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David Ley, DVM, PhD

Professor, Poultry Health Management (Retired)

Contact:

dley@ncsu.edu
Office: 919.513.6269
Lab: Mycoplasma Diagnostics and Research
Lab Phone: 919.513.6249

Certifications
Diplomate, American College of Veterinary Microbiologists
Diplomate, American College of Poultry Veterinarians
Infectious Diseases
Poultry diseases, Avian mycoplasmosis, Biosecurity, Identification and control of emerging avian diseases, Enteric and respiratory avian disease pathogenesis, Interaction of management and disease
Mycoplasma species are important respiratory tract and systemic pathogens of commercial poultry causing substantial economic losses worldwide due to increased mortality, downgrading and condemnations of carcasses, reduced egg production and hatchability, and decreased feed efficiency. Strategies to reduce the adverse impact of mycoplasmosis in commercial poultry include: surveillance, control, and eradication programs, the use of antimicrobials, and vaccination.

Research in my laboratory is focused on improving the health of commercial poultry by developing new knowledge that will contribute to the elimination or reduction of losses due to mycoplasmosis. Specific objectives are to 1) develop and evaluate rapid diagnostic capabilities for the identification of Mycoplasma species and strains causing diseases, 2) to delineate the epidemiology of avian mycoplasmosis by developing and using strain-specific molecular markers and gene sequencing, and 3) to study the dynamics of Mycoplasma gallisepticum conjunctivitis in songbirds from emergence to endemicity.Her research interests include neurohormonal activation in heart failure – specifically the pharmacologic blockade of the renin-angiotensin-aldosterone system (RAAS), the effects of various drugs on RAAS, aldosterone breakthrough, and new applications for pimobendan in refractory heart failure.

  • Parallel patterns of increased virulence in a recently emerged wildlife pathogen.Hawley DM, Osnas EE, Dobson AP, Hochachka WM, Ley DH, Dhondt AA. | PLoS Biol 11(5): e1001570. doi:10.1371/journal.pbio.1001570. 2013.
  • Extensive variation in surface lipoprotein gene content and genomic changes associated with virulence during evolution of a novel North American house finch epizootic strain of Mycoplasma gallisepticum .Tulman ER, Liao X, Szczepanek SM, Ley DH, Kutish GF, Geary SJ. | Microbiology 158(8), 2073-88. 2012.
  • Effects of route of inoculation on Mycoplasma gallisepticum infection in captive house finches.Dhondt KV, Dhondt AA, Ley DH. | Avian Pathology 36(3):205-8, 2007.
  • Pneumonia of turkey breeder hens associated with Mycoplasma synoviae.Osorio C, Fletcher OJ, Abdul-Aziz T, Gonder E, Tilley B, Ley DH. | Avian Diseases 51:791-796, 2007.
  • Experimental infection of chickens and turkeys with Mycoplasma gallisepticum reference strain S6 and North Carolina field isolate RAPD type B.Sanei B, Barnes HJ, Vaillancourt J-P, Ley DH. | Avian Diseases 51:106-111, 2007.
  • Dynamics of mycoplasmal conjunctivitis in the native and introduced range of the host.Dhondt AA, Badyaev AV, Dobson AP, Hawley DM, Driscoll MJL, Hochachka WM, Ley DH. | EcoHealth 3, 95–102, 2006.
  • Genotypic analyses of Mycoplasma gallisepticum isolates from songbirds by random amplification of polymorphic DNA and amplified-fragment length polymorphism.Cherry JJ, Ley DH, Altizer S. | Journal of Wildlife Diseases 42:421-428, 2006.
  • Further western spread of Mycoplasma gallisepticum infection of house finches.Ley DH, Sheaffer DS, Dhondt AA. | Journal of Wildlife Diseases 42:429-431, 2006.
