Prevalence and infection levels of Nosema spores in honey bees, Apis mellifera in two highland Agro-Ecological Zones (AEZs) of Uganda

Abstract

Nosema spp. are obligate intracellular parasites belonging to phylum Microsporidia. These parasites are the causative agents of nosemosis in honey bees. This study was conducted to; i) determine Nosema spore infection levels in honey bees from two agro-ecological zones of Uganda and ii) assess the influence of environmental factors on Nosema infection levels in honey bees from the Eastern and Western agro-ecological zones (AEZs) of Uganda. To achieve this, a total of 100 samples were randomly sampled from samples collected from two AEZs of Uganda. The samples were examined for infection with Nosema spores. The findings indicate presence of Nosema in both study sites. However, there was a significant variation in Nosema spore counts between the two AEZs (U= 844, p=0.003). Specifically, the western AEZ had significantly higher Nosema spore count (173320000± 172822717 spores per bee) compared to the eastern AEZ (75360000 ±107064306 spores per bee). The results also showed that there was a negative correlation between Nosema spore counts and elevation in the western highland AEZ (rho = -0.342, n=50, p=0.015). However, in the eastern AEZ, there was no correlation between Nosema spore counts and elevation (rho=-0.009, n=50, p=0.951). Based on the results, effort should be made to build the capacity of beekeeping extension workers in the country on the Nosema spp. and how they can be managed so that they can provide beekeepers with up to date information and skills.