAC-Antimicrobial Resistance, Volume 3, Issue 1, March 2021, dlab022, https://doi.org/10.1093/jacamr/dlab022
  • Kue, J.; Bersani, A.; Stevenson, K.; Yimer, G.;  Wang, S.; Gebreyes, W. et al. (2021). Standardizing clinical culture specimen collection in Ethiopia: a training‐of‐trainers. BMC Medical Education volume 21, Article number: 195. DOI: https://doi.org/10.1186/s12909-021-02631-w
  • Galdino da Cruz Silva, G.; Campana, E.H.; Vasconcelos, P.C.; Vieira da Silva, N.M.; Filho, L.S.; Leite, E.L.; Naves Givisiez, P.E.; Gebreyes, W.A.; Bruno de Oliveira, C.E. (2021). Occurrence of KPC-Producing Escherichia coli in Psittaciformes Rescued from Trafficking in Paraíba, Brazil. Int. J. Environ. Res. Public Health 2021, 18(1), 95; https://doi.org/10.3390/ijerph18010095
  • Atlaw, N.A.; Keelara, S.; Correa, M.; Foster D.; Gebreyes, W.; Aidara-Kane. A.; Harden, L.; Thakur, S.; Fedorka Cray, P.J. (2021). Identification of CTX-M Type ESBL E. coli from Sheep and Their Abattoir Environment Using Whole-Genome Sequencing. Academic Editor: Csaba Varga Pathogens 2021, 10(11), 1480; https://doi.org/10.3390/pathogens10111480
  • Souza Saraiva, M.M.;  Gomes de Leon, C.M.C.; Vieira da Silva, N.M.; Freitas Raso, T.; Pereira Serafini, P.; Naves Givisiez, P.E.; Gebreyes, W.A.; Bruno de Oliveira, C.J. (2021). Staphylococcus sciuri as a Reservoir of mecA to Staphylococcus aureus in Non-Migratory Seabirds from a Remote Oceanic Island. Published Online:15 Apr 2021https://doi.org/10.1089/mdr.2020.0189
  •  Souza Saraiva, M.M.; Lim, K.; Marinho do Monte, D.F.; Naves Givisiez, P.E.; Rodrigues Alves, L.B.; Caetano de Freitas Neto, O.; Kariuki, S.;  Júnior, A.B.; Bruno de Oliveira, C.J.; Gebreyes, W.A.; (2021). Antimicrobial resistance in the globalized food chain: a One Health perspective applied to the poultry industry, Brazilian Journal of Microbiology. Volume 53, pages 465–486 DOI; https://doi.org/10.1007/s42770-021-00635-8
  • Chen, D.;  McKune, S.L.; Singh, N.; Hassen, J.Y.; Gebreyes, W.A.;  Manary, M.J.; Bardosh, K.;  Yang, Y.; Diaz, N.; Mohammed, A.; Terefe, Y.;  Roba, ;.T., Ketema, M.; Ameha, N.  Assefa, N.; Rajashekara, G.;  Deblais, L.;  Ghanem, M.; Yimer, G.; Havelaar, A.H.  (2021). Campylobacter Colonization, Environmental Enteric Dysfunction, Stunting, and Associated Risk Factors Among Young Children in Rural Ethiopia: A Cross-Sectional Study From the Campylobacter Genomics and Environmental Enteric Dysfunction (CAGED) Project. Front. Public Health, 21 January 2021 | https://doi.org/10.3389/fpubh.2020.615793
  • Fekadu, A., Oppenheim, C., Manyazewal, T., Gebreyes, W. et al. (2021). Understanding the key processes of excellence as a prerequisite to establishing academic centres of excellence in Africa. BMC Med Educ 21, 36. DOI: https://doi.org/10.1186/s12909-020-02471-0
  • Binkley, L.; Deressa, A.; Shi, M.; Jara, M.;  Escobar, L.E.; Mauldin, M.R.; Matheny, A.; O'Quin, J.; Pieracci, E.G.; Kling, C.; Hartloge, C.; Yimer, G.; Abate, E.; Gebreyes, W. et. al. (2021). Use of partial N-gene sequences as a tool to monitor progress on rabies control and elimination efforts in Ethiopia, Acta Tropica, Volume 221, 106022, ISSN 0001-706X. https://doi.org/10.1016/j.actatropica.2021.106022.
