Vomeronasal organ volume increases with body size and is dissociated with the loss of a visual signal in Sceloporus lizards.

Many organisms communicate using signals in different sensory modalities (multicomponent or multimodal). When one signal or component is lost over evolutionary time, it may be indicative of changes in other characteristics of the signalling system, including the sensory organs used to perceive and process signals. Sceloporus lizards predominantly use chemical and visual signals to communicate, yet some species have lost the ancestral ventral colour patch used in male-male agonistic interactions and exhibit increased chemosensory behaviour. Here, we asked whether evolutionary loss of this sexual signal is associated with larger vomeronasal organ (VNO) volumes (an organ that detects chemical scents) compared with species that have retained the colour patch. We measured VNO coronal section areas of 7-8 adult males from each of 11 Sceloporus species (4 that lost and 7 that retained the colour patch), estimated sensory and total epithelium volume, and compared volumes using phylogenetic analysis of covariance, controlling for body size. Contrary to expectations, we found that species retaining the ventral patch had similar relative VNO volumes as did species that had lost the ancestral patch, and that body size explains VNO epithelium volume. Visual signal loss may be sufficiently compensated for by increased chemosensory behaviour, and the allometric pattern may indicate sensory system trade-offs for large-bodied species.

Technology Access and Perceptions of Telehealth Services Among Young Adults Involved in the Court System.

PURPOSE: This study examined access to technology and telehealth among young adults (ages 18-24) who were court-involved and were recruited from an alternative sentencing program in New York City. METHODS: Using sequential mixed methods design, we examined demographic factors linked with access to technology and perceived usefulness of the Internet among n = 321 young adults who were court-involved (75% male, 65% African American, 35% Latinx). We then conducted in-depth interviews with 27 young adults to elicit first-person account of their access to, interest in, and experience with technology and telehealth. RESULTS: Although most participants had access to a phone with a data plan, a substantial proportion reported inconsistent access to the technology critical to telehealth. Certain young adults were more likely to lack consistent access to the technology needed for telehealth, including Black young adults, males, those with less than a high school diploma, those with a history of homelessness, and those who had difficulties paying for basic necessities. Qualitative interviews revealed that most had a strong self-efficacy using technology, while distrust of technology, inexperience with and skepticism of telehealth, low perceived need for care, and medical mistrust were common significant barriers in this underserved population. DISCUSSION: Findings underscored the critical need to address medical mistrust and increase access to and utilization of care among young adults who are court-involved. Results can inform the development and implementation of interventions designed to improve accessibility and acceptability of telehealth.

Overdose education and naloxone distribution program design informed by people who use drugs and naloxone distributors.

People who use drugs (PWUD) are the most directly affected by the overdose epidemic. However, they are not often targets of overdose education and naloxone distribution (OEND) programs. Instead, these programs target friends or family members of people prescribed opioids or general community members. This study aimed to understand the perspectives of PWUD and community naloxone distributors on OEND program design. We used a community-based participatory research model to elucidate participant perspectives on what OEND programs should look like in the context of each individual's specific risk environment. We conducted semi-structured in-depth interviews with PWUD and naloxone distributors (n = 30) in New Brunswick and Newark, New Jersey between February and November of 2022. We analyzed interviews using thematic analysis and identified the following themes: increasing naloxone knowledge, peer-based naloxone access, increasing PWUD-informed OEND program design, and desired broader OEND program scope. All Participants knew what naloxone was and emphasized that naloxone needed to be ubiquitous in the community. Participants prioritized peer-based distribution, integrating distribution into community organizations, and addressing psychosocial issues related to naloxone administration and drug use. In summary, PWUD and community naloxone distributors emphasized peer-led community naloxone distribution that prioritized novel ways for PWUD to access naloxone. OEND program design should prioritize PWUD's perspectives and direct community naloxone distribution.

Understanding why racial/ethnic inequities along the HIV care continuum persist in the United States: a qualitative exploration of systemic barriers from the perspectives of African American/Black and Latino persons living with HIV.

