Comparative study of Nosema ceranae (Microsporidia) isolates from two different geographic origins

Area of Science:

• Apiculture
• Insect Pathology
• Parasitology

Background:

• Nosema ceranae (Microsporidia) is an intestinal parasite of honey bees.
• Its impact on honey bee colonies varies geographically, with some regions experiencing colony losses while others do not.
• This study investigates if differences in N. ceranae strains contribute to varied honey bee responses.

Purpose of the Study:

• To compare the genetic variability of N. ceranae isolates from Spain and France.
• To assess the infection capacity and impact of these isolates on honey bee (Apis mellifera iberiensis) health.
• To determine if geographic origin influences N. ceranae virulence.

Main Methods:

• Genetic analysis of an rDNA fragment from Spanish and French N. ceranae isolates.
• Comparison of infection development, midgut lesions, spore loads, and survival rates in honey bees exposed to both isolates.
• Anatomopathological examination of honey bee midguts.

Main Results:

• No significant genetic differences were found between the Spanish and French N. ceranae isolates.
• Infection development, spore loads, and honey bee survival rates were similar for both isolates.
• No distinct differences in virulence were observed between the tested N. ceranae strains.

Conclusions:

• The geographic origin of the studied N. ceranae isolates does not appear to influence their virulence in Spanish honey bees.
• Honey bee subspecies tolerance or experimental conditions may play a larger role in varied responses to N. ceranae infection.
• Further research is needed to elucidate the contribution of honey bee factors and experimental settings to infection outcomes.