Search Results (51)

Nosema ceranae is a common and highly contagious fungal pathogen that primarily infects the gut of adult honeybees, causing nosemosis. As a chronic disease of the digestive system, it poses a global threat to honeybee health and colony sustainability. This study aimed to investigate the inhibitory effects of different concentrations of Scutellaria baicalensis aqueous extract on N. ceranae in the intestines of infected Apis cerana through feeding experiments. In addition, the therapeutic efficacy of its major active component, baicalin, was evaluated, and its potential molecular mechanisms of action were explored. The results showed that, compared with the control group, administration of S. baicalensis aqueous extract at concentrations of 1 mg/mL, 5 mg/mL, and 10 mg/mL significantly reduced midgut spore loads (p < 0.05). Further experiments showed that a 0.5 mg/mL baicalin sucrose solution, prepared with 0.5% (v/v) DMSO as co-solvent, exhibited optimal solubility and significantly inhibited the proliferation of spores in the honeybee midgut. Transcriptomic analysis of A. cerana revealed varying numbers of significantly differentially expressed genes among the baicalin-treated (HG) group, the co-solvent control (DMSO) group, and the blank control (C) group. Four candidate DEGs associated with the effects of baicalin were further identified, namely LOC108003965, LOC108000905, LOC107996681, and CYP4G11. Gene Ontology enrichment analysis showed that, in the comparison between the HG group and the C group, these DEGs were significantly enriched in six functional categories: iron ion binding, phosphoric ester hydrolase activity, heme binding, tetrapyrrole binding, hydrolase activity (acting on ester bonds), and oxidoreductase activity (acting on paired donors, with incorporation or reduction of molecular oxygen). Collectively, these results demonstrate that S. baicalensis aqueous extract effectively inhibits the proliferation of N. ceranae within the host, and its active component, baicalin, exhibits a similar inhibitory effect. The present study proposes a novel strategy in which baicalin may enhance host endogenous chitinase-related activity to target and disrupt the spore wall, offering a new perspective for the prevention and control of honeybee nosemosis. Full article

Honeybee (Apis mellifera) colony density is frequently assumed to influence the level of Nosema ceranae infestation in managed colonies. In Slovakia, winter bottom beehive debris (dead worker bees) is routinely collected between January and February, providing a unique and uniform material for evaluating the degree of Nosema infestation prior to the breeding season. This study assesses the suitability of winter hive debris for estimating the infestation intensity of Nosema species and examines whether regional differences in beekeeping density are associated with variation in Nosema ceranae infestation levels. A total of 6221 samples from 43 Slovak districts collected between 2022 and 2024 were examined using microscopy confirmed by duplex PCR. Nosema ceranae was detected in 74.3% of samples, while Nosema apis was not detected. Although higher colony densities tended to be associated with increased proportions of moderately and strongly infested colonies, statistical modelling confirmed a statistically significant but modest positive association between colony density and infestation intensity. These results indicate that winter bottom beehive debris is a valuable material for assessing Nosema infestation pressure at the colony and regional levels, while also highlighting the contribution of additional environmental and management factors. Full article

The development of beekeeping in Ecuador has generated the need to strengthen the bee health program. Research on the main pathogens responsible for diseases like nosemosis, which can severely impact bee health, is of special interest. This study aims to identify the Nosema apis and/or Nosema ceranae species infecting honey bee colonies located in the northern Andean region of Ecuador using multiplex PCR targeting the RNA polymerase II gene (RPB1), and the phylogenetic analysis of N. ceranae based on the 16 S rRNA gene sequences. Among the 164 honey bee samples collected from colonies in the provinces of Carchi, Imbabura, and Pichincha, the prevalence of Nosema apis and Nosema ceranae was 14.63% and 21.34%, respectively. Phylogenetic analysis showed that N. ceranae from Ecuador is closely related to the sequences from Argentina and Brazil. These findings provide the first molecular confirmation of N. ceranae in Ecuador and support the need for molecular monitoring of honey bee pathogens in the region. Full article