  • Terefe Y, Deblais L, Ghanem M, Helmy YA, Mummed B, Chen D, Singh N, Ahyong V, Kalantar K, Yimer G, Yousuf Hassen J, Mohammed A, McKune SL, Manary MJ, Ordiz MI, Gebreyes W, Havelaar AH, Rajashekara G. 2020. Co-occurrence of Campylobacter Species in Children From Eastern Ethiopia, and Their Association With Environmental Enteric Dysfunction, Diarrhea, and Host Microbiome. Front Public Health 8. Front Public Health. 2020 Apr 15;8:99. doi: 10.3389/fpubh.2020.00099.
  • Chen D, McKune SL, Singh N, Hassen JY, Gebreyes W, Manary M, Bardosh K, Yang Y, Diaz N, Mohammed A, Terefe Y, Roba KT, Ketema M, Ameha N, Assefa N, Rajashekara G, Deblais L, Ghanem M, Yimer G, Ordiz I, Havelaar AH. 2020. Campylobacter Colonization, Environmental Enteric Dysfunction, Stunting, and Associated Risk Factors among Young Children in Rural Ethiopia: a Cross-sectional Study from the Campylobacter Genomics and Environmental Enteric Dysfunction (CAGED) Project. Front. Public Health, 21 January 2021. doi.org/10.3389/fpubh.2020.615793.
  • Gebreyes, W.A.; Jackwood, D.; Bruno de Oliveira, C.J.; Lee, C.W.; Hoet, A.E.; Thakur, S. Molecular Epidemiology of Infectious Zoonotic and Livestock Diseases. Microbiol Spectr. 2020 Mar;8(2). doi: 10.1128/microbiolspec.AME-0011-2019.
  • Hoet, A.E.; Feyes, E.E.; Fentie, T.; Melaku, A.; Nigatu, S.; Tomasi, S.; Coniglio, R.; O’Quin, J.; Stull, J.W.; Gebreyes, W.; Berrian. A. M. Development of an OIE Harmonized Day 1 Competency-Based Veterinary School Curriculum in Ethiopia: A Partnership Model for Curriculum Evaluation and Implementation. J Vet Med Educ. 2020 Sep;47(s1):8-19. doi: 10.3138/jvme-2019-0115.
  • Medardus, J.J.; Kazwala, R.R.; W.A. Gebreyes, W.A. 2020. Role of Biocides in Occurrence and Persistence of Biocide-tolerant and Multi-drug Resistant Salmonellae. Tanzania Veterinary Journal. Vol. 35 No. 1.
  • Medardus, J.J.; Kazwala, R.R.; W.A. Gebreyes, W.A. 2020. Molecular Characterization of Multidrug Resistant Salmonella Isolates From Food Animals and Animal Products in Tanzania. Tanzania Veterinary Journal. Vol. 35 No. 1.
  • Afework Kassu, A.; Yimer, G.; Benor, S.; Kassahun, T.; Tefera, Y.; Admassu, M.; Abate, T.; Gallagher, K.; Pan, X.; Mekuria, Z.; Gebreyes, W. 2020. Multi-Disciplinary COVID-19 Research Prioritization in Low-Resource Settings: The Ethiopia. Model.SSRN Electronic Journal DOI:10.2139/ssrn.3608055
  • Munyalo, J.; Gebreyes, W.; Mutai, W.; Anzala, O.; Ponte, A.; Merdadus, J.; Kariuki, S. Detection of Fluoroquinolone and other Multi-drug Resistance Determinants in Multi-drug Resistant Non -Typhoidal Salmonella Isolated from Swine. African Journal of Health Sciences. Vol. 33 No. 2 (2020).
