Israeli Acute Paralysis Virus: Epidemiology, Pathogenesis and Implications for Honey Bee Health

Abstract

Israeli acute paralysis virus (IAPV) is a widespread RNA virus of honey bees that has been linked with colony losses. Here we describe the transmission, prevalence, and genetic traits of this virus, along with host transcriptional responses to infections. Further, we present RNAi-based strategies for limiting an important mechanism used by IAPV to subvert host defenses. Our study shows that IAPV is established as a persistent infection in honey bee populations, likely enabled by both horizontal and vertical transmission pathways. The phenotypic differences in pathology among different strains of IAPV found globally may be due to high levels of standing genetic variation. Microarray profiles of host responses to IAPV infection revealed that mitochondrial function is the most significantly affected biological process, suggesting that viral infection causes significant disturbance in energy-related host processes. The expression of genes involved in immune pathways in adult bees indicates that IAPV infection triggers active immune responses. The evidence that silencing an IAPV-encoded putative suppressor of RNAi reduces IAPV replication suggests a functional assignment for a particular genomic region of IAPV and closely related viruses from the Family Dicistroviridae, and indicates a novel therapeutic strategy for limiting multiple honey bee viruses simultaneously and reducing colony losses due to viral diseases. We believe that the knowledge and insights gained from this study will provide a new platform for continuing studies of the IAPV–host interactions and have positive implications for disease management that will lead to mitigation of escalating honey bee colony losses worldwide.

Seasonal benefits of a natural propolis envelope to honey bee immunity and colony health

“…Azzami et al (2012) reported that antimicrobial peptide (e.g. hymenoptaecin and abaecin) expression is not altered upon viral challenge, while a more recent study showed that IAPV infection up-regulates multiple immune signaling pathways in adult bees (Chen et al, 2014). In our study, the lack of a significant difference in viral level between treatments, in both replicate years, strongly indicates that the differences in immune system activity observed are not due to viral infection.…”

Israeli acute paralysis virus associated paralysis symptoms, viral tissue distribution and Dicer-2 induction in bumblebee workers (Bombus terrestris)

“…FISH is a powerful method to determine DNA or RNA molecules in multiple types of samples. In honeybees, in situ hybridization has been applied to detect viruses such as DWV, IAPV and Kakugo virus (KV) and bacterial diseases in both adult and larval tissues (Chen et al, 2014;Fujiyuki et al, 2009;Martinson et al, 2012;Möckel, et al, 2011;Shah et al, 2009;Yue et al, 2008). In the present study, we localized IAPV in different parts of the brains of B. terrestris workers using paraffin-embedded tissue sections.…”

Morphological and functional characterization of honey bee, Apis mellifera, hemocyte cell communities

“…Despite this progress, much of our current knowledge about honey bee host-pathogen interactions is derived from sequence-based genetic, transcriptomic, and metagenomic investigations (Weinstock et al 2006;Runckel et al 2011;Chen et al 2014). As of yet, we know relatively little about honey bee immunity at the proteomic and cellular levels.…”