consecutive outpatients were recruited at 2 primary healthcare centers and hospitalized patients at a governmental referral center ( dr .
all eligible auf patients ( > 5 years of age ) were included who met the following criteria : fever > 38c ( central ) for < 14 days with no apparent other disease .
the study was approved by the local medical ethical committee . a specific microimmunofluorescent antibody ( ifa )
assay for rickettsia spp . was performed in marseille , france , by using whole - cell antigens of o. tsutsugamushi , r. japonica , r. heilongjiangensis , r. slovaca , r. honei , r. conorii subsp .
indica , rickettsia ati , r. helvetica , r. felis , r. typhi , and r. prowazekii .
the assay results were considered positive when 1 ) antibody titers were > 256 for immunoglobulin ( ig ) g and > 64 for igm , or 2 ) seroconversion was observed , or 3 ) a > 4-fold increase in titers between the acute - phase and the convalescent - phase serum specimen was detected .
convalescent - phase samples were screened with the leptotek dri dot ( biomrieux , marcy letoile , france ) .
all positive samples were tested by the microscopic agglutination test ( mat ) and igg elisa ( 8) . additionally , a real - time pcr specifically targeting the secy gene of pathogenic leptospira spp .
, a panel of 31 serovars was used containing 28 pathogenic and 3 nonpathogenic serovars . for patient samples tested by elisa or mat ,
a titer > 320 on a single sample was considered positive ; also considered positive were those samples that showed seroconversion or a > 4-fold increase in titers between paired samples , as well as any patient sample with a positive pcr , irrespective of the serologic result .
the main symptoms were headache ( 85% ) , myalgia ( 70% ) , nausea ( 64% ) , cough ( 44% ) , and abdominal pain ( 38% ) .
murine typhus and leptospirosis were found to cause auf in this clinical series ( appendix table ) . in total , 9 patients ( 7% ) had evidence of an acute infection with r. typhi ; none showed a rash .
murine typhus could be diagnosed in 6 ( 9% ) of 67 hospitalized patients ; 3 ( 4% ) of 70 outpatients had acute murine typhus .
one patient showed evidence of a past infection with r. typhi ( ifa igg / igm titer 128/0 in both serum specimens ) .
leptospirosis was diagnosed in 13 ( 10% ) of 137 patients ; results for 2 of these patients were positive only by pcr .
eleven leptospirosis patients were recruited in the hospital ; 2 patients were recruited outside the hospital .
consequently , the percentage of auf caused by leptospirosis in hospitalized patients was 16% and in outpatients 3% .
no dual infections were detected ; however , 3 ( 23% ) leptospirosis patients showed titers in the r. typhi ifa assay .
we report that murine typhus and leptospirosis are important causes of auf in semarang , indonesia .
a previous study from rural thailand identified both diseases in 2.8% and 36.9% of auf cases , respectively ( 6,7 ) . in vientiane ,
the capital of laos , r. typhi was reported to cause fever in 9.6% of investigated persons , results that closely resembling our data ( 10 ) .
unfortunately , leptospirosis was not investigated . in the present study , we expected leptospirosis to be a cause of auf because the dr .
these cases were not included in the study because of the high clinical suspicion of leptospirosis on admission with jaundice , azotemia , and/or bleeding . a definite diagnosis of murine typhus and leptospirosis co - infections could not be made , but in 3 cases this scenario was plausible .
we did not find evidence for scrub typhus , which we expected , because o. tsutsugamushi transmission occurs primarily in rural areas ( 11 ) .
although sfgr have been reported in southeast asia and proof for their presence in indonesia is accumulating ( 2,12 ) , these rickettsia were not identified as a cause of auf in the present study . from an epidemiologic point of view , semarang , indonesia , seems to encompass environmental circumstances that are prerequisites for r. typhi and leptospirosis transmission .
previous studies have shown that murine typhus is particularly prevalent in tropical port cities where rats are abundant ( 13,14 ) . in the indonesian urban situation ,
r. rattus and r. norvegicus rats are likely to be the main hosts harboring r. typhi  infected x. cheopsis fleas ( 12,15 ) .
these rats are also likely to be the maintenance hosts for pathogenic leptospira spp . in indonesia .
although serologic analysis might be hampered by cross - reactions and test sensitivity issues , we believe that our data are representative for the area .
the chosen cut - off values are unlikely to cause false - positive results in a disease - endemic setting . in regard to leptospirosis serologic analysis
this panel included serovars recommended by the world health organization and serovars that were previously isolated in indonesia .
moreover , most serogroups were represented in our panel , and cross - reactions are likely to detect missing serovars . because of nonspecific clinical features , both diseases are difficult to diagnose on clinical grounds only .
therefore , rapid , cheap , and reliable diagnostic tests are needed to support clinical decision making .
clinical and laboratory data of patients with rickettsioses and leptospirosis , indonesia , february 2005-february 2006 *
 to investigate rickettsioses and leptospirosis among urban residents of semarang , indonesia , we tested the blood of 137 patients with fever . 
 evidence of rickettsia typhi , the agent of murine typhus , was found in 9 patients . 
 another 9 patients showed inconclusive serologic results . 
 thirteen patients received a diagnosis of leptospirosis . 
 no dual infections were detected . 