Faculty Profile


Viveka Vadyvaloo

Viveka Vadyvaloo

Associate Professor

Departments

Affiliated Organizations

  • American Society for Microbiology (member)
  • Center for Health in the Human Ecosytem, University of Idaho (member)

vvadyvaloo@wsu.edu
Phone: 509-335-6043

 

Biography

Dr Vadyvaloo was born and raised on the East coast of South Africa where the waters are warm due to the warm Mozambique current in the Indian ocean.  In early 2003 she obtained her PhD in Biochemistry from the University of Stellenbosch on the West coast of South Africa where the cold Benguela current waters are home to many great white sharks.  She then moved to the US for postdoctoral training in the lab of Ronald Kaback at Howard Hughes Medical Institute at UCLA from 2003-2004 where she studied biochemical and structural aspects of membrane transport proteins that facilitate their activity.  She continued further postdoctoral training at the Rocky Mountain Laboratories/NIH/NIAID.  Here she first conducted research in pathogenesis of Staphylococci in the lab of Michael Otto, and then from 2005-2008 she joined Joe Hinnebusch’s lab where she began research in understanding the Yersinia pestis – flea vector interaction.  She was hired as an Assistant Professor at the Paul G Allen School for Global Animal Health in 2010.

Personal Statement

As far as a career in science goes I cannot say that there was any defining experience that inspired me to pursue this career path; perhaps during my formative years I seemed to have a greater aptitude for science compared to many of my peers – then pursuing studies and a career in science just happened! I don’t have any hobbies but I do enjoy running to keep fit and de-stress, scratch cooking, and hiking when the opportunity presents itself. What else is in my life other than research? A big fluffy grey doodle-dog, of course!!

Education and Training

  • 2009-2010: Research Assistant Professor, Washington State University, Pullman WA
  • 2004-2008:Postdoctoral fellow, Rocky Mountain Laboratories, NIAID, NIH
  • 2003-2004:Postdoctoral Fellow, Howard Hughes Medical Institute at UCLA
  • 2000-2003: PhD, Biochemistry, University of Stellenbosch, Stellenbosch
  • 1997-1999: MS, Molecular Microbiology, University of Kwazulu-Natal, Pietermaritzburg
  • 1996: BS (Hons), Microbiology, University of Kwazulu-Natal, Pietermaritzburg
  • 1995: BS (Microbiology, Human Physiology), University of Kwazulu-Natal, Durban-Westville

General Research / Expertise

Dr Vadyvaloo does research on the flea-borne zoonotic disease, bubonic plague.  This often fatal disease is notorious for causing devastating loss of human life, and profoundly influencing human civilization in three major plague pandemics: The 5-7th century Justinian plague, the 14th century Black Death and the Modern plague (spanning ~1860 – 1950).  Bubonic plague has however re-emerged as a public health concern since the 1990’s.  Yersinia pestis is the bacterial etiological agent of the plague and it is primarily spread by flea-bite. Because Y. pestis is maintained in nature in plague sylvatic cycles by a plethora of wild rodent species and the fleas that parasitize them, the disease is difficult to eradicate. Sylvatic cycles are composed of an epizootic phase, which increases the risk of transmission and human disease, and an enzootic/quiescent stage in which Y. pestis persists and maintains its reservoir.  

The general mechanisms of how Y. pestis quiescently persists in nature are unknown as the vertebrate host of Y. pestis is usually a dead-end host because the bacteria are either eliminated by the immune system, or cause death to the host. In contrast some flea species have the ability to maintain a chronic infection of Y. pestis and have potential to serve as reservoir hosts for this pathogen. The overall research focus of the Vadyvaloo lab is to identify how the plague bacterium establishes infection in the flea to be subsequently transmitted and/or persist in certain flea species to maintain the reservoir. Additionally, we are in search of alternate natural long term reservoir hosts for this pathogen.

