Murine Typhus from Vietnam, Imported into Japan

摘要

To the Editor: In Vietnam, manyfebrile diseases such as malaria,dengue fever, Japanese encephalitis,scrub typhus, and more recently,severe acute respiratory syndrome(SARS) and avian influenza havebeen reported. Murine typhus caseswere also reported during and beforethe 1960s but not thereafter (1–5).On May 3, 2003, a 54-year-oldmale resident of Tokushima, Japan,had onset of fever in the suburbantown of Cu Chi, ≈60 km northwest ofHo Chi Minh City, Vietnam.Exanthema appeared on his trunk andlimbs on May 7. He returned to Japanon May 9 and was admitted to Tokushima University Hospital onMay 10. His body temperature was39.0°C, and serum, C-reactive proteinlevel was high (17.06 mg/dL) onadmission (day 8 of illness).Unfortunately, the blood sample takenon that day was discarded. We thencollected blood on days 10, 11, 12, 14,17, and 24 of illness for diagnosis.Minocycline was administered on day8 and resulted in a gradual decrease infever and rash. Weil-Felix tests on day12 showed the serum to be positive forProteus vulgaris OX19 (titer 160);tests for P. vulgaris OX2 and OXKwere negative (titer of 10 for both).We examined blood samples for pos-sible diseases such as malaria, denguefever, SARS, and rickettsioses.Giemsa-stained peripheral blood sam-ples obtained on day 11 showed nomalarial parasites. Results ofimmunoglobulin M (IgM)-captureELISA of serum on days 10, 11, and17 of illness were negative for dengueantibodies. Reverse transcription(RT)–PCR of the serum on day 11 wasalso negative. RT-PCRs of a pharyn-geal swab and urine collected on day11 were both negative for the SARScoronavirus. These specimens werealso injected into Vero cells, and nocytopathic effects were generated. RT-PCR of these cultures was also nega-tive for SARS coronavirus. Moreover,SARS antibodies were not found inserum samples on days 11 and 14 ofillness. Serum was also tested forOrientia tsutsugamushi and Coxiellaburnttii on day 12 to exclude scrubtyphus and Q fever as diagnoses.Indirect immunofluorescence testsfor etiologic agents of spotted fever,murine typhus, and epidemic typhuswere then performed with serum sam-ples collected on days 10, 14, and 24.We used Rickettsia typhi and R.prowazekii as typhus group (TG) rick-ettsial antigens and R. japonica and R.conorii as spotted fever group (SFG)rickettsiae. IgM antibody was detectedfor these antigens, indicating that thedisease was a primary infection ofrickettsiae (Table). When TG and SFGrickettsioses were compared, TG rick-ettsiae represented markedly higherelevated titers than SFG rickettsiae,which excluded a diagnosis of SFGrickettsiosis. PCR for the TG rick-ettsial genome in the convalescent-phase serum on day 10 was negative