Nosemosis is a disease caused by microsporidia, which are strictly intracellular pathogens, currently considered to be most closely related to fungi. These microscopic parasites infect a variety of hosts, significantly affecting honeybees (Apis mellifera). Nosemosis is one of the most serious diseases of bees and is caused primarily by two species: Nosema apis and Nosema ceranae. This infection adversely affects the digestive tract of the bees, causes a reduction in their vitality, and can lead to the death of entire colonies. The diagnosis of nosemosis has undergone extensive development. Traditionally, the identification of microsporidia was performed by examination of bee digestive tract (macerated) by light microscopy. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are expensive methods that require skilled personnel and were used only when high resolution was necessary. Modern methods, such as polymerase chain reaction (PCR), allow detection of infection at species and genotype levels, thereby increasing the accuracy of diagnosis. Despite advances in molecular techniques, research into nosemosis still faces challenges. This review focuses on a comparison of different diagnostic techniques and their pitfalls that can be integrated into strategies to combat nosemosis and protect the health of honeybee colonies. Full article

Nosemosis is an intestinal infection caused by intracellular fungal organisms from the Vairimorpha (formerly Nosema) group, which seriously harms honeybee colonies and is a factor in their worldwide decline. With the ban on fumagillin use in European apiculture and the limitations of conventional treatments, it is essential to identify sustainable alternative solutions. This study presents new environmentally friendly microbe-based strategies to prevent and treat infection, focusing on probiotics, postbiotics, synbiotics, and mixes with plant extracts, as well as suggesting a new approach for the future. This review discusses the latest results based on using beneficial bacteria (e.g., Lactobacillus and Enterococcus faecium) and their byproducts to decrease the spore levels and modulate the gut bacteria pattern. Moreover, innovative approaches, such as genetically engineered gut bacteria to target pathogen gene expression through RNA interference, have been mentioned. Although results vary depending on microbial strain, delivery method, season, and ecological context, microbial treatments represent a promising, safe, and adaptable alternative for modern apiculture. The paper is necessary to validate these strategies’ real-world efficacy and to develop standardized microbial formulations suitable for practical implementation by beekeepers. Full article

Nosemosis, caused by microsporidians of the genus Vairimorpha, is one of the most significant diseases affecting the honey bee Apis mellifera L. (Apidae: Hymenoptera), with negative impacts on its health and productivity. This study aimed to assess the presence of Vairimorpha ceranae in apiaries from the state of Campeche, Mexico. Honey bee samples were collected from 79 colonies across 29 apiaries, and DNA was extracted for analysis. Detection of the microsporidian parasite was achieved through amplification of the 16S small subunit ribosomal RNA gene by PCR and PAGE, revealing a high prevalence of Vairimorpha ceranae. The results represent the first confirmed record of Vairimorpha ceranae in this region, with widespread infection detected among sampled colonies. This finding is crucial for identifying the frequency and geographic distribution of this parasite in Mexico and will support the development of targeted management and control strategies adapted to local conditions, ultimately contributing to the conservation and health of honey bee populations in Campeche. Full article

One of the common causes of mass death in bee colonies is the infectious disease nosemosis, which is caused by two types of microsporidia, Nosema apis and Nosema ceranae. Of the many factors contributing to the spread of nosemosis, in this paper we consider the hybridization of subspecies of Apis mellifera L. In most of Russia, the native subspecies is the dark forest bee Apis mellifera mellifera, which is representative of the evolutionary lineage M. The export of bee packages and queens from the southern regions of Russia and other countries has led to the fragmentation of the range of these subspecies. First, we determined the maternal and paternal ancestry of 349 honey bee colonies across 12 beekeeping regions of Russia using the mitochondrial tRNAleu-COII locus and nine nuclear SSR markers (Ap243, 4a110, A024, A008, A43, A113, A088, Ap049, and A028). Among them, 140 colonies belonged to subspecies A. m. mellifera, 58 colonies were of hybrid origin, and 151 colonies belonged to evolutionary lineage C. Then, using microscopy and PCR analysis, we performed diagnostics of nosemosis in the studied colonies: N. apis was detected in 87 colonies, N. ceranae in 102 colonies, and coinfection was observed in 36 colonies. The results of our study indicate that the main reservoir of Nosema microsporidia was bees of evolutionary lineage C. Full article

Nosema apis and Nosema ceranae are two well-known pathogens affecting the health of honeybees. To help understand how honeybee colonies are affected by these pathogens, the aim of this study was to analyze the impact of Nosema ceranae and Nosema apis in hives in the Apulian Region through a Citizen Science approach. First, a form about the health status of the beehives was filled out by beekeepers. After an inspection visit to confirm the signs observed by beekeepers, adult honeybee samples collected from beehives in four Apulian provinces (Taranto, Bari, Foggia and Brindisi) were subjected to light microscopy investigation for the detection of Nosema spp. spores and to molecular analysis using species-specific primers for the discrimination of Nosema apis spores from those of Nosema ceranae. Among the forty-eight samples, thirty-six tested positive for Nosema ceranae, and one sample tested positive for Nosema apis. The forms filled out by beekeepers revealed that only 5/36 beehives that tested positive for Nosema ceranae showed signs of depopulation and reduced honey production, while 19/36 had only low honey yield. This study provides data on Nosema apis and Nosema ceranae prevalence in Italy and correlates the presence of these intestinal pathogens with the most important problems encountered by local beekeepers. Full article

