This project seeks to improve our knowledge of the relationships between bats and their bacterial and fungal symbionts, as well as how these symbiont communities can shape or influence viral pathogens. Initial sampling for this work has focused primarily in the East African countries of Uganda and Kenya, transecting a broad range of ecosystems and habitat types. These samples will provide baseline data for a large number of bat species with diverse life histories, and will also allow us to examine the effects of anthropogenic disturbance and unnatural habitat selection on chiropteran symbionts - including parasites, and pathogens. In addition to exploring the diversity of symbionts in African bats, we are utilizing chiropteran cell lines and germ-free mouse models to explore how microbes influence the immune response of bats to viral pathogens.
Malaria parasite diversity in the Afrotropical birds and mammals
Malaria parasites affect nearly all terrestrial vertebrates, and their impact on vertebrate hosts ranges from mild to severe, in some cases leading to extinction of entire species. Advances in molecular methods have revealed an astonishing degree of diversity among malaria parasites and closely-related haemosporidia, and host switching has occurred frequently throughout their evolutionary history. Without an accurate account of parasite diversity, we may only guess at the evolutionary history underlying current relationships. Exploration of novel parasite diversity is therefore a large component of my research. Since 2009, I have collected data for genetic and morphological analyses of haemosporidian parasites in birds, small mammals, and reptiles.
My research has focused primarily in the east African tropics, but has included Neotropical parasites as well. Samples included in my research are collected as part of a larger effort led by the Field Museum of Natural History to survey biodiversity, including parasites and pathogens, of birds and mammals. I use phylogenetic and comparative genomic approaches to resolve evolutionary relationships between malaria parasites of birds and mammals, and to explore the factors leading to diversification and host switching in haemosporidian parasites. Listed below are a few of my current projects.
Host life history and ecology as predictors of malaria parasite infection
Prevalence and host-specificity of malaria parasites are highly variable across avian taxa. By comparing rates of parasitism across a broad range of bird species, we can assess the extent to which host life history traits and ecological factors are linked to infection by Plasmodium, Haemoproteus, or Leucocytozoon. To study the relationship between host traits and probability of haemosporidian infection, colleagues and I examined a broad range of bird species from 16 avian orders in Northern Malawi, discovering over 200 new parasite lineages in the process. This study is the first to test such associations in Afrotropical birds. This work is in collaboration with the Cornell Lab of Ornithology, Field Museum of Natural History, and University of North Dakota.
Phylogenetics of avian malaria parasites and closely related haemosporidia
To identify and describe malaria parasite diversity, I have sequenced the mitochondrial cytochrome b gene. While useful for differentiation between parasite lineages (see MalAvi database), this marker does not provide sufficient data for resolution of relationships between most lineages of avian malaria (Plasmodium and Haemoproteus). I am therefore collecting additional data from nuclear and apicoplast genomes to improve phylogentic resolution for a diverse assemblage of malaria parasites I have identified in east African vertebrates.
Host associations and phylogenetics of haemosporidia in Old World bats
Among the many African mammals I have tested, bats have proven to be consistent hosts of haemosporidian parasites - most of which represent new genetic lineages, and possibly new species. I am collecting additional genetic data to examine their phylogenetic placement with respect to avian Plasmodium and haemosporidia of other mammalian taxa.
Micrographs of blood stage gametocytes of bat haemosporidians: (A-C) Hepatocystis cf. epomophori macrogametocytes ex. Epomops franquetti; (D-E) Polychromophilus melanipherus microgametocytes and (F) macrogametocyte ex. Miniopterus natalensis; (G-H) Nycteria sp. microgametocyte, (I) macrogametocyte, and (J) gametocyte ex. Hipposideros cyclops.
Laser capture and comparative genomics of Plasmodium parasites
Currently there are few publicly available genomes of Plasmodium parasites, with no representation of avian Plasmodium species. My colleagues and I have used laser capture microdissection microscopy (LCMM) methods to obtain parasite isolates from birds for genomic sequencing and comparative analyses. We have demonstrated that LCMM, paired with whole genome amplification methods, is a viable option for obtaining genomic material for comparative genomic analyses and the development of phylogenetic markers.
Lutz, H. L., Carryl, S., Santymire, R. M. In Press. Wildlife Microbial Genomics and Endocrinology. In D. Marco (editor). Microbial Ecology: Current advances from genomics, metagenomics, and other “omics” approaches. Horizon/Caister Academic Press, Poole, UK. Pre-order Book
Lutz, H. L., Tkach, V. T., Weckstein, J. D. 2017. Methods for Specimen-based Studies of Avian Symbionts. Pp. 157-183 in M. S. Webster (editor). The Extended Specimen: Emerging Frontiers in Collections-based Ornithological Research. Studies in Avian Biology (no. 50). CRC Press, Boca Raton, FL. Order Book
Lutz, H. L., Marra, N. J., Grewe, F., Carlson, J., Palinauskas, V. Valkiūnas, G., Stanhope, M. J. 2016. Laser capture microdissection microscopy and next generation genome sequencing of the avian malaria parasite, Plasmodium relictum. Parasitology Reseach, doi:10.1007/s00436-016-5237-5. PubMed, PDF Lutz, H. L., Patterson, B. D., Kerbis, J. C., Webala, P. W., Stanley, W. T., Gnoske, T. P., Hackett, S. J., Stanhope, M. J. 2016. Diverse sampling of East African haemosporidians reveals chiropteran origin of malaria parasites in primates and rodents. Molecular Phylogenetics and Evolution, 99, 7-15. PubMed, PDF
Lutz, HL, Hochachka, WM, Engel, JI, Bell, JA, Tkach, VV, Bates, JM, Hackett, SJ, Weckstein, JD. 2015. Parasite prevalence corresponds to host life history in a diverse assemblage of Afrotropical birds and haemosporidian parasites. PLoS ONE doi:10.1371/journal/pone.012154. PubMed, PDF
Lutz, HL, Weckstein, JD, Patané, JL, Bates, JM, Aleixo, A. 2013. Biogeography and spatio-temporal diversification of Selenidera and Andigena toucans (Aves:Ramphastidae). Molecular Phylogenetics and Evolution, 69, 873 – 883. PubMed, PDF
Awards & Support
2017 - 2019 NSF Postdoctoral Research Fellowship in Biology 2015 - pres. Edward A. Bouchet Graduate Honor Society Fellow 2014 - 2015 Lester Armour and William A. & Stella M. Rowley Fellow, Field Museum of Natural History 2013 - 2016 NSF Graduate Research Fellowship 2011 - 2012 Presidential Life Sciences Fellowship, Cornell University
2016 Council on Africa, Field Museum of Natural History 2015 Athena Fund, Cornell Lab of Ornithology 2014 Cornell Center for Comparative and Population Genomics 2014 Cornell College of Agriculture and Life Sciences Alumni Grant 2014 Next Gen/Illumina Grant, Pritzker Laboratory of Molecular Systematics and Evolution 2013 Athena Fund, Cornell Lab of Ornithology 2013 American Society of Naturalists 2013 NSF Malaria Research Coordination Network 2012 NSF Malaria Research Coordination Network 2012 Andrew W. Mellon Grant 2012 Sigma Xi, Cornell Chapter 2011 Krammer Graduate Research Grant