Susceptibility of Aedes albopictus and Aedes aegypti to three imported Chikungunya virus strains, including the E1/226V variant in Taiwan

Background/purpose: An E1/226V variant Chikungunya virus (CHIKV) efficiently transmitted by Aedes albopictus to humans poses a significant threat to public health for those areas with the presence of Aedes albopictus, including Taiwan. Methods: We infected three imported CHIKV isolates including the E1/226V variant with Ae. albopictus and Aedes aegypti in the laboratory to understand the disease risk. Viral RNA was measured by real time reverse transcription polymerase chain reaction. Results: The viral susceptibility varied by virus strain and mosquito species and strain. The Asian virus strain started to replicate at 5-6 days post infection (dpi) with the maximum virus yield, ranging from 10(3.63) to 10(3.87) at 5-10 dpi in both species. The variant CHIKV Central/East/South African (CESA) virus genotype replicated earlier at 1 dpi with the maximum virus yield ranging from 10(5.63) to 10(6.52) at 3-6 dpi in Ae. albopictus females while the nonvariant virus strain replicated at 1-2 dpi with the maximum virus yield ranging from 10(5.51) to10(6.27) at 6-12 dpi. In Ae. aegypti, these viruses replicated at 1-2 dpi, with maximum yields at 4 -5 dpi (range from 10(5.38) to 10(5.62)). Conclusion: We concluded that the risk of CHIKV in Taiwan is high in all distribution areas of Ae. aegypti and Ae. albopictus for the CESA genotype and that the E1/226V variant virus strain presents an even higher risk. Copyright (C) 2015, Elsevier Taiwan LLC Et Formosan Medical Association. All rights reserved.