Volume 24, Number 4—April 2018
CME ACTIVITY - Research
Rickettsial Illnesses as Important Causes of Febrile Illness in Chittagong, Bangladesh
Table
Results of PCR and serologic tests for rickettsial illness among 416 patients, Chittagong Medical College Hospital, Chittagong, Bangladesh, August 2014–September 2015*
Organism and test type | No. positive/no. tested (%) |
---|---|
Orientia tsutsugamushi | 70/416 (16.8) |
Blood PCR, rPCR 47-kDa positive | 45/414 (10.9) |
nPCR 47 kDa positive | 45/45 (100) |
nPCR 56 kDa positive | 45/45 (100) |
Eschar swab, rPCR 47 kDa and n56kDa positive; crust (n = 1), swab (n = 3) | 3/416 (0.7) |
Indirect immunofluorescence assay | 57/415 (13.7) |
Admission titer >3,200 | 54/415 (13.0) |
4-fold rise to >3,200 | 31/255 (12.1) |
PCR+ and serology+, 32/70 (45.7% of ST positives) | 32/413 (7.7) |
PCR+ and serology–, 13/70 (18.6% ST positives) | 13/413 (3.1) |
PCR– and serology+, 25/70 (35.7% of ST positives) |
25/413 (6.0) |
Rickettsia spp. | 29/416 (7.0) |
Blood PCR, rPCR 17 kDa positive | 23/414 (5.6) |
nPCR 17 kDa positive | 16/23 (69.6) |
Rickettsia typhi, 24/29 (83.0%) of Rickettsia spp. | 24/416 (5.8) |
Blood PCR | 17/414 (4.1) |
rPCR OmpB positive | 12/414 (2.9) |
nPCR 17-kDa sequencing | 15/16 (93.8) |
Indirect immunofluorescence assay | 15/415 (3.6) |
Admission titer >3,200 | 11/415 (2.7) |
4-fold rise to >3,200 | 5/255 (2.0) |
PCR+ and serology+, 8/24 (33.3% of MT positives) | 8/413 (1.9) |
PCR+ and serology–, 9/24 (37.5% of MT positives) | 9/413 (2.2) |
PCR– and serology+, 7/24 (29.1% of MT positives) | 7/413 (1.7) |
Undifferentiated Rickettsia spp., 3/29 (10.3% of Rickettsia spp.) | 3/416 (0.7) |
rPCR 17-kDa positive, ompB negative | 3/416 (0.7) |
nPCR 17-kDa negative, gltA negative | 3/416 (0.7) |
MT serology negative | 3/416 (0.7) |
Rickettsia felis | 2/416 (0.5) |
Blood PCR, 17-kDa rPCR and nPCR | 1/416 (0.2) |
Eschar swab, 17-kDa rPCR and nPCR |
1/416 (0.2) |
All rickettsial illnesses† | 96/416 (23.1) |
*MT, murine typhus; nPCR, nested PCR; rPCR, real-time PCR; ST, scrub typhus.
†Twenty-nine patients had evidence of Rickettsia spp. Infection; 70 had evidence of O. tsutsugamushi infection. Because 2 case-patients had mixed blood O. tsutsugamushi and Rickettsia spp. infections and 1 case-patient with O. tsutsugamushi infection in addition to an eschar-positive swab for R. felis, the total number of rickettsial illness cases was 96.