This research examines the shifting landscape of nosema disease within Ontario honey bee populations, focusing on the rise of the parasitic fungus Nosema ceranae. Historically, Nosema apis was viewed as the primary threat, but newer data suggests that N. ceranae has become the dominant species in the region. Recent surveys demonstrate a significant increase in prevalence, with the parasite appearing in the vast majority of infected samples compared to earlier years. Furthermore, studies indicate that infections involving this newer variant reach higher spore counts, potentially signaling increased virulence and better adaptation to the local environment. While the exact timeline of its arrival in North America remains uncertain, it is clear that this microsporidian is actively outpacing its predecessor in Canadian apiaries. These findings highlight an urgent need for continued study to understand the long-term impact of this parasite on colony health.
