Production of Chikungunya virus propagated in Aedes albopictus Cells compared to the virus propagated in Vero cells

Chikungunya virus (CHIKV), the cause of chikungunya fever, is a member of genus Alphavirus and family Togaviridae. Chikungunya fever is a reemerging infectious disease that is endemic to Africa and Asia and the classic clinical symptoms after infection by CHIKV are sudden febrile illness, headache, rash, myalgia, althalgia, edema of the extremities, and gastrointestinal complaints. Moreover, severe dermatological lesions, lethal hepatitis and encephalitis can occur in newborns and old people. CHIKV has been shown to infect a wide variety of cell lines with differential pathogenicity. In Thailand, CHIKV recently re-emerged in a large outbreak in 2008-2009. Working with a CHIKV isolate from the recent outbreak in Thailand, this study aimed to investigate CHIKV infection in mosquito Aedes albopictus C6/36 cells, which are representative of one of the main natural vectors, and in African green monkey kidney (Vero) cells. CHIKV propagation, microscopic and standard plaque assay were applied the results showed different patterns of infectivity. The growth curve of CHIKV in C6/36 cells was first determined to obtain primary information of which day had the maximum viral yield, and the results showed that the highest viral titer of CHIKV in C6/36 cells was produced on day 2 post infection. Observation of cytopathic effect (CPE) was utilized to assay productivity in Vero cells and optimal collection occurred when Vero cells were undergoing 30-40% CPE, as reduced virus titer was observed when CPE reached 50-70%. Virus titer in Vero cells was found to depend upon the degree of CPE, amount of input virus, time of virus collection and cell type used for propagating the infecting virus. These studies are primary information and are useful for further developing studies of CHIKV.