OBJECTIVE: State public health departments use federal funding to examine and address social determinants of health (SDOH) within their communities to improve health and advance health equity. Yet, most federal funding is categorical (ie, funding used for a specific program or narrow purpose), which can create barriers to addressing social and structural drivers of inequity. The Preventive Health and Health Services Block Grant (PHHS Block Grant) is a flexible funding mechanism that provides health departments the latitude to identify and fund initiatives that address local public health needs. It is unclear, however, to what extent health departments use this flexible resource to incorporate SDOH into their programs. DESIGN: Cross-sectional, descriptive analysis of state health department PHHS Block Grant program administrative data. SETTING: This study examined PHHS Block Grant budgets and workplans for the federal Fiscal Year 2021 to assess whether state health departments aligned their grant-funded program with the national objectives associated with the Healthy People 2030 SDOH Framework. PARTICIPANTS: Forty-seven states and the District of Columbia were included in this study. MAIN OUTCOME MEASURES: Percent of states that used PHHS Block Grant funds to address SDOH; proportion of funding allocated to address SDOH; percentage of programs that addressed SDOH. RESULTS: Three-fourths (75%) of states allocated funds to 97 programs aligning with at least 1 Healthy People 2030 SDOH-related objective. Fifty of the programs were fully or primarily funded by the PHHS Block Grant. Results also show that as the states' PHHS Block Grant funding level increased so did the percent of states that allocated funding toward SDOH programs. CONCLUSION: This study shows that state health departments are using the PHHS Block Grant to address SDOH, and that the grant plays an important funding role for these programs. States are incorporating the grant into their funding strategies to address SDOH.

Program evaluation is a critical tool for understanding and improving organizational activities and systems. This report updates the 1999 CDC Framework for Program Evaluation in Public Health (CDC. Framework for program evaluation in public health. MMWR Recomm Rep 1999;48[No. RR-11];1-40) by integrating major advancements in the fields of evaluation and public health, lessons learned from practical applications of the original framework, and current Federal agency policies and practices. A practical, nonprescriptive tool, the updated 2024 framework is designed to summarize and organize essential elements of program evaluation, and can be applied at any level from individual programs to broader systems by novices and experts for planning and implementing an evaluation. Although many of the key aspects from the 1999 framework remain, certain key differences exist. For example, this updated framework also includes six steps that describe the general process of evaluation planning and implementation, but some content and step names have changed (e.g., the first step has been renamed Assess context). The standards for high-quality evaluation remain central to the framework, although they have been updated to the five Federal evaluation standards. The most substantial change from the 1999 framework is the addition of three cross-cutting actions that are core tenets to incorporate within each evaluation step: engage collaboratively, advance equity, and learn from and use insights. The 2024 framework provides a guide for designing and conducting evaluation across many topics within and outside of public health that anyone involved in program evaluation efforts can use alone or in conjunction with other evaluation approaches, tools, or methods to build evidence, understand programs, and refine evidence-based decision-making to improve all program outcomes.

Multisectoral, One Health collaboration is essential for addressing national and international health threats that arise at the human-animal-environment interface. Thanks to the efforts of multiple organisations, countries now have an array of One Health tools available to assess capacities within and between sectors, plan and prioritise activities, and strengthen multisectoral, One Health coordination, communication, and collaboration. By doing so, they are able to address health threats at the human-animal-environment interface, including emerging zoonotic and infectious diseases, more efficiently. However, to ensure optimal outcomes for the countries using these One Health tools, the partners responsible for implementation should regularly collaborate and share information such as implementation timelines, results and lessons learned, so that one process can inform the next. This paper presents a consensus framework on how commonly implemented One Health tools might align to best support countries in strengthening One Health systems. Twelve One Health tools were selected based on their high implementation rates, authors' experience with these tools and their focus on multisectoral, One Health coordination. Through a four-step process, the authors: a) jointly carried out a landscape analysis of One Health tools, using a Cloudbased spreadsheet to share the unique characteristics and applications of each tool; b) performed an implementation analysis to identify and share implementation dynamics and identify respective outcomes and synergies; c) jointly created a consensus conceptual model of how the authors suggest the tools might logically work together; and d) extrapolated from steps 1-3 an agreed-upon overarching conceptual framework for how current and future One Health tools could be categorised to best support One Health system strengthening at the national level. Highlighted One Health tools include the States Parties Annual Reporting Tool under the International Health Regulations (IHR), the World Organisation for Animal Health Performance of Veterinary Services (PVS) Pathway, the Joint External Evaluation process, IHR/PVS National Bridging Workshops, the Centers for Disease Control and Prevention One Health Zoonotic Disease Prioritization Tool, the Food and Agriculture Organization (FAO) Laboratory Mapping Tool, the FAO Assessment Tool for Laboratories and Antimicrobial Resistance Surveillance Systems, the FAO Surveillance Evaluation Tool, the One Health Systems Mapping and Analysis Resource Toolkit, the National Action Plan for Health Security, and IHR Monitoring and Evaluation Framework tools for After Action Reviews and Simulation Exercises. A new guidance document entitled, Taking a Multisectoral, One Health Approach: A Tripartite Guide to Addressing Zoonotic Diseases in Countries was also included as a framework that provides guidance to support the implementation of the outputs of the tools described.