BACKGROUND: Racial/ethnic inequities along the HIV care continuum persist in the United States despite substantial federal investment. Numerous studies highlight individual and social-level impediments in HIV, but fewer foreground systemic barriers. The present qualitative study sought to uncover and describe systemic barriers to the HIV care continuum from the perspectives of African American/Black and Latino persons living with HIV (PLWH) with unsuppressed HIV viral load, including how barriers operated and their effects. METHODS: Participants were African American/Black and Latino PLWH with unsuppressed HIV viral load (N = 41). They were purposively sampled for maximum variability on key indices from a larger study. They engaged in semi-structured in-depth interviews that were audio-recorded and professionally transcribed. Data were analyzed using directed content analysis. RESULTS: Participants were 49 years old, on average (SD = 9), 76% were assigned male sex at birth, 83% were African American/Black and 17% Latino, 34% were sexual minorities (i.e., non-heterosexual), and 22% were transgender/gender-nonbinary. All had indications of chronic poverty. Participants had been diagnosed with HIV 19 years prior to the study, on average (SD = 9). The majority (76%) had taken HIV medication in the six weeks before enrollment, but at levels insufficient to reach HIV viral suppression. Findings underscored a primary theme describing chronic poverty as a fundamental cause of poor engagement. Related subthemes were: negative aspects of congregate versus private housing settings (e.g., triggering substance use and social isolation); generally positive experiences with health care providers, although structural and cultural competency appeared insufficient and managing health care systems was difficult; pharmacies illegally purchased HIV medication from PLWH; and COVID-19 exacerbated barriers. Participants described mitigation strategies and evidenced resilience. CONCLUSIONS: To reduce racial/ethnic inequities and end the HIV epidemic, it is necessary to understand African American/Black and Latino PLWH's perspectives on the systemic impediments they experience throughout the HIV care continuum. This study uncovers and describes a number of salient barriers and how they operate, including unexpected findings regarding drug diversion and negative aspects of congregate housing. There is growing awareness that systemic racism is a core determinant of systemic barriers to HIV care continuum engagement. Findings are interpreted in this context.

A virtual pilot optimization trial for African American/Black and Latino persons with non-suppressed HIV viral load grounded in motivational interviewing and behavioral economics.

Introduction: Virtual and low-touch behavioral interventions are needed for African American/Black and Latino persons living with HIV (PLWH) with barriers to HIV viral suppression, particularly during COVID-19. Guided by the multiphase optimization strategy, we explored three components for PLWH without viral suppression, grounded in motivational interviewing and behavioral economics: (1) motivational interviewing counseling, (2) 21-weeks of automated text messages and quiz questions about HIV management, and (3) financial rewards for viral suppression (lottery prize vs. fixed compensation). Methods: This pilot optimization trial used sequential explanatory mixed methods to explore the components' feasibility, acceptability, and preliminary evidence of effects using an efficient factorial design. The primary outcome was viral suppression. Participants engaged in baseline and two structured follow-up assessments over an 8-month period, and provided laboratory reports to document HIV viral load. A subset engaged in qualitative interviews. We carried out descriptive quantitative analyses. Then, qualitative data were analyzed using directed content analysis. Data integration used the joint display method. Results: Participants (N = 80) were 49 years old, on average (SD = 9), and 75% were assigned male sex at birth. Most (79%) were African American/Black, and the remainder were Latino. Participants were diagnosed with HIV 20 years previously on average (SD = 9). Overall, components were feasible (>80% attended) and acceptability was satisfactory. A total of 39% (26/66) who provided laboratory reports at follow-up evidenced viral suppression. Findings suggested no components were entirely unsuccessful. The lottery prize compared to fixed compensation was the most promising component level. In qualitative analyses, all components were seen as beneficial to individual wellbeing. The lottery prize appeared more interesting and engaging than fixed compensation. However, structural barriers including financial hardship interfered with abilities to reach viral suppression. The integrated analyses yielded areas of convergence and discrepancy and qualitative findings added depth and context to the quantitative results. Conclusions: The virtual and/or low-touch behavioral intervention components tested are acceptable and feasible and show enough potential to warrant refinement and testing in future research, particularly the lottery prize. Results must be interpreted in the context of the COVID-19 pandemic. Trial registration: NCT04518241 (https://clinicaltrials.gov/ct2/show/NCT04518241).

