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Volume 15, Number 8—August 2009


Tick-Borne Rickettsiosis in Traveler Returning from Honduras

Lin H. ChenComments to Author  and Mary E. Wilson
Author affiliations: Mount Auburn Hospital, Cambridge, Massachusetts, USA (L.H. Chen, M.E. Wilson); Harvard Medical School, Boston, Massachusetts, USA (L.H. Chen, M.E. Wilson); Harvard School of Public Health, Boston (M.E. Wilson)

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Rickettsia spp. serologic titers for a man who returned from Honduras, 2005*

Test Titers on specific date
May 26 Jun 10 Jul 14 Aug 25 Nov 22
RMSF IgG† Positive, >1,024 Positive, >1,024 Positive, >1,024 Positive, >1,024
RMSF IgM† Positive, 512 Positive, 256 Positive, 128 Positive, 256
R. conorii IgG† >1,024 512 512
R. conorii IgM† 64 64 64
R. africae IgG‡ 2,048 4,096
R. africae IgM‡ 512
R. conorii IgG‡ 2,048 4,096
R. conorii IgM‡ 512
R. rickettsii IgG‡ 1,024
R. rickettsii IgM‡ 256

*Reference titer for negative/normal result is <64. RMSF, Rocky Mountain spotted fever; Ig, immunoglobulin.
†Testing done by Focus Diagnostics, Cypress, CA, USA.
‡Testing done by Centers for Disease Control and Prevention, Atlanta, GA, USA.

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