BACKGROUND: Multidisciplinary and multisectoral approaches such as One Health and related concepts (e.g., Planetary Health, EcoHealth) offer opportunities for synergistic expertise to address complex health threats. The connections between humans, animals, and the environment necessitate collaboration among sectors to comprehensively understand and reduce risks and consequences on health and wellbeing. One Health approaches are increasingly emphasized for national and international plans and strategies related to zoonotic diseases, food safety, antimicrobial resistance, and climate change, but to date, the possible applications in clinical practice and benefits impacting human health are largely missing. METHODS: In 2018 the "Application of the One Health Approach to Global Health Centers" conference held at the Albert Einstein College of Medicine convened experts involved in One Health policy and practice. The conference examined issues relevant to One Health approaches, sharing examples of challenges and successes to guide application to medical school curricula and clinical practice for human health. This paper presents a synthesis of conference proceedings, framed around objectives identified from presentations and audience feedback. FINDINGS AND RECOMMENDATIONS: The following objectives provide opportunities for One Health involvement and benefits for medical schools and global health centers by: 1) Improving One Health resource sharing in global health and medical education; 2) Creating pathways for information flow in clinical medicine and global health practice; 3) Developing innovative partnerships for improved health sector outcomes; and 4) Informing and empowering health through public outreach. These objectives can leverage existing resources to deliver value to additional settings and stakeholders through resource efficiency, more holistic and effective service delivery, and greater ability to manage determinants of poor health status. We encourage medical and global health educators, practitioners, and students to explore entry points where One Health can add value to their work from local to global scale.

Avian, swine and other zoonotic influenza viruses may cause disease with significant impact in both human and animal populations. The Asia Pacific Strategy for Emerging Diseases (APSED), long recognizing the increased global impact of zoonotic diseases on human populations, has been used as the foundation for improving national preparedness and regional coordination for response to zoonotic diseases in the World Health Organization (WHO) Western Pacific Region. (1) APSED encourages multisectoral coordination at the human–animal–environment interface as the primary action required for zoonotic disease control. (2) In this article we emphasize the effectiveness of these multisectoral collaborations in responding to zoonotic diseases at the regional and country level, using avian influenza as an example.

Transposable elements (TEs) are mobile DNA and constitute approximately half of the human genome. LINE-1 (L1) is the only active autonomous TE in the mammalian genome and has been implicated in a number of diseases as well as aging. We have previously reported skeletal muscle L1 expression is lower following acute and chronic exercise training in humans. Herein, we used a rodent model of voluntary wheel running to determine if long-term exercise training affects markers of skeletal muscle L1 regulation. Selectively-bred high running female Wistar rats (n=11 per group) were either given access to a running wheel (EX) or not (SED) at 5 weeks of age, and these conditions were maintained until 27 weeks of age. Thereafter, mixed gastrocnemius tissue was harvested and analyzed for L1 mRNA expression and DNA content along with other L1 regulation markers. We observed significantly (p<0.05) lower L1 mRNA expression, higher L1 DNA methylation, and less L1 DNA in accessible chromatin regions in EX versus SED rats. We followed these experiments with 3-h in vitro drug treatments in L6 myotubes to mimic transient exercise-specific signaling events. The AMPK agonist 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR; 4mM) significantly decreased L1 mRNA expression in L6 myotubes. However, this effect was not facilitated through increased L1 DNA methylation. Collectively, these data suggest long-term voluntary wheel running downregulates skeletal muscle L1 mRNA, and this may occur through chromatin modifications. Enhanced AMPK signaling with repetitive exercise bouts may also decrease L1 mRNA expression, albeit the mechanism of action remains unknown.

