Detection of dengue virus by in situ hybridization

A non-radioactive in situ hybridization protocol was developed for the detection of dengue virus RNA in fixed tissues and cells. For this purpose a riboprobe was constructed from a 39 base sequence, from the capsid protein coding region of the genome, which is conserved in the four dengue serotypes. The ability of this probe to specifically detect dengue RNA from each serotype was confirmed on brain sections from infected mice. Dengue viral RNA was also detected in in vitro infected human primary endothelial cells which release infectious virus without showing gross cytopathic effect. With clinical samples dengue viral RNA was detected in some preparations of white blood cells from dengue fever patients and in thymus autopsy sections following suspected death from dengue shock syndrome. For dengue samples of undetermined serotype the sensitivity of the short probe was compared to that of an equimolar mixture of long (260 base) probes from the envelope coding region of the four dengue serotypes, provided by Dr. V. Deubel. In those samples examined, sensitivity of the long probe mixture was greater and higher numbers of infected cells were detected.