Patterns and contexts of polysubstance use among young and older adults who are involved in the criminal legal system and use opioids: A mixed methods study.

INTRODUCTION: Opioid prevention and treatment programs tailored to young adults involved in the criminal legal system are rare. We examined profiles of polysubstance use among younger and older adults involved in the criminal legal system who use opioids, and explored their experiences and motivations related to substance use. Information gleaned can inform the adaptation of existing programs and the development of novel approaches for young adults in the criminal legal system. METHODS: Using a sequential mixed methods design we 1) quantitatively identified typologies of polysubstance users among adults aged 18-24 (n = 92) and those age 25 and over (n = 27) involved in the criminal legal system who use opioids, using latent class analysis and 2) qualitatively explored differences in personal motivations, cultural influences, and psychosocial contexts of substance use by class. RESULTS: Our quantitative results supported a three-class typology: the majority of participants were in Class I (73 %, n = 87) and reported using primarily alcohol and marijuana. Participants in Classes II (15 %, n = 18) and III (12 %, n = 14) endorsed distinct and complicated polysubstance use profiles. Further, participants in Classes I and III were significantly younger than those in Class II. Qualitative analysis allowed us to understand associations between patterns of use, motivations, and contexts among young and older adults, comparing across classes. CONCLUSIONS: Our results highlight the importance of attending to the needs of subpopulations based on age and use patterns to adapt and develop targeted treatment and prevention programs for high-risk adults involved in the criminal legal system.

Readiness to change among justice-involved young adults in an alternative sentencing program who screened positive for alcohol or drug risk.

Introduction: Readiness to change is a key component of substance use behavioral change; yet little is known about readiness to change among justice-involved young adults. This study 1) describes readiness to change alcohol and drug use and 2) examines predictors of readiness to change alcohol and drug use among justice-involved young adults. Method: Justice-involved young adults (18-24 years; n = 137) who were positive on a validated alcohol and/or drug screening tool completed an interview assessing substance use, readiness to change, and reasons to quit. A multivariable linear regression model examined whether reasons to change and substance use severity, and interactions between these, predicted readiness. Results: More than half of participants were contemplating or had decided to quit/cut down substance use. Personal reasons to quit were positively related to readiness to change; interpersonal reasons were negatively associated. Conclusions: This study contributes information needed to design motivational interventions for substance use among justice-involved young adults. Personal reasons to quit using drugs are a potential intervention target.

Signaler's Vasotocin Alters the Relationship between the Responder's Forebrain Catecholamines and Communication Behavior in Lizards (Anolis carolinensis).

Dynamic fluctuations in the distribution of catecholamines across the brain modulate the responsiveness of vertebrates to social stimuli. Previous work demonstrates that green anoles (Anolis carolinensis) increase chemosensory behavior in response to males treated with exogenous arginine vasotocin (AVT), but the neurochemical mechanisms underlying this behavioral shift remains unclear. Since central catecholamine systems, including dopamine, rapidly activate in response to social stimuli, we tested whether exogenous AVT in signalers (stimulus animals) impacts catecholamine concentrations in the forebrain (where olfactory and visual information are integrated and processed) of untreated lizard responders. We also tested whether AVT influences the relationship between forebrain catecholamine concentrations and communication behavior in untreated receivers. We measured global catecholamine (dopamine = DA, epinephrine = Epi, and norepinephrine = NE) concentrations in the forebrain of untreated responders using high-performance liquid chromatography-mass spectrometry following either a 30-min social interaction with a stimulus male or a period of social isolation. Stimulus males were injected with exogenous AVT or vehicle saline (SAL). We found that global DA, but not Epi or NE, concentrations were elevated in lizards responding to SAL-males relative to isolated lizards. Lizards interacting with AVT-males had DA, Epi and NE concentrations that were not significantly different from SAL or isolated groups. For behavior, we found a significant effect of social treatment (AVT vs. SAL) on the relationships between (1) DA concentrations and the motivation to perform a chemical display (latency to tongue flick) and (2) Epi concentrations and time spent displaying mostly green body coloration. We also found a significant negative correlation between DA concentrations and the latency to perform a visual display but found no effect of social treatment on this relationship. These data suggest that catecholamine concentrations in the forebrain of untreated responders are associated with chemical and visual communication in lizards and that signaler AVT alters this relationship for some, but not all, aspects of social communication.

