Seasonality of Nosema ceranae Infections and Their Relationship with Honey Bee Populations, Food Stores, and Survivorship in a North American Region

Abstract

Nosema ceranae is an emerging pathogen of the western honey bee (Apis mellifera L.), and thus its seasonality and impact on bee colonies is not sufficiently documented for North America. This study was conducted to determine the infection intensity, prevalence, and viability of N. ceranae in >200 honey bee colonies during spring, summer, and fall, in a North American region. We also determined the relationship of N. ceranae infections with colony populations, food stores, bee survivorship, and overwinter colony mortality. The highest rates of N. ceranae infection, prevalence, and spore viability were found in the spring and summer, while the lowest were recorded in the fall. N. ceranae spore viability was significantly correlated with its prevalence and infection intensity in bees. Threshold to high levels of N. ceranae infections (>1,000,000 spores/bee) were significantly associated with reduced bee populations and food stores in colonies. Furthermore, worker bee survivorship was significantly reduced by N. ceranae infections, although no association between N. ceranae and winter colony mortality was found. It is concluded that N. ceranae infections are highest in spring and summer and may be detrimental to honey bee populations and colony productivity. Our results support the notion that treatment is justified when infections of N. ceranae exceed 1,000,000 spores/bee.

Amplicon Sequencing of Variable 16S rRNA from Bacteria and ITS2 Regions from Fungi and Plants, Reveals Honeybee Susceptibility to Diseases Results from Their Forage Availability under Anthropogenic Landscapes

“…During Nosema -infection the honeybee intestine is covered by a layer of mature spores which is the cause of deprivation of the physiological function of the bee alimentary tract for food absorption [ 64 ]. Recent studies have revealed the N. ceranae infection course, showing a spring peak, and a subsequent decline in summer and autumn [ 19 , 66 , 67 ]. These studies also confirmed the seasonal pattern of Nosema infection, as in samples taken during April (PL1) and July (PL4, UK2) N. ceranae was detected.…”

Variation in the Distribution of Nosema Species in Honeybees (Apis mellifera Linnaeus) between the Neighboring Countries Estonia and Latvia

“…However, several studies have confirmed that it is difficult to find clear links between seasonality and species occurrence. Although spore counts are usually higher in the springtime, they can vary annually and depend on several other factors [ 19 , 26 , 35 ]. In our experiment, forager bees were collected, which may have affected the study results, because, according to Meana et al [ 48 ], in-hive bees had fewer spore counts than foragers.…”

“…DNA was isolated using the DNeasy Blood and Tissue Kit (Qiagen, Hilden, Germany) according to the manufacturer’s protocol. A multiplex PCR (M-PCR) assay was performed to identify the Nosema species using 2 μL of DNA and primers as described by Fries et al (2013) [ 26 ] ( Table 1 ). The PCR program consisted of a 2-min initial denaturation at 95 °C, followed by 35 cycles of denaturation for 30 s at 95 °C, annealing for 30 s at 57 °C, and elongation for 1 min at 72 °C, with a final elongation step at 72 °C for 5 min.…”

“…Despite their generally similar descriptions, these two species affect honey bees differently. N. apis outbreaks occur mostly during the springtime and tend to be less severe, while N. ceranae outbreaks are detected during the entire period of active colony growth and can cause gradual fading [ 26 ]. The hidden course of the disease is also one of the reasons why it is difficult to eliminate.…”

Effects of Prebiotics and Probiotics on Honey Bees (Apis mellifera) Infected with the Microsporidian Parasite Nosema ceranae

“…The fungus, Nosema ceranae, is an obligate intracellular parasite that apparently originated in the Asian honey bee Apis cerana and spread to the western honey bee, Apis mellifera [1]. Infection with this parasite occurs in the alimentary tract, and can have a number of detrimental effects on A. mellifera, including degeneration of the hypopharyngeal glands [2], degeneration of the midgut epithelium, reduced nutrient absorption and increased energetic stress [3,4], suppression of apoptosis [5], immunosuppression [6,7], early onset of foraging behavior [8], decreased homing and orientation [9,10], and decreased lifespan and food stores in colonies [11,12]. N. ceranae infections have been associated with honey bee colonies losses in North America [13][14][15] and Europe [16][17][18].…”