  • Re-exposure of captive house finches that recovered from Mycoplasma gallisepticum infection.Sydenstricker KV, Dhondt AA, Ley DH, Kollias GV. | Journal of Wildlife Diseases 41:326-333. 2005.
  • Dynamics of a novel pathogen in an avian host: Mycoplasmal conjunctivitis in house finches.Dhondt AA, Altizer S, Cooch EG, Davis AK, Dobson A, Driscoll MJL, Hartup BK, Hawley DM, Hochachka WM, Hosseini PR, Jennelle CS, Kollias GV, Ley DH, Swarthout ECH, Sydenstricker KV. | Acta Tropica Vol. 94, No. 1, pp 77-93. 2005.
  • Differentiation of Mycoplasma gallisepticum strains using amplified fragment length polymorphism and other DNA-based typing methods.Hong Y, Garcia M, Levisohn S, Savelkoul P, Leiting V, Lysnyansky I, Ley DH, Kleven SH. | Avian Diseases 49:43-49. 2005.
  • Health survey of house finches (Carpodacus mexicanus) from Wisconsin.Hartup BK, Stott-Messick B, Guzy M, Ley DH. | Avian Diseases, 48:84-90. 2004.
  • Experimental infection of house finches with Mycoplasma gallisepticum.Kollias GV, Sydenstricker KV, Kollias HW, Ley DH, Hosseini PR, Connolly V, Dhondt AA. | Journal of Wildlife Diseases, 40:79-86. 2004.
  • Molecular variability of house finch Mycoplasma gallisepticum isolates as revealed by sequencing and restriction fragment length polymorphism analysis of the pvpA gene.Pillai, SR, Mays HL, Jr., Ley DH, Luttrell P, Panangala VS, Farmer KL, Roberts SR. | Avian Diseases, 47:640-648. 2003.
  • Enhancement of enteropathogenic Escherichia coli pathogenicity in young turkeys by concurrent turkey coronavirus infection.Pakpinyo S, Ley DH, Barnes HJ, Vaillancourt JP, Guy JS. | Avian Diseases, 47:396-405. 2003.
  • Prevalence of enteropathogenic Escherichia coli in naturally occurring cases of poult enteritis-mortality syndrome.Pakpinyo S, Ley DH, Barnes HJ, Vaillancourt JP, Guy JS. | Avian Diseases, 46:360-369. 2002.
  • Dynamics of conjunctivitis and Mycoplasma gallisepticum infections in house finches.Hartup BK, Bickal JM, Dhondt AA, Ley DH, Kollias GV. | The Auk 118(2):327-333. 2001.
  • Mycoplasmosis in evening and pine grosbeaks with conjunctivitis in Quebec.Mikaelian I, Ley DH, Claveau R, Lemieux M, Berube J-P. | J Wildl Dis 37:826-830. 2001.
  • Mycoplasmal conjunctivitis in songbirds from New York.Hartup BK, Kollias GV, Ley DH. | Journal of Wildlife Diseases, 36:257-264. 2000.
  • Mycoplasma sturni from blue jays and northern mockingbirds with conjunctivitis in Florida.Ley DH, Geary SJ, Berkhoff JE, McLaren JM and Levisohn S. | Journal of Wildlife Diseases, 34:403-406. 1998.
  • Molecular epidemiological investigations of Mycoplasma gallisepticum (MG) conjunctivitis in songbirds by random amplified polymorphic DNA (RAPD) analyses.Ley DH, JE Berkhoff and S Levisohn. | Emerging Infectious Diseases, 3:375-380. 1997.
  • Mycoplasma synoviae has two distinct phase-variable major membrane antigens, one of which is a putative hemagglutinin.Noormohammadi AH, PF Markham, KG Whithear, ID Walker, VA Gurevich, DH Ley, and GF Browning. | Infection and Immunity 65:2542-2547. 1997.
