Madagascar is a biodiversity hotspot, whose unique environment is undergoing major changes due to climate change, population growth, market integration and human-driven land use changes. These environmental transitions increase direct and indirect risks to infectious and non-communicable diseases. Working with rural communities surrounding the Marojejy National Park, our research explores these complex global health links.

Land Use Change, Transmission Potential Networks and Disease Spread in Madagascar.

Funded by the Ecology and Evolution of Infectious Disease Program (NIH, $2,451,309)

This highly interdisciplinary team of natural and social scientists investigates anthropogenic land use and its impact on infectious disease transmission among humans and animals in Madagascar.  We are:

  • Using network science and geographic approaches to model transmission pathways in rural communities.
  • Testing whether the transmission pathways explain patterns of infection.
  • Identifying the factors that influence the contact patterns, which is crucial for understanding social networks and controlling disease transmission.
  • Investigating the role of land use change and small mammal communities (especially rats) on human infectious disease risk.

Selected Publications

  1. Kauffman, K., C. Werner, G. Titcomb, M. Pender, J.Y. Rabezara, J.P. Herrera, J.T. Shapiro, A. Solis, V. Soarimalala, P. Tortosa, R. Kramer, J. Moody and C.L. Nunn (2022). Comparing transmission potential networks based on social network surveys, close contacts, and environmental overlap in rural Madagascar. Journal of the Royal Society Interface 19: 20210690.
  2. Barrett, T., G.C. Titcomb, M.M. Janko, M. Pender, K. Kauffman, A. Solis, T.M. Randriamoria, H.S. Young, P.J. Mucha, J. Moody, R.A. Kramer, V. Soarimalala, C.L. Nunn (2024). Disentangling Social, Environmental, and Zoonotic Transmission Pathways of a Gastrointestinal Protozoan (Blastocystis spp.) in Northeast Madagascar. American Journal of Biological Anthropology e25030.
  3. M.V. Evans, T. Ramiadantsoa, K. Kauffman, J. Moody, C.L. Nunn, J.Y. Rabezara, P. Raharimalala, T.M. Randriamoria, V. Soarimalala, G. Titcomb, A. Garchitorena, B. Roche (2023). Socio-demographic variables can guide prioritized testing strategies for epidemic control in resource-limited contexts. Journal of Infectious Diseases 228: 1189-1197
  4. Dubrulle, J., K. Kauffman, V. Soarimalala, T. Randriamoria, S.M. Goodman, J. Herrera, C.L. Nunn, P. Tortosa (in press). Effect of land-use on hantavirus infection among introduced and endemic small mammals of Madagascar. Ecology and Evolution.
  5. Kramer, R.A., J.P. Herrera, M. Pender, V. Soarimalala, C.L. Nunn (2023). Ecosystem change, market participation, and human health in villages proximate to Parc National de Marojejy. Malagasy Nature, 17: 267-280.

Impact of Climate Change on Transmission Potential Networks and Disease Spread in Madagascar

Funded by National Institutes of Health ($94,500)

We are investigating perceptions of climate change among smallholder farmers and their climate adaptation practices.  We are:

  • Using survey instruments to quantify farmers’ perceptions of how climate is changing and impacting their crops.
  • Collecting data on rainfall, temperature, humidity and environmental variables to ground-truth satellite data.
  • Positioning our team to investigate the connections between climate change, infectious disease risk, and food security.

Selected Publications

  1. Barrett, T., V. Soarimalala, M. Pender, R.A. Kramer, C.L. Nunn (in revision).  Climate change perceptions and adaptive behavior among smallholder farmers in Northeast Madagascar. PLoS Climate.
  2. Titcomb, G., J. Eulmen, and C.L. Nunn (2024). Infectious disease responses to human climate change adaptations.  Global Change Biology 30: e17433.

Market Integration, Land Use, and Pathogen Transmission in Rural Madagascar

Funded by Ecology and Evolution of Infectious Diseases Program (NSF and BSF, $3,219,697)

Building on our existing NIH-funded EEID project, we are investigating connections that exist among rural communities and their consequences for infectious disease transmission.  We hypothesize that movement among villages is predicted by variation in market integration, and this has consequences for regional transmission of infectious diseases.  We are:

  • Using travel surveys and other data to characterize inter-community movement.
  • Characterizing variation in different dimensions of market integration, and exposure to infectious diseases using high-throughput serology (VirScan).
  • Investigating how important market crops (rice and vanilla) influence the abundance of rats and mice and their movement in and out of villages.

Selected Publications

  1. Kolinski, L., T. Barrett, R. Kramer, and C.L. Nunn (2024). How Market Integration Impacts Human Disease Ecology.  Evolution, Medicine, and Public Health.

Bass Connections

Funded by the Bass Connections Program at Duke.

This program supports faculty to build interdisciplinary and vertically integrated teams, composed of undergraduates, graduate students, postdocs and faculty.  Past projects have explored topics such as:

  • Zoonotic disease dynamics
  • Health effects of cookstoves and indoor pollution
  • Double burden of infectious and non-infectious diseases

Selected Publications

  1. Herrera, J., N. Wickenkamp, M. Turpin, F. Baudino, P. Tortosa, S.M. Goodman, V. Soarimalala, T.N. Ranaivoson, C.L. Nunn (2020).  Effects of land use, habitat characteristics, and small mammal community composition on Leptospira prevalence in northeast Madagascar.  PLOS Neglected Tropical Diseases 14:e0008946.
  2. Samson, D.R., M. Manus, A. Krystal, E. Fakir, J.J. Yu and C.L. Nunn (2017). Segmented sleep in a non-electric, small-scale agricultural society in Madagascar. American Journal of Human Biology 29: 10.1002/ajhb.22979.
  3. Manus, M.B., J.J. Yu, L.P. Park, O. Mueller, S.C. Windsor, J.E. Horvath, and C.L. Nunn (2017). Environmental influences on the skin microbiome of humans and cattle in rural Madagascar. Evolution, Medicine and Public Health, doi.org/10.1093/emph/eox013.
  4. Manus, M.B., G. Bloomfield, A.S. Leonard, L.N. Guidera, D.R. Samson, and C.L. Nunn (2018). High prevalence of hypertension in an agricultural village in Madagascar. PLoS One E 13(8): e0201616.
  5. Herrera, J., R. Jean Yves, N.A.F Ravelomanantsoa, M. Metz, C. France, A. Owens, M. Pender, C.L. Nunn, and R.A. Kramer (2021). Food insecurity related to agricultural practices and household characteristics in rural communities of northeast Madagascar. Food Security 13: 1393-1405.