  • Stevenson, K.; Balada-Llasat, J.; Kue, J.; Bersani, A.; Yimer, G.; Wang, S.; Gebreyes, W.; Alebachew, G.; Fentaw Dinku, S.; Abubeker, R.; Tigabu Seyoum, E.; Hazim, C.; Omondi, M.; Kirley, D.; Berhanu, A.; Kanter, T.; Gallagher, K.; Bancroft, E.; VanderEnde, D.; Park, B. 2020. Training to Improve Clinical Specimen Collection and Antimicrobial Resistance (AMR) Diagnostics and Surveillance in Ethiopia. Infection Control and Hospital Epidemiology 41(S1):s414-s414. DOI:10.1017/ice.2020.1069.
  • Lim, K.; Pennell, M.; Lewis, S.; El-Gazzar, M.; Gebreyes, W. 2020. Effects of flavophospholipol on conjugation and plasmid curing of multidrug-resistant Salmonella Enteritidis in broiler chickens. JAC-Antimicrobial Resistance, Volume 3, Issue 1, March 2021, dlab022, https://doi.org/10.1093/jacamr/dlab022.
  • Saraiva, M.; Moreira Filho, A.; Vasconcelos,P.; Nascimento,P.; Azevedo, P.; Freitas Neto, O.; Givisiez, P.; Gebreyes W.; Oliveira, C. 2020. Chemical treatment of poultry litter affects the conjugation of plasmid-mediated extended-spectrum beta-lactamase resistance genes in E. coli. Journal of Applied Poultry Research. Volume 29, Issue 1, March 2020, Pages 197-203.
  • Yimer, G., Gebreyes, W., Havelaar, A. et al. Community engagement and building trust to resolve ethical challenges during humanitarian crises: experience from the CAGED study. Confl Health 14, 68 (2020). https://doi.org/10.1186/s13031-020-00313-w.
  • Kalayu, A.A., Woldetsadik, D.A., Woldeamanuel, Y.; Wang, S.H.; Gebreyes, W.A.; Teferi, T. Burden and antimicrobial resistance of S. aureus in dairy farms in Mekelle, Northern Ethiopia. BMC Vet Res 16, 20 (2020). doi.org/10.1186/s12917-020-2235-8.
  • Lemos, M.; Saraiva, M.; Leite, E.; Silva, N.; Vasconcelos, P.; Giachetto, P.; Freitas Neto, O.;  Givisiez, P.; Gebreyes, W.;  Oliveira, C. 2020. The posthatch prophylactic use of ceftiofur affects the cecal microbiota similar to the dietary sanguinarine supplementation in broilers. Poultry Science,Volume 99, Issue 11, Pages 6013-6021, ISSN 0032-5791, https://doi.org/10.1016/j.psj.2020.06.078.
  • Kelley, H.; Waibel, S.M.; Sidiki, S.; Tomatis-Souverbielle, C.; Scordo, J.M.; Hunt, W.G; Barr, N.; Smith, R.; Silwani, S.N.; Averill, J.J.; Baer, S.; Hengesbach, J.; Yildiz, V.O.; Pan, X.; Gebreyes, W.A.; Balada-Llasat, J.M.; Wang, S.H.; Torrelle, J.B. Accuracy of Two Point-of-Care Tests for Rapid Diagnosis of Bovine Tuberculosis at Animal Level using Non-Invasive Specimens. Sci Rep 10, 5441 (2020). https://doi.org/10.1038/s41598-020-62314-2.
  • Shibabaw, A.; Gelaw, B.; Gebreyes, W.; Robinson, R.; Wang, S.; Tessema, B. The burden of pre-extensively and extensively drug-resistant tuberculosis among MDR-TB patients in the Amhara region, Ethiopia. PLoS One. 2020 Feb 13;15(2):e0229040. doi: 10.1371/journal.pone.0229040. eCollection 2020. DOI: 10.1371/journal.pone.0229040.
  • O’Shaughnessy RA, Habing GG, Gebreyes WA, Bowman AS, Weese JS, Rousseau J, Stull JW. Clostridioides difficile on Ohio swine farms (2015): A comparison of swine and human environments and assessment of on‐farm risk factors. Zoonoses and public health. 2019 Nov;66(7):861-70.
