The occurrence and movement of Fancisella tularensis McCoy and Chapin across landscapes

Abstract

Tularemia is a one of the most complex zoonotic diseases. Francisella tularensis McCoy and Chapin, the causative agent of tularemia is considered endemic in Texas, but outbreaks are rare and there are few human cases each year. Tularemia is listed as a Category A biological weapon and air samples are taken daily in select major metropolitan areas, including Houston, to monitor for its presence. I determined the potential risk for tularemia introduction and spread in southeast Texas through field surveillance for the pathogen and its major arthropod vector in the region, Amblyomma americanum (L.); completion of a habitat capability map for A. americanum, based on landscape analysis of the study area; and potential movement and long-term establishment of tularemia through development of a spatially explicit, agent-based, simulation model. Field and laboratory investigations resulted in the identification of two samples positive for F. tularensis. A feral cat tested positive for Type B tularemia using a new aptamer-based assay, and one sample returned positive in Amblyomma maculatum by polymerase chain reaction. This work sheds light on a complex host-pathogen-vector interaction in the rural to urban interface and establishes a framework for future tularemia field work and pathogen modeling in the rural to urban interface.