# Chemosensation in skin-penetrating parasitic nematodes

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2020 · $512,557

## Abstract

PROJECT SUMMARY
Skin-penetrating nematodes, including the human-parasitic threadworm Strongyloides stercoralis, infect nearly
one billion people worldwide and are a major source of morbidity in low-resource settings. Infections can cause
chronic gastrointestinal distress, stunted growth and cognitive impairment in children, and even death in the case
of S. stercoralis infection. S. stercoralis has a complex life cycle that includes a parasitic generation inside the
host and a free-living generation outside the host. In previous work, we showed that the detection of carbon
dioxide (CO2) and host-emitted odorants is important for multiple stages of the S. stercoralis life cycle. Moreover,
we showed that CO2 and many host-emitted odorants elicit life-stage-specific behavioral responses, such that
the chemosensory preferences of the infective larvae are distinct from those of the non-infective life stages.
However, the neural mechanisms that mediate these chemosensory responses have not yet been investigated.
Here, we propose to elucidate the molecular, cellular, and circuit mechanisms of chemosensation in
S. stercoralis. In Aim 1, we will elucidate the neural mechanisms that mediate CO2 response in S. stercoralis.
We will also investigate how CO2 microcircuit function is modulated across life stages to generate life-stage-
specific responses to CO2. In Aim 2, we will elucidate the neural mechanisms that mediate responses to host-
emitted odorants in S. stercoralis. We will also investigate how olfactory microcircuit function is modulated across
life stages. In Aim 3, we will address the molecular mechanisms of chemosensation. We will identify genes and
signaling pathways that mediate responses to CO2 and host-emitted odorants in S. stercoralis. We will also
identify molecular mechanisms that contribute to parasite-specific and life-stage-specific chemosensory
responses. Taken together, our results will provide key insights into the chemosensory mechanisms that underlie
the complex interactions of parasitic nematodes with their human hosts.

## Key facts

- **NIH application ID:** 9937697
- **Project number:** 5R01DC017959-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** ELISSA ANYON HALLEM
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $512,557
- **Award type:** 5
- **Project period:** 2019-06-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9937697

## Citation

> US National Institutes of Health, RePORTER application 9937697, Chemosensation in skin-penetrating parasitic nematodes (5R01DC017959-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9937697. Licensed CC0.

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