(1) Background: Microsporidiosis (nosemosis) is an intestinal disorder of adult honey bees caused by the microsporidian pathogens Vairimorpha apis and Vairimorpha ceranae. In Canada, fumagillin is an approved antibiotic used to treat this disease. However, the recommended dosage is based on efficacy studies for V. apis, the native pathogen in European honey bees. Since the detection of V. ceranae in Apis mellifera, V. ceranae became more prevalent in managed European honey bees and seems to have replaced V. apis due to yet unknown reasons. (2) Methods: This colony study investigated the efficacy of fumagillin administered in the fall to colonies infected with both V. apis and V. ceranae and its effects on the Vairimorpha species’ prevalence overwinter. Spore loads in control and fumagillin-treated colonies were analysed by microscopy; Vairimorpha species prevalence was determined molecularly and infection and treatment effects on colony productivity were assessed. (3) Results: Fall fumagillin treatment was associated with a temporary reduction in spore load, but there was no difference in spore loads between treated and control colonies the following spring. Interestingly, fumagillin-treated colonies had a significantly greater prevalence of V. ceranae relative to V. apis the following spring, suggesting fumagillin is less effective in controlling V. ceranae. Full article

Background/Objectives: In a collaborative effort, FAO, the International Federation of Beekeepers’ Association “Apimondia”, the Appalachian State University, and the Istituto Zooprofilattico Sperimentale del Lazio e Toscana (IZSLT), the FAO Reference Centre for Animal Health and Food Security Discipline Apiculture, health, and biosecurity, designed an online international survey (“Knowledge, Awareness and Practice”-KAP) as a risk assessment tool to validate biosecurity measures able to prevent and control the main honeybee (Apis mellifera subsp.) infectious diseases. Methods: The KAP survey was disseminated through various channels for 14 months (January 2019–March 2020). Beekeepers’ knowledge on nosemosis, American foulbrood (AFB), and European foulbrood (EFB) management was assessed. Beekeepers’ attitudes were investigated by asking them to provide a score called “Acceptance by beekeepers”. Results: Of the 410 respondents, the majority of them (68.3%, n = 252) were from Europe. European beekeepers (n = 252) considered “Highly acceptable” the following practices: removing combs that show signs of dysentery and feeding colonies for nosemosis; the quick identification and management of affected hives for American foulbrood and European foulbrood. Instead, the following practices were considered as not acceptable by beekeepers: for nosemosis, the use of antibiotics and sampling of hive debris for early detection; for American foulbrood and European foulbrood, the shook swarm, the destruction of the whole apiary, as well as their treatment with antibiotics. Conclusion: This study demonstrated the validity of the present “Knowledge, Awareness and Practice” (KAP) survey to validate the best practices for the main infectious honeybee diseases, considering the pragmatic point of view of beekeepers. Sustainable practices for disease control are preferred by the European beekeepers. While having an adequate knowledge base for the early detection of the investigated honeybee diseases, European beekeepers tend to be aware of the health status of their hives, embracing advanced, practice-oriented training. Authors highlight that the selection of practices and their validation should be revised on a regular basis, to be adapted in a timely manner to the current infectious honeybee disease situation, in order to build up a resilient and effective stock of practices. Full article

Nosema ceranae (N. ceranae) infection is prevalent globally, causing a decline in bee populations and significant economic losses to apiarists. Although several methods have been proposed for diagnosing Nosema infections, limitations in these methods have hindered their broad applications. Therefore, this current study aimed to develop a specialized method for diagnosing Nosema infections. To achieve this, a sandwich enzyme-linked immunosorbent assay (ELISA) and immunochromatography assay (ICG) were developed, and their effectiveness in screening and diagnosing Nosema infection was assessed. In sandwich ELISA, the combination of the monoclonal antibodies (mAb) 19B2 and biotinylated-19B2 exhibited stronger binding affinity to the antigen than did other combinations of mAbs that were tested. Furthermore, the antigen detection limit achieved with the sandwich ELISA surpassed that previously reported with Western blotting. The ICG was designed using the same antibody combination as that used in sandwich ELISA; however, the assay exhibited a lower diagnostic ability for Nosema infection than the ELISA. The diagnostic models developed in this study offer practical applications for conducting rapid nosemosis detection tests. These innovative techniques will help to improve the timely identification and management of nosemosis. Full article