  • Transmissibility of live Mycoplasma gallisepticum vaccine strains ts-11 and 6/85 from vaccinated layer pullets to sentinel poultry.Ley DH, JM McLaren, AM Miles, HJ Barnes, S Heins Miller and G Franz. | Avian Dis. 41:186-193. 1997.
  • Mycoplasma gallisepticum isolated from house finches (Carpodacus mexicanus) with conjunctivitis.Ley DH, Berkhoff JE and JM McLaren. | Avian Dis. 40:480-483. 1996.
  • Multiple host transfers, but only one successful lineage in a continent-spanning emergent pathogen.Hochachka WM, Dhondt AA, Dobson AP, Hawley DM, Ley DH, Osnas EE. | Proceedings of the Royal Society B: Biological Sciences 280: 20131068. http://dx.doi.org/10.1098/rspb.2013.1068. 2013.
  • Multiple host transfers, but only one successful lineage in a continent-spanning emergent pathogen.Hochachka WM, Dhondt AA, Dobson AP, Hawley DM, Ley DH, Osnas EE. | Proceedings of the Royal Society B: Biological Sciences 280: 20131068. http://dx.doi.org/10.1098/rspb.2013.1068. 2013.
  • Parallel patterns of increased virulence in a recently emerged wildlife pathogen.Hawley DM, Osnas EE, Dobson AP, Hochachka WM, Ley DH, Dhondt AA. | PLoS Biol 11(5): e1001570. doi:10.1371/journal.pbio.1001570. 2013.
  • Extensive variation in surface lipoprotein gene content and genomic changes associated with virulence during evolution of a novel North American house finch epizootic strain of Mycoplasma gallisepticum .Tulman ER, Liao X, Szczepanek SM, Ley DH, Kutish GF, Geary SJ. | Microbiology 158(8), 2073-88. 2012.
  • Effects of route of inoculation on Mycoplasma gallisepticum infection in captive house finches.Dhondt KV, Dhondt AA, Ley DH. | Avian Pathology 36(3):205-8, 2007.
  • Experimental infection of chickens and turkeys with Mycoplasma gallisepticum reference strain S6 and North Carolina field isolate RAPD type B.Sanei B, Barnes HJ, Vaillancourt J-P, Ley DH. | Avian Diseases 51:106-111, 2007.
  • Dynamics of mycoplasmal conjunctivitis in the native and introduced range of the host.Dhondt AA, Badyaev AV, Dobson AP, Hawley DM, Driscoll MJL, Hochachka WM, Ley DH. | EcoHealth
  • Genotypic analyses of Mycoplasma gallisepticum isolates from songbirds by random amplification of polymorphic DNA and amplified-fragment length polymorphism.Cherry JJ, Ley DH, Altizer S. | Journal of Wildlife Diseases 42:421-428, 2006.
  • Further western spread of Mycoplasma gallisepticum infection of house finches.Ley DH, Sheaffer DS, Dhondt AA. | Journal of Wildlife Diseases 42:429-431, 2006.
  • Re-exposure of captive house finches that recovered from Mycoplasma gallisepticum infection.Sydenstricker KV, Dhondt AA, Ley DH, Kollias GV. | Journal of Wildlife Diseases 41:326-333. 2005.
  • Dynamics of a novel pathogen in an avian host: Mycoplasmal conjunctivitis in house finches.Dhondt AA, Altizer S, Cooch EG, Davis AK, Dobson A, Driscoll MJL, Hartup BK, Hawley DM, Hochachka WM, Hosseini PR, Jennelle CS, Kollias GV, Ley DH, Swarthout ECH, Sydenstricker KV. | Acta Tropica Vol. 94, No. 1, pp 77-93. 2005.
  • Differentiation of Mycoplasma gallisepticum strains using amplified fragment length polymorphism and other DNA-based typing methods.Hong Y, Garcia M, Levisohn S, Savelkoul P, Leiting V, Lysnyansky I, Ley DH, Kleven SH. | Avian Diseases 49:43-49. 2005.
