Worldwide, there has been a shift in disease research and interests from infectious, communicable diseases to non-communicable, chronic, human-induced diseases (e.g., obesity, diabetes, heart disease), as these non-infectious diseases increasingly threaten human health and overall public health (1). This shift, termed the “epidemiologic transition,” describes the changes in patterns of population age distributions, mortality, fertility, life expectancy, and causes of death (1, 2). The epidemiologic transition is associated with industrialization and urbanization, with impacts on the environment and all living things within it. As such, chronic, non-communicable diseases are at the forefront of health care for humans, and these diseases result in increasing health-care costs and are strongly associated with obesity. Depression, for example, is the second leading cause of disability adjusted life years worldwide (3).

During this time of shifting human health challenges, conservation challenges have also increased. Since the 1970s, average global population sizes of wildlife have decreased by more than 50%, leading to the development of the field of conservation medicine in the 1990s (4–7). This is a holistic approach that evolved at a time when infectious and non-infectious diseases increasingly threatened the conservation of wildlife, wild lands, and the humans dependent on both (4). While conservation medicine provides a broad approach to the ecological context of health, a newer movement has emerged in response to the increase in emerging infectious diseases and their often zoonotic origins (8, 9). This initiative, most recently named One Health, has been defined as “a transdisciplinary approach to sustainable management of complex health problems arising from the interaction of animals, humans, and their environment” (10). The One Health initiative may best be considered from its two core components: translational, focusing on comparative medicine, and ecological.

One Health initiatives from zoos have primarily focused on research and messaging about zoonotic diseases and the human–wildlife interface (8, 11–13). Communicating to people about these threats to both human and wildlife health is an important part of One Health (11). One goal of these communications has been to generate public support for healthy wildlife populations with the assumption that if disease risks are well communicated, then public attitudes toward zoonotic disease management should be impacted (11, 14). As the field of One Health grows and public awareness increases, broader communications about the role of One Health are necessary, and zoological institutions should be at the forefront of the One Health movement, because of the transdisciplinary nature of their work and their strong focus on recreation, education, research, and conservation (8, 12, 15). Recreation is of increasing importance in the context of One Health because of the health benefits for zoo visitors in a largely urbanized and sedentary world. On average, Americans spend 87% of their time indoors, and 6% of their time in enclosed vehicles, which has drastic impacts on human health (16). Zoos connect people with nature and encourage healthy human habits through physical movement across zoo campuses and interactions with exhibits and animals (17, 18).

Zoos have a unique position within One Health, for which we have identified seven important tenets. These include (1) providing health care for zoo wildlife to help sustain biodiversity; (2) studies on diseases of conservation concern; (3) understanding diseases in zoo wildlife as sentinels for emerging diseases of humans and other animals; (4) surveillance of disease in wild animals at the interface of wildlife, domestic animals, and humans; (5) contributing to the field of comparative medicine and the discovery of all life forms; (6) exploration of the diversity of life at both micro and macro levels; and (7) human health benefits from nature (5, 8, 18). These roles inform the actions that zoos take in regards to One Health messaging and encourage zoos to invest resources into promoting One Health to visitors, members, and communities.

In linking the roles of zoos in One Health and current public health issues, it has been demonstrated that exposure to nature for at least 5 h a month has lasting restorative effects, such as elevating mood and decreasing risk of depression (10). Studies have indicated that public health strategies should address these concerns via an upstream approach that provides opportunities for people to connect with nature, such as spending time in greenspaces, including zoos (19–21). Nature can promote health through many different pathways, but most broadly does so through environmental conditions, physiological and psychological states, and behaviors (17). We also know that children with attention-deficit disorders exhibit diminished symptoms following activities in green settings, such as zoos (22). Finally, it has been shown that zoos may improve both psychological and physiological well-being through decreasing stress and increasing physical activity (18, 23).

