Murine typhus in Austin, Texas, USA, 2008

Abstract

In August 2008, Texas authorities and the Centers for Disease Control and Prevention investigated reports of increased numbers of febrile rash illnesses in Austin to confirm the causative agent as Rickettsia typhi, to assess the outbreak magnitude and illness severity, and to identify potential animal reservoirs and peridomestic factors that may have contributed to disease emergence. Thirty-three human cases of confirmed murine typhus were identified. Illness onset was reported from March to October. No patients died, but 23 (70%) were hospitalized. The case-patients clustered geographically in central Austin; 12 (36%) resided in a single ZIP code area. Specimens from wildlife and domestic animals near case-patient homes were assessed; 18% of cats, 44% of dogs, and 71% of opossums had antibodies reactive to R. typhi. No evidence of R. typhi was detected in the whole blood, tissue, or arthropod specimens tested. These findings suggest that an R. typhi cycle involving opossums and domestic animals may be present in Austin.

Figure 1

Month of illness onset for laboratory-confirmed murine typhus cases (n = 33) reported in Austin/Travis County, Texas, USA, 2008.

Figure 2

Distribution of confirmed murine typhus case-patients and animals by serologic status for antibodies to Rickettsia typhi in Travis County, Texas, USA, 2008. Red circles, confirmed case-patients; black circles, sereopostive animals; gray circles, seronegative animals.