Tom G. Schwan, Ph.D.

Chief, Laboratory of Zoonotic Pathogens
Chief, Medical Entomology Section
Senior Investigator

Dr. Schwan received his Ph.D. in 1983 in parasitology from the University of California at Berkeley, studying the ecology of fleas and plague in Lake Nakuru National Park, Kenya. From 1983 to 1986, he was a postdoctoral fellow at the Yale Arbovirus Research Unit, Yale University School of Medicine, studying tick-borne viruses. He joined the Rocky Mountain Laboratories in 1986. He served on the editorial board of the Journal of Clinical Microbiology for 9 years and is on the editorial boards of Vector Borne and Zoonotic Diseases and Emerging Infectious Diseases.

Description of Research Program

The Medical Entomology Section investigates bacterial pathogens transmitted by blood-feeding arthropods. Emphasis is directed toward the Lyme disease spirochete, Borrelia burgdorferi, and a relapsing fever spirochete, Borrelia hermsii, in their respective tick vectors. Other pathogenic spirochetes are also studied. Live colonies of ticks allow for studies to elucidate factors important for the infection of these bacteria in arthropods and for their biological transmission when ticks feed. Understanding bacterial adaptations associated with transmission is linked to developing better prevention and diagnostic strategies.

Major Areas of Research

• Adaptations of Borrelia spirochetes in ticks
• Genetic diversity of Lyme disease and relapsing fever spirochetes
• Development of better serological tests for human spirochetal infection
• Genomic studies of relapsing fever spirochetes
• Elucidation of geographic areas of risk for relapsing fever

Research Group Members

Left to right: Job Lopez, Merry Schrumpf, Sandy Stewart, Bob Fischer, Paul Policastro, Tom Schwan

Selected Publications

(View list in PubMed.)

Schwan TG, Raffel SJ, Schrumpf ME, Porcella SF. Diversity and distribution of Borrelia hermsii. Emerg Infect Dis. 2007 Mar;13(3):436-42.

Pettersson J, Schrumpf ME, Raffel SJ, Porcella SF, Guyard C, Lawrence K, Gherardini FC, Schwan TG. Purine salvage pathways among Borrelia species. Infect Immun. 2007 Aug;75(8):3877-84.

Guyard C, Battisti JM, Raffel SJ, Schrumpf ME, Whitney AR, Krum JG, Porcella SF, Rosa PA, DeLeo FR, Schwan TG. Relapsing fever spirochaetes produce a serine protease that provides resistance to oxidative stress and killing by neutrophils. Mol Microbiol. 2006 May;60(3):710-22.

Porcella SF, Raffel SJ, Anderson DE Jr, Gilk SD, Bono JL, Schrumpf ME, Schwan TG. Variable tick protein in two genomic groups of the relapsing fever spirochete Borrelia hermsii in western North America. Infect Immun. 2005 Oct;73(10):6647-58.

Schwan TG, Raffel SJ, Schrumpf ME, Policastro PF, Rawlings JA, Lane RS, Breitschwerdt EB, Porcella SF. Phylogenetic analysis of the spirochetes Borrelia parkeri and Borrelia turicatae and the potential for tick-borne relapsing fever in Florida. J Clin Microbiol. 2005 Aug;43(8):3851-9.

Schwan TG, Policastro PF, Miller Z, Thompson RL, Damrow T, Keirans JE. Tick-borne relapsing fever caused by Borrelia hermsii, Montana. Emerg Infect Dis. 2003 Sep;9(9):1151-4.

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