  • Delgado-Suárez EJ, Ortíz-López R, Gebreyes WA, Allard MW, Barona-Gómez F, Rubio-Lozano MS. Genomic surveillance links livestock production with the emergence and spread of multi-drug resistant non-typhoidal Salmonella in Mexico. Journal of Microbiology. 2019 Apr 1;57(4):271-80.
  • D.F. Marinho Monte, W.D. Dias Lopes Júniora, M. Abley, W.A. Gebreyes, C.J. Bruno de Oliveira. Antimicrobial resistance and genotypic relatedness of environmental staphylococci in semi-extensive dairy farms. doi.org/10.1016/j.vas.2018.07.007.
  • Saraiva MMS, Moreira Filho ALB, Freitas Neto OC, Silva NMV, Givisiez PEN, Gebreyes WA, Oliveira CJB. Off-label use of ceftiofur in one-day chicks triggers a short-term increase of ESBL-producing E. coli in the gut. PLoS One. 2018 Sep 11;13(9):e0203158. doi: 10.1371/journal.pone.0203158. 
  • Moura GS, Gebreyes WA, Marques MFS, Stipp DT, Souza FN, Da Costa LB, Oliveira CJB. Short communication: Occurrence of methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci in dairy goat herds in Ohio, United States. J Dairy Sci. 2018 Sep;101(9):7804-7807. doi: 10.3168/jds.2017-13361. 
  • Eguale T, Asrat D, Alemayehu H, Nana I, Gebreyes WA, Gunn JS, Engidawork E. Phenotypic and genotypic characterization of temporally related nontyphoidal Salmonella strains isolated from humans and food animals in central Ethiopia. Zoonoses Public Health. 2018 Nov;65(7):766-776. doi: 10.1111/zph.12490. 
  • Delgado-Suárez EJ, Selem-Mojica N, Ortiz-López R, Gebreyes WA, Allard MW, Barona-Gómez F, Rubio-Lozano MS. Whole genome sequencing reveals widespread distribution of typhoidal toxin genes and VirB/D4 plasmids in bovine-associated nontyphoidal Salmonella. Sci Rep. 2018 Jun 29;8(1):9864. doi: 10.1038/s41598-018-28169-4.
  • Saraiva MM, De Leon CM, Santos SC, Stipp DT, Souza MM, Santos Filho L, Gebreyes WA, Oliveira CJ. Accuracy of PCR targeting different markers for Staphylococcus aureus identification: a comparative study using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as the gold standard. J Vet Diagn Invest. 2018 Mar;30(2):252-255. doi: 10.1177/1040638717732370. 
  • Moura GS; Marques M; Gebreyes WA; Stipp DT, da Costa MM; Souza FN; da Costa L; Oliveira CJ. "Occurrence of Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (MRCoNS) in dairy goat herds in Ohio, USA." May 2017. (Accepted with minor revisions - Journal of Dairy Science).
  • Gebreyes, WA, Wittum TE, Habing, G, Alali, W, Usui, M, Suzuki, S, "Spread of Antibiotic Resistance in Food Animal Production Systems". In "Foodborne Diseases". [Editor-Review]. Published. 15% Authorship
  • Gebreyes W, Lee CW, Jackwood D, Hoet AE. Chapter 18: Molecular epidemiology of zoonotic and livestock diseases. ED. Lee Riley.  2nd edition Molecular Epidemiology of Infectious Diseases. ASM publisher. Submitted.
  • Eguale T, Engidawork E, Gebreyes WA, Asrat D, Alemayehu H, Medhin G, Johnson RP, Gunn JS. Fecal prevalence, serotype distribution and antimicrobial resistance of Salmonellae in dairy cattle in central Ethiopia. BMC Microbiol. 2016 Feb 16;16:20. doi: 10.1186/s12866-016-0638-2.
