Sleep Continuity, Sleep Related Daytime Dysfunction, and Problem Endorsement: Do These Vary Concordantly by Age?

OBJECTIVES: Sleep continuity (i.e., ability to initiate and/or maintain sleep) worsens with age. It is unclear whether problem endorsement and/or daytime dysfunction show similar age-related trends. Accordingly, a large archival dataset was used to examine age differences in sleep continuity, problem endorsement, and sleep related daytime dysfunction. METHOD: Participants were categorized as: Young Adults (18-29 years); Adults (30-44 years); Middle Aged Adults (45-64 years); and Older Adults (65-89 years). Young Adults, Adults, and Middle Aged Adults were 1:1 matched with Older Adults (n = 233) on the basis of gender, race, ethnicity, and BMI. MANOVA, ANOVAs, and chi-square analysis were performed to assess for age-related differences. RESULTS: In a sample of 932 adults with self-reported sleep continuity disturbance (i.e., insomnia), sleep continuity was significantly worse in older age groups. This effect was limited to middle and late insomnia with middle aged and older adults waking up with greater frequency and for longer durations of time during the night and in the early morning than younger cohorts. Problem endorsement largely increased across age groups (except for sleep latency) but reports of overall sleep-related daytime dysfunction showed no difference by age. CONCLUSION: When evaluating sleep continuity disturbance, assessing whether the patient identifies their sleep continuity disturbance as a problem and whether it affects their daytime function can be informative, particularly in older adults. It may serve to reveal (case-by-case) when there are discordances between incidence/severity of illness and problem endorsement/daytime dysfunction. Such information may better inform if treatment should be initiated.

Insomnia Severity and Degree of Dysfunction: What Is to Be Learned When These Domains are Discordant?

OBJECTIVE/BACKGROUND: Illness severity and resultant dysfunction are often linearly related and tightly coupled (concordant). Some percentage of individuals, however, exhibit discordant associations (high illness severity and low dysfunction [HL] or low illness severity and high dysfunction [LH]). In the present study, a sample of subjects with insomnia complaints were evaluated to determine what percentage of subjects exhibited discordant associations. PARTICIPANTS: Archival data were drawn from a community-based sample (n = 4,680; 61.8% female; Ages 18-105). METHODS: Median splits were calculated for illness severity and daytime dysfunction and each individual was typed as High (H) or Low (L) for the concordant (HH and LL) and discordant domains (HL and LH). RESULTS: Given this typology, 61% were classified as concordant and 39% were classified as discordant. Of these, 38% were sub-typed as HH, 23% as LL, 26% as LH, and 13% as HL. CONCLUSIONS: We propose that some of the discordance may be ascribable to a mismatch between sleep need and sleep ability. Those "who need a lot, may suffer a lot, in the face of only a little (LH)", whereas those "who need a little, may suffer only a little, in the face of a lot (HL)".

A toolbox of immunoprecipitation-grade monoclonal antibodies to human transcription factors.

A key component of efforts to address the reproducibility crisis in biomedical research is the development of rigorously validated and renewable protein-affinity reagents. As part of the US National Institutes of Health (NIH) Protein Capture Reagents Program (PCRP), we have generated a collection of 1,406 highly validated immunoprecipitation- and/or immunoblotting-grade mouse monoclonal antibodies (mAbs) to 737 human transcription factors, using an integrated production and validation pipeline. We used HuProt human protein microarrays as a primary validation tool to identify mAbs with high specificity for their cognate targets. We further validated PCRP mAbs by means of multiple experimental applications, including immunoprecipitation, immunoblotting, chromatin immunoprecipitation followed by sequencing (ChIP-seq), and immunohistochemistry. We also conducted a meta-analysis that identified critical variables that contribute to the generation of high-quality mAbs. All validation data, protocols, and links to PCRP mAb suppliers are available at http://proteincapture.org.

The natural history of insomnia: Does sleep extension differentiate between those that do and do not develop chronic insomnia?

