Nosema ceranae can infect honey bee larvae and reduces subsequent adult longevity

Nosema ceranae causes a widespread disease that reduces honey bee health but is only thought to infect adult honey bees, not larvae, a critical life stage. We reared honey bee (Apis mellifera) larvae in vitro and provide the first demonstration that N. ceranae can infect larvae and decrease subsequent adult longevity. We exposed three-day-old larvae to a single dose of 40,000 (40K), 10,000 (10K), zero (control), or 40K autoclaved (control) N. ceranae spores in larval food. Spores developed intracellularly in midgut cells at the pre-pupal stage (8 days after egg hatching) of 41% of bees exposed as larvae. We counted the number of N. ceranae spores in dissected bee midguts of pre-pupae and, in a separate group, upon adult death. Pre-pupae exposed to the 10K or 40K spore treatments as larvae had significantly elevated spore counts as compared to controls. Adults exposed as larvae had significantly elevated spore counts as compared to controls. Larval spore exposure decreased longevity: a 4...

东方蜜蜂微孢子虫（Nosema ceranae）可引发广泛传播的病害，削弱蜜蜂健康，但此前仅被认为会侵染成年蜜蜂，而非蜜蜂发育的关键生命阶段——幼虫。我们通过体外（in vitro）培育西方蜜蜂（Apis mellifera）幼虫，首次证实东方蜜蜂微孢子虫能够侵染幼虫，并降低其后续成虫的寿命。
我们将3日龄幼虫暴露于添加了单剂量40000（40K）、10000（10K）、0（对照组），以及40K经高压灭菌（autoclaved）的东方蜜蜂微孢子虫孢子的幼虫饲料中。在预蛹期（pre-pupal stage，卵孵化后第8天），41%经幼虫期暴露处理的蜜蜂的中肠（midgut）细胞内可观察到孢子的细胞内增殖。
我们分别统计了预蛹期解剖的蜜蜂中肠内的东方蜜蜂微孢子虫孢子数量，以及另一组样本在成虫死亡后的孢子载量。结果显示，幼虫期接受10K或40K孢子处理的预蛹个体，其孢子载量较对照组显著升高；幼虫期暴露于孢子的成虫个体，其孢子载量同样较对照组显著升高。幼虫期的孢子暴露会缩短成虫寿命：4...