  • Lira MC, Givisiez PE, De Sousa FG, Magnani M, De Souza EL, Spricigo DA, Gebreyes WA, De Oliveira CJ. Biofilm-forming and antimicrobial resistance traits of staphylococci isolated from goat dairy plants. J Infect Dev Ctries. 2016 Sep 30;10(9):932-938. doi: 10.3855/jidc.6714.
  • Sisay Z, Djikeng A, Berhe N, Belay G, Gebreyes W, Abegaz WE, Njahira MN, Wang QH, Saif LJ.Prevalence and molecular characterization of human noroviruses and sapoviruses in Ethiopia. Arch Virol. 2016 Aug;161(8):2169-82. doi: 10.1007/s00705-016-2887-7. Epub 2016 May 19. PMID: 27193022
  • Nigatu Kebede, Alemayehu Worku, Ahmed Ali, Abebe Animut, Yohannes Negash, Wondwossen A Gebreyes, Abhay Satoskar, Community knowledge, attitude and practice towards cutaneous leishmaniasis endemic area Ochello, Gamo Gofa Zone, South Ethiopia, Asian Pacific Journal of Tropical Biomedicine 6(7) · May 2016 DOI: 10.1016/j.apjtb.2016.01.018 · License: CC BY-NC-ND 4.0
  • Seyoum ET, Mekonene TK, Woldetsadik DA, Zewudie BM, Gebreyes WA. Enterotoxin gene profile of Staphylococcus aureus isolates recovered from bovine milk produced in central Ethiopia. J Infect Dev Ctries. 2016 Feb 28;10(2):138-42. doi: 10.3855/jidc.6797.
  • Kashoma IP, Kassem II, Kumar A, Kessy BM, Gebreyes W, Kazwala RR, Rajashekara G. 2015. Antimicrobial Resistance and Genotypic Diversity of Campylobacter Isolated from Pigs, Dairy, and Beef Cattle in Tanzania. Front Microbiol. 6:1240.
  • Seyoum ET, Woldetsadik DA, Mekonen TK, Gezahegn HA, Gebreyes WA. 2015. Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia. J Infect Dev Ctries. 9 (11):1204-9. doi: 10.3855/jidc.6211. PMID: 26623629
  • Eguale T, Gebreyes WA, Asrat D, Alemayehu H, Gunn JS, Engidawork E. 2015. Nontyphoidal Salmonella serotypes, antimicrobial resistance and co-infection with parasites among patients with diarrhea and other gastrointestinal complaints in Addis Ababa, Ethiopia. BMC Infect Dis. 15:497. doi: 10.1186/s12879-015-1235-y. PMID: 26537951
  • Artuso-Ponte V, Moeller S, Rajala-Schultz P, Medardus JJ, Munyalo J, Lim K, Gebreyes WA*. 2015. Supplementation with Quaternary Benzo(c)phenanthridine Alkaloids Decreased Salivary Cortisol and Salmonella Shedding in Pigs After Transportation to the Slaughterhouse. Foodborne Pathog Dis. 12(11):891-7. doi: 10.1089/fpd.2015.2009. PMID: 26393495
  • Oliveira CJ, Tiao N, de Sousa FG, de Moura JF, Santos Filho L, Gebreyes WA*. 2015. Methicillin-Resistant Staphylococcus aureus from Brazilian Dairy Farms and Identification of Novel Sequence Types. Zoonoses Public Health. doi: 10.1111/zph.12209. PMID: 26178302
  • Kashoma IP, Kassem II, John J, Kessy BM, Gebreyes W, Kazwala RR, Rajashekara G. 2015. Prevalence and Antimicrobial Resistance of Campylobacter Isolated from Dressed Beef Carcasses and Raw Milk in Tanzania. Microb Drug Resist. [Epub ahead of print]. PMID: 26153978.
  • Tigabu E, Asrat D, Kassa T, Sinmegn T, Molla B, Gebreyes W*. 2015. Assessment of Risk Factors in Milk Contamination with Staphylococcus aureus in Urban and Peri- Urban Small-Holder Dairy Farming in Central Ethiopia. Zoonoses Public Health. doi: 10.1111/zph.12199. PMID: 25916167.