According to the "3P model" of insomnia, the variable that mediates the transition from acute insomnia (AI) to chronic insomnia is "sleep extension" (the behavioural tendency to expand sleep opportunity to compensate for sleep loss). In the present analysis, we sought to evaluate how time in bed (TIB) varies relative to the new onset of AI and chronic insomnia. A total of 1,248 subjects were recruited as good sleepers (GS). Subjects were monitored over 1 year with sleep diaries. State transitions were defined, a priori, for AI, recovered from AI (AI-REC), and for chronic insomnia (AI-CI). Two additional groupings were added based on profiles that were unanticipated: subjects that exhibited persistent poor sleep following AI (AI-PPS [those that neither recovered or developed chronic insomnia]) and subjects that recovered from chronic insomnia (CI-REC). All the groups (GS, AI-REC, AI-CI, AI-PPS and CI-REC) were evaluated for TIB differences with longitudinal mixed effects models. Post hoc analyses for the percentage of the groups that were typed as TIB "restrictors, maintainers, and expanders" were conducted using longitudinal mixed effects models and contingency analyses. Significant differences for pre-post AI TIB were not detected for the insomnia groups. Trends were apparent for the AI-CI group, which suggested that minor increases in TIB occurred weeks before the declared onset of AI. Additionally, it was found that a significantly larger percentage of AI-CI subjects engaged in sleep extension (as compared to GS). The present data suggest that transition from AI to chronic insomnia does not appear to be initiated by sleep extension and the transition may occur before the elapse of 3 months of ≥3 nights of sleep continuity disturbance. Given these findings, it may be that the mismatch between sleep ability and sleep opportunity is perpetuated over time given the failure to "naturally" engage in sleep restriction (as opposed to sleep extension).

Early life stress sensitizes youth to the influence of stress-induced cortisol on memory for affective words.

Early life stress (ELS) is a well-established risk factor for psychopathology across the lifespan. Cognitive vulnerability to stress-induced cortisol may explain risk and resilience. The current study aimed to elucidate a psychobiological pathway linking stress to altered memory for affective words among youth with and without exposure to ELS. One hundred and fifteen youth (ages 9-16, 47% female) were randomized either to a psychosocial stressor or a control condition. Immediately following the stress or control condition, participants completed a memory task for affective words. Change in salivary cortisol from immediately before to 25 min after stress onset were used to predict memory for affective words. Exposure to the acute laboratory stressor led to activation of the HPA axis. Greater cortisol reactivity was associated with less accurate recognition of negative valence words. Among youth exposed to ELS, greater cortisol reactivity to acute stress was associated with poorer recognition of dysphoric and neutral words. Acute increases in cortisol may interfere with negatively-valenced information processing that has implications for memory. Youth exposed to high ELS may be particularly vulnerable to the effects of cortisol, which may explain one pathway through which stress leads to psychopathology among at-risk youth.

Insomnia Symptoms and Suicide-Related Ideation in U.S. Army Service Members.

Background: Insomnia has been identified as a key risk factor for suicide, though most studies have been limited to global measures of these constructs. The aim of the present study was to evaluate the link between insomnia symptoms and five different aspects of suicide-related ideation. Participants: 1,160 active U.S. Army service members (719 male; Mage = 31.2; SDage = 8.62). Methods: As part of an archival analysis, retrospectively assessed insomnia, depression, anxiety symptoms, as well as suicide-related ideation, were evaluated. Suicide-related ideation was assessed in terms of: thoughts of death, thoughts of suicide, suicidal plan, suicidal intent, and suicidal communication. Results: Subjects with clinically significant insomnia symptoms were 3.5 times more likely to report any suicide-related ideation, and approximately 3 times more likely to report thoughts of death and thoughts of suicide. More frequent nocturnal awakenings (i.e., waking up three or more times during a single night) were associated with a greater likelihood of reporting thoughts of death or suicide, whereas greater middle insomnia (i.e., waking up and having difficulty getting back to sleep) was associated with lower odds of experiencing thoughts of suicide, suicidal plan, and suicidal intent. Conclusions: A more refined delineation of insomnia and suicide-related ideation may serve to clarify the nature of the association, and potentially offer some clues as to the underlying mechanisms. With regard to potential clinical implications, the results support that careful assessment of insomnia symptoms, suicide-related ideation, and their respective subtypes, is important and may influence how we estimate risk for suicide.

Acute sleep deprivation and the selective consolidation of emotional memories.

