Michael P. Muehlenbein, PhD, MsPH
Professor, Chair, & Graduate Program Director
Research in Progress
1. One Health, including emerging infectious diseases, anthrozoology, travel medicine, and conservation medicine;
2. Evolutionary endocrinology, including behavioral endocrinology and reproductive ecology;
3. Ecological immunology, including laboratory/field methods development;
4. Public education in evolutionary medicine and human/non-human primate evolutionary biology.
Hormones and infectious diseases underpin most aspects of my primary, long-term research agenda. I have maintained both field- and laboratory-based research projects, with independent ventures in behavioral endocrinology and infectious disease ecology, but with a predominant campaign in evolutionary and ecological endocrinology and immunology. These projects/ideas have built upon one another in an effort to identify logical direction in research on fundamental questions regarding the physiologies and behaviors of humans, monkeys and apes, with particular focus on explicating the proximate and ultimate causes and consequences of immune-endocrine interactions.
Immunity has evolved into a complex system of components whose proper performance is regulated by many physiological systems, including the endocrine system. Assuming a limited supply of energy and time, organisms are required to allocate physiological resources among a number of competing functions, most notably growth, reproduction, work, storage, temperature regulation and all other forms of maintenance, including immune responses. Organisms are under selection to develop and maintain physiological systems that allow for efficient allocation of resources between these functions. Many have argued that hormones function as important information transducers, regulating differential investment in competing trade-offs according to several factors, including availability of energy and mates, and disease risk in the environment. I have attempted to add to and expand this literature base by characterizing immune-endocrine interactions in humans, monkeys and apes. My focus has been primarily on testosterone, which is hypothesized to suppress immune functions. But how does it do this, and under what host conditions? Does having higher testosterone really increase susceptibility to infectious diseases, and how/why do testosterone levels change in response to illness in a human, monkey or ape host? These ‘why’ questions come from evolutionary biology: ‘why’ should such relationships exist? The ‘how’ questions are enabled through the application of endocrinological and immunological methods.
The complex costs of altered hormone levels during illness likely account for the functional significance of high variability in hormone levels within and between men and women. Evaluating immune-endocrine relationships has important implications for understanding differences in disease severity, progression, and convalescence, as well as the basic nature of phenotypic plasticity and adaptability. Formulating an explanatory framework for differential susceptibility to infectious diseases is valuable for obvious reasons, particularly as legal and illegal anabolic androgenic steroid use is at an all-time high in U.S. adolescents and adults. A better understanding of the immunomodulatory actions of hormones may inform treatment patterns for hypogonadism and other endocrine dysregulations during illness. Equally important is the realization that, because hormones influence and regulate immune, metabolic and reproductive functions, identifying the complex interactions between hormones and immune factors will have an important impact on understanding the optimization of hormonal activity under varying environmental conditions, and consequently the evolution of the life history trade-offs between endocrine and immune functions.
Given my training in public health, I have attempted to maintain a separate research agenda focusing on infectious disease ecology of humans, monkeys and apes, as well as disease risk associated with tourism and travel. Because of their genetic relatedness with humans, monkeys and apes are particularly susceptible to human infections. They are usually immunologically-naïve to these pathogens, and primate populations can be quickly decimated because of the slow reproductive rates of most species, particularly great apes. They also serve as a source of several human infections, including malaria, yellow fever and Chikungunya virus. However, there is increasing pressure of ecotourism on these wild and rehabilitated animals, requiring the establishment of disease monitoring systems, and guidelines to protect visitors from possible risks as well as ensure long-term well-being of wildlife.
My students and I have now surveyed over 10,000 people in Malaysia, Japan, St. Kitts, Gibraltar, and South Africa. It would appear that ecotourists concerned about environmental protection are themselves largely unaware of their potential contribution to the spread of diseases to animals. The risks of negatively affecting animal populations must be communicated to all concerned parties, and I am glad to play a role in this, particularly as the ecotourism industry continues its rapid expansion, and is seen increasingly as a possible tool to save great ape populations from extinction.
Certificate in Travel Medicine, Swiss Tropical Institute, 2010
Certificate in Teaching Research Ethics, Indiana University, 2010
PhD in Biological Anthropology, Yale University, 2004
MPhil in Biological Anthropology, Yale University, 2002
MsPH in Tropical Medicine and Biostatistics, Tulane University, 2000
BA in Anthropology and Environmental Sciences, Northwestern University, 1998
My goal as a teacher is to help students develop a conceptual framework for independent, critical thought. I try to do this by communicating the fundamental concepts of different subjects in an enjoyable manner that promotes active retention of information and the application of concepts and processes. I believe the best way to nurture good critical thinking practices is to be encouraging, empathetic, flexible, fair-minded and respectful to students, to treat them as junior colleagues when possible/practical, to establish clear expectations of them at all times, and to support their respectful inquisition and analysis of others’ research. It is critical to motivate students using realistic examples of general principles applied to current events, to show them examples of good science and how to replicate it, to cultivate written and oral presentation skills, to support the development of argumentation skills, all while providing them with cognitive autonomy. I accomplish this most effectively by creating a relaxed learning atmosphere. Most importantly, I try to inspire others via enthusiasm for the learning process.
