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.