  • Health survey of house finches (Carpodacus mexicanus) from Wisconsin.Hartup BK, Stott-Messick B, Guzy M, Ley DH. | Avian Diseases, 48:84-90. 2004.
  • Experimental infection of house finches with Mycoplasma gallisepticum.Kollias GV, Sydenstricker KV, Kollias HW, Ley DH, Hosseini PR, Connolly V, Dhondt AA. | Journal of Wildlife Diseases, 40:79-86. 2004.
  • Molecular variability of house finch Mycoplasma gallisepticum isolates as revealed by sequencing and restriction fragment length polymorphism analysis of the pvpA gene.Pillai, SR, Mays HL, Jr., Ley DH, Luttrell P, Panangala VS, Farmer KL, Roberts SR. | Avian Diseases, 47:640-648. 2003.
  • Enhancement of enteropathogenic Escherichia coli pathogenicity in young turkeys by concurrent turkey coronavirus infection.Pakpinyo S, Ley DH, Barnes HJ, Vaillancourt JP, Guy JS. | Avian Diseases, 47:396-405. 2003.
  • Prevalence of enteropathogenic Escherichia coli in naturally occurring cases of poult enteritis-mortality syndrome.Pakpinyo S, Ley DH, Barnes HJ, Vaillancourt JP, Guy JS. | Avian Diseases, 46:360-369. 2002.
  • Dynamics of conjunctivitis and Mycoplasma gallisepticum infections in house finches.Hartup BK, Bickal JM, Dhondt AA, Ley DH, Kollias GV. | The Auk 118(2):327-333. 2001.
  • Mycoplasmosis in evening and pine grosbeaks with conjunctivitis in Quebec.Mikaelian I, Ley DH, Claveau R, Lemieux M, Berube J-P. | J Wildl Dis 37:826-830. 2001.
  • Mycoplasmal conjunctivitis in songbirds from New York.Hartup BK, Kollias GV, Ley DH. | Journal of Wildlife Diseases, 36:257-264. 2000.
  • Mycoplasma sturni from blue jays and northern mockingbirds with conjunctivitis in Florida.Ley DH, Geary SJ, Berkhoff JE, McLaren JM and Levisohn S. | Journal of Wildlife Diseases, 34:403-406. 1998.
  • Molecular epidemiological investigations of Mycoplasma gallisepticum (MG) conjunctivitis in songbirds by random amplified polymorphic DNA (RAPD) analyses.Ley DH, JE Berkhoff and S Levisohn. | Emerging Infectious Diseases, 3:375-380. 1997.
  • Mycoplasma synoviae has two distinct phase-variable major membrane antigens, one of which is a putative hemagglutinin.Noormohammadi AH, PF Markham, KG Whithear, ID Walker, VA Gurevich, DH Ley, and GF Browning. | Infection and Immunity 65:2542-2547. 1997.
  • Transmissibility of live Mycoplasma gallisepticum vaccine strains ts-11 and 6/85 from vaccinated layer pullets to sentinel poultry.Ley DH, JM McLaren, AM Miles, HJ Barnes, S Heins Miller and G Franz. | Avian Dis. 41:186-193. 1997.
  • Mycoplasma gallisepticum isolated from house finches (Carpodacus mexicanus) with conjunctivitis.Ley DH, Berkhoff JE and JM McLaren. | Avian Dis. 40:480-483. 1996.
  • (2010) Mycoplasma iowae associated with chondrodystrophy in commercial turkeys.Ley DH, Marusak RA, Vivas EJ, Barnes HJ, Fletcher OJ.  | Avian Pathol 39:87-93. 2010.  [Erratum: Avian Pathol 39 :307]
  • (2007) Pneumonia of turkey breeder hens associated with Mycoplasma synoviae.Osorio C, Fletcher OJ, Abdul-Aziz T, Gonder E, Tilley B, Ley DH. | Avian Diseases 51:791-796, 2007.