病媒蚊對日本腦炎病毒感受性與傳播之探討

Abstract

This study is to investigate the virus susceptibility of Culex quinquefasciatus, Aedes albopictus, and Armigeres subalbatus to Japanese encephalitis virus. The infection rate of Cx. quinquefasciatus, Ae. albopictus, and Ar. subalbatus to JEV at 14 days post infection by oral feeding were 16.67%, 15.28% and 11.11% at 20C; 34.24%, 37.50% and 15.66% at 25C; 76.67%, 66.67% and 52.63% at 30C, respectively. There were significant differences in the susceptibility of JEV among these three mosquitoes. Tissue tropism of JEV showed that head and midgut were the highest infected tissues, followed by salivary glands, while the reproductive tissue was rarely infected by JEV. Generally, the virus infection rate is higher when the temperature increases from 20C to 30C, and also increases with the days after post infection. When these mosquitoes were infected by JEV via intrathoracic injection, the oral transmission rate of Cx. quinquefasciatus, Ae. albopictus, and Ar. subalbatus to JEV were 96%, 76% and 72%, respectively. High oral transmission rate suggests these mosquitoes can effectively transmit JEV when it was infected with JEV. No vertical transmission of JEV in the three mosquitoes had been found. Whether Cx. quinquefasciatus, Ae. albopictus, and Ar. subalbatus are the vectors of JEV should be further studied.

本研究探討熱帶家蚊(Culex quinquefasciatus)、白線斑蚊(Aedes albopictus)及白腹叢蚊(Armigeres subalbatus)等三種病媒蚊於不同溫度條件對日本腦炎病毒之感受性，以瞭解這些蚊種在人類日本腦炎疾病傳播之病媒角色。以吸食感染法使病媒蚊感染日本腦炎病毒，結果顯示熱帶家蚊、白線斑蚊及白腹叢蚊皆能被日本腦炎病毒感染，在第14天於20°C其感染率分別為16.67%、15.28%及11.11%，於25°C為34.24%、37.50%及15.66%，於30°C則分別為76.67%、66.67%及52.63%，且三種病媒蚊之間有顯著差異，而感染率最高之組織皆為頭部及中腸，唾腺組織次之，最不易感染之組織為生殖系統。整體而言，感受性隨著溫度之上升及感染天數增加而增加。以胸部注射接種法使三種病媒蚊感染日本腦炎病毒，探討經口傳播日本腦炎病毒之能力，結果顯示熱帶家蚊、白線斑蚊及白腹叢蚊皆具有經口傳播日本腦炎病毒之能力，且傳播率分別有96%、76%及72%。至於垂直傳播，於本次試驗未能證實此三種病媒蚊具有將日本腦炎病毒垂直傳播給子代之能力。總結，三種病媒蚊皆具有感染日本腦炎病毒並經口傳播此病毒之能力，然在自然界中是否為日本腦炎病毒之病媒蚊，則有待進一步探討。