Next time you’re drawn to the kitchen after smelling something delicious in the air, you can thank olfaction: your sense of smell. Olfaction is one type of sensory input that we rely on to survive and thrive in our environment. Just like we’re drawn to the smell of particular foods, parasites also use olfaction to sense and guide them to hosts from which they can feed. Parasites affect over one billion people worldwide, causing a variety of health issues including chronic gastrointestinal distress and stunted growth, yet we still understand very little about them. By learning more about how parasites use olfaction to find their hosts, and how the parasitic brain transmits these signals, we can develop more effective treatments to combat these pathogens.
UCLA Neuroscientist Elissa Hallem’s research focuses on the behavior of parasitic worms seeking out a host based on sensory cues. She seeks to understand how the circuits of cells in the worm brain transmit these cues. When an odor like carbon dioxide or sweat is sensed by an olfactory neuron, it sends a signal to the brain, which influences the muscles to move. Dr. Hallem’s lab studies behavior by exposing worms to certain smells and determining whether they move toward or away from the source. In addition to studying parasitic worms, Dr. Hallem’s lab also uses the well-understood C. elegans worm to better understand how the parasitic nervous system evolved to support host-finding behavior. Her findings about the genetics, neurobiology, and behavior of these worms contribute to our understanding of how many parasites work.