Dengue 2 and 4 viruses obtained from dengue-infected patients were maintained in a C6/36 Aedes albopictus Skuse cell line and used to infect adult female Aedes aegypti mosquitoes. Each serotype was mixed separately with fresh human erythrocytes and fed to adult female mosquitoes using an artificial membrane feeding technique. Fully engorged mosquitoes were selected and retained at 26 degrees C, 28 degrees C and 30 degrees C to observe dengue virus development in Aedes vectors. Virus detection was carried out by reverse-transcriptase polymerase chain reaction (RT-PCR). The virus was first detected on Day 9 at 26 degrees C and 28 degrees C and on Day 5 at 30 degrees C for both dengue 2 and 4. The study shows the incubation period of the viruses decreased when the extrinsic incubation temperature increases.