Research suggests that sleep preferentially consolidates the negative aspects of memories at the expense of the neutral aspects. However, the mechanisms by which sleep facilitates this emotional memory trade-off remain unknown. Although active processes associated with sleep-dependent memory consolidation have been proposed to underlie this effect, this trade-off may also be modulated by non-sleep-related processes, such as the circadian factors, stress-related factors, and/or mood congruent context effects involved in sleep deprivation. We sought to examine the potential role of these factors by randomizing 39 young adults into either a total sleep deprivation condition (26 consecutive hours awake) or a sleep condition (8 h sleep opportunity). Replicating the emotional memory trade-off effect, negative objects were better remembered than neutral objects or background images. However, in spite of generally worse memory performance (for neutral and background information), sleep-deprived participants showed similar recognition rates for negative emotional memories relative to participants who were given a full night of sleep.

Spores of Beauveria bassiana and Trichoderma lignorum as a bioinsecticide for the control of Atta cephalotes.

BACKGROUND: The leafcutter ant (Atta cephalotes) is associated with losses in the agricultural sector, due to its defoliating activity; for its control, biological, mechanical and chemical methods have been developed, the latter associated with adverse effects on human and environmental health. This research validated in the field for the control of the leafcutter ant (A. cephalotes) using a mixture of Beauveria bassiana and Trichoderma lignorum spores. METHODS: The effectiveness from the combination of spores of B. bassiana and T. lignorum with an initial concentration of 2 × 109 spores/ml, in the following proportions of B. bassiana and T. lignorum, A (1:1), of each fungus. It was evaluated within the university campus, comparing it with two commercial formulations, Mycotrol (B. bassiana) and Mycobac (T. lignorum). Additionally, this formulation was evaluated in 49 nests distributed 16 in 14 locations in Colombia. The formulation application was carried out by direct application, using a pump at a speed of 10 ml/m2. The effectiveness was estimated from the reduction of the flow of ants, evaluating the statistically significant differences using the ANOVA and Tukey-test. RESULTS: Effective control of 90% of the nests was observed in the field phase in 60 days, except in nests with areas > 50 m2 that were located in regions with high rainfall (annual average precipitation above 7000 mm), such as Buenaventura. CONCLUSIONS: In this work, it was demonstrated that the combination of B. bassiana and T. lignorum spores represent a viable alternative for the control of the leafcutter ant, in which the effectiveness is related to several factors, including the size of the nest and the rainfall in the area.

A kidney-disease gene panel allows a comprehensive genetic diagnosis of cystic and glomerular inherited kidney diseases.

Molecular diagnosis of inherited kidney diseases remains a challenge due to their expanding phenotypic spectra as well as the constantly growing list of disease-causing genes. Here we develop a comprehensive approach for genetic diagnosis of inherited cystic and glomerular nephropathies. Targeted next generation sequencing of 140 genes causative of or associated with cystic or glomerular nephropathies was performed in 421 patients, a validation cohort of 116 patients with previously known mutations, and a diagnostic cohort of 207 patients with suspected inherited cystic disease and 98 patients with glomerular disease. In the validation cohort, a sensitivity of 99% was achieved. In the diagnostic cohort, causative mutations were found in 78% of patients with cystic disease and 62% of patients with glomerular disease, mostly familial cases, including copy number variants. Results depict the distribution of different cystic and glomerular inherited diseases showing the most likely diagnosis according to perinatal, pediatric and adult disease onset. Of all the genetically diagnosed patients, 15% were referred with an unspecified clinical diagnosis and in 2% genetic testing changed the clinical diagnosis. Therefore, in 17% of cases our genetic analysis was crucial to establish the correct diagnosis. Complex inheritance patterns in autosomal dominant polycystic kidney disease and Alport syndrome were suspected in seven and six patients, respectively. Thus, our kidney-disease gene panel is a comprehensive, noninvasive, and cost-effective tool for genetic diagnosis of cystic and glomerular inherited kidney diseases. This allows etiologic diagnosis in three-quarters of patients and is especially valuable in patients with unspecific or atypical phenotypes.

Contribution of the TTC21B gene to glomerular and cystic kidney diseases.

