Reemergence of murine typhus in Galveston, Texas, USA, 2013.

Twelve patients with murine typhus were identified in Galveston, Texas, USA, in 2013. An isolate from 1 patient was confirmed to be Rickettsia typhi. Reemergence of murine typhus in Galveston emphasizes the importance of vector control and awareness of this disease by physicians and public health officials.

Rickettsiae Within the Fleas of Feral Cats in Galveston, Texas.

Murine typhus is a flea-borne typhus group rickettsiosis caused by Rickettsia typhi. Once a prevalent disease in the United States, the use of dichlorodiphenyltrichloroethane in the 1940s broke the classic rat-rat flea cycle of transmission, and the remaining endemic foci are now believed to be associated with opossums and the cat flea (Ctenocephalides felis). In Galveston, Texas murine typhus has re-emerged as a cause of febrile illness, and 7% of fleas collected from opossums are infected with R. typhi. In this study, we sought to explore the prevalence of rickettsiae associated with fleas on cats, as these animals have been speculated to play a role in the epidemiology of murine typhus. Fleas were collected from feral cats entering a local veterinary clinic as part of a trap, spay, neuter, and release program. Fleas were identified and subjected to analysis by PCR and sequencing. An estimation of the minimum infection rate (MIR) of pooled samples was performed. Three hundred fourteen fleas (all C. felis) were collected from 24 cats. Sequences for the outer membrane protein B gene revealed R. typhi in one pool (MIR 0.3%), Rickettsia felis in four pools (MIR 1.3%), Rickettsia asembonensis in one pool (MIR 0.3%), and "Candidatus R. senegalensis" in six pools (MIR 2.0%). Results were confirmed by sequencing portions of the rickettsial citrate synthase and 17-kD protein gene. In this study, the presence of R. typhi in fleas from cats suggests that in Galveston, there exists a small but measurable risk to humans who come into contact with flea-infested cats. Despite this, we believe that the low prevalence from cat-collected fleas, compared with that previously detected from opossums, makes cats less likely to play a role in the maintenance of R. typhi in this region. The significance of other identified flea-borne rickettsiae is yet to be elucidated.

Analysis of Health-Care Charges in Murine Typhus: Need for Improved Clinical Recognition and Diagnostics for Acute Disease.

Murine typhus, caused by Rickettsia typhi, is an undifferentiated febrile illness with no available rapid and sensitive diagnostic assay for use during early disease. We aimed to compare the health-care charges in those diagnosed with murine typhus to those with influenza, a febrile illness with an available rapid diagnostic test. A comparison of health-care-associated charges at the University of Texas Medical Branch at Galveston demonstrated a median of $817 for influenza versus $16,760 for murine typhus (P < 0.0001). Median laboratory ($184 versus $3,254 [P < 0.0001]) and imaging charges ($0 versus $514 [P < 0.0001]) were also higher in those with murine typhus. Those receiving at least one imaging study during their illness were greater in the murine typhus group (91.3% versus 20.3%) (P < 0.0001). The median time needed to establish a confirmed or presumptive diagnosis was 2 days for influenza compared with 9 days for murine typhus (P < 0.0001). The median number of health-care encounters was greater for those with murine typhus (2 versus 1) (P < 0.0001). Eleven patients (15.9%) with influenza were hospitalized as a result of their illness compared with 16 (69.6%) with murine typhus (P < 0.0001). The estimated mortality based on disease severity at presentation by Acute Physiology and Chronic Health Evaluation II scoring was similar in the two groups-both had a median 4% mortality risk (P = 0.0893). These results highlight the need for improved clinical recognition and diagnostics for acute rickettsioses such as murine typhus.