Q fever, spotted fever group, and typhus group rickettsioses among hospitalized febrile patients in Northern Tanzania

Abstract

Background. The importance of Q fever, spotted fever group rickettsiosis (SFGR), and typhus group rickettsiosis (TGR) as causes of febrile illness in sub-Saharan Africa is unknown; the putative role of Q fever as a human immunodeficiency virus (HIV) coinfection is unclear. Methods. We identified febrile inpatients in Moshi, Tanzania, from September 2007 through August 2008 and collected acute-and convalescent-phase serum samples. A ≥4-fold increase in immunoglobulin (Ig) G immunfluorescence assay (IFA) titer to Coxiella burnetii phase II antigen defined acute Q fever. A ≥4-fold increase in IgG IFA titer to Rickettsia conorii or Rickettsia typhi antigen defined SFGR and TGR, respectively. Results. Among 870 patients, 483 (55.5%) were tested for acute Q fever, and 450 (51.7%) were tested for acute SFGR and TGR. Results suggested acute Q fever in 24 (5.0%) patients and SFGR and TGR in 36 (8.0%) and 2 (0.5%) patients, respectively. Acute Q fever was associated with hepato-or splenomegaly (odds ratio [OR], 3.1; P = .028), anemia (OR, 3.0; P = .009), leukopenia (OR, 3.9; P = .013), jaundice (OR, 7.1;P = .007), and onset during the dry season (OR, 2.7;P = .021). HIV infection was not associated with acute Q fever (OR, 1.7;P = .231). Acute SFGR was associated with leukopenia (OR, 4.1;P = .003) and with evidence of other zoonoses (OR, 2.2;P = .045) Conclusions. Despite being common causes of febrile illness in northern Tanzania, Q fever and SFGR are not diagnosed or managed with targeted antimicrobials. C. burnetii does not appear to be an HIV-associated coinfection. © The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved.