title: Nosema ceranae Infection Promotes Proliferation of Yeasts in Honey Bee Intestines.
abstract: BACKGROUND
  Nosema ceranae infection not only damages honey bee (Apis melifera) intestines, but we believe it may also affect intestinal yeast development and its seasonal pattern. In order to check our hypothesis, infection intensity versus intestinal yeast colony forming units (CFU) both in field and cage experiments were studied.
  
  
  RESULTS
  Field tests were carried out from March to October in 2014 and 2015. N. ceranae infection intensity decreased more than 100 times from 7.6 x 108 in March to 5.8 x 106 in October 2014. A similar tendency was observed in 2015. Therefore, in the European eastern limit of its range, N. ceranae infection intensity showed seasonality (spring peak and subsequent decline in the summer and fall), however, with an additional mid-summer peak that had not been recorded in other studies. Due to seasonal changes in the N. ceranae infection intensity observed in honey bee colonies, we recommend performing studies on new therapeutics during two consecutive years, including colony overwintering. A natural decrease in N. ceranae spore numbers observed from March to October might be misinterpreted as an effect of Nosema spp. treatment with new compounds. A similar seasonal pattern was observed for intestinal yeast population size in field experiments. Furthermore, cage experiments confirmed the size of intestinal yeast population to increase markedly together with the increase in the N. ceranae infection intensity. Yeast CFUs amounted to respectively 2,025 (CV = 13.04) and 11,150 (CV = 14.06) in uninfected and N. ceranae-infected workers at the end of cage experiments. Therefore, honey bee infection with N. ceranae supported additional opportunistic yeast infections, which may have resulted in faster colony depopulations.
authors.affiliation: Department of Botany and Mycology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
authors.forename: Aneta A
authors.identifier: http://orcid.org/0000-0001-6413-6028
authors.initials: AA
authors.lastname: Ptaszyńska
authors.affiliation: Department of Zoology, Ecology and Wildlife Management, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Paleolog
authors.affiliation: Department of Biological Basis of Animal Production, Faculty of Biology and Animal Breeding, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Borsuk
mesh_terms: D000818:Animals; D001516:Bees / Q000382:microbiology*; D004271:DNA, Fungal / Q000378:metabolism; D007422:Intestines / Q000382:microbiology*; D016881:Microsporidiosis / Q000473:pathology / Q000662:veterinary; D016818:Nosema / Q000235:genetics / Q000302:isolation & purification*; D012440:Saccharomyces / Q000254:growth & development / Q000302:isolation & purification; D012621:Seasons
chemical_list: D004271:DNA, Fungal