The Cambridge-based biotech has taken a major step forward in its search for a vaccine for Japanese encephalitis. A vaccine, using Acambis' ChimeriVax(TM) technology has successfully passed Phase I/II trials, which test for safety and non-toxicity in patients. Japanese encephalitis is caused by mosquito bites and is found all over Asia, yet the existing vaccine is rarely used by visitors to the area because it requires a multiple dose. The ChimeriVax(TM) technology is currently also being used to develop a vaccine for dengue fever, West Nile encephalitis and hepatitis C.