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College of Veterinary Medicine

Roman Reddy Ganta

 r gantaProfessor and Director, Center of Excellence for Vector-Borne Diseases

BS 1978, Andhra University, Waltair, India
MS 1980, Andhra University, Waltair, India
PhD 1987, All India Institute of Medical Sciences, New Delhi, India

Phone:(785) 532-4612/4343
Fax: (785) 532-4851
Email: rganta@vet.k-state.edu



Our research for over two and half decades has focused on important human and animal vector-borne infectious diseases.  We currently work on tick-borne diseases caused by Ehrlichia and Anaplasma species pathogens.  Our studies involve assessing pathogen molecular structure, host responses, the effect of tick and host cell environments on the pathogens’ adaptation, mutagenesis, vaccine development, and developing molecular diagnostic tests for various vector-borne pathogens and the disease surveillance.  Over the years, we have worked on several animal and human vector-borne pathogens, including the mosquito-borne human malaria parasite, Plasmodium falciparum; tick-borne bovine babesiosis parasites, Babesia bigemina and Babesia bovis; snail-borne liver fluke of sheep, Fasiola hepatica; mosquito-borne canine heartworm, Dirofilaria immitis; tick-borne rickettsial pathogens of the genera Ehrlichia (E. ruminantium, E. canis and E. chaffeensis) and Anaplasma (A. marginale and A. phagocytophilum), and mosquito-borne West Nile Virus.  Our recent research also focuses on Rickettsia and Borrelia species.

Selected publications

Ehrlichia chaffeensis infection in the reservoir host (white-tailed deer) and in an incidental host (dog) is impacted by its prior growth in macrophage and tick cell environments. Nair AD, Cheng C, Jaworski DC, Willard LH, Sanderson MW, Ganta RR.  PLoS One. 2014 Oct 10;9(10):e109056. doi: 10.1371/journal.pone.0109056. eCollection 2014. PMID: 25303515 

Bayesian spatio-temporal analysis and geospatial risk factors of human monocytic ehrlichiosis.  Raghavan RK, Neises D, Goodin DG, Andresen DA, Ganta RR  PLoS One. 2014 Jul 3;9(7):e100850. doi: 10.1371/journal.pone.0100850. eCollection 2014. PMID: 24992684 

Transcription of Ehrlichia chaffeensis genes is accomplished by RNA polymerase holoenzyme containing either sigma 32 or sigma 70. Liu H, Von Ohlen T, Cheng C, Faburay B, Ganta RR.  PLoS One. 2013 Nov 21;8(11):e81780. doi: 10.1371/journal.pone.0081780. eCollection 2013. PMID: 24278458 

Aggregate-reactivation activity of the molecular chaperone ClpB from Ehrlichia chaffeensis.  Zhang T, Kedzierska-Mieszkowska S, Liu H, Cheng C, Ganta RR, Zolkiewski M. PLoS One. 2013 May 7;8(5):e62454. doi: 10.1371/journal.pone.0062454. Print 2013. PMID: 23667479 

Targeted and random mutagenesis of Ehrlichia chaffeensis for the identification of genes required for in vivo infection. Cheng C, Nair AD, Indukuri VV, Gong S, Felsheim RF, Jaworski D, Munderloh UG, Ganta RR. PLoS Pathog. 2013 Feb;9(2):e1003171. doi: 10.1371/journal.ppat.1003171. Epub 2013 Feb 14. Erratum in: PLoS Pathog. 2013 May;9(5). doi: 10.1371/annotation/322c8bba-8dae-4196-b85d-5de315e44d76.  PMID: 23459099 

Identification of critical host mitochondrion-associated genes during Ehrlichia chaffeensis infections. Von Ohlen T, Luce-Fedrow A, Ortega MT, Ganta RR, Chapes SK.  Infect Immun. 2012 Oct;80(10):3576-86. doi: 10.1128/IAI.00670-12. Epub 2012 Jul 30.  PMID: 22851751 

Transmission electron microscopy reveals distinct macrophage- and tick cell-specific morphological stages of Ehrlichia chaffeensis. Dedonder SE, Cheng C, Willard LH, Boyle DL, Ganta RR. PLoS One. 2012;7(5):e36749. doi: 10.1371/journal.pone.0036749. Epub 2012 May 15.  PMID: 22615806 

Isolation and characterization of Ehrlichia chaffeensis RNA polymerase and its use in evaluating p28 outer membrane protein gene promoters. Faburay B, Liu H, Peddireddi L, Ganta RR.  BMC Microbiol. 2011 Apr 22;11:83. doi: 10.1186/1471-2180-11-83. PMID: 21513529 

Comparison of iatrogenic transmission of Anaplasma marginale in Holstein steers via needle and needle-free injection techniques. Reinbold JB, Coetzee JF, Hollis LC, Nickell JS, Riegel CM, Christopher JA, Ganta RR. Am J Vet Res. 2010 Oct;71(10):1178-88. doi: 10.2460/ajvr.71.10.1178.  PMID: 20919904 

