Honey bee (Apis mellifera) - associated viruses are increasingly detected in wild bees, but the extent and direction of transmission between wild bees and honey bees remain unclear. We surveyed wild bees from 23 genera alongside sympatric A. mellifera across seasons in north-central Florida, USA, quantifying prevalence, viral load, and co-occurrence of four common viruses: Black queen cell virus (BQCV), Deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and Sacbrood virus (SBV). At least one virus was detected in 98% of honey bees and 58% of wild bees. DWV and BQCV dominated overall, but IAPV occurred more frequently, and at higher levels in wild bees, particularly Halictidae than in honey bees. Seasonal dynamics differed markedly between groups: IAPV and SBV persisted year-round in wild bees but were undetectable in honey bees in spring. Co-infections were common, particularly in honey bees, and showed phylogenetic structuring among wild bee families. Therefore, while BQCV and DWV in wild bees likely reflects spillover from managed bees, IAPV and possibly SBV may circulate independently within wild bee communities. These results challenge assumptions of unidirectional pathogen flow from honey bees to wild bees, highlighting the value of seasonal sampling and virus quantification for understanding transmission.

Abstract This chapter highlights the inevitability of infectious diseases, diseases that are transmitted from another person or organism by a biological agent called a pathogen or parasite. For most of human history, using quarantines to prevent transmission was the only effective way to combat infectious disease. Immunization was the first of several major breakthroughs in individual-focused infectious disease control, followed centuries later by the discovery of antibiotics. If enough of the population are protected from disease, transmission can be reduced sufficiently to stamp out an epidemic; if we protect the population on a global scale, we can drive a disease extinct. But both humans and infectious disease agents are living organisms that undergo ecological and evolutionary change, making infectious disease a moving target.

Abstract Batrachochytrium dendrobatidis (Bd) is a fungal non-human pathogen that infects hundreds of different amphibian species, driving some of them to extinction. ‘Amphibian chytrid fungus’ considers the physiology and natural history of this emerging pathogen; its discovery in the late 1990s in Australia and Central America; and the concepts and strategies used to try to determine its origins. Did it arrive recently in the communities it has destroyed, or had it lain dormant in those communities for millennia before suddenly beginning to cause harm? The debate between the novel pathogen hypothesis and the endemic pathogen hypothesis, versions of which apply to most emerging diseases of wildlife, has lately been settled by genomic samples from Asia that show that the fungus coexisted with amphibians there for millions of years before spreading globally in the mid-20th century. Like many wildlife diseases, controlling Bd in the wild is difficult. While antifungal compounds can be spread in the environment, the most effective way to save amphibian populations may be to promote population health more generally by limiting other threats such as habitat destruction and overhunting.

Abstract This chapter details the various ways disease can be transmitted between organisms. Respiratory viruses such as influenza are airborne; some pathogens such as HIV and hepatitis can be transmitted through bodily fluids; some infectious diseases, such as cholera, can survive in water; and still other pathogens have evolved to use other organisms, especially blood-sucking insects and mites, as vectors to travel from one host to another. The concepts of the encounter and compatibility filters describe the competition between hosts and pathogens to enhance or reduce the pathogen’s ability to move into new hosts (the encounter filter) and replicate within them (the compatibility filter). Mathematical models help understand how pathogens spread both among hosts and within individual hosts’ bodies. Virulence, resistance, and tolerance describe the pathogen and host factors that determine how badly pathogens will compromise an infected host’s health.

Abstract This chapter shows how our understanding of how diseases are transmitted, and the development of vaccines and treatments that can close the compatibility filter, has revolutionized disease management. But what is the outlook for the future control of infectious diseases? A future free of infectious diseases is simply unrealistic. Living things have parasitized one another since the beginning of life itself, and will certainly continue to do so. New diseases will be created by mutation or recombination of existing ones, and existing diseases will continually evolve to escape our methods of control. Urbanization and population growth will change the ways in which we contact animal hosts, leading to new zoonoses. Controlling disease depends on combining strategies to prevent transmission and protect individuals, as well as communicating the importance of these efforts to the public. We can minimize the impact of diseases even if we can never fully eliminate them.

