Prolonged Detection of Japanese Encephalitis Virus in Urine and Whole Blood in a Returned Short-term Traveler

Huang, G Khai Lin; Tio, Shio Yen; Caly, Leon; Nicholson, Suellen; Thevarajan, Irani; Papadakis, Georgina; Catton, Mike; Tong, Steven Y C; Druce, Julian

To our knowledge, this is the first reported detection of JEV RNA in whole blood and the first report of JEV isolation in cell culture from urine. This is an interesting finding in light of recent detection of a number of other flaviviruses in urine samples, including Zika, Dengue, and West Nile Virus (WNV) [4] [5] . This is only the second reported case of detection of JEV RNA in urine, with the first reported case initially detected via deep sequencing [6] . We demonstrate prolonged detection of JEV in urine to day 26. These findings are in contrast to a report from China, where JEV RNA was not detected by real-time PCR from the urine of 52 children with serologically confirmed infection [7] . Our experience with a single, possibly exceptional case has been different, and the reasons why are not clear. This might reflect differences in the patients studied, the diagnostic assays employed, or the timing of the urine samples collected. Our PCR assay targeted loci within the NS5 region, in contrast to the consensus NS3 region targeted in the previous report. Alternatively, in the previous report [7] , all urine specimens were collected early on in illness (3-9 days after onset) whereas the first urine specimen tested in our patient was 14 days after the onset of symptoms. In light of previous descriptions of prolonged detection of Dengue, Zika, and West Nile virus from whole blood specimens [3, [8] [9] [10] , we undertook serial testing of whole blood in parallel with testing of plasma. JEV RNA was detectable in whole blood, but not plasma, out to the final specimen tested, 28 days after the onset of illness. Testing of whole blood by PCR has not traditionally been performed due to the potential presence of inhibitors [11] ; however, this report and other recent publications suggest that testing of whole blood may offer additional diagnostic information in certain situations. Notably, West Nile virus has been found to bind to red blood cells (RBCs), and the WNV viral load in RBC components has been found to exceed that in plasma by 1 order of magnitude [12] .