The microsporidian parasite Vavraia culicis as a potential late life-acting control agent of malaria

Microsporidian parasites are being considered as alternatives to conventional insecticides for malaria control. They should reduce malaria transmission by shortening the lifespan of female mosquitoes and thus killing them before they transmit malaria. As the parasite replicates throughout the mosquito’s life, it should have little detrimental effects on young mosquitoes, thus putting less selection pressure on the hosts to evolve resistance. Here we examined these expectations for the microsporidian Vavraia culicis on Anopheles gambiae Giles sensu stricto mosquitoes under varying environmental conditions. Infection by the microsporidian delayed pupation by 10%, decreased fecundity by 23% and reduced adult lifespan by 27%, with higher infectious doses causing greater effects. The decrease of the lifespan was mostly due to an increase of the mortality rate with age. Similarly, the parasite’s effect on mosquito fecundity increased with the mosquitoes’ age. Neither infection nor food availa...

微孢子虫（Microsporidian）寄生虫被视为疟疾防控领域传统杀虫剂的替代方案。这类寄生虫可通过缩短雌蚊寿命、使其在传播疟疾前死亡，从而降低疟疾传播风险。由于该寄生虫会在蚊子的整个生命周期内增殖，因此对幼蚊几乎无有害影响，由此对宿主施加的选择压力更低，可减缓宿主演化出抗药性的进程。本研究在不同环境条件下，针对冈比亚按蚊冈比亚亚种（Anopheles gambiae Giles sensu stricto），检验了微孢子虫Vavraia culicis的上述效应预期。实验结果显示，该微孢子虫感染可使蚊子化蛹时间延迟10%、繁殖力下降23%、成虫寿命缩短27%，且感染剂量越高，上述效应越显著。成虫寿命缩短主要源于随蚊龄增长而升高的死亡率。类似地，该寄生虫对蚊子繁殖力的影响随蚊龄增长而增强。无论是感染与否，食物可及性……