Nosema apis and Nosema ceranae Tissue Tropism in Worker Honey Bees (Apis mellifera)

Abstract

The microsporidia Nosema apis and Nosema ceranae are major honey bee pathogens that possess different characteristics in terms of the signs they produce, as well as disease development and transmission. Although the ventricular epithelium is generally considered the target tissue, indirect observations led to speculation that N. ceranae may also target other structures, possibly explaining at least some of the differences between these 2 species. To investigate the tropism of Nosema for honey bee tissues, we performed controlled laboratory infections by orally administering doses of 50 000 or 100 000 fresh mature spores of either species. The fat body was isolated from the infected bees, as well as organs from the digestive (esophagus, ventriculus, ileum, rectum), excretory (Malpighian tubules), circulatory (aorta, heart), respiratory (thoracic tracheas), exocrine (hypopharyngeal, mandibular and labial, cephalic, thoracic salivary glands), and sensory/nervous (brain, eyes and associated nerve structures, thoracic nerve ganglia) systems. Tissues were examined by light and electron microscopy at 7, 10, and 15 days postinfection. Both Nosema species were found to infect epithelial cells and clusters of regenerative cells in the ventriculus, and while the ileum and rectum contained spores of the microsporidia in the lumen, these structures did not show overt lesions. No stages of the parasites or cellular lesions were detected in the other organs tested, confirming the high tropism of both species for the ventricular epithelium cells. Thus, these direct histopathological observations indicate that neither of these 2 Nosema species exhibit tropism for honey bee organs other than the ventriculus.

Effect of Api-Bioxal® and ApiHerb® Treatments against Nosema ceranae Infection in Apis mellifera Investigated by Two qPCR Methods

“…N. ceranae is an intracellular obligate parasite and infects the epithelial cells of the ventriculum [ 2 , 6 ] with high tropism for this organ [ 7 ]. Nosemosis Type C shows symptoms both at the individual and colony level, including lifespan reduction, lethargic behavior and poor honey and pollen harvest [ 5 , 8 , 9 ].…”

Impact of Protoporphyrin Lysine Derivatives on the Ability of Nosema ceranae Spores to Infect Honeybees

“…Honeybees, which are important for the development and maintenance of natural ecosystems, are infected by two species of microsporidia, Nosema apis and N. ceranae , and they both cause the disease nosemosis [ 9 , 10 , 11 , 12 , 13 ]. However, in North America and Europe, infections caused by N. ceranae have become increasingly common, and N. ceranae exhibits stronger virulence than N. apis [ 14 , 15 , 16 , 17 ].…”

A high quality method for hemolymph collection from honeybee larvae

“…The honeybee Apis mellifera has been used worldwide as a model organism in several studies because it is a species with widely known biology, has a wide geographical distribution, is easily managed and maintained in laboratories, a great indicator of environmental quality and the most frequent floral visitor of agricultural crops [1,2,3]. Therefore, several studies in different areas of science use this species, including studies that evaluate the impact of pesticides [4,5,6,7], host-parasite interactions [8,9,10,11,12,13], behavioral tests [14,15,16] and at the molecular level genomic, transcriptomic and epigenetic patterns [17,18,19,20].…”