Detection of Anaplasma marginale and A. phagocytophilum in bovine peripheral blood samples by duplex real-time reverse transcriptase PCR assay. Reinbold JB, Coetzee JF, Sirigireddy KR, Ganta RR. J Clin Microbiol. 2010 Jul;48(7):2424-32. doi: 10.1128/JCM.02405-09. Epub 2010 May 12. Erratum in: J Clin Microbiol. 2012 Aug;50(8):2841.  PMID: 20463162 

The efficacy of three chlortetracycline regimens in the treatment of persistent Anaplasma marginale infection. Reinbold JB, Coetzee JF, Hollis LC, Nickell JS, Riegel C, Olson KC, Ganta RR.  Vet Microbiol. 2010 Sep 28;145(1-2):69-75. doi: 10.1016/j.vetmic.2010.02.031. Epub 2010 Mar 3.  PMID: 20346598 

Promoter analysis of macrophage- and tick cell-specific differentially expressed Ehrlichia chaffeensis p28-Omp genes. Peddireddi L, Cheng C, Ganta RR. BMC Microbiol. 2009 May 19;9:99. doi: 10.1186/1471-2180-9-99. PMID: 19454021 

Molecular characterization of Ehrlichia interactions with tick cells and macrophages.  Ganta RR, Peddireddi L, Seo GM, Dedonder SE, Cheng C, Chapes SK. Front Biosci (Landmark Ed). 2009 Jan 1;14:3259-73. Review. PMID: 19273271 

Defining the immune response to Ehrlichia species using murine models.  Chapes SK, Ganta RR. Vet Parasitol. 2008 Dec 20;158(4):344-59. doi: 10.1016/j.vetpar.2008.09.028. Epub 2008 Oct 17. PMID: 19028013 

Isolation and molecular detection of Ehrlichia from vertebrate animals.  Cheng C, Sirigireddy KR, Ganta RR. Curr Protoc Microbiol. 2008 May;Chapter 3:Unit 3A.3. doi: 10.1002/9780471729259.mc03a03s9. PMID: 18770538 

Laboratory maintenance of Ehrlichia chaffeensis and Ehrlichia canis and recovery of organisms for molecular biology and proteomics studies. Cheng C, Ganta RR. Curr Protoc Microbiol. 2008 May; Chapter 3:Unit 3A.1. doi: 10.1002/9780471729259.mc03a01s9.  PMID: 18770537 

Total, membrane, and immunogenic proteomes of macrophage- and tick cell-derived Ehrlichia chaffeensis evaluated by liquid chromatography-tandem mass spectrometry and MALDI-TOF methods.  Seo GM, Cheng C, Tomich J, Ganta RR.  Infect Immun. 2008 Nov;76(11):4823-32. doi: 10.1128/IAI.00484-08. Epub 2008 Aug 18.  PMID: 1871087 

Use of Drosophila S2 cells as a model for studying Ehrlichia chaffeensis infections.  Luce-Fedrow A, Von Ohlen T, Boyle D, Ganta RR, Chapes SK.  Appl Environ Microbiol. 2008 Mar;74(6):1886-91. doi: 10.1128/AEM.02467-07. Epub 2008 Feb 1.  PMID: 18245255  

High prevalence of West Nile virus: a continuing risk in acquiring infection from a mosquito bite.  Sirigireddy KR, Kennedy GA, Broce A, Zurek L, Ganta RR.  Vector Borne Zoonotic Dis. 2006 Winter;6(4):351-60.  PMID: 17187569 

Multiplex detection of Ehrlichia and Anaplasma pathogens in vertebrate and tick hosts by real-time RT-PCR.  Sirigireddy KR, Mock DC, Ganta RR.  Ann N Y Acad Sci. 2006 Oct;1078:552-6.  PMID: 17114775 

Differential clearance and immune responses to tick cell-derived versus macrophage culture-derived Ehrlichia chaffeensis in mice.  Ganta RR, Cheng C, Miller EC, McGuire BL, Peddireddi L, Sirigireddy KR, Chapes SK.  Infect Immun. 2007 Jan;75(1):135-45. Epub 2006 Oct 23.  PMID: 17060466 

Unique macrophage and tick cell-specific protein expression from the p28/p30-outer membrane protein multigene locus in Ehrlichia chaffeensis and Ehrlichia canis.  Singu V, Peddireddi L, Sirigireddy KR, Cheng C, Munderloh U, Ganta RR.  Cell Microbiol. 2006 Sep;8(9):1475-87.  PMID: 16922866 

Multiplex detection of Ehrlichia and Anaplasma species pathogens in peripheral blood by real-time reverse transcriptase-polymerase chain reaction.  Sirigireddy KR, Ganta RR.  J Mol Diagn. 2005 May;7(2):308-16.  PMID: 15858156 

Ehrlichia chaffeensis expresses macrophage- and tick cell-specific 28-kilodalton outer membrane proteins.  Singu V, Liu H, Cheng C, Ganta RR.  Infect Immun. 2005 Jan;73(1):79-87.  PMID: 15618143