Mazzei, M. | bioRxiv Science

bioRxiv2019

Effect of oral administration of 1,3-1,6 β-glucans in DWV naturally infected newly emerged bees (Apis mellifera L.)

Honeybee pathogens have an important role in honeybee colony mortality and colony losses, most of them are widely spread and necessitate worldwide solutions to contrast honeybees decline. Possible accepted solutions to cope with the spread of honeybees pathogen are focused on the study of experimental protocols to enhance the insects immune defences. Honeybees artificial diet capable to stimulate the immune system is a promising field of investigation as ascertained by the introduction of 1,3-1,6 {beta}-glucans as a dietary supplement. In this work, by collecting faecal samples of honeybees exposed to different dietary conditions of 1,3-1,6 {beta}-glucans (0.5% and 2% w/w), it has been possible to investigate the DWV viral load kinetic without harming the insects. Virological data obtained by a one-step TaqMan RT-PCR highlights the ability of 1,3-1,6 {beta}-glucans to reduce the viral load at 24th day of rearing. Furthermore, results indicated that the diet supplemented with 1,3-1,6 {beta}-glucans was associated with a dose-dependent activation of phenoloxidase. Control group showed a higher survival rate than honeybees exposed to different dietary conditions of 1,3-1,6 {beta}-glucans while no differences have been observed concerning syrup daily consumption.

microbiology↗

bioRxiv2018

Global genetic diversity of small ruminant lentiviruses, and a hypothesis regarding their pandemic spread.

Small ruminant lentiviruses (SRLVs) cause chronic, persistent infections in populations of domestic sheep and goats throughout the world. In this study, we use genomic data to investigate the origins and history of the SRLV pandemic. To explore the hypothesis that SRLV infection disseminated during Neolithic times, we performed a serology and DNA sequencing-based investigation of SRLVs diversity in the Fertile Crescent region, where domestication of sheep and goats is thought to have originally occurred. While we found an elevated level of viral genetic diversity compared to other regions of the world, we did not find unambiguous evidence that the Fertile Crescent region was the centre of the contemporary SRLV pandemic. We therefore examined historical reports to investigate the relationship between contemporary SRLV distribution and diversity and the emergence of SRLV-associated disease. Historical data suggested that the emergence of SRLV-associated disease might be associated with the long-distance export of exotic small ruminant breeds - in particular, karakul sheep from Central Asia - during the late 19th and early 20th centuries. Phylogeographic analysis could neither confirm nor refute this hypothesis. However, we anticipate that future accumulation of genomic data from SRLV strains found throughout the world may allow for a more definitive assessment. The openly available data and resources assembled in this study will facilitate future investigations in this area.\n\nImportanceViruses that cause chronic, persistent infections have circulated in animals for millions of years. However, many have only emerged as pathogens within the far shorter timeframe of recorded human history. It is important to understand the history of chronic viral infections in domestic animals, so that more effective control and eradication programs can be developed.

evolutionary biology↗