INTRODUCTION: Teen dating violence is a serious public health problem with few effective prevention strategies. This study examines whether the Dating Matters comprehensive prevention model, compared with a standard of care intervention, prevented negative relationship behaviors and promoted positive relationship behaviors. STUDY DESIGN: This longitudinal, cluster-RCT compared the effectiveness of Dating Matters with standard of care across middle school. Standard of care was an evidence-based teen dating violence prevention curriculum (Safe Dates) implemented in eighth grade. SETTING/PARTICIPANTS: Forty-six middle schools in high-risk urban neighborhoods in four U.S. cities were randomized. Schools lost to follow-up were replaced with new schools, which were independently randomized (71% school retention). Students were surveyed in fall and spring of sixth, seventh, and eighth grades (2012-2016). The analysis sample includes students from schools implementing Dating Matters or standard of care for >2 years who started sixth grade in the fall of 2012 or 2013 and had dated (N=2,349 students, mean age 12 years, 49% female, and 55% black, non-Hispanic, 28% Hispanic, 17% other). INTERVENTION: Dating Matters is a comprehensive, multicomponent prevention model including classroom-delivered programs for sixth to eighth graders, training for parents of sixth to eighth graders, educator training, a youth communications program, and local health department activities to assess capacity and track teen dating violence-related policy and data. MAIN OUTCOME MEASURES: Self-reported teen dating violence perpetration and victimization, use of negative conflict resolution strategies, and positive relationship skills were examined as outcomes. Imputation and analyses were conducted in 2017. RESULTS: Latent panel models demonstrated significant program effects for three of four outcomes; Dating Matters students reported 8.43% lower teen dating violence perpetration, 9.78% lower teen dating violence victimization, and 5.52% lower use of negative conflict resolution strategies, on average across time points and cohorts, than standard of care students. There were no significant effects on positive relationship behaviors. CONCLUSIONS: Dating Matters demonstrates comparative effectiveness, through middle school, for reducing unhealthy relationship behaviors, such as teen dating violence and use of negative conflict resolution strategies, relative to the standard of care intervention. TRIAL REGISTRATION: This study is registered at www.clinicaltrials.gov NCT01672541.

Transgenic Anopheles gambiae Giles (Diptera: Culicidae) mosquitoes have been developed that confer sexual sterility on males that carry a transgene encoding a protein which cuts ribosomal DNA. A relevant risk concern with transgenic mosquitoes is that their capacity to transmit known pathogens could be greater than the unmodified form. In this study, the ability to develop two human pathogens in these transgenic mosquitoes carrying a homing endonuclease which is expressed in the testes was compared with its nontransgenic siblings. Infections were performed with Plasmodium falciparum (Welch) and o'nyong-nyong virus (ONNV) and the results between the transgenic and nontransgenic sibling females were compared. There was no difference observed with ONNV isolate SG650 in intrathoracic infections or the 50% oral infectious dose measured at 14 d postinfection or in mean body titers. Some significant differences were observed for leg titers at the medium and highest doses for those individuals in which virus titer could be detected. No consistent difference was observed between the transgenic and nontransgenic comparator females in their ability to develop P. falciparum NF54 strain parasites. This particular transgene caused no significant effect in the ability of mosquitoes to become infected by these two pathogens in this genetic background. These results are discussed in the context of risk to human health if these transgenic individuals were present in the environment.

BACKGROUND: Meta-analyses of observational studies have shown that women with a shorter interpregnancy interval (the time from delivery to start of a subsequent pregnancy) are more likely to experience adverse pregnancy outcomes, such as preterm delivery or small for gestational age birth, than women who space their births further apart. However, the studies used to inform these estimates have methodological shortcomings. METHODS: In this commentary, we summarise the discussions of an expert workgroup describing good practices for the design, analysis, and interpretation of observational studies of interpregnancy interval and adverse perinatal health outcomes. RESULTS: We argue that inferences drawn from research in this field will be improved by careful attention to elements such as: (a) refining the research question to clarify whether the goal is to estimate a causal effect vs describe patterns of association; (b) using directed acyclic graphs to represent potential causal networks and guide the analytic plan of studies seeking to estimate causal effects; (c) assessing how miscarriages and pregnancy terminations may have influenced interpregnancy interval classifications; (d) specifying how key factors such as previous pregnancy loss, pregnancy intention, and maternal socio-economic position will be considered; and (e) examining if the association between interpregnancy interval and perinatal outcome differs by factors such as maternal age. CONCLUSION: This commentary outlines the discussions of this recent expert workgroup, and describes several suggested principles for study design and analysis that could mitigate many potential sources of bias.