In response to the growing conservation and public health challenges, the Saint Louis Zoo launched the Institute for Conservation Medicine (ICM) in 2011 to advance the goals of One Health. The ICM’s mission statement reads as follows, “The Saint Louis Zoo Institute for Conservation Medicine takes a holistic approach to research on wildlife, public health and sustainable ecosystems to ensure healthy animals and healthy people.” The 50,000 ± Saint Louis Zoo member households, which equates to more than one-third of total annual Zoo visitation, often receive One Health messaging. This includes a quarterly magazine, often with a feature on the ICM’s activities, and weeks prior to the Zoo’s annual One Health Fair a promotional email is distributed to all Zoo members (24). Zoo members also consistently report being significantly more aware of the Zoo’s conservation work in Missouri and around the world than those Zoo visitors who are not members [Niedbalski, unpublished data]. Additionally, the Zoo’s social media accounts, which have nearly half a million followers, provide occasional updates on One Health activities and the ICM.

While the ICM was founded over 5 years ago, it had yet to be evaluated whether the presence of ICM in our newsletters, social media and other layperson friendly publications, and zoo-sponsored activities was having an impact on Zoo goers’ understanding of One Health. The primary objective of this study was to evaluate Zoo member understanding of the concept of One Health 5 years after the establishment of the ICM to provide department evaluation and direction for the coming 5 years. Additionally, we wished to determine what health concerns/issues were at the forefront of Zoo members’ thinking.

Our hypotheses were that Zoo members would have a high level of awareness regarding One Health and that they would be aware of and care about infectious disease issues, since the survey was administered during significant media coverage of the spread of the Zika virus in North America. Therefore, we asked respondents’ awareness of types of One Health projects in which the Zoo is involved, rating of concern of zoonotic disease transmission (with an open-ended follow-up response), and awareness and explanation of the terms One Health and Conservation Medicine. Finally, we asked ratings of awareness, interest, and importance of five of the various roles of the Zoo’s involvement in One Health areas.

We distributed an online survey via email to 2,983 Zoo members selected from the member database in June 2016 (Table 1). Zoo members were defined as individuals or households who purchased an annual membership through the Saint Louis Zoo. The Saint Louis Zoo maintains a database of approximately 50,000 member households, with just over 30,000 providing permission to utilize their email addresses for receiving communication from the Zoo. The Audience Research department of the Saint Louis Zoo provides data-driven evidence for informed decision-making that contributes to the achievement of the Saint Louis Zoo’s mission-oriented goals. Audience Research staff at the Zoo sends approximately 10 member surveys per year, with no member household receiving more than one survey in a 365-day period. Therefore, email addresses are subset into 10 smaller samples (of approximately 3,000 email addresses), and each subset is representative of the total member population based on membership level. This study involved an online survey of members and was exempt from Institutional Review Board approval. Completion of the survey indicated consent.

We used IBM SPSS Version 24 to analyze the data and run descriptive statistics. We obtained data on median household income from https://www.incomebyzipcode.com and matched it to each respondent’s zip code. These data were dichotomized into higher or lower than the median household income in the United States, which the census reported as $56,516 (25). For the open-ended questions, two individuals (HP and ET) sorted and independently coded the qualitative data into different categories, and then a third individual (AN) assessed and made the final decision on the coding when there were discrepancies between the original two coders. Survey answers were stratified by age, gender, and income category and then analyzed in a crosstab analysis. We collapsed age categories into three categories for the crosstab analysis: 18–34, 35–54, and 55+.

The findings from the survey revealed that Zoo members primarily cared about chronic, non-communicable diseases, and their associated costs. These results were initially surprising, because at the time of the survey, Zika outbreaks were receiving heavy media attention. However, when examined in the context of population surveyed and the political climate at the time, these results were more understandable. The United States has already undergone an epidemiologic transition and thus, more people are afflicted with chronic, non-communicable diseases that are associated with increased health-care costs. Leading up to the 2016 United States Presidential election, there was growing unrest in the general American population around the recent implementation of the Affordable Care Act, mostly aimed at the lack of affordability of health care. While the survey results indicated Zoo members focused on health-care costs, these results may not be representative of the larger American population. Possibly related to the physical geography of the United States and the varying population densities, there may be a higher perceived threat from zoonotic diseases in people residing in coastal areas compared to the Midwest. Although One Health initiatives by zoos and other conservation organizations have primarily focused on messaging about infectious, zoonotic diseases (11, 13) to more effectively promote One Health programs at zoos, it may be beneficial for zoos to address the health concerns more specific to their zoo-going population. The results of this study may serve as a template to help guide zoos in their development of One Health messaging.

