Roman Reddy Ganta

 r gantaUniversity Distinguished Professor 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



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

Protein aggregation in Ehrlichia chaffeensis during infection of mammalian cells.

Kuczynska-Wisnik D, Cheng C, Ganta RR, Zolkiewski M.

FEMS Microbiol Lett. 2017 Mar 1;364(6). doi: 10.1093/femsle/fnx059.

Initial development and preliminary evaluation of a multiplex bead assay to detect antibodies to Ehrlichia canis, Anaplasma platys, and Ehrlichia chaffeensis outer membrane peptides in naturally infected dogs from Grenada, West Indies.

Wilkerson MJ, Black KE, Lanza-Perea M, Sharma B, Gibson K, Stone DM, George A, Nair AD, Ganta RR.

J Vet Diagn Invest. 2017 Jan;29(1):109-114. doi: 10.1177/1040638716671979. Epub 2016 Nov 16.

PMID: 27852813

Amblyomma americanum ticks infected with in vitro cultured wild-type and mutants of Ehrlichia chaffeensis are competent to produce infection in naïve deer and dogs.

Jaworski DC, Cheng C, Nair AD, Ganta RR.

Ticks Tick Borne Dis. 2017 Jan;8(1):60-64. doi: 10.1016/j.ttbdis.2016.09.017. Epub 2016 Sep 28.

PMID: 27729288

Heterogeneous Associations of Ecological Attributes with Tick-Borne Rickettsial Pathogens in a Periurban Landscape.

Raghavan RK, Goodin DG, Dryden MW, Hroobi A, Gordon DM, Cheng C, Nair AD, Jakkula LU, Hanzlicek GA, Anderson GA, Ganta RR.

Vector Borne Zoonotic Dis. 2016 Sep;16(9):569-76. doi: 10.1089/vbz.2016.1975. Epub 2016 Jul 25.

PMID: 27454144

Sequence determinants spanning -35 motif and AT-rich spacer region impacting Ehrlichia chaffeensis Sigma 70-dependent promoter activity of two differentially expressed p28 outer membrane protein genes.

Liu H, Jakkula LU, Von Ohlen T, Ganta RR.

DNA Res. 2016 Jul 8. pii: dsw034. [Epub ahead of print]

PMID: 27402867

Bayesian Space-Time Patterns and Climatic Determinants of Bovine Anaplasmosis.

Hanzlicek GA, Raghavan RK, Ganta RR, Anderson GA.

PLoS One. 2016 Mar 22;11(3):e0151924. doi: 10.1371/journal.pone.0151924. eCollection 2016.

PMID: 27003596

Hierarchical Bayesian Spatio-Temporal Analysis of Climatic and Socio-Economic Determinants of Rocky Mountain Spotted Fever.

Raghavan RK, Goodin DG, Neises D, Anderson GA, Ganta RR.

PLoS One. 2016 Mar 4;11(3):e0150180. doi: 10.1371/journal.pone.0150180. eCollection 2016.

PMID: 26942604

Vaccination with an Attenuated Mutant of Ehrlichia chaffeensis Induces Pathogen-Specific CD4+ T Cell Immunity and Protection from Tick-Transmitted Wild-Type Challenge in the Canine Host.

McGill JL, Nair AD, Cheng C, Rusk RA, Jaworski DC, Ganta RR.

PLoS One. 2016 Feb 3;11(2):e0148229. doi: 10.1371/journal.pone.0148229. eCollection 2016.

PMID: 26841025

Comparative Experimental Infection Study in Dogs with Ehrlichia canis, E. chaffeensis, Anaplasma platys and A. phagocytophilum.

Nair AD, Cheng C, Ganta CK, Sanderson MW, Alleman AR, Munderloh UG, Ganta RR.

PLoS One. 2016 Feb 3;11(2):e0148239. doi: 10.1371/journal.pone.0148239. eCollection 2016.

PMID: 26840398 [PubMed - indexed for MEDLINE] Free PMC Article

Maximum Entropy-Based Ecological Niche Model and Bio-Climatic Determinants of Lone Star Tick (Amblyomma americanum) Niche.

Raghavan RK, Goodin DG, Hanzlicek GA, Zolnerowich G, Dryden MW, Anderson GA, Ganta RR.

Vector Borne Zoonotic Dis. 2016 Mar;16(3):205-11. doi: 10.1089/vbz.2015.1837. Epub 2016 Jan 29.

PMID: 26824880

Mutations in Ehrlichia chaffeensis Causing Polar Effects in Gene Expression and Differential Host Specificities.

Cheng C, Nair AD, Jaworski DC, Ganta RR.

PLoS One. 2015 Jul 17;10(7):e0132657. doi: 10.1371/journal.pone.0132657. eCollection 2015.

PMID: 26186429

Attenuated Mutants of Ehrlichia chaffeensis Induce Protection against Wild-Type Infection Challenge in the Reservoir Host and in an Incidental Host.

Nair AD, Cheng C, Jaworski DC, Ganta S, Sanderson MW, Ganta RR.

Infect Immun. 2015 Jul;83(7):2827-35. doi: 10.1128/IAI.00487-15. Epub 2015 Apr 27.

PMID: 25916990

High prevalence of "Candidatus Rickettsia andeanae" and apparent exclusion of Rickettsia parkeri in adult Amblyomma maculatum (Acari: Ixodidae) from Kansas and Oklahoma.

Paddock CD, Denison AM, Dryden MW, Noden BH, Lash RR, Abdelghani SS, Evans AE, Kelly AR, Hecht JA, Karpathy SE, Ganta RR, Little SE.

Ticks Tick Borne Dis. 2015 Apr;6(3):297-302. doi: 10.1016/j.ttbdis.2015.02.001. Epub 2015 Mar 13.

PMID: 25773931

E hrlichia 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


For a complete list of publications, please visit My Bibliography.