Mulholland Grace E, Traver Brenna E, Johnson Nels G, Fell Richard D
Department of Entomology, Virginia Tech, 324 Price Hall, Blacksburg, VA 24061, USA.
Laboratory for Interdisciplinary Statistical Analysis (LISA), Department of Statistics, Virginia Tech, 405 Hutcheson Hall, Blacksburg, VA 24061, USA.
Insects. 2012 Nov 1;3(4):1143-55. doi: 10.3390/insects3041143.
Since 2006, beekeepers have reported increased losses of Apis mellifera colonies, and one factor that has been potentially implicated in these losses is the microsporidian Nosema ceranae. Since N. ceranae is a fairly recently discovered parasite, there is little knowledge of the variation in infection levels among individual workers within a colony. In this study we examined the levels of infection in individual bees from five colonies over three seasons using both spore counting and quantitative real-time PCR. The results show considerable intra-colony variation in infection intensity among individual workers with a higher percentage of low-level infections detected by PCR than by spore counting. Colonies generally had the highest percentage of infected bees in early summer (June) and the lowest levels in the fall (September). Nosema apis was detected in only 16/705 bees (2.3%) and always as a low-level co-infection with N. ceranae. The results also indicate that intra-colony variation in infection levels could influence the accuracy of Nosema diagnosis.
自2006年以来，养蜂人报告称意大利蜜蜂蜂群的损失有所增加，而这些损失中一个可能涉及的因素是微孢子虫——东方蜜蜂微孢子虫。由于东方蜜蜂微孢子虫是一种相当新发现的寄生虫，对于蜂群内个体工蜂感染水平的差异了解甚少。在本研究中，我们在三个季节里使用孢子计数和定量实时PCR检测了来自五个蜂群的个体蜜蜂的感染水平。结果显示，个体工蜂之间在感染强度上存在相当大的蜂群内差异，通过PCR检测到的低水平感染百分比高于通过孢子计数检测到的。蜂群中通常在初夏（6月）感染蜜蜂的百分比最高，而在秋季（9月）水平最低。在仅16/705只蜜蜂（2.3%）中检测到西方蜜蜂微孢子虫，并且总是作为与东方蜜蜂微孢子虫的低水平合并感染。结果还表明，蜂群内感染水平的差异可能会影响微孢子虫诊断的准确性。
