# Determining the vector ecology and epidemiology of tick-borne spotted fever group Rickettsia in a large urban setting of Houston, TX.

> **NIH NIH R03** · BAYLOR COLLEGE OF MEDICINE · 2022 · $80,250

## Abstract

Summary. Spotted fever group rickettsioses (SFGR) are a family of closely related tick-borne rickettsial
pathogens that cause a febrile illness and, depending on the causative agent, can be fatal. In Texas, Rocky
Mountain Spotted Fever and another emerging SFGR pathogen, Rickettsia parkeri, are known to cause human
disease and likely represent a growing public health problem. We recently identified an unexpected number of
autochthonous cases of SFGR presenting to a large pediatric hospital in Houston, TX. These emergent cases
represent transmission of SFGR in a dense urban environment and indicate that our current understanding of
the risk of SFGR in the southern United States is critically outdated. In order to effectively gauge the public health
impact of SFGR, we must improve our understanding of its transmission dynamics, vector ecology and risk of
clinical disease in the southern US; especially in large urban center where millions could be at risk for infection.
Our central hypothesis is that SFGR is endemic in tick vectors in southeast Texas, including densely populated
urban centers. Using hospital-based geospatial data of locally acquired SFGR from three major pediatric and
adult hospital systems in the City of Houston/Harris County area, we will conduct targeted tick surveillance.
Additionally, we will work with municipal animal shelters to collect tick vectors off of dogs presenting to the shelter.
We will conduct molecular and geospatial analysis to determine the burden and distribution of rickettsial
pathogens and their associated vectors in the region. Our collaborative team of vector-borne disease
epidemiologists at Baylor College of Medicine, entomologists at Harris County Vector Control, and veterinarians
at City of Houston and Harris County are uniquely qualified to tackle this emerging public health problem. The
aims of this project are 1) determine the prevalence of spotted fever group rickettsioses in questing tick vectors
through targeted collections based on location of autochthonous human cases in Harris County, Texas, and 2)
determine the prevalence of rickettsial pathogens among tick vectors collected from domestic dogs in Harris
County, Texas. Our hope is that the novel data collected from this pilot study will ultimately aid in preventing
transmission and mitigating disease risk to humans. Our targeted approach, coupled with a molecular
epidemiologic investigation, will allow us to determine where tick vectors and SFGR pathogens are a relevant
threat to human health. Our long-term goals are to define the epidemiology of SFGR transmission in the densely
populated region of Harris County, and to design targeted public health to prevent further infection in the region.
This study will critically impact our understanding of SFGR in southeast Texas and will allow us the opportunity
to identify high-risk populations for targeted prevention and intervention efforts.

## Key facts

- **NIH application ID:** 10359130
- **Project number:** 5R03AI151609-02
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** Sarah Murphy Gunter
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $80,250
- **Award type:** 5
- **Project period:** 2021-02-24 → 2024-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10359130

## Citation

> US National Institutes of Health, RePORTER application 10359130, Determining the vector ecology and epidemiology of tick-borne spotted fever group Rickettsia in a large urban setting of Houston, TX. (5R03AI151609-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10359130. Licensed CC0.

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