Background: The TTC21B gene was initially described as causative of nephronophthisis (NPHP). Recently, the homozygous TTC21B p.P209L mutation has been identified in families with focal segmental glomerulosclerosis (FSGS) and tubulointerstitial lesions. Heterozygous TTC21B variants have been proposed as genetic modifiers in ciliopathies. We aimed to study the causative and modifying role of the TTC21B gene in glomerular and cystic kidney diseases. Methods: Mutation analysis of the TTC21B gene was performed by massive parallel sequencing. We studied the causative role of the TTC21B gene in 17 patients with primary diagnosis of FSGS or NPHP and its modifying role in 184 patients with inherited glomerular or cystic kidney diseases. Results: Disease-causing TTC21B mutations were identified in three families presenting nephrotic proteinuria with FSGS and tubulointerstitial lesions in which some family members presented hypertension and myopia. Two families carried the homozygous p.P209L and the third was compound heterozygous for the p.P209L and a novel p.H426D mutation. Rare heterozygous TTC21B variants predicted to be pathogenic were found in five patients. These TTC21B variants were significantly more frequent in renal patients compared with controls (P = 0.0349). Two patients with a heterozygous deleterious TTC21B variant in addition to the disease-causing mutation presented a more severe phenotype than expected. Conclusions: Our results confirm the causal role of the homozygous p.P209L TTC21B mutation in two new families with FSGS and tubulointerstitial disease. We identified a novel TTC21B mutation demonstrating that p.P209L is not the unique causative mutation of this nephropathy. Thus, TTC21B mutation analysis should be considered for the genetic diagnosis of families with FSGS and tubulointerstitial lesions. Finally, we provide evidence that heterozygous deleterious TTC21B variants may act as genetic modifiers of the severity of glomerular and cystic kidney diseases.

HPA-axis stress reactivity in youth depression: evidence of impaired regulatory processes in depressed boys.

Given the link between youth depression and stress exposure, efforts to identify related biomarkers have involved examinations of stress regulation systems, including the hypothalamic-pituitary-adrenal (HPA) axis. Despite these vast efforts, the underlying mechanisms at play, as well as factors that may explain heterogeneity of past findings, are not well understood. In this study, we simultaneously examined separate components of the HPA-axis response (e.g. activation intensity, peak levels, recovery) to the Socially Evaluated Cold-Pressor Test in a targeted sample of 115 youth (age 9-16), recruited to overrepresent youth with elevated symptoms of depression. Among youth who displayed a cortisol response to the task, depression symptoms were associated with higher peak responses but not greater rate of activation or recovery in boys only. Among those who did not respond to the task, depression symptoms were associated with greater cortisol levels throughout the visit in boys and girls. Results suggest that depression symptoms are associated with a more prolonged activation of the axis and impaired recovery to psychosocial stressors primarily in boys. We discussed two potential mechanistic explanations of the link between depression symptoms and the duration of activation: (1) inhibitory shift (i.e. point at which the ratio of inhibitory and excitatory input into the axis shifts from greater excitatory to greater inhibitory input) or (2) inhibitory threshold (i.e. level of cortisol exposure required to activate the axis' feedback inhibition system).

Age of Trauma Onset and HPA Axis Dysregulation Among Trauma-Exposed Youth.

The hypothalamic-pituitary-adrenal axis (HPA axis) is a pathway through which childhood trauma may increase risk for negative health outcomes. The HPA axis is sensitive to stress throughout development; however, few studies have examined whether timing of exposure to childhood trauma is related to differences in later HPA axis functioning. Therefore, we examined the association between age of first trauma and HPA axis functioning among adolescents, and whether these associations varied by sex. Parents of 97 youth (aged 9-16 years) completed the Early Trauma Inventory (ETI), and youth completed the Socially-Evaluated Cold-Pressor Task (SECPT). We measured salivary cortisol response to the SECPT, the cortisol awakening response, and diurnal regulation at home across 2 consecutive weekdays. Exposure to trauma during infancy related to delayed cortisol recovery from peak responses to acute stress, d = 0.23 to 0.42. Timing of trauma exposure related to diverging patterns of diurnal cortisol regulation for males, d = 0.55, and females, d = 0.57. Therefore, the HPA axis may be susceptible to developing acute stress dysregulation when exposed to trauma during infancy, whereas the consequences within circadian cortisol regulation may occur in the context of later trauma exposure and vary by sex. Further investigations are warranted to characterize HPA axis sensitivity to exposure to childhood trauma across child development.

Quantitative measures of nocturnal insomnia symptoms predict greater deficits across multiple daytime impairment domains.

This study examined the associations between reported quantitative sleep measures and multiple daytime impairment domains. We collected data from a subsample of adults (n = 513) from the Colorado Longitudinal Twin Study and Community Twin Study. Results revealed that greater insomnia symptom frequency (days per week) significantly predicted greater global sleep-related functional impairment and depressive symptoms. Sleep onset latency was also positively associated with depressive symptoms. Receiver operating characteristic curve analyses indicated 3-4 nights per week and 36-40 min provided optimal sensitivity and specificity for impairment. Thus, insomnia frequency and sleep latency are critical in understanding the impact of insomnia on multiple impairment domains. Using functional impairment as criterion, these findings also support the use of specific quantitative cutoffs for sleep measures in diagnostic systems.

