Evolutionary Comparisons of Chelonid Alphaherpesvirus 5 (ChHV5) Genomes from Fibropapillomatosis-Afflicted Green (Chelonia mydas), Olive Ridley (Lepidochelys olivacea) and Kemp's Ridley (Lepidochelys kempii) Sea Turtles.

The spreading global sea turtle fibropapillomatosis (FP) epizootic is threatening some of Earth's ancient reptiles, adding to the plethora of threats faced by these keystone species. Understanding this neoplastic disease and its likely aetiological pathogen, chelonid alphaherpesvirus 5 (ChHV5), is crucial to understand how the disease impacts sea turtle populations and species and the future trajectory of disease incidence. We generated 20 ChHV5 genomes, from three sea turtle species, to better understand the viral variant diversity and gene evolution of this oncogenic virus. We revealed previously underappreciated genetic diversity within this virus (with an average of 2035 single nucleotide polymorphisms (SNPs), 1.54% of the ChHV5 genome) and identified genes under the strongest evolutionary pressure. Furthermore, we investigated the phylogeny of ChHV5 at both genome and gene level, confirming the propensity of the virus to be interspecific, with related variants able to infect multiple sea turtle species. Finally, we revealed unexpected intra-host diversity, with up to 0.15% of the viral genome varying between ChHV5 genomes isolated from different tumours concurrently arising within the same individual. These findings offer important insights into ChHV5 biology and provide genomic resources for this oncogenic virus.

Prolonged hypo-salinity to control Neobenedenia spp. monogenean infection in large display aquaria.

The majority of public aquaria have at least one very large tank (>370,000 liters, 100,000 gallons) as part of their collection. The large water volumes can make treatment difficult when pathogens escape quarantine or cross contamination occurs. The cost and methods of dispersion of chemotherapeutics to control infectious agents (bacterial, protozoal, or metazoan) can be prohibitive in large volumes. Currently there are few treatments for stenohaline monogeneans in large aquaria that are efficacious, safe, and affordable. This case demonstrates the safety and efficacy of a decade long use of prolonged hyposalinity that replaced the repeated use of copper and organophosphate treatments to control a Neobenedenia spp. monogenean infestation. The use of prolonged 20 ppt saline water is safe for a list of species traditionally listed as stenohaline which makes altering salinity a useful tool in treating parasites with restricted saline tolerances.