BACKGROUND: The World Health Organization (WHO) recommends that women wait at least 24 months after a livebirth before attempting a subsequent pregnancy to reduce the risk of adverse maternal, perinatal, and infant health outcomes. However, the applicability of the WHO recommendations for women in the United States is unclear, as breast feeding, nutrition, maternal age at first birth, and total fertility rate differs substantially between the United States and the low- and middle-resource countries upon which most of the evidence is based. METHODS: To inform guideline development for birth spacing specific to women in the United States, the Office of Population Affairs (OPA) convened an expert work group meeting in Washington, DC, on 14-15 September 2017 among reproductive, perinatal, paediatric, social, and public health epidemiologists; obstetrician-gynaecologists; biostatisticians; and experts in evidence synthesis related to women's health. RESULTS: Presentations and discussion topics included the methodological quality of existing studies, evaluation of the evidence for causal effects of short interpregnancy intervals on adverse perinatal and maternal health outcomes, good practices for future research, and identification of research gaps and priorities for future work. CONCLUSIONS: This report provides an overview of the presentations, discussions, and conclusions from the expert work group meeting.

Transgenic mosquitoes are being developed as novel components of area-wide approaches to vector-borne disease control. Best practice is to develop these in phases, beginning with laboratory studies, before moving to field testing and inclusion in control programs, to ensure safety and prevent costly field testing of unsuitable strains. The process of identifying and developing good candidate strains requires maintenance of transgenic colonies over many generations in containment facilities. By working in disease endemic countries with target vector populations, laboratory strains may be developed and selected for properties that will enhance intended control efficacy in the next phase, while avoiding traits that introduce unnecessary risks. Candidate strains aiming toward field use must consistently achieve established performance criteria, throughout the process of scaling up from small study colonies to production of sufficient numbers for field testing and possible open release. Maintenance of a consistent quality can be demonstrated by a set of insect quality and insectary operating indicators, measured over time at predetermined intervals. These indicators: inform comparability of studies using various candidate strains at different times and locations; provide evidence of conformity relevant to compliance with terms of approval for regulated use; and can be used to validate some assumptions related to risk assessments covering the contained phase and for release into the environment.

CONTEXT: Increasing the adoption and implementation of evidence-based policies and practices is a key strategy for improving public health. Although there is widespread agreement about the importance of implementing evidence-based public health policies and practices, there are gaps between what has been shown to be effective and what is implemented at the state level. OBJECTIVE: The Centers for Disease Control and Prevention (CDC) developed the Prevention Status Reports (PSRs), a performance measurement system, to highlight evidence-based public health policies and practices and catalyze state performance and quality improvement efforts across the nation. DESIGN: CDC selected a set of 10 topics representing some of the most important public health challenges in the nation. Stakeholders, including state health departments and other partners, helped conceptualize the PSRs and informed the development of the PSR framework, which provides an organizational structure for the system. CDC subject matter experts developed criteria for selecting policies and practices, indicators for each policy and practice, and a criteria-based rating system for each indicator. PARTICIPANTS AND SETTING: The PSRs were developed for all 50 states and the District of Columbia. MAIN OUTCOME: The PSRs were developed and serve as a performance measurement system for monitoring the adoption, reach, and implementation fidelity of evidence-based public health policies and practices nationwide. RESULTS: The PSRs include 33 policy and practice indicators across the 10 health topics. They use a simple 3-level rating system-green, yellow, and red-to report the extent to which each state (and the District of Columbia) has implemented the policy or practice in accordance with supporting evidence or expert recommendations. Results from aggregate analyses show positive change or improvement. CONCLUSION: The PSRs are a unique part of CDC's work to improve the performance and accountability of the public health system, serving as both a monitoring tool and a call to action to improve health outcomes. The PSRs can be used to track the reach of and fidelity to evidence-based policies and practices nationally over time, as well as inform state efforts to improve their use of evidence-based policies and practice.

