Rickettsia parkeri in Amblyomma maculatum Ticks, North Carolina, USA, 2009–2010 - Vol. 17 No. 12 - December 2011 - Emerging Infectious Disease journal - CDC
Volume 17, Number 12—December 2011
Rickettsia parkeri in Amblyomma maculatum Ticks, North Carolina, USA, 2009–2010
Author affiliations: Mississippi State University, Starkville, Mississippi, USA (A.S. Varela-Stokes); Centers for Disease Control and Prevention, Atlanta, Georgia, USA (C.D. Paddock); North Carolina Department of Environment and Natural Resources, Raleigh, North Carolina, USA (B. Engber, M. Toliver)Suggested citation for this article
North Carolina historically reports some of the highest annual case counts of Rocky Mountain spotted fever (RMSF) and has accounted for >20% of total cases reported in the United States during the past 30 years (1–4). However, a species-specific diagnosis directly implicating infection with Rickettsia rickettsii is obtained for <10% of reported US cases. In 2010, the Centers for Disease Control and Prevention and Council of State and Territorial Epidemiologists modified the RMSF case designation to spotted fever rickettsiosis, acknowledging the complex epidemiology of tick-borne rickettsioses (5). Currently, R. parkeri is the only other tick-borne spotted fever group Rickettsia (SFGR) species known to cause disease in the southeastern United States, with >30 recognized cases from at least 9 states, including North Carolina (6). R. parkeri is detected in 20%−43% of Amblyomma maculatum ticks from the southeast, far greater than the recognized occurrence of R. rickettsii in any other tick species (6–8). We surveyed A. maculatum ticks collected from North Carolina for evidence of R. parkeri infection to assess the possibility that SFGR other than R. rickettsii result in cases categorized as RMSF in this state.
AbstractWe detected Rickettsia parkeri in 20%−33% of Amblyomma maculatum ticks sampled in North Carolina. Results highlight the high frequencies of R. parkeri–infected ticks in the state with the highest annual incidence of Rocky Mountain spotted fever. Epidemiologic studies are needed to definitively link R. parkeri to cases of spotted fever rickettsiosis.
Suggested citation for this article: Varela-Stokes AS, Paddock CD, Engber B, Toliver M. Rickettsia parkeri in Amblyomma maculatum ticks, North Carolina, USA, 2009–2010. Emerg Infect Dis [serial on the Internet]. 2011 Dec [date cited]. http://dx.doi.org/10.3201/eid1712.110789