Project Details

Epidemiologic investigation of emergent spotted fever group rickettsioses in Belize

Sarah Gunter, PhD, MPH

Summary

BACKGROUND: Spotted fever group rickettsioses are a family of closely related tick-borne rickettsial pathogens that cause a febrile illness and, depending on the causative agent, is more often severe and fatal in pediatric patients. The prevalence and distribution of SFGR has increased significantly over the last decade with over 6,000 cases reported in the US annually; in Belize, SFGR pathogens have been identified in tick vectors but the burden of human disease remains unknown due to limited clinical resources. GAP: In Central America, 13 species of SFGR have been characterized including pathogenic species such as R. parkeri, R. rickettsii, and Rickettsia sp. Strain Atlantic Rainforest. In Belize, specifically, SFGR has been identified in the tick population but has not yet been implicated in acute clinical infection; though surrounding countries have identified SFGR cases. This limited surveillance that has been done in Belize indicates that SFGR is endemic to the region and is potentially causing unrecognized disease in this population. HYPOTHESIS: Surveillance within this population will identify cases presenting with acute spotted fever group infection, predominately clustered in the southern lowland region. R. parkeri and Rickettsia sp. Strain Atlantic Rainforest will be detected in tick-vectors collected predominately in the southern lowland region of Belize. METHODS: We will conduct an active surveillance study and advanced molecular characterization of spotted fever group Rickettsia specimens from children enrolled in the parent acute febrile illness study; we will use this data to inform tick collection. RESULTS: To date, we have enrolled and screened 3,015 cases presenting to health care facilities in Belize for Rickettsia. From this initial screening we have identified 0.7% (20/3,015) have presented with an eschar and febrile illness. Assessment of seroprevalence of SFGR in this population identified 10.8% were reactive. A collection of ticks in 4 ecoregions of Belize identified competent vectors of SFGR broadly distributed across the country. IMPACT: Data generated from this study will inform area clinicians, help guide diagnostic and treatment practices, and improve our ability to direct public health interventions to prevent transmission.