Abstract HIV is the virus that causes acquired immunodeficiency syndrome, or AIDS. It is transmitted by the exchange of bodily fluids. Untreated HIV infections are usually fatal within five to 10 years, but people with AIDS die from opportunistic infections, rather than from HIV itself. HIV uses its surface protein gp120 to enter immune cells; a mutation in the human genome called CCR5-Δ32 blocks this mechanism of entry. HIV’s rapid replication, mutation, and recombination rates make it highly evolvable and thus very hard to treat, cure, or prevent via vaccine. Despite these challenges, a regimen of highly active anti-retroviral therapies (HAART), developed in the mid-1990s, is extraordinarily effective against HIV, and is now being used preventively as well. While researchers have used extraordinary efforts to cure a handful of people of HIV, large-scale efforts to control HIV depend on education, condom use, needle exchange, pre-exposure prophylaxis, and HAART. Phylogenetic and historical analyses show that the ancestor of HIV first jumped from chimpanzees to humans in Africa in the early 20th century; some combination of colonial practices, use of non-sterilized syringes, and changing sexual practices then spread the virus throughout Africa and worldwide.

Abstract SARS-CoV-2 is the virus that caused the recent COVID-19 pandemic. Its global impact comes from its transmissibility, its ability to be transmitted by asymptomatic people, and its intermediate virulence. Comparing the related SARS-CoV-1 and MERS viruses, which have caused severe disease without generating a pandemic, shows differences in both virulence (infection and case fatality rates) and transmissibility. The chapter considers whether SARS-CoV-2 spilled over into human populations through transmission between bats and humans or a leak from a virology lab. It describes how SARS-CoV-2 continues to evolve in the human population, considering the transmission and virulence of the variants that emerged over the course of the pandemic. While lockdowns, distancing, and masking were the only control methods early in the pandemic, rapidly developed vaccines offer the possibility of keeping up with continued transmission and evolution of SARS-CoV-2 into the future.

The Almendravirus and Sigmavirus genera belong to the Rhabdoviridae family. Their members infect exclusively arthropods and are distributed worldwide. Viruses from both genera are bullet shaped and enveloped and have negative sense, single stranded RNA genomes. Their genomes code for the five canonical rhabdovirus genes (N, P, M, G and L); however they also code for extra genes (X and 1a viroporin-like, respectively). Sigma virus is the most studied insect rhabdovirus and is vertically transmitted by both parents to their offspring and can cause paralysis and death when the flies are exposed to high concentrations of CO2. In laboratory populations of Drosophila melanogaster, sigma virus can decrease fecundity and viability as well as increasing development time.

Adenosine Deaminases that Act on RNA (ADARs) are RNA editing enzymes that play a dynamic and nuanced role in regulating transcriptome and proteome diversity. This editing can be highly selective, affecting a specific site within a transcript, or nonselective, resulting in hyperediting. ADAR editing is important for regulating neural functions and autoimmunity, and has a key role in the innate immune response to viral infections, where editing can have a range of pro- or antiviral effects and can contribute to viral evolution. Here we examine the role of ADAR editing across a broad range of viral groups. We propose that the effect of ADAR editing on viral replication, whether pro- or antiviral, is better viewed as an axis rather than a binary, and that the specific position of a given virus on this axis is highly dependent on virus- and host-specific factors, and can change over the course of infection. However, more research needs to be devoted to understanding these dynamic factors and how they affect virus-ADAR interactions and viral evolution. Another area that warrants significant attention is the effect of virus-ADAR interactions on host-ADAR interactions, particularly in light of the crucial role of ADAR in regulating neural functions. Answering these questions will be essential to developing our understanding of the relationship between ADAR editing and viral infection. In turn, this will further our understanding of the effects of viruses such as SARS-CoV-2, as well as many others, and thereby influence our approach to treating these deadly diseases.

Hybridization is a fundamental evolutionary and ecological process with significant conservation ramifications. Sea turtle hybridization occurs at unusually high frequencies along the northeastern coast of Brazil. To better understand the process, we studied the reproductive output, migration patterns (through satellite telemetry), and isotopic niches of loggerhead turtles Caretta caretta and olive ridley turtles Lepidochelys olivacea and their hybrids. We classified 154 nesting females as loggerhead (n = 91), olive ridley (n = 38), or hybrid (n = 25) based on mitochondrial and nuclear DNA. Further, we compared nesting female morphological data and reproductive parameters (clutch size, emergence success, hatchling production, incubation period) of 405 nests among hybrids and parental species. We found no significant differences among the 3 groups when hatchling production was corrected for female body size, indicating that hybrids and parental species produce similar numbers of hatchlings per clutch. Satellite tracking of 8 postnesting hybrid females revealed shared foraging grounds with both parental species, as well as neritic migrations between foraging and nesting areas similar to those previously reported for loggerheads and olive ridleys. Analyses of 13C and 15N isotope values (n = 69) further confirmed this pattern, as hybrid isotopic niches overlapped extensively with both parental species. Thus, given the similarities presented between hybrids and their parental species in reproductive, ecological, and behavioral characteristics, we conclude that these hybrids may persist along with other sea turtle nesting populations in the area, with research and conservation implications.