The natural history of insomnia: evaluating illness severity from acute to chronic insomnia; is the first the worst?

STUDY OBJECTIVES: The 3P and 4P models represent illness severity over the course of insomnia disorder. The 3P model suggests that illness severity is worst during acute onset. The 4P model suggests that illness severity crescendos with chronicity. The present analysis from an archival dataset assesses illness severity with new onset illness (i.e. from good sleep [GS] to acute insomnia [AI] to chronic insomnia [CI]). Illness severity is quantified in terms of total wake time (TWT). METHODS: GSs (N = 934) were followed up to 1 year with digital sleep diaries, and classified as GS, AI, or CI. Data for CIs were anchored to the first of 14 days with insomnia so that day-to-day TWT was represented prior to and following AI onset. A similar graphic (+/-acute onset) was constructed for number of days per week with insomnia. GS data were temporally matched to CI data. Segmented linear mixed regression models were applied to examine the change in slopes in the AI-to-CI period compared to GS-to-AI period. RESULTS: Twenty-three individuals transitioned to AI and then CI. Average TWT rose during the first 2 weeks of AI onset (b = 1.8, SE = 0.57, p = 0.001) and was then stable for 3 months (b = -0.02, SE = 0.04, p = 0.53). Average number of affected days was stable from AI to CI (b = 0.0005, SE = 0.002, p = 0.81). That is, while there was week-to-week variability in the number of days affected, no linear trend was evident. CONCLUSIONS: In our sample of CIs, primarily with middle insomnia, the average severity and number of affected days were worst with the onset of AI (worst is first) and stable thereafter.

Highly pathogenic avian influenza A (H5N1) virus outbreak in Peru in 2022-2023.

Background: An epizootic of highly pathogenic avian influenza A (H5N1) has spread worldwide since 2022. Even though this virus has been extensively studied for many decades, little is known about its evolution in South America. Methods: Here, we describe the sequencing and characterization of 13 H5N1 genomes collected from wild birds, poultry, and wild mammals in Peru during the genomic surveillance of this outbreak. Results: The samples belonged to the highly pathogenic avian influenza (H5N1) 2.3.4.4b clade. Chilean and Peruvian samples clustered in the same group and therefore share a common ancestor. An analysis of the hemagglutinin and neuraminidase genes detected new mutations, some dependent upon the host type. Conclusions: The genomic surveillance of highly pathogenic avian influenza is necessary to promote the One Health policy and to overcome the new problems entailed by climate change, which may alter the habitats of resident and migratory birds.

A peer-based mentoring program for reducing anxiety and depression symptoms among college students: A preliminary study.

Objective: The study evaluated the feasibility and acceptability, as well as conducted an initial test of effectiveness, of a peer-based mentoring program for mental health problems among college students. Participants: Thirty-two undergraduate students from a University in the southern part of the United States who exhibited moderate depression or anxiety symptoms were assessed. The participants were primarily white and in their freshman year. Methods: Participants were randomized into two groups. Participants in the intervention group met with a trained peer mentor once a week for four weeks, while participants in the control group were placed on a waitlist. All participants completed pre- and post-treatment surveys to assess anxiety and depression symptoms. Results: The data indicated that participants in the intervention group had significantly greater post-treatment reductions in depression symptoms. Conclusion: These findings provide preliminary support for the use of peer-based mentoring programs in treating mental health problems on college campuses.

Insomnia symptoms predict longer COVID-19 symptom duration.

