. 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environment and indicate that our current understanding of the risk of SFGR in the southern United States is critically outdated.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.
Spotted fever group rickettsioses (SFGR) are a family of tick-borne pathogens that represent a significant and growing public health problem in the United States. Recent studies indicate that ongoing transmission of SFGR is occurring in Houston, TX with the epidemiology of transmission poorly defined. Our proposal aims to determine the vector ecology, transmission dynamics, and the risk of clinical disease in the City of Houston/Harris County area in order to effectively gauge the public health impact in a large urban population center where > 6 million could be at risk for infection.