Organisms clear infections by mounting an immune response that is normally turned off once the pathogens have been cleared. However, sometimes this immune response is not properly or timely arrested, resulting in the host damaging itself. This immune dysregulation may be referred to as immunopathology. While our knowledge of immune and metabolic pathways in insects, particularly in response to viral infections, is growing, little is known about the mechanisms that regulate this immune response and hence little is known about immunopathology in this important and diverse group of organisms. In this chapter we focus both on documenting the molecular mechanisms described involved in restoring immune homeostasis in insects after viral infections and on identifying potential mechanisms for future investigation. We argue that learning about the immunopathological consequences of an improperly regulated immune response in insects will benefit both insect and human health.

Previous studies of Zika virus (ZIKV) pathogenesis have focused primarily on virus-driven pathology and neurotoxicity, as well as host-related changes in cell proliferation, autophagy, immunity, and uterine function. It is now hypothesized that ZIKV pathogenesis arises instead as an (unintended) consequence of host innate immunity, specifically, as the side effect of an otherwise well-functioning machine. The hypothesis presented here suggests a new way of thinking about the role of host immune mechanisms in disease pathogenesis, focusing on dysregulation of post-transcriptional RNA editing as a candidate driver of a broad range of observed neurodevelopmental defects and neurodegenerative clinical symptoms in both infants and adults linked with ZIKV infections. The authors collect and synthesize existing evidence of ZIKV-mediated changes in the expression of adenosine deaminases acting on RNA (ADARs), known links between abnormal RNA editing and pathogenesis, as well as ideas for future research directions, including potential treatment strategies.

BioEssaysVolume 41, Issue 2 1970022 MastheadFree Access BioEssays 2∕2019 First published: 18 February 2019 https://doi.org/10.1002/bies.201970022AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume41, Issue2February 20191970022 RelatedInformation

Sea turtle hybridization is a common phenomenon in Brazil between loggerheads (Caretta caretta) and hawksbills (Eretmochelys imbricata) as well as between loggerheads and olive ridleys (Lepidochelys olivacea). In a previous study we showed that the reproductive output of loggerhead/hawksbill hybrids is similar to that of parental species, suggesting no negative effect of hybridization at this life stage. In this study, we used pooled amplicon sequencing to assign species identity to dams and their progeny, and to investigate the fitness consequences of hybridization, using hatchling viability as a proxy for fitness. We genotyped 4829 hatchlings from egg clutches laid by 78 loggerheads, 13 hawksbills, seven loggerhead/hawksbill hybrids, and three loggerhead/olive ridley hybrids. The proportion of viable hybrid (heterozygous) hatchlings was similar to that of homozygous hatchlings (based on data at two loci), independent of the dam's genotype. Multiple species paternity was observed in 35.7% of the nests. Both hybrid males and females were fertile and produced viable offspring, and we found no evidence for hybrid breakdown. We suggest a genome-wide study of the hybrids and parental species to better characterize hybrids, as well as studies on additional demographic and ecological parameters to further assess the effects of hybridization and its consequences for sea turtles and their environment.

Many Zika virus (ZIKV) pathogenesis-related studies have focused primarily on virus-driven pathology and neurotoxicity, instead of considering the possibility of pathogenesis as an (unintended) consequence of host innate immunity: specifically, as the side-effect of an otherwise well-functioning machine. The hypothesis presented here suggests a new way of thinking about the role of host immune mechanisms in disease pathogenesis, focusing on dysregulation of post-transcriptional RNA editing as a candidate driver of a broad range of observed neurodevelopmental defects and neurodegenerative clinical symptoms in both infants and adults linked with ZIKV infections. We collect and synthesize existing evidence of ZIKV-mediated changes in expression of adenosine deaminases that act on RNA (ADARs), known links between abnormal RNA editing and pathogenesis, as well as ideas for potential translational applications, including genomic profile-based molecular diagnostic tools and/or treatment strategies.

