Importantly, the most common carrier in the south is the Aedes aegysti mosquito. Its sensitivity to viruses is low, so that it only picks up the more serious forms. It thus makes for more serious cases than the Aedes albopictus mosquito, the other major carrier. Right now deaths are far fewer than anticipated.
值得注意的是，南部地區的主要病媒蚊是對病毒感受力低的埃及斑蚊，它們只接收毒性較強的病毒，「就好像替病毒做『篩選』，使病毒一代代增強，因此被埃及斑蚊叮咬的病患，發病的情形較被白線斑蚊叮咬的嚴重」，衛生署預防醫學研究所吳盈昌博士指出。