Mycobacterium tuberculosis is recognised as the primary cause of human tuberculosis worldwide. However, substantial evidence suggests that the burden of Mycobacterium bovis, the cause of bovine tuberculosis, might be underestimated in human beings as the cause of zoonotic tuberculosis. In 2013, results from a systematic review and meta-analysis of global zoonotic tuberculosis showed that the same challenges and concerns expressed 15 years ago remain valid. These challenges faced by people with zoonotic tuberculosis might not be proportional to the scientific attention and resources allocated in recent years to other diseases. The burden of zoonotic tuberculosis in people needs important reassessment, especially in areas where bovine tuberculosis is endemic and where people live in conditions that favour direct contact with infected animals or animal products. As countries move towards detecting the 3 million tuberculosis cases estimated to be missed annually, and in view of WHO's end TB strategy endorsed by the health authorities of WHO Member States in 2014 to achieve a world free of tuberculosis by 2035, we call on all tuberculosis stakeholders to act to accurately diagnose and treat tuberculosis caused by M bovis in human beings.

OBJECTIVE: This study reports the use of exploratory factor analysis to describe essential skills and knowledge for an important segment of the domestic public health workforce-Centers for Disease Control and Prevention (CDC) project officers-using an evidence-based approach to competency development and validation. DESIGN:: A multicomponent survey was conducted. Exploratory factor analysis was used to examine the underlying domains and relationships between competency domains and key behaviors. The Cronbach alpha coefficient determined the reliability of the overall scale and identified factors. SETTING AND PARTICIPANTS: All domestic (US state, tribe, local, and territorial) grantees who received funding from the CDC during fiscal year 2011 to implement nonresearch prevention or intervention programs were invited to participate in a Web-based questionnaire. MAIN OUTCOME MEASURE(S): A total of 34 key behaviors representing knowledge, skills, and abilities, grouped in 7 domains-communication, grant administration and management, public health applied science and knowledge, program planning and development, program management, program monitoring and improvement, and organizational consultation-were examined. RESULTS: There were 795 responses (58% response rate). A total of 6 factors were identified with loadings of 0.40 or more for all 34 behavioral items. The Cronbach alpha coefficient was 0.95 overall and ranged between 0.73 and 0.91 for the factors. CONCLUSIONS: This study provides empirical evidence for the construct validity of 6 competencies and 34 key behaviors important for CDC project officers and serves as an important first step to evidence-driven workforce development efforts in public health.

This systematic review examined 140 outcome evaluations of primary prevention strategies for sexual violence perpetration. The review had two goals: 1) to describe and assess the breadth, quality, and evolution of evaluation research in this area; and 2) to summarize the best available research evidence for sexual violence prevention practitioners by categorizing programs with regard to their evidence of effectiveness on sexual violence behavioral outcomes in a rigorous evaluation. The majority of sexual violence prevention strategies in the evaluation literature are brief, psycho-educational programs focused on increasing knowledge or changing attitudes, none of which have shown evidence of effectiveness on sexually violent behavior using a rigorous evaluation design. Based on evaluation studies included in the current review, only three primary prevention strategies have demonstrated significant effects on sexually violent behavior in a rigorous outcome evaluation: Safe Dates (Foshee et al., 2004); Shifting Boundaries (building-level intervention only, Taylor, Stein, Woods, Mumford, & Forum, 2011); and funding associated with the 1994 U.S. Violence Against Women Act (VAWA; Boba & Lilley, 2009). The dearth of effective prevention strategies available to date may reflect a lack of fit between the design of many of the existing programs and the principles of effective prevention identified by Nation et al. (2003).

Phytoestrogens have been associated with subtle hormonal changes, although effects on fecundity are unknown. Our objective was to evaluate the association between male and female urinary phytoestrogen (isoflavone and lignan) concentrations and time to pregnancy (TTP) in a population-based cohort of 501 couples desiring pregnancy and discontinuing contraception. Couples were followed for 12 mo or until pregnancy. Fecundability ORs (FORs) and 95% CIs were estimated after adjusting for age, body mass index, race, site, creatinine, supplement use, and physical activity in relation to female, male, and joint couple concentrations. Models included the phytoestrogen of interest and the sum of the remaining individual phytoestrogens. FORs <1 denote a longer TTP and FORs >1 a shorter TTP. Urinary lignan concentrations were higher, on average, among female partners of couples who became pregnant during the study compared with women who did not become pregnant (median enterodiol: 118 vs. 80 nmol/L; P < 0.10; median enterolactone: 990 vs. 412 nmol/L; P < 0.05) and were associated with significantly shorter TTP in models based on both individual and couples' concentrations (couples' models: enterodiol FOR, 1.13; 95% CI: 1.02, 1.26; enterolactone FOR, 1.11; 95% CI: 1.01, 1.21). Male lignan concentrations were not associated with TTP, nor were isoflavone concentrations. Sensitivity analyses showed that associations observed are unlikely to be explained by potential unmeasured confounding by lifestyle or other nutrients. Our results suggest that female urinary lignan concentrations at levels characteristic of the U.S. population are associated with a shorter TTP among couples who are attempting to conceive, highlighting the importance of dietary influences on fecundity.