Increasing the diversity of tomorrow's healthcare work force remains a challenge despite many thoughtful published reports and recommendations. As part of an effort to grow a more diverse pre-professional health population, we created an undergraduate minor, Health Disparities in Society, at the University of Florida. Most courses for the minor were identified from existing offerings, and we created only two new courses, an introduction course and a capstone service-learning course. The new minor quickly became the most popular in the College of Liberal Arts and Sciences (which has approximately 12,000 total undergraduate students), and importantly, students selecting the minor were more likely to be under-represented minorities than would be expected given undergraduate demographics. Pre-professional students choosing this minor reflect the desired diversity of the healthcare workforce of tomorrow.

Abstract Alternative life history strategies are mechanisms by which organisms are able to maximize fitness across a range of environmental conditions. Fitness is maximized by different strategies depending on context, resulting in trade-offs between life history strategies. Monarch butterflies (Danaus plexippus) employ both migratory and resident life history strategies. Since residents breed throughout the year, but migrants overwinter in reproductive diapause, there are fitness trade-offs between the two strategies. We used stable isotope analysis to evaluate the geographic origins of monarchs in a yearround population in south Florida. Based on stable isotope profiles of hydrogen and carbon (δ2H and δ13C values), we found that 48% (16/33) of monarchs collected in south Florida are migrants that originated from outside the sampling region. Migrants had a larger wing length than residents; thus, switching to a resident strategy could alter their probability of reproductive success. Further work is needed to investigate the mechanism underlying this pattern, but these findings show that alternate life history strategies and sex-specific behaviors are underexplored factors influencing monarch migration and evolution.

Zika virus (ZIKV) is a mosquito-transmitted flavivirus, linked to microcephaly and fetal death in humans. Here, we investigate whether host-mediated RNA editing of adenosines (ADAR) plays a role in the molecular evolution of ZIKV. Using complete coding sequences for the ZIKV polyprotein, we show that potential ADAR substitutions are underrepresented at the ADAR-resistant GA dinucleotides of both the positive and negative strands, that these changes are spatially and temporally clustered (as expected of ADAR editing) for three branches of the viral phylogeny, and that ADAR mutagenesis can be linked to its codon usage. Furthermore, resistant GA dinucleotides are enriched on the positive (but not negative) strand, indicating that the former is under stronger purifying selection than the latter. ADAR editing also affects the evolution of the rhabdovirus sigma. Our study now documents that host ADAR editing is a mutation and evolutionary force of positive- as well as negative-strand RNA viruses.

Parasites are known to profoundly affect resource allocation in their host. In order to investigate the effects of Cryphonectria Hypovirus 1 (CHV1) on the life-history traits of its fungal host Cryphonectria parasitica, an infection matrix was completed with the cross-infection of six fungal isolates by six different viruses. Mycelial growth, asexual sporulation, and spore size were measured in the 36 combinations, for which horizontal and vertical transmission of the viruses was also assessed. As expected by life-history theory, a significant negative correlation was found between host somatic growth and asexual reproduction in virus-free isolates. Interestingly this trade-off was found to be positive in infected isolates, illustrating the profound changes in host resource allocation induced by CHV1 infection. A significant and positive relationship was also found in infected isolates between vertical transmission and somatic growth. This last relationship suggests that in this system, high levels of virulence could be detrimental to the vertical transmission of the parasite. Those results underscore the interest of studying host-parasite interaction within the life-history theory framework, which might permit a more accurate understanding of the nature of the modifications triggered by parasite infection on host biology.

The immune response of Drosophila melanogaster is complex and involves both specific and general responses to parasites. In this study we tested for cross-immunity for bacteria and viruses by scoring the incidence of infection with the vertically transmitted Sigma virus (DMelSV) in the progeny of a cross between females transmitting DMelSV at high frequencies and males from lines subjected to three selection regimes related to resistance to Bacillus cereus . There was no significant difference in transmission of DMelSV among selection regimes, though results suggest that the B. cereus selected lines had lower rates of infection by DMelSV. We found a significant difference in viral infection with respect to the sex of the progeny, with males consistently less likely to be infected than females. Given a finite energy budget, flies that have experienced immune system challenge may show alterations in other life history traits. Later eclosing progeny were also less likely to be infected than earlier eclosing progeny, indicating a relationship with development time. Finally, there was a significant interaction between the timing of collection and the sex of the progeny, such that later eclosing males were the most resistant group. Increased development time is sometimes associated with increased energy acquisition; from this perspective, increased development time may be associated with acquiring sufficient resources for effective resistance.