Research Contributions

1) Identifying the Y. pestis molecular determinants that enable adaption, chronic infectivity and transmission of this pathogen from its flea vector brings more understanding to the large knowledge gap that is present in the understanding of the Y. pestis flea life stage. To address this gap we have been involved in characterizing the whole genome bacterial gene expression profiles in the fleas and subsequently have described regulatory factors that shape adaptation of the bacterium to form a transmissible infection.

2) We have described that Y. pestis has the ability to enter and survive within ubiquitous soil amoeba. This implicates soil amoeba as a potential reservoir host for the bacterium during the inter-epizootic plague cycles. We envisage that this research finding will have future implications for understanding of plague re-mergence and the ecological attributes of plague disease cycles, as well as, for implementation of improved plague surveillance strategies.

Research Details

The Vadyvaloo lab is primarily interested in understanding the molecular processes and genetic determinants for Y. pestis adaptation to the flea digestive tract that support formation of a transmissible and/or persistent infection. Currently the lab mainly focuses on understanding mechanisms of gene regulation of Y. pestis at both transcriptional (e.g. DNA binding transcriptional regulators) and post-transcriptional (e.g. small non-coding RNAs) levels as they relate to Y. pestis adaptation to its flea life stage. We use a number of molecular biology techniques (e.g. mutant generation, qRT-PCR, RNAseq, Northern analysis, EMSA, transcriptional and post-transcriptional fusions) to determine gene regulation mechanisms.  Understanding flea responses to Y. pestis infection is also being pursued.  An interesting feature of the research is the rare ability of the lab to test Y. pestis mutants in the natural and biologically relevant flea host model.  We are currently one of a very few labs in the world that, maintains flea vectors and, performs research in understanding the Y. pestis-insect specific life stage of plague disease cycles.

Newer reasearch in the lab focusses on undertanding how Y. pestis persists during the quiescent inter-epizootic cycle that is aimed at identifying potential alternate reservoir hosts for Y. pestis.  As an initial step in this research direction we have established that Y. pestis enters and is able to survive in association with ubiquitous soil free-living amoeba. Continued work in this field is to establish the relevance of this model in a natural setting.

https://www.asm.org/index.php/newsroom/item/6394-plague-bacteria-take-refuge-in-amoebae

 

Select Publications
  • Benavides-Montaño JA, Vadyvaloo V. (2017) Yersinia pestis resists predation by Acanthamoeba castellanii and exhibits prolonged intracellular survival.  Applied Environmental Microbiology 83(13). pii: e00593-17. doi: 10.1128/AEM.00593-17. Print 2017 Jul 1. PMID: 28455335 PMCID: MC5478993
  • Vadyvaloo V and Hinz AK. (2015) A LysR-Type Transcriptional Regulator, RovM, Senses Nutritional Cues Suggesting that It Is Involved in Metabolic Adaptation of Yersinia pestis to the Flea Gut. PloS One. 10(9):e0137508. Doi: 10.1371/journal.pone.0137508 PMID: 26348850 PMCID: PMC4562620
  • Vadyvaloo V, Viall AK, Jarrett CO, Hinz AK, Sturdevant DE, Hinnebusch BJ. (2015) Role of the PhoP-PhoQ gene regulatory system in adaptation of Yersinia pestis to environmental stress in the flea digestive tract. Microbiology 161(6):1198-1210 PMID: 25804213 PMCID: PMC4635514
  • Rempe KA, Hinz AK, Vadyvaloo V. (2012) Hfq regulates biofilm gut blockage that facilitates flea-borne transmission of Yersinia pestis. J Bacteriol. 194(8):2036-40. PMID: 22328669 PMCID: PMC3318476
  • Vadyvaloo V, Jarrett C, Sturdevant DE, Sebbane F, Hinnebusch BJ. (2010) Transit through the flea vector induces a pretransmission innate immunity resistance phenotype in Yersinia pestis. PLoS Pathog 6(2):e1000783. PMID: 20195507 PMCID: PMC2829055

PubMed List of Publications