Information out of the blue: phenotypic correlates of abdominal color patches in Sceloporus lizards.

Colorful ornaments are important visual signals for animal communication that can provide critical information about the quality of the signaler. In this study, we focused on different color characteristics of the abdominal patches of males of six lizard species from the genus Sceloporus. We addressed three main objectives. First, we examined if size, brightness, saturation, and conspicuousness of these ornaments are indicative of body size, condition, immune function, or levels of testosterone and corticosterone. Second, we evaluated if the distinct components of these abdominal patches (blue or green patches and black stripes) transmit similar information about the signaler, which would support the redundant signal hypothesis, or if these components are related to different phenotypic traits, which would support the multiple message hypothesis. Third, we compared the phenotypic correlates of these ornaments among our six species to understand the degree of conservatism in the signaling patterns or to find species-specific signals. Using data collected from males in natural conditions and a multi-model inference framework, we found that in most species the area of the patches and the brightness of the blue component are positively related to body size. Thus, these color characteristics are presumably indicative of the physical strength and competitive ability of males and these shared signals were likely inherited from a common ancestor. In half of the species, males in good body condition also exhibit relatively larger blue and black areas, suggesting that the expression of these ornaments is condition-dependent. Abdominal patches also provide information about immunocompetence of the males as indicated by different correlations between certain color characteristics and ectoparasite load, counts of heterophils, and the heterophil:lymphocyte ratio. Our findings reveal that area and brightness of the abdominal patches signal the size and body condition of males, whereas blue saturation and conspicuousness with respect to the surrounding substrate are indicative of immune condition, thus supporting the multiple message hypothesis. However, some of these correlations were not shared by all species and, hence, point to intriguing species-specific signals.

Brain transcriptomic responses of Yarrow's spiny lizard, Sceloporus jarrovii, to conspecific visual or chemical signals.

Species with multimodal communication integrate information from social cues in different modalities into behavioral responses that are mediated by changes in gene expression in the brain. Differences in patterns of gene expression between signal modalities may shed light on the neuromolecular mechanisms underlying multisensory processing. Here, we use RNA-Seq to analyze brain transcriptome responses to either chemical or visual social signals in a territorial lizard with multimodal communication. Using an intruder challenge paradigm, we exposed 18 wild-caught, adult, male Sceloporus jarrovii to either male conspecific scents (femoral gland secretions placed on a small pebble), the species-specific push-up display (a programmed robotic model), or a control (an unscented pebble). We conducted differential expression analysis with both a de novo S. jarrovii transcriptome assembly and the reference genome of a closely related species, Sceloporus undulatus. Despite some inter-individual variation, we found significant differences in gene expression in the brain across signal modalities and the control in both analyses. The most notable differences occurred between chemical and visual stimulus treatments, closely followed by visual stimulus versus the control. Altered expression profiles could explain documented aggression differences in the immediate behavioral response to conspecific signals from different sensory modalities. Shared differentially expressed genes between visually- or chemically-stimulated males are involved in neural activity and neurodevelopment and several other differentially expressed genes in stimulus-challenged males are involved in conserved signal-transduction pathways associated with the social stress response, aggression and the response to territory intruders across vertebrates.

Chemical Communication in Lizards and a Potential Role for Vasotocin in Modulating Social Interactions.

