Nosemosis type c of bees caused by microsporidia Nosema (Vairimorpha) ceranae: current views, pathogenesis, prevention, diagnosis and treatment (review)

Nosemosis type C is a parasitic disease of honey bees caused by the obligate intracellular parasite microsporidia Nosema (Vairimorpha) cerana. This disease is widespread worldwide and can lead to a decrease in honey production, a sharp reduction in the population of adults in bee families and their final death (M. Higes et al., 2007; P.J. Marín-García et al., 2022). The purpose of this review is to present up-to-date data on this disease and its causative agent, as well as on modern methods of diagnosis, prevention and treatment in beekeeping. The parasite is mainly transmitted between bees by the fecal-oral route and infects the cells of the middle intestine of insects (R. Galajda et al., 2021).. Vertical transmission of the parasite is also possible, as N. ceranae spores have been found in ovarian cells of infected queens (C. Alaux et al., 2011). The pathogenesis of N. ceranae is associated with the destruction of infected cells, the restructuring of the host’s metabolic processes to meet the needs of the parasite, the shortage of spare resources and vital metabolites in sick bees. hormonal imbalance; negative consequences of part of the immune responses to the pathogen invasion, such as oxidative stress (L. Paris et al., 2017). Ability of N. ceranae specifically inhibits such protective reactions of bees as activation of apoptosis of infected cells and production of antimicrobial peptides can enhance the pathogenic nature of nosemosis type C (K. Antunez et al., 2009; C. Kurze et al., 2015). The method of diagnosis of infection includes the primary detection of the parasite using light microscopy, including with the use of various dyes (N.J. Ryan et al., 1993), and further determination of the species of microsporidia using molecular methods such as standard polymerase chain reaction (PCR) or loop-mediated isothermal amplification (LAMP). The most effective drug for the treatment of nosemosis of bees for a long time remained the antibiotic fumagillin, despite the fact that N. ceranae can acquire resistance to this drug (W.-F. Huang et al., 2013; I. Tlak Gajger et al., 2018). However, the discovery of residues of this drug in honey produced by bees after treatment and its toxicity to humans led to the prohibition of this drug in a number of countries and the cessation of its production in 2018 (I. Tlak Gajger et al., 2018). In this regard, many studies have been conducted in recent years aimed at finding new ways to treat nosemosis. For example, extracts from various fungi and plants, probiotics such as eugenol, chitosan, naringenin, proteksin, proteasome function inhibitors ixazomib, and ixazomib citrate are considered as agents for the treatment of this disease (V. Chaimanee et al., 2021; S.S. Klassen et al., 2021; E.M. Huntsman et al., 2021). Despite the fact that many of the tested methods have shown encouraging results, a safe analogue of fumagillin, similar to it in terms of the effectiveness of the fight against nosemosis, has not yet been found. The article also provides recommendations for the care of beehives for the prevention of nosemosis type C in beekeeping.