Along with learning about human health benefits, Zoo members were overwhelmingly interested in learning about the Zoo’s activities in One Health and believed these to be an important role for the Zoo. People were more familiar with the term “Conservation Medicine” (16%) than “One Health” (6%), but their general lack of awareness of the terms themselves indicates that we should do more to effectively disseminate information about the ICM and the role of the Saint Louis Zoo in One Health.

The survey indicated that there is interest in One Health in the St. Louis community of Zoo members and to promote it messaging should include One Health in the context of chronic, non-communicable diseases, in addition to our other more ecological research-focused programming. This messaging should also be aimed at individuals over the age of 55, who were consistently interested in the Zoo’s activities, but less aware. People were generally aware of One Health activities, but then were unable to put a term to these activities. The messaging from the ICM about One Health, via newsletters, magazines, talks, and social media outlets did appear to have some impact on the member community. The ICM continues to pave the way for further more effective messaging to the Zoo’s membership and visitors regarding One Health.

This study provided a brief, but valuable insight into Zoo members’ understanding of One Health, which may help inform not only our future work at the ICM, but also at other zoos as they develop programs to promote and disseminate information regarding the One Health initiative. While the results obtained are valuable, it is important to note the limitations of the study itself. The surveyed population was Zoo members, who primarily reside in St. Louis and the surrounding areas. As the Saint Louis Zoo does not have an admission fee for visitors, its members may be distinct socioeconomically from the general population of Zoo visitors. Even with this distinction, the study population still represented a varied socioeconomic demographic, with 40% of study respondents being from zip codes below the median household income in the United States. The study is also subject to volunteer bias, as we sent the survey to over 3,000 individuals, but only 285 provided complete answers. In regards to how the respondents answered questions, the survey was distributed when there was heavy media attention on the Zika outbreak, which may have influenced responses to health concerns: however, our data do not support this line of thinking. Additionally, survey respondents primarily lived in urban/suburban areas, and thus the results are not generalizable to rural settings. Overall, this survey offered a valuable initial look into the minds of Zoo visitors/members, with results that may help assist other zoos in One Health program development and/or implementation.

On the survey, individuals identified poor diet/obesity/lack of nutrition as one of their top three concerns. This concern may be easily addressed by One Health messaging since zoos help tackle this challenge by efforts to protect pollinators, like bees and bats, thus increasing food security and enabling a higher quality diet. Zoos provide communities with access to greenspace, and it has been shown that increased time in nature may mitigate the negative health impacts of urbanization (17, 19, 20, 22, 26, 27). Zoos promote healthy lifestyles by providing access to exercise and requiring movement by visitors, thus potentially having an impact on obesity, and health-care costs (18). Zoos also play an important role in conservation, which has long-term health impacts for individuals, reduces health-care costs, and increases healthy behaviors (5, 27).

While individuals’ concerns over health-care costs and chronic diseases need to be addressed by One Health practitioners, infectious diseases should not be neglected in communication between zoos and the public. As climate change progresses and human habitats expand, there will be an increase in human–wildlife interactions, leading to an increase in zoonotic disease transmission (21, 28–30). Zoos have both the resources and capabilities to promote One Health, and they may provide messaging about it by sharing information on the positive health impacts zoos offer to their human visitors, while continuing to work to promote healthy habitats for humans and animals.

This study involved an online survey of members and was exempt from Institutional Review Board (IRB) approval. Completion of the survey indicated consent.

Conception or design of the work and acquisition, analysis or interpretation of data for the work; drafting the work or revising it critically for important intellectual content; final approval of the version to be published: and agreement to be accountable for all aspects of the work: HP, AN, ET, and SD.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.