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physicians who were aware of the study alerted our team of investigators to patients > 18 years of age who had reported fever during february  december 2013 .
alternative syndromes that warranted exclusion included skin and soft tissue infections , urinary tract infections , cavitary or lobar pneumonia , and pyogenic intraabdominal processes ( e.g. , abscesses , appendicitis , cholecystitis , and diverticulitis ) .
we obtained informed consent , medical history , and physical examination to record symptoms , signs , and laboratory data from each patient .
we collected blood for use in real - time pcr , shell vial culture , and immunofluorescence assay ( ifa ) for the diagnosis of murine typhus ( 46 ) .
the conjugate used in ifa assays was alexa fluor 488 goat anti - human igg ( -chain  specific ) at a dilution of 1:400 ( jackson immunoresearch laboratories , west grove , pa , usa ) .
further pcr analysis to amplify portions of the 17-kda antigen , citrate synthase , and outer membrane protein b ( ompb ) genes were performed on dna from a cell culture isolate ( 79 ) .
amplicons were cloned and sequenced ( 4 ) . a confirmed case of murine typhus was defined as having compatible signs and symptoms and seroconversion ( diagnostic cutoff of 1:64 ) or a 4-fold increase in igg titer against r. typhi from acute- and convalescent - phase serum samples ; pcr detection of rickettsial dna within acute - phase blood ; or isolation of r. typhi from blood .
a probable case was defined as having a single igg titer of > 1:256 during acute illness .
in addition to identifying acutely ill patients , we sought to determine the local prevalence of those who had r. typhi reactive antibodies .
we repurposed serum samples collected from 500 galveston residents ; the samples were scheduled to be discarded after being used for routine clinical testing from outpatient clinics during the summer and fall of 2013 .
we screened for the presence of r. typhi igg at a titer of 1:128 by ifa as described above .
we performed ifa against spotted fever antigens ( r. rickettsii ) and western blot analysis using r. typhi and r. rickettsii antigens to confirm the specificity of samples reactive to r. typhi as previously described ( 6,10 ) .
eighteen patients who met study criteria were enrolled . of these , 10 were determined to have murine typhus ( 7 confirmed and 3 probable ) ( table 1 ) .
this patient was an alcoholic man , 48 years of age , who sought care 4 days after the onset of fever , chills , and myalgias .
kj648946 ) genes of this isolate revealed 100% homology to r. typhi wilmington strain , and the sequence of the 17-kda antigen gene ( accession no .
real - time pcr screening of dna extracted from whole blood demonstrated the presence of rickettsial dna in the patient from whom the r. typhi isolate was obtained . * nr , nonreactive at a titer of 1:64 ; na , not available . 
in addition to fever , the 12 patients , all reported headache , 7 ( 58% ) had chills , 6 ( 50% ) reported myalgias , 6 ( 50% ) had rashes , and 9 ( 75% ) had elevated hepatic transaminases ( 75% ) .
seven ( 58% ) were hospitalized , and 2 ( 17% ) were admitted to the intensive care unit .
except for 1 of the retrospectively identified cases , all patients were treated empirically for murine typhus ( table 1 ) .
eleven ( 92% ) were treated with either doxycycline or minocycline ; minocycline was prescribed for some because of a national shortage of oral doxycycline .
all patients had subsequent resolution of illness with no obvious difference in recovery between the 2 drugs .
one patient ( identified retrospectively ) was treated with levofloxacin and reported slow resolution of her symptoms .
the 500 serum samples screened by ifa represent 1% of galveston s population ( 48,733 by the 2013 census [ http://quickfacts.census.gov/qfd/states/48/4828068.html ; cited 2014 dec 27 ] ) .
ifa and western blot testing showed 8 ( 1.6% ) samples to be reactive , which supported typhus group specificity ( table 2 ) .
of those seroreactive , the mean age was 60.9 years , and 5 ( 62.5% ) were women .
* omp , outer membrane protein ; nr , nonreactive at a titer of 1:128 . 
 all serum samples reacted with r. rickettsii ompb as described for spotted fever and typhus group ompb antigens ( 10 ) . 
galveston is a small city on a barrier island off the upper texas coast , along the gulf of mexico . as with other port cities where rat population numbers are high , the incidence of murine typhus in this city was historically high .
however , in 1946 , as part of an ectoparasite eradication program , the insecticide ddt was applied to common rat paths ; subsequently , the number of ectoparasites spread by rats in human habitats was reduced . as a result ,
the incidence of murine typhus in galveston decreased dramatically ( 2 ) and continued to decline through subsequent decades ( 11 ) .
the patients in this study exhibited typical signs and symptoms consistent with murine typhus ( 12 ) .
although we can not exclude the possibility of a different fleaborne rickettsia ( i.e. , r. felis ) infecting some patients , the single rickettsial isolate identified supports r. typhi as a causative agent .
based solely on the titers of these reactive serum samples , it is not possible to elucidate recent versus distant infections .
dynamic shifts in the epidemiology and transmission of murine typhus are not unprecedented . although the rat - to - rat cycle of transmission by fleas is often referred to as an urban cycle , the rural south experienced high rates of murine typhus in the 1940s as a result of a proliferation of rats after a change in crop production from cotton to peanuts , because rats were attracted to the peanuts as a source of food ( 13 ) . in southern
california , opossums infested with r. typhi and r. felis  infected cat fleas ( c. felis ) have been associated with a shift of fleaborne rickettsioses from the urban center of los angles to suburban areas ( 14 ) .
this suburban cycle of transmission involving c. felis plays a recognized role in corpus christi , texas , a coastal city 220 miles southwest of galveston ( 1 ) . additionally , this cycle has been suspected in a recent outbreak of murine typhus in the central texas city of austin ( 15 ) .
the recent recognition of murine typhus in galveston may reflect the reemergence of r. typhi in rats ; it may also reflect a cycle involving opossums and cats .
additionally , r. felis may play a role as a serologically cross - reacting culprit of illness .
further study is required to better understand the ecology and epidemiology of murine typhus as it reemerges in galveston .
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 .