In order to understand host responses to viral infection at the transcriptional level, differential display reverse-transcription PCR (DDRT-PCR) was used to identify molecular genetic changes in virus-infected Aedes albopictus (Diptera: Culicidae) following infection with dengue 2 virus (DENV-2). Seven differentially expressed cDNA fragments were identified. Five were up-regulated in virus-infected mosquitoes and two were up-regulated in refractory individuals. Sequence comparisons at the nucleotide level in GenBank showed that clone AS09A had 100% homology to Ae. albopictus ribosomal S5 protein mRNA, 98% homology to Ae. aegypti clone AE-198A ribosomal protein S5 mRNA and the 5-prime end of clone KWOAAA2YJ20AAMI from strain Liverpool of Ae. aegypti, and 91% homology to Drosophila melanogaster ribosomal protein S5a mRNA sequence. The deduced amino acidic sequence of clone AS09A showed 100% identity or conservation to the above sequence. AS12C clone showed significant homology (95%) to Ae. aegypti strain Liverpool. Other clones did not show homology with previously reported gene sequences. The fragment of AS09A may be the ribosomal protein S5 gene of Ae. albopictus that becomes differentially expressed as a result of infection. These results may be helpful in understanding the mechanism of differential susceptibility of Ae. albopictus following dengue virus infection.