Dickson Laura B, Sanchez-Vargas Irma, Sylla Massamba, Fleming Karen, Black William C
Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, United States of America.
PLoS Negl Trop Dis. 2014 Oct 2;8(10):e3153. doi: 10.1371/journal.pntd.0003153. eCollection 2014 Oct.
Vector competence of Aedes aegypti mosquitoes is a quantitative genetic trait that varies among geographic locations and among different flavivirus species and genotypes within species. The subspecies Ae. aegypti formosus, found mostly in sub-Saharan Africa, is considered to be refractory to both dengue (DENV) and yellow fever viruses (YFV) compared to the more globally distributed Ae. aegypti aegypti. Within Senegal, vector competence varies with collection site and DENV-2 viral isolate, but knowledge about the interaction of West African Ae. aegypti with different flaviviruses is lacking. The current study utilizes low passage isolates of dengue-2 (DENV-2-75505 sylvatic genotype) and yellow fever (YFV BA-55 -West African Genotype I, or YFV DAK 1279-West African Genotype II) from West Africa and field derived Ae. aegypti collected throughout Senegal to determine whether vector competence is flavivirus or virus genotype dependent.
METHODOLOGY/PRINCIPAL FINDINGS: Eight collections of 20-30 mosquitoes from different sites were fed a bloodmeal containing either DENV-2 or either isolate of YFV. Midgut and disseminated infection phenotypes were determined 14 days post infection. Collections varied significantly in the rate and intensity of midgut and disseminated infection among the three viruses.
CONCLUSIONS/SIGNIFICANCE: Overall, vector competence was dependent upon both viral and vector strains. Importantly, contrary to previous studies, sylvatic collections of Ae. aegypti showed high levels of disseminated infection for local isolates of both DENV-2 and YFV.
埃及伊蚊的媒介能力是一种数量遗传性状，在不同地理位置以及同一物种内不同黄病毒种类和基因型之间存在差异。埃及伊蚊指名亚种主要分布于撒哈拉以南非洲，与分布更为广泛的埃及伊蚊埃及亚种相比，被认为对登革病毒（DENV）和黄热病毒（YFV）均具有抗性。在塞内加尔，媒介能力随采集地点和DENV - 2病毒分离株的不同而变化，但对于西非埃及伊蚊与不同黄病毒之间相互作用的了解尚少。本研究利用来自西非的登革热2型（DENV - 2 - 75505野生基因型）和黄热病毒（YFV BA - 55 -西非基因型I，或YFV DAK 1279 -西非基因型II）的低代分离株以及在塞内加尔各地采集的野外埃及伊蚊，以确定媒介能力是否取决于黄病毒或病毒基因型。
方法/主要发现：从不同地点采集了8组每组20 - 30只蚊子，给它们喂食含有DENV - 2或任一YFV分离株的血餐。感染后14天确定中肠和播散感染表型。在三种病毒中，不同采集组的中肠和播散感染率及感染强度存在显著差异。
结论/意义：总体而言，媒介能力取决于病毒株和蚊株。重要的是，与先前研究相反，野生埃及伊蚊对当地DENV - 2和YFV分离株表现出高水平的播散感染。