BACKGROUND: Metals can interfere with hormonal functioning by binding at the receptor site and through indirect mechanisms; thus, they may be associated with hormonal changes in premenopausal women. OBJECTIVES: We examined the associations between cadmium, lead, and mercury, and anovulation and patterns of reproductive hormones [estradiol, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone] among 252 premenopausal women 18-44 years of age who were enrolled in the BioCycle Study in Buffalo, New York. METHODS: Women were followed for up to two menstrual cycles, with serum samples collected up to eight times per cycle. Metal concentrations were determined at baseline in whole blood by inductively coupled mass spectroscopy. Marginal structural models with stabilized inverse probability weights and nonlinear mixed models with harmonic terms were used to estimate the effects of cadmium, lead, and mercury on reproductive hormone levels during the menstrual cycle and anovulation. RESULTS: Geometric mean (interquartile range) cadmium, lead, and mercury levels were 0.29 (0.19-0.43) mcg/L, 0.93 (0.68-1.20) mcg/dL, and 1.03 (0.58-2.10) mcg/L, respectively. We observed decreases in mean FSH with increasing cadmium [second vs. first tertile: -10.0%; 95% confidence interval (CI), -17.3% to -2.5%; third vs. first tertile: -8.3%; 95% CI, -16.0% to 0.1%] and increases in mean progesterone with increasing lead level (second vs. first tertile: 7.5%; 95% CI, 0.1-15.4%; third vs. first tertile: 6.8%; 95% CI, -0.8% to 14.9%). Metals were not significantly associated with anovulation. CONCLUSION: Our findings support the hypothesis that environmentally relevant levels of metals are associated with modest changes in reproductive hormone levels in healthy, premenopausal women.

BACKGROUND: The threat posed by highly pathogenic avian influenza A H5N1 viruses to humans remains significant, given the continued occurrence of sporadic human cases (499 human cases in 15 countries) with a high case fatality rate (approximately 60%), the endemicity in poultry populations in several countries, and the potential for reassortment with the newly emerging 2009 H1N1 pandemic strain. Therefore, we review risk factors for H5N1 infection in humans. METHODS AND FINDINGS: Several epidemiologic studies have evaluated the risk factors associated with increased risk of H5N1 infection among humans who were exposed to H5N1 viruses. Our review shows that most H5N1 cases are attributed to exposure to sick poultry. Most cases are sporadic, while occasional limited human-to-human transmission occurs. The most commonly identified factors associated with H5N1 virus infection included exposure through contact with infected blood or bodily fluids of infected poultry via food preparation practices; touching and caring for infected poultry; consuming uncooked poultry products; exposure to H5N1 via swimming or bathing in potentially virus laden ponds; and exposure to H5N1 at live bird markets. CONCLUSIONS: Research has demonstrated that despite frequent and widespread contact with poultry, transmission of the H5N1 virus from poultry to humans is rare. Available research has identified several risk factors that may be associated with infection including close direct contact with poultry and transmission via the environment. However, several important data gaps remain that limit our understanding of the epidemiology of H5N1 in humans. Although infection in humans with H5N1 remains rare, human cases continue to be reported and H5N1 is now considered endemic among poultry in parts of Asia and in Egypt, providing opportunities for additional human infections and for the acquisition of virus mutations that may lead to more efficient spread among humans and other mammalian species. Collaboration between human and animal health sectors for surveillance, case investigation, virus sharing, and risk assessment is essential to monitor for potential changes in circulating H5N1 viruses and in the epidemiology of H5N1 in order to provide the best possible chance for effective mitigation of the impact of H5N1 in both poultry and humans. DISCLAIMER: The opinions expressed in this article are those of the authors and do not necessarily reflect those of the institutions or organizations with which they are affiliated.