Prospective students: The Department of Anthropology now has a graduate program (see link above), and I am also recruiting PhD students through the Department of Biology, the Department of Environmental Sciences, The Institute for Biomedical Studies, and the Institute of Ecological, Earth, and Environmental Studies. I am particularly interested in recruiting students who would like to work on hormones and immunity in women, hormones and immunity in fathers, education of health professionals on evolutionary medicine and One Health, and the experimental alteration of human behaviors to prevent emerging infectious diseases.
Muehlenbein MP, Dore KM, Gassen J, Nguyen V, Jolley GO, Gallagher C. 2021. Travel medicine meets conservation medicine: Disinhibition, cognitive-affective inconsistency, and disease risk among vacationers around green moneys. American Journal of Primatology DOI: 10.1002/ajp.23301.
Gassen J, Nowak TJ, Henderson AD*, Weaver SP, Baker EJ, Muehlenbein MP. 2021. Unrealistic optimism and risk for COVID-19 disease. Frontiers in Psychology 12:647461.doi: 10.3389/fpsyg.2021.647461.
Ryan BJ, Muehlenbein MP, Allen J, Been J, Boyd K, Brickhouse M, Brooks BW, Burchett M, Chambliss CK, Cook JD, Ecklund A, Fogleman L, Granick P, Hynes S, Hudson T, Huse M, Lamb M, Lowe T, Marsh J, Matthews W, Stern S, Wheelis M, Brickhouse N. Sustaining university operations during the COVID-19 pandemic. Disaster Medicine and Public Health Preparedness doi: https://doi.org/10.1017/dmp.2021.69.
Ponzi D, Flinn MV, Muehlenbein MP, Nepomnaschy PA. 2020. Hormones and human developmental plasticity. Molecular and Cellular Endocrinology 505:110721.
Muehlenbein MP, Angelo KM, Schlagenhaul P, Chen L, Grobusch MP, Gautret P, Duvignaud A, Chappuis F, Kain KC, Bottieau E, Epelboin L, Shaw M, Hynes N, Hamer DG, GeoSentinel Surveillance Network. 2020. Traveller exposures to animals: A GeoSentinel analysis. Journal of Travel Medicine doi: 10.1093/jtm/taaa010
Muehlenbein MP. 2019. Ecotourism. In: Keystone JS,Kozarsky PE, Freedman DO, Nothdurft HD, Connor BA, eds. Travel Medicine, 4th edition. Elsevier, p. 363-370.
Shattuck EC, Muehlenbein MP. 2018. Religiosity/spirituality and physiological markers of health. Journal of Religion and Health. DOI 10.1007/s10943-018-0663-6.
Prall SP, Muehlenbein MP. 2018. DHEA modulates immune function: A review of evidence. Vitamins and Hormones 108:125-144.
Prall SP, Muehlenbein MP. 2018. Hormonal correlates of dominance. In: Fuentes A (ed). The International Encyclopedia of Primatology. Wiley-Blackwell.
Miller IF, Schneider-Crease I, Nunn CL, Muehlenbein MP. 2018. Estimating infection prevalence: Best practices and their theoretical underpinnings. Ecology and Evolution 8:6738-6747.
Muehlenbein MP. 2018. Health assessment. In: Fuentes A (ed). The International Encyclopedia of Primatology. Wiley-Blackwell.
Muehlenbein MP. 2018. Anthroponoses. In: Fuentes A (ed). The International Encyclopedia of Primatology. Wiley-Blackwell.
Muehlenbein MP. 2017. Primates on display: Potential disease consequences beyond bushmeat. Yearbook of Physical Anthropology 162:32-43.
Muehlenbein MP, Prall SP, DeHays HN. 2017. Immunity, hormones, and life history trade-offs. In: Jasienska G, Sherry DS, Holmes DJ (eds). The Arc of Life: Evolution and Health Across the Life Course. Springer, p. 99-120.
