Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Dr., Fairbanks, AK 99775, USA.
J Med Entomol. 2010 Jul;47(4):639-48. doi: 10.1603/me09192.
Tularemia is a zoonotic disease caused by the Category A bioterrorism agent Francisella tularensis. In Scandinavia, tularemia transmission by mosquitoes has been widely cited in the literature. We tested >2,500 mosquitoes captured in Alaska and found Francisella DNA in 30% of pooled samples. To examine the potential for transmission of Francisella by mosquitoes, we developed a mosquito model of Francisella infection. Larvae of Anopheles gambiae Giles and Aedes aegypti (L.) readily ingest F. tularensis but do not efficiently transfer infective doses of the bacterium to the pupal or adult stage. After a bloodmeal containing Francisella, adult female An. gambiae and Ae. aegypti retained detectable levels of Francisella DNA for 3 d, but when they took a second bloodmeal, the mammalian host was not infected. This study suggests that although Francisella DNA can be detected in a significant portion of wild-caught mosquitoes, transmission of Francisella is either very inefficient or is species dependent for the Francisella strain or the arthropod vector.
兔热病是一种由 A 类生物恐怖主义剂弗朗西斯菌引起的人畜共患病。在斯堪的纳维亚，蚊媒传播兔热病在文献中被广泛引用。我们检测了在阿拉斯加捕获的超过 2500 只蚊子，发现 30%的混合样本中存在弗朗西斯菌 DNA。为了研究蚊子传播弗朗西斯菌的潜力，我们建立了一个蚊子感染弗朗西斯菌的模型。冈比亚按蚊和埃及伊蚊的幼虫容易摄入弗朗西斯菌，但不能有效地将感染剂量的细菌转移到蛹或成虫阶段。在含有弗朗西斯菌的血餐之后，携带弗朗西斯菌的成年雌性冈比亚按蚊和埃及伊蚊能保持 3 天可检测到的弗朗西斯菌 DNA 水平，但当它们再次吸血时，哺乳动物宿主不会被感染。这项研究表明，尽管在大量野生捕获的蚊子中可以检测到弗朗西斯菌 DNA，但弗朗西斯菌的传播效率非常低，或者对弗朗西斯菌株或节肢动物载体来说是物种依赖性的。
