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Kansas State University



M.M. Chengappa





Tonia Von Ohlen

Assistant Professor
Phone: (785)532-3887



Ehrlichia chaffeensis is an obligate, intracellular bacterium, vectored by Amblyomma americanum ticks, and is the causative agent of human monocytic ehrlichiosis (HME).  This arthropod borne pathogen is considered an emerging infectious agent and is closely related to other significant domestic, agricultural and human disease agents. We are interested in understanding the mechanism of pathogenesis on multiple levels.

My research efforts in this area are two fold: First, we are developing of an assay for characterizing regulation of gene expression of E. chaffeensis. Our long term goals are to understand the molecular basis of infection and pathogenicity. Understanding the mechanism of infection for this and other similar pathogens has multiple implications for disease prevention and therapies.

Additional research includes demonstration that E. chaffeensis replicates in adult Drosophila  melanogaster and to identify host genes necessary for replication of the bacteria. The ability to utilize D. melanogaster to study E. chaffeensis infections will enable the use of an array of molecular and genetic tools to better understand these arthropod-borne bacteria and the genetic requirements for the replication of E. chaffeensis in both vertebrate and invertebrate hosts. Ultimately, we will identify homologous genes in relevant species such as tick for further study.