OBJECTIVE: /Background: The goal of the present study was to assess the prevalence and incidence of insomnia in the United States during the COVID-19 pandemic, and whether, among those that contracted COVID-19, insomnia predicted worse outcomes (e.g., symptoms of greater frequency, duration, or severity). METHODS: A nationwide sample of 2980 adults living in the United States were surveyed online at two points during the COVID-19 pandemic (T1 = April-June 2020; T2 = January-March 2021). Insomnia symptoms were assessed at both time points using the Insomnia Severity Index (ISI). The T2 survey also asked questions regarding COVID-19 testing and symptoms. RESULTS: The prevalence of insomnia (defined as ISI ≥15) was 15% at T1 and 13% at T2. The incidence rate of insomnia (i.e., new cases from T1 to T2) was 5.6%. Participants with insomnia were not more likely to contract COVID-19 relative to those participants without insomnia. Among those participants in our sample that contracted the virus during the study interval (n = 149), there were no significant group differences in COVID-19 symptom outcomes, with one exception, participants with insomnia were more likely to report a longer symptom duration (insomnia = 24.8 sick days, no insomnia = 16.1 sick days). CONCLUSIONS: The present study suggests the prevalence of insomnia in the U.S. population remained high during the COVID-19 pandemic. The data also support that insomnia may be related to experiencing more chronic COVID-19 symptoms. These findings have more general implications for the role of sleep and insomnia on immune functioning.

The Assessment of Post-COVID Fatigue and Its Relationship to the Severity and Duration of Acute COVID Illness.

Emerging data suggests that COVID-19 is associated with fatigue well beyond the acute illness period. The present analysis aimed to: (1) characterize the prevalence and incidence of high fatigue at baseline and follow-up; (2) examine the impact of COVID-19 diagnosis on fatigue level following acute illness; and (3) examine the impact of acute COVID-19 symptom severity and duration on fatigue at follow-up. Subjects (n = 1417; 81.0% female; 83.3% White; X¯age = 43.6 years) completed the PROMIS-Fatigue during the initial wave of the pandemic at baseline (April-June 2020) and 9-month follow-up (January-March 2021). A generalized linear model (binomial distribution) was used to examine whether COVID-19 positivity, severity, and duration were associated with higher fatigue level at follow-up. Prevalence of high fatigue at baseline was 21.88% and 22.16% at follow-up, with 8.12% new cases at follow-up. Testing positive for COVID-19 was significantly associated with higher fatigue at follow-up. COVID-19 symptom duration and severity were significantly associated with increased fatigue at follow-up. COVID-19 symptom duration and severity during acute illness may precipitate longer-term fatigue, which could have implications for treatment planning and future research. Future studies should further evaluate the relationship between symptom severity, duration, and fatigue.

Learning Experiences of Future Healthcare Support Workers Enrolled in a Dual Mode Vocational Training Programme.

BACKGROUND: With life expectancy increasing, there is a growing need to train healthcare support workers who provide care for dependent people in healthcare centres and at home. This qualitative study, based on Gadamer's hermeneutic philosophy, aimed to understand the learning experiences of future healthcare support workers currently enrolled in an intermediate, dual modality vocational training programme with regard to caring for dependent people. METHODS: Convenience sampling was used to recruit the participants, who were all students enrolled in an intermediate level vocational training programme in care for dependent people. Fourteen in-depth interviews and one focus group session were conducted with the students. Atlas.ti 8.0 software was used to analyse the participants' accounts. RESULTS: The students highlighted the vocational nature of their studies and the need to feel competent and useful as a healthcare support worker for dependent people. Practice-based learning and the need for training in core competences are complementary and essential elements of the training process. CONCLUSIONS: The participants' previous experiences were key in determining their academic trajectory and reflect their motivation and interest to learn. However, they feel vulnerable, unprotected, and lack training in psychosocial skills. Educational institutions should focus training programmes on the practice and development of psychosocial skills that motivate students to acquire transversal competences.

Ecological and anthropogenic drivers of rabies exposure in vampire bats: implications for transmission and control.

Despite extensive culling of common vampire bats in Latin America, lethal human rabies outbreaks transmitted by this species are increasingly recognized, and livestock rabies occurs with striking frequency. To identify the individual and population-level factors driving rabies virus (RV) transmission in vampire bats, we conducted a longitudinal capture-recapture study in 20 vampire bat colonies spanning four regions of Peru. Serology demonstrated the circulation of RV in vampire bats from all regions in all years. Seroprevalence ranged from 3 to 28 per cent and was highest in juvenile and sub-adult bats. RV exposure was independent of bat colony size, consistent with an absence of population density thresholds for viral invasion and extinction. Culling campaigns implemented during our study failed to reduce seroprevalence and were perhaps counterproductive for disease control owing to the targeted removal of adults, but potentially greater importance of juvenile and sub-adult bats for transmission. These findings provide new insights into the mechanisms of RV maintenance in vampire bats and highlight the need for ecologically informed approaches to rabies prevention in Latin America.