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Prolonged survival of dengue virus in blood and excretion in urine after clinical recovery

Abstract number: O508

Laosakul C., Sriprapun M., Chaiyo K., Krajiw S., Chansinghakul D., Suwanpimolkul G., Pupaibool J., Arunyingmongkol K., Pancharoen C., Thisyakorn U., Kulwichit W.

Objectives: Dengue is a flavivirus and is among the most widely-spread viral diseases. Our previous report demonstrates existence of live dengue virus in blood and urine even in the convalescent postfebrile period. In some cases, excretion in the patient's urine can be detected as late as 28 days after the onset of illness. This goes along with the model of West Nile virus, another type of flavivirus, which can be excreted in the urine for months after acute infection in both animal studies and human case report. Here we report a pilot study to address a magnitude of such findings.

Methods: Between April 2007 and October 2008, paediatric and adult febrile patients suspected of dengue infection were enrolled. Diagnosis of dengue was based on standard specific serology on paired sera. Patients with negative serology served as controls. Blood and urine specimens were collected at several time points. Whole blood was separated into plasma and peripheral blood mononuclear cells (PBMC). These have been aliquoted and used for earlier studies and some stored in freezers. Available plasma, PBMC, and urine were processed and inoculated into Aedes aegypti. Surviving mosquitoes at 14 days after inoculation were employed for viral detection by dengue-specific RT-PCR. Indirect fluorescence antibody (IFA) staining of mosquito heads was performed on all positive RT-PCR specimens, except for the one from PBMC (awaiting IFA result).

Results: 5 and 45 cases of primary and secondary infections, respectively, and 4 negative controls were included. These translated into 55 and 59 early and late dengue specimens, and 6 and 4 early and late negative-control counterparts, respectively. Dengue virus were isolated in some blood and urine specimens as late as 46 days after the onset of illness. No virus was isolated from control specimens. All but 5 positive RT-PCR specimens also demonstrated positive IFA. 4 out of 5 negatives were from early-phase specimens.

Conclusion: Our study demonstrates prolonged survival of dengue virus after clinical recovery. This finding has pathologic and epidemiologic significance, adding a potential role of urine in the transmission of the disease. Spread of the virus to humans might occur through infectious urine with help from arthropod vectors. This research could provide new insights into our understanding of the pathogenesis of DENV infection.

Isolation of dengue virus from blood and urine specimens during early (days 1–7 after onset of illness) and late (days 8–46) phases of infection (specimens with dengue isolated/total specimens for mosquito inoculation)

 Early phaseLate phase
Plasma16/25 (64%)0/13 (0%)
PBMCnot performed1/2 (50%)
Urine8/29 (28%)12/44 (27%)
All specimens24/54 (44%)13/59 (22%)

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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