Lizards use chemical communication to mediate many reproductive, competitive, and social behaviors, but the neuroendocrine mechanisms underlying chemical communication in lizards are not well understood and understudied. By implementing a neuroendocrine approach to the study of chemical communication in reptiles, we can address a major gap in our knowledge of the evolutionary mechanisms shaping chemical communication in vertebrates. The neuropeptide arginine vasotocin (AVT) and its mammalian homolog vasopressin are responsible for a broad spectrum of diversity in competitive and reproductive strategies in many vertebrates, mediating social behavior through the chemosensory modality. In this review, we posit that, though limited, the available data on AVT-mediated chemical communication in lizards reveal intriguing patterns that suggest AVT plays a more prominent role in lizard chemosensory behavior than previously appreciated. We argue that these results warrant more research into the mechanisms used by AVT to modify the performance of chemosensory behavior and responses to conspecific chemical signals. We first provide a broad overview of the known social functions of chemical signals in lizards, the glandular sources of chemical signal production in lizards (e.g., epidermal secretory glands), and the chemosensory detection methods and mechanisms used by lizards. Then, we review the locations of vasotocinergic populations and neuronal projections in lizard brains, as well as sites of peripheral receptors for AVT in lizards. Finally, we end with a case study in green anoles (Anolis carolinensis), discussing findings from recently published work on the impact of AVT in adult males on chemosensory communication during social interactions, adding new data from a similar study in which we tested the impact of AVT on chemosensory behavior of adult females. We offer concluding remarks on addressing several fundamental questions regarding the role of AVT in chemosensory communication and social behavior in lizards.

Evolutionary loss of a signalling colour is linked to increased response to conspecific chemicals.

Behavioural responses to communicative signals combine input from multiple sensory modalities and signal compensation theory predicts that evolutionary shifts in one sensory modality could impact the response to signals in other sensory modalities. Here, we conducted two types of field experiments with 11 species spread across the lizard genus Sceloporus to test the hypothesis that the loss of visual signal elements affects behavioural responses to a chemical signal (conspecific scents) or to a predominantly visual signal (a conspecific lizard), both of which are used in intraspecific communication. We found that three species that have independently lost a visual signal trait, a colourful belly patch, responded to conspecific scents with increased chemosensory behaviour compared to a chemical control, while species with the belly patch did not. However, most species, with and without the belly patch, responded to live conspecifics with increased visual displays of similar magnitude. While aggressive responses to visual stimuli are taxonomically widespread in Sceloporus, our results suggest that increased chemosensory response behaviour is linked to colour patch loss. Thus, interactions across sensory modalities could constrain the evolution of complex signalling phenotypes, thereby influencing signal diversity.

Black and Latino Persons Living with HIV Evidence Risk and Resilience in the Context of COVID-19: A Mixed-Methods Study of the Early Phase of the Pandemic.

The COVID-19 pandemic has great potential to disrupt the lives of persons living with HIV (PLWH). The present convergent parallel design mixed-methods study explored the early effects of COVID-19 on African American/Black or Latino (AABL) long-term survivors of HIV in a pandemic epicenter, New York City. A total of 96 AABL PLWH were recruited from a larger study of PLWH with non-suppressed HIV viral load. They engaged in structured assessments focused on knowledge, testing, trust in information sources, and potential emotional, social, and behavioral impacts. Twenty-six of these participants were randomly selected for in-depth semi-structured interviews. Participants were mostly men (64%), African American/Black (75%), and had lived with HIV for 17 years, on average (SD=9 years). Quantitative results revealed high levels of concern about and the adoption of recommended COVID-19 prevention recommendations. HIV care visits were commonly canceled but, overall, engagement in HIV care and antiretroviral therapy use were not seriously disrupted. Trust in local sources of information was higher than trust in various federal sources. Qualitative findings complemented and enriched quantitative results and provided a multifaceted description of both risk factors (e.g., phones/internet access were inadequate for some forms of telehealth) and resilience (e.g., "hustling" for food supplies). Participants drew a direct line between structural racism and the disproportional adverse effects of COVID-19 on communities of color, and their knowledge gleaned from the HIV pandemic was applied to COVID-19. Implications for future crisis preparedness are provided, including how the National HIV/AIDS Strategy can serve as a model to prevent COVID-19 from becoming another pandemic of the poor.

