Unique Strain of Rickettsia parkeri Associated with the Hard Tick Dermacentor parumapertus Neumann in the Western United States

Authors

• Christopher D. Paddock, Centers for Disease Control and Prevention
• Michelle E. J. Allerdice, Centers for Disease Control and Prevention
• Sandor E. Karpathy, Centers for Disease Control and Prevention
• William L. Nicholson, Centers for Disease Control and Prevention
• Michael L. Levin, Centers for Disease Control and Prevention
• Travis C. Smith, Texas Department of Parks and Wildlife
• Tom Becker, Utah Division of Wildlife Resources
• Robert J. Delph, United States Army
• Robert N. Knight, US Army Dugway Proving Ground
• Jana M. Ritter, National Center for Emerging and Zoonotic Infectious Diseases
• Jeanine H. Sanders, National Center for Emerging and Zoonotic Infectious Diseases
• Jerome Goddard, Mississippi State University

ORCID

Goddard: https://orcid.org/0000-0002-2617-7141

MSU Affiliation

College of Agriculture and Life Sciences; Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology

Creation Date

2026-07-30

Abstract

In 1953, investigators at the Rocky Mountain Laboratories in Hamilton, MT, described the isolation of a spotted fever group Rickettsia (SFGR) species from Dermacentor parumapertus ticks collected from black-tailed jackrabbits (Lepus californicus) in northern Nevada. Several decades later, investigators characterized this SFGR (designated the parumapertus agent) by using mouse serotyping methods and determined that it represented a distinct rickettsial serotype closely related to Rickettsia parkeri; nonetheless, the parumapertus agent was not further characterized or studied. To our knowledge, no isolates of the parumapertus agent remain in any rickettsial culture collection, which precludes contemporary phylogenetic placement of this enigmatic SFGR. To rediscover the parumapertus agent, adult-stage D. parumapertus ticks were collected from black-tailed jackrabbits shot or encountered as roadkills in Arizona, Utah, or Texas from 2011 to 2016. A total of 339 ticks were collected and evaluated for infection with Rickettsia species. Of 112 D. parumapertus ticks collected in south Texas, 16 (14.3%) contained partial ompA sequences with the closest identity (99.6%) to Rickettsia sp. strain Atlantic rainforest Aa46, an SFGR that is closely related or identical to an SFGR species that causes a mild rickettsiosis in several states of Brazil. A pure isolate, designated strain Black Gap, was cultivated in Vero E6 cells, and sequence analysis of the rrs, gltA, sca0, sca5, and sca4 genes also revealed the closest genetic identity to Rickettsia sp. Atlantic rainforest Aa46. Phylogenetic analysis of the five concatenated rickettsial genes place Rickettsia sp. strain Black Gap and Rickettsia sp. Atlantic rainforest Aa46 with R. parkeri in a distinct and well-supported clade.

Publication Date

4-17-2017

Publication Title

Applied and Environmental Microbiology

Publisher

American Society for Microbiology

Rights

© 2017 American Society for Microbiology

Recommended Citation

Paddock CD, Allerdice MEJ, Karpathy SE, Nicholson WL, Levin ML, Smith TC, Becker T, Delph RJ, Knight RN, Ritter JM, Sanders JH, Goddard J.2017.Unique Strain of Rickettsia parkeri Associated with the Hard Tick Dermacentor parumapertus Neumann in the Western United States. Appl Environ Microbiol83:e03463-16.https://doi.org/10.1128/AEM.03463-16