Risk Factors for Spotted Fever Group Rickettsioses in Kilimanjaro Region, Tanzania.

BACKGROUND: Knowledge gaps exist on risk factors for spotted fever group rickettsioses (SFGR) in sub-Saharan Africa. We sought to identify SFGR risk factors in Kilimanjaro Region, Tanzania. METHODS: We recruited febrile patients presenting at 2 hospitals in Moshi from February 2012 through May 2014. Standardized clinical and risk factor questionnaires were administered. SFGR exposure was defined as a Rickettsia africae immunofluorescence antibody reciprocal titer ≥64, and acute SFGR as a ≥4-fold rise between paired sera. Logistic regression was used to identify associations. RESULTS: Of 1190 participants providing ≥1 serum sample, the median age was 21.8 (range, 0.3-100.2) years, 646 (54.3%) were female, and 650 (54.6%) had SFGR exposure. Of 731 participants with paired sera, 67 (9.2%) had acute SFGR. On multivariable analysis, odds of acute SFGR were higher in the age group 0-2 years (adjusted odds ratios [aORs] for older age groups, <0.36; P < .011), rural residence (aOR, 4.1; P = .007), and areas with maximum daily temperature <26°C (aORs for higher temperature groups, <0.42; P < .035). Odds of SFGR exposure were higher in those working in the garden (aOR, 1.8; P = .010) and seeing a dog (aOR, 1.5; P = .010). Odds of SFGR exposure were lower in the age group 0-2 years (aORs for older age groups, >1.5; P < .026), female sex (aOR, 0.62; P < .001), and being from the Chaga tribe (aOR, 0.68; P = .003). CONCLUSIONS: Those aged <2 years, rural residents, and persons residing in areas with cooler temperatures had increased odds of SFGR. Our results identify groups for further research on tick exposure and for targeted prevention interventions.

Duke Scholars

Author John Andrew Crump Medicine, Infectious Diseases

Author Matthew P. Rubach Medicine, Infectious Diseases

Author Ganga Moorthy Pediatrics, Infectious Diseases