Volatile fatty acid and aldehyde abundances evolve with behavior and habitat temperature in Sceloporus lizards.

Animal signals evolve by striking a balance between the need to convey information through particular habitats and the limitations of what types of signals can most easily be produced and perceived. Here, we present new results from field measures of undisturbed behavior and biochemical analyses of scent marks from 12 species of Sceloporus lizards to explore whether evolutionary changes in chemical composition are better predicted by measures of species behavior, particularly those associated with visual displays, chemoreception, and locomotion, or by measures of habitat climate (precipitation and temperature). We found that more active lizard species used fewer compounds in their volatile scent marks, perhaps conveying less specific information about individual and species identity. Scent marks from more active lizard species also had higher proportions of saturated fatty acids, and the evolution of these compounds has been tracking the phylogeny closely as we would expect for a metabolic byproduct. In contrast, the proportions of unsaturated fatty acids were better explained by evolutionary shifts in habitat temperature (and not precipitation), with species in warmer climates using almost no volatile unsaturated fatty acids. The proportion of aldehydes was explained by both behavior and environment, decreasing with behavioral activity and increasing with habitat temperature. Our results highlight the evolutionary flexibility of complex chemical signals, with different chemical compounds responding to different elements of the selective landscape over evolutionary time.

Arginine vasotocin impacts chemosensory behavior during social interactions of Anolis carolinensis lizards.

In reptiles, arginine vasotocin (AVT) impacts the performance of and response to visual social signals, but whether AVT also operates within the chemosensory system as arginine vasopressin (AVP) does in mammals is unknown, despite social odors being potent modifiers of competitive and appetitive behavior in reptiles. Here, we ask whether elevated levels of exogenous AVT impact rates of chemical display behavior (e.g. tongue flicks) in adult males, and whether conspecific males or females can chemically discriminate between competitor males based on differing levels of exogenous AVT in green anoles (Anolis carolinensis). We injected wild-caught green anole males with either AVT (AVT-Males) or a vehicle control (CON-Males) solution, then presented treated males with a conspecific stimulus (Intruder-Male or Intruder-Female) and filmed 30-minute interactions. We found that AVT-Males were faster than CON-Males to perform a tongue flick to conspecifics, and faster to chemically display toward Intruder-Females, suggesting AVT increased male interest in available chemical information during social encounters. Intruders performed more lip smack behavior when interacting with AVT-Males than with CON-Males, and Intruder-Males performed more tongue flick behavior when interacting with AVT-Males than with CON-Males, suggesting anoles can discriminate between conspecifics based on exogenous AVT levels. We also found a reduction in Intruder movement behavior when Intruders were paired with AVT-Males. This study provides empirical support for AVT-mediated chemosensory behavior in reptilian social interactions, in a microsmatic lizard species, suggesting the mechanism by which mammalian AVP and non-mammalian AVT mediate chemosensory behavior during social interactions may be evolutionarily conserved.

Structural Identification, Synthesis and Biological Activity of Two Volatile Cyclic Dipeptides in a Terrestrial Vertebrate.

Single substances within complex vertebrate chemical signals could be physiologically or behaviourally active. However, the vast diversity in chemical structure, physical properties and molecular size of semiochemicals makes identifying pheromonally active compounds no easy task. Here, we identified two volatile cyclic dipeptides, cyclo(L-Leu-L-Pro) and cyclo(L-Pro-L-Pro), from the complex mixture of a chemical signal in terrestrial vertebrates (lizard genus Sceloporus), synthesised one of them and investigated their biological activity in male intra-specific communication. In a series of behavioural trials, lizards performed more chemosensory behaviour (tongue flicks, lip smacks and substrate lickings) when presented with the synthesised cyclo(L-Pro-L-Pro) chemical blend, compared to the controls, the cyclo(L-Leu-L-Pro) blend, or a combined blend with both cyclic dipeptides. The results suggest a potential semiochemical role of cyclo(L-Pro-L-Pro) and a modulating effect of cyclo(L-Leu-L-Pro) that may depend on the relative concentration of both compounds in the chemical signal. In addition, our results stress how minor compounds in complex mixtures can produce a meaningful behavioural response, how small differences in structural design are crucial for biological activity, and highlight the need for more studies to determine the complete functional landscape of biologically relevant compounds.