One of the most important approaches in the prevention and treatment of nosemosis is the use of herbal preparations as food supplements for bees. Therefore, the aim of this study was to investigate the effects of a plant-based supplement branded as “B+” on honeybees in a laboratory experiment. Four experimental groups were established: treated group (T), N. ceranae-infected and treated group (IT), N. ceranae-infected group (I) and non-infected group (NI). Survival, N. ceranae spore load and oxidative stress parameters together with expression levels of antioxidant enzyme genes and vitellogenin gene were monitored. The mortality in the T, IT and NI groups was significantly (p < 0.001) lower than in than in the I group. Within Nosema-infected groups, the IT group had a significantly lower (p < 0.001) number of N. ceranae spores than the I group. In addition, expression levels of genes for antioxidant enzymes were lower (p < 0.001) in the IT group compared to the I group. The concentration of malondialdehyde and the activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione S-transferase) were significantly lower (p < 0.001) in the IT group compared to the I group. No negative effects of the tested supplement were observed. All these findings indicate that the tested supplement exerted beneficial effects manifested in better bee survival, reduced N. ceranae spore number and reduced oxidative stress of bees (lower expression of genes for antioxidant enzymes and oxidative stress parameters). Full article

This study aimed to select the most effective culture extracts for controlling honeybee nosemosis using 342 entomopathogenic fungi of 24 species from 18 genera. The germination inhibitory activity of the fungal culture extract on Nosema ceranae spores was evaluated using an in vitro germination assay method. Among 89 fungal culture extracts showing germination inhibitory activity of approximately 80% or more, 44 fungal culture extracts that maintained their inhibitory activity even at a concentration of 1% were selected. Finally, the honeybee nosemosis inhibitory activity was evaluated using the cultured extracts of five fungal isolates having a Nosema inhibitory activity of approximately 60% or more, even when the extract was removed after treatment. As a result, the proliferation of Nosema spores was reduced by all fungal culture extract treatments. However, only the treatment of the culture extracts from Paecilomyces marquandii 364 and Pochonia bulbillosa 60 showed a reduction in honeybee mortality due to nosemosis. In particular, the extracts of these two fungal isolates also increased the survival of honeybees. Full article

The declining honeybee populations are a significant risk to the productivity and security of agriculture worldwide. Although there are many causes of these declines, parasites are a significant one. Disease glitches in honeybees have been identified in recent years and increasing attention has been paid to addressing the issue. Between 30% and 40% of all managed honeybee colonies in the USA have perished annually over the past few years. American foulbrood (AFB) and European foulbrood (EFB) have been reported as bacterial diseases, Nosema as a protozoan disease, and Chalkbrood and Stonebrood as fungal diseases. The study aims to compare the bacterial community related to the Nosema ceranae and Ascosphaera apis infection on the gut of the honeybee and compare it with the weakly active honeybees. The Nosema-infected honeybees contain the phyla Proteobacteria as the significantly dominant bacterial phyla, similar to the weakly active honeybees. In contrast, the Ascosphaera (Chalkbrood) infected honeybee contains large amounts of Firmicutes rather than Proteobacteria. Full article

Background: Microsporidia from the Nosema (Vairimorpha) genus are pathogenic fungi that complete their life cycle in the honeybee intestine. Therefore, the aim of this study was to determine the impact of the course of infection on the viability of honeybee intestine cells. Methods and Results: Intestines isolated from healthy and N. ceranae-infected honeybees were stained using two dyes, SYTO 9 and propidium iodide, and analyzed under an Axiovert 200M fluorescence microscope immediately after the isolation of the intestines. The ImageJ program was used for the quantitative analysis of the cell structure parameters. Our study demonstrated for the first time that healthy bees have a higher number of live cells in their intestines than infected bees, and that the intestines of N. ceranae-infected honeybees contain dead cells concentrated in spots. The results obtained for these two cases differed significantly, and were confirmed by statistical tests. Conclusions: The intestines of infected honeybees contain dead cells concentrated in red/dead spots, which can lead to necrotic changes, the interruption of the host’s intestinal continuity, intestinal leaking and the increased mortality of the host. Full article