# Emerging understanding of the rat flea response to Yersinia pestis infection

> **NIH NIH R21** · WASHINGTON STATE UNIVERSITY · 2024 · $194,954

## Abstract

PROJECT SUMMARY
Fleas are obligate blood-feeding arthropods that are associated with several notable bacterial-derived human
diseases, i.e. rickettsioses, bartonelloses, and plague. Plague caused by the Gram negative bacterium, Yersinia
pestis, is difficult to eradicate because flea-borne transmission is endemic in natural foci of wild rodents and their
associated fleas world-wide. Insecticide control is the primary strategy for disease management, but like many
vector-borne diseases this is compromised by development of insecticide resistance in fleas. Development of
novel vector-based strategies for bacterial pathogen control are therefore a priority. However, to accomplish this,
we must overcome the dearth in knowledge regarding flea biology, particularly the detailed processes of the flea
host response to infection. Towards this goal our lab has recently made novel observations that the Y. pestis
factor Ymt is involved in manipulating the bloodmeal digestion processes related to detoxification of heme in a
blood source dependent manner. Our goals are to understand the Ymt-mediated flea responses to infection that
underlie successful Y. pestis infection of rat fleas. Therefore, our central hypothesis is that Ymt modulates mouse
blood digestion processes related to heme detoxification and antioxidant defense to enable Y. pestis infection in
rat fleas. Two aims will test this hypothesis. In Aim 1 we will determine if bloodmeal derived heme is correlated
with flea ROS-mediated immune responses in a Ymt and blood source dependent manner. In Aim 2 we will use
comparative transcriptomics to identify flea transcripts that are modulated in a Ymt-specific manner. Our
proposed exploratory studies have potential to uncover biological processes related to blood digestion and
immune processes in flea vectors that can be targeted to reduce establishment of transmissible infections to
humans. Therefore, the proposed research lies within a part of the NIH's mission to develop fundamental
knowledge that will assist in reducing the burden of infectious diseases on human health.

## Key facts

- **NIH application ID:** 10739323
- **Project number:** 5R21AI164730-02
- **Recipient organization:** WASHINGTON STATE UNIVERSITY
- **Principal Investigator:** Viveka Vadyvaloo
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $194,954
- **Award type:** 5
- **Project period:** 2022-11-11 → 2025-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10739323

## Citation

> US National Institutes of Health, RePORTER application 10739323, Emerging understanding of the rat flea response to Yersinia pestis infection (5R21AI164730-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10739323. Licensed CC0.

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