Elissa Hallem, Ph.D.

Work Titles
UCLA Professor, Brain Research Institute Professor, Microbiology, Immunology & Molecular Genetics Member, Immunity, Microbes & Molecular Pathogenesis GPB Home Area Member, Molecular, Cellular & Integrative Physiology GPB Home Area Member, Neuroscience GPB Home Area

Contact Information:

Work Email Address:



Hallem lab website

Office Phone Number:

(310) 825-1778

Office Address:

Los Angeles, CA 90095

Research Interest:

The neural basis of parasitic behaviors

Our research focuses on sensory circuit function in parasitic and free-living animals, and lies at the interface of neurobiology and parasitology. Nearly all organisms respond to sensory stimuli, but how sensory circuits specify behavior is poorly understood. We are investigating the neural basis of sensory behaviors in the context of human parasitism. We use parasitic nematodes and the free-living nematode C. elegans as models. The goals of our research are to understand how parasitic worms use sensory cues to locate hosts to infect, how sensory circuits of parasitic animals differ from those of free-living animals to enable parasitic behaviors, and how sensory microcircuits generate flexible outputs. Our research addresses fundamental questions of sensory circuit function and evolution. In addition, human-parasitic worms are a major cause of morbidity worldwide, and a better understanding of their behaviors may enable the development of novel strategies for preventing infections.


A selected list of publications:

Chavez IN, Brown TM, Assié A, Bryant AS, Samuel BS, Hallem EA   Skin-penetrating nematodes exhibit life-stage-specific interactions with host-associated and environmental bacteria BMC biology, 2021; 19(1): 221.
Bryant AS, DeMarco SF, Hallem EA   Strongyloides RNA-seq Browser: a web-based software platform for on-demand bioinformatics analyses of Strongyloides species G3, 2021; 11(5): 221.
Bryant AS, Hallem EA   The Wild Worm Codon Adapter: a web tool for automated codon adaptation of transgenes for expression in non-Caenorhabditis nematodes G3, 2021; 11(5): 221.
Gang SS, Castelletto ML, Yang E, Ruiz F, Brown TM, Bryant AS, Grant WN, Hallem EA   Chemosensory mechanisms of host seeking and infectivity in skin-penetrating nematodes Proc Natl Acad Sci USA, 2020; .
Banerjee N, Hallem EA   Decoding Inter-individual Variability in Experience-Dependent Behavioral Plasticity Neuron, 2020; 105(1): 7-9.
Castelletto ML, Gang SS, Hallem EA   Recent advances in functional genomics for parasitic nematodes of mammals J Exp Biol, 2020; 223(Pt Suppl 1): 841-854.
Banerjee N, Hallem EA   The role of carbon dioxide in nematode behaviour and physiology Parasitology, 2020; 147(8): 841-854.
Rengarajan S, Yankura KA, Guillermin ML, Fung W, Hallem EA   Feeding state sculpts a circuit for sensory valence in Caenorhabditis elegans Proc Natl Acad Sci USA, 2019; 116(5): 1776-1781.
Bryant AS, Ruiz F, Gang SS, Castelletto ML, Lopez JB, Hallem EA   A critical role for thermosensation in host seeking by skin-penetrating nematodes Curr Biol, 2018; 28: 2338–2347.
Banerjee N, Hallem E   Sexual Dimorphisms: How sex-shared neurons generate sex-specific behaviors Curr Biol, 2018; 28: R254-R256.
Bryant AS, Hallem EA   Temperature-dependent behaviors of parasitic helminths Neurosci Lett, 2018; 687(3): 290-303.
Bryant AS, Hallem EA   Terror in the dirt: Sensory determinants of host seeking in soil-transmitted mammalian-parasitic nematodes Int J Parasitol Drugs Drug Resist, 2018; 8(3): 496-510.
Guillermin ML, Carrillo MA, Hallem EA   A single set of interneurons drives opposite behaviors in C. elegans Curr Biol, 2017; 27: 2630-2639.
Ruiz F, Castelletto ML, Gang SS, Hallem EA   Experience-dependent olfactory behaviors of the parasitic nematode Heligmosomoides polygyrus PLoS Pathog, 2017; 13: e1006709.
Cevallos JA, Okubo RP, Perlman SJ, and Hallem EA   Olfactory preferences of the parasitic nematode Howardula aoronymphium and its insect host Drosophila falleni J Chem Ecol, 2017; 43: 362-373.
Gang SS, Castelletto ML, Bryant AS, Yang E, Mancuso N, Lopez JB, Pellegrini M, Hallem EA   Targeted mutagenesis in a human-parasitic nematode PLoS Pathog, 2017; 13: e1006675.
Gang SS and Hallem EA   Mechanisms of host seeking by parasitic nematodes Mol Biochem Parasitol, 2016; 208: 23-32.
Rengarajan S and Hallem EA   Olfactory circuits and behaviors of nematodes Curr Opin Neurobiol, 2016; 41: 136-148.
Lee J, Dillman AR, Hallem EA   Temperature-dependent changes in the host-seeking behaviors of parasitic nematodes BMC Biol, 2016; 14: 36.
Carrillo MA and Hallem EA   Gas sensing in nematodes Mol Neurobiol, 2015; 51: 919-931.
Pena JM, Carrillo MA, and Hallem EA   Variation in the susceptibility of Drosophila to different entomopathogenic nematodes Infect Immun, 2015; 83: 1130-8.
Castelletto ML, Gang SS, Okubo RP, Tselikova AA, Nolan TJ, Platzer EG, Lok JB, and Hallem EA   Diverse host-seeking behaviors of skin-penetrating nematodes PLoS Pathog, 2014; 10: e1004305.
Carrillo MA, Guillermin ML, Rengarajan S, Okubo RP, and Hallem EA   O2-sensing neurons control CO2 response in C. elegans J Neurosci, 2013; 33: 9675-83.
Chaisson KE and Hallem EA   Chemosensory behaviors of parasites Trends Parasitol, 2012; 28: 427-436.
Dillman AR, Guillermin ML, Lee J, Kim B, Sternberg PW, and Hallem EA   Olfaction shapes host-parasite interactions in parasitic nematodes Proc Natl Acad Sci USA, 2012; 109: E2324-E2333.
Guillermin ML, Castelletto ML, and Hallem EA   Differentiation of carbon dioxide-sensing neurons in Caenorhabditis elegans requires the ETS-5 transcription factor Genetics, 2011; 189: 1327-39.

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