Prall SP, Larson EE, Muehlenbein MP. 2017. The role of dehydroepiandrosterone on functional innate immune responses to acute stress. Stress and Health. DOI 10.1002/smi.2752
Longman D, Prall SP, Shattuck EC, Stock J, Wells J, Muehlenbein MP. 2017. Short-term resource allocation during extensive athletic competition. American Journal of Human Biology. DOI 10.1002/ajhb.23052
Muehlenbein MP. 2016. Disease and human-animal interactions. Annual Review of Anthropology 45:395-416.
Ponzi D, Muehlenbein MP, Geary DC, Flinn MV. 2016. Cortisol, salivary alpha-amylase and children's perceptions of their social networks. Social Neuroscience 11(2):164-174.
Shattuck EC, Muehlenbein MP. 2016. Towards an integrative picture of human sickness behavior. Brain, Behavior, and Immunity 57:255-262.
Muehlenbein MP, Delgado MP, Prall SP, Ambu L, Nathan S, Alsisto S, Ramirez D, Selgado M, Escalante A. 2015. Evolutionary relationships among malaria (Plasmodium) species in nonhuman primates of Borneo. Molecular Biology and Evolution 32:422-439.
Prall SP, Muehlenbein MP. 2015. Dehydroepiandrosterone and multiple measures of functional immunity in young adults. American Journal of Human Biology 27:877-880.
Brenner S, Jones JP, Rutanen Whaley RH, Parker W, Flinn M, Muehlenbein MP. 2015. Evolutionary mismatch and chronic psychological stress. Journal of Evolutionary Medicine 3:235885.
Georgiev A, Muehlenbein MP, Prall SP, Emory Thompson M, Maestripieri D. 2015. Male quality, dominance rank and mating success in free-ranging rhesus macaques. Behavioral Ecology 26(3)763-772.
Shattuck EC, Muehlenbein MP. 2015. Human sickness behavior: Ultimate and proximate explanations. American Journal of Physical Anthropology 157:1-18.
Shattuck EC, Muehlenbein MP. 2015. Mood, behavior, testosterone, cortisol, and interleukin-6 in adults during immune activation: A pilot study to assess sickness behaviors in humans. American Journal of Human Biology 27:133-135.
Prall SP, Ambu L, Nathan S, Alsisto S, Ramirez D, Muehlenbein MP. 2015. Androgens and innate immunity in rehabilitated free-ranging Orangutans (Pongo pygmaeus morio) from Malaysian Borneo. American Journal of Primatology 77:642-650.
Muehlenbein MP (ed). 2015. Basics in Human Evolution. Elsevier. (39 chapters, 47 authors)
Muehlenbein MP, Wallis J. 2014. Understanding risks of disease transmission associated with primate-based tourism. In: Russon A, Wallis J, eds. Primate-Focused Tourism. Cambridge University Press, p. 278-291.
Prall SP, Muehlenbein MP. 2014. Testosterone and immune function in primates: A brief summary with methodological considerations. International Journal of Primatology 35:805-824.
Ponzi D, Muehlenbein MP, Sgoifo A, Geary DC, Flinn MV. 2014. Day-to-day variation of salivary cortisol and dehydroepiandrosterone (DHEA) in children from a rural Dominican community. Adaptive Human Behavior and Physiology 1:12-24.
Borniger JC, Chaudhry A, Muehlenbein MP. 2013. Relationships among musical aptitude, digit ratio, testosterone and cortisol in men and women. PLoS ONE 8(3):e57637.
Muehlenbein MP, Lewis CM. 2013. Health assessment and epidemiology. In: Sterling, Bynum and Blair, eds. Primate Ecology and Conservation: A Handbook of Techniques. Oxford University Press, 40-57.
Samson DR, Muehlenbein MP, Hunt KD. 2013. Do chimpanzees (Pan troglodytes schweinfurthii) exhibit sleep related behaviors that minimize exposure to parasitic arthropods? A preliminary report on sleep site choice and the arthropod-repellent properties of tree species (Cynometra alexandri). Primates 54:73-80.
Flinn MV, Ponzi D, Muehlenbein MP. 2012. Hormonal mechanisms for regulation of aggression in human coalitions. Human Nature 23:68-88.
Parker W, Perkins SE, Harker M, Muehlenbein MP. 2012. A prescription for clinical immunology: The pills are available and ready for testing. Current Medical Research and Opinion 28:1193-1202.
Muehlenbein MP. 2012. Emerging infectious diseases and human-wildlife interactions. In: Brondizio and Moran, eds. Human-Environment Interactions. Springer, p. 79-94.
Muehlenbein MP, Ancrenaz M, Sakong R, Ambu L, Prall SP, Fuller G, Raghanti MA. 2012. Ape conservation physiology: Fecal glucocorticoid responses in wild Pongo pygmaeus morio following human visitation. PLoS ONE 7(3): e33357.