Polysubstance use patterns and novel synthetics: A cluster analysis from three U.S. cities.

The rapid emergence of novel psychoactive substances within the past decade has raised new concerns about the harms associated with unregulated drug use. Synthetic analogues-chemically related to established psychoactive substances like cannabis sativa and catha edulis-in particular have proliferated rapidly, allowing little opportunity for scientific research or the establishment of informal guidelines for safe use among consumers. To explore how synthetic substance use relates to other forms of use, this paper presents an analysis of polysubstance use among a sample of 676 people who use illicit substances in the United States. Participants were sampled from three greater metropolitan areas (Houston/Galveston, Texas; New York City; and New Orleans, Louisiana). Study researchers used cluster-type analyses to develop dendrogram visualizations of the interrelationships between substance types. Results suggest a considerable variation in substance and polysubstance use patterns across states in the U.S. Polysubstance use clustered around well-observed combinations like MDMA/cannabis and cocaine/heroin. Synthetic cannabinoids and cathinones showed no strong clustering with other substances. High rates of binge drinking among users of other substances further support the importance of interventions sensitive to the clinical challenges of polysubstance use.

Zika infection decreases Aedes aegypti locomotor activity but does not influence egg production or viability.

BACKGROUND: Zika has emerged as a new public health threat after the explosive epidemic in Brazil in 2015. It is an arbovirus transmitted mainly by Aedes aegypti mosquitoes. The knowledge of physiological, behavioural and biological features in virus-infected vectors may help the understanding of arbovirus transmission dynamics and elucidate their influence in vector capacity. OBJECTIVES: We aimed to investigate the effects of Zika virus (ZIKV) infection in the behaviour of Ae. aegypti females by analysing the locomotor activity, egg production and viability. METHODOLOGY: Ae. aegypti females were orally infected with ZIKV through an artificial feeder to access egg production, egg viability and locomotor activity. For egg production and viability assays, females were kept in cages containing an artificial site for oviposition and eggs were counted. Locomotor activity assays were performed in activity monitors and an average of 5th, 6th and 7th days after infective feeding was calculated. FINDINGS: No significant difference in the number of eggs laid per females neither in their viability were found between ZIKV infected and non-infected females, regardless the tested pair of mosquito population and virus strain and the gonotrophic cycles. Locomotor activity assays were performed regardless of the locomotor activity in ZIKV infected females was observed, in both LD and DD conditions. MAIN CONCLUSIONS: The lower locomotor activity may reduce the mobility of the mosquitoes and may explain case clustering within households reported during Zika outbreaks such as in Rio de Janeiro 2015. Nevertheless, the mosquitoes infected with ZIKV are still able to disseminate and to transmit the disease, especially in places where there are many oviposition sites.

The signaling lipid sphingosine 1-phosphate regulates mechanical pain.

Somatosensory neurons mediate responses to diverse mechanical stimuli, from innocuous touch to noxious pain. While recent studies have identified distinct populations of A mechanonociceptors (AMs) that are required for mechanical pain, the molecular underpinnings of mechanonociception remain unknown. Here, we show that the bioactive lipid sphingosine 1-phosphate (S1P) and S1P Receptor 3 (S1PR3) are critical regulators of acute mechanonociception. Genetic or pharmacological ablation of S1PR3, or blockade of S1P production, significantly impaired the behavioral response to noxious mechanical stimuli, with no effect on responses to innocuous touch or thermal stimuli. These effects are mediated by fast-conducting A mechanonociceptors, which displayed a significant decrease in mechanosensitivity in S1PR3 mutant mice. We show that S1PR3 signaling tunes mechanonociceptor excitability via modulation of KCNQ2/3 channels. Our findings define a new role for S1PR3 in regulating neuronal excitability and establish the importance of S1P/S1PR3 signaling in the setting of mechanical pain thresholds.