Unexplained Deaths Possibly Related to Bioterrorism


The purpose of the Unexplained Deaths Possibly Related to Bioterrorism project is to identify patients who die in the hospital of unknown causes and who have the clinical profile suggestive of a bioterrorism agent etiology. An assessment of the degree which diagnostic testing was performed to rule in or out the possibility of exposure to such agents was performed.   

Goals & Objectives

  • Identify unexplained deaths of possible infectious etiology among previously healthy Connecticut residents who were hospitalized at the time of death.
  • Identify the subset of decedents who presented with signs and symptoms that may be consistent with early stages of infection compatible with inhalational anthrax, botulism, smallpox, or inhalational tularemia.
  • Assess the extent and completeness of the work-up received by these patients.  


Electronic files of all Connecticut death certificates were obtained from the Connecticut Department of Public Health Section of Vital Records. These files included the original text cause of death fields, as completed by the certifier, and ICD-10 coded cause of death data. These data were screened electronically using SAS to identify death certificates that contained at least one ICD-10 inclusion code in either the primary (or underlying) cause of death field or any of the contributing cause of death fields. Death certificates with at least one inclusion code were further screened to exclude those that contained any ICD-10 exclusion codes in the cause of death fields. Death certificates not excluded by ICD-10 codes were then screened and excluded based on residency, hospital status, and manner of death. Death Certificates not excluded through computer processing underwent a text review of the non-coded cause of death fields to exclude deaths that might have been erroneously included due to ICD-10 coding errors or data entry errors. Medical charts of the included decedents were reviewed and data were collected on a standardized data collection instrument.

There were 59,971 deaths certified in Connecticut in 2002 and 2003. Of these, 4,054 (6.8%) were identified as a potentially unexplained infectious death based on data from the death certificate, and were flagged for chart review. Of these, 3,974 medical charts were available for review which 354 (8.9%) of these were classified as an unexplained infectious death. Although there were no diagnosed cases of bioterrorism-related infections in CT during 2002 and/or 2003, 133 (38%) of the 354 unexplained infectious deaths met at least one of our suspect case definitions. Of the 133, 127 (95%) deaths met the suspect case definition for inhalational anthrax, and 6 (5%) met the suspect case definition for both inhalational anthrax and inhalational tularemia. None of the suspect cases met the smallpox or botulism case definition.

To assess the extent and completeness of the patient work-up, we examined the testing that was performed within the first 48 hours of hospitalization for the 133 suspect cases. The minimal appropriate testing in order to rule in or out one of these agents was determined to be having a white blood cell count performed, a chest radiograph performed, and blood cultures obtained prior to antibiotic administration within the first 48 hours of hospitalization. All 133 cases had a peripheral white blood cell count and a chest radiograph performed within the first 48 hours. 115 (86%) had blood cultures drawn. Of the 18 who did not have blood cultures drawn, all 18 met the suspect case definition for inhalational anthrax. None of the suspect cases had tularemia or anthrax listed in their differential diagnosis nor did they have disease specific serology performed. A detailed assessment of the extent and completeness of the diagnostic testing performed on these decedents are ongoing.

Related Links

JP Palumbo, JI Meek, DM Fazio, SB Turner, JL Hadler, AN Sofair.  Unexplained Deaths in Connecticut, 2002-2003: Failure to consider Category A Bioterrorism Agents in Differential Diagnoses.Disaster Med Public Health Preparedness. 2008;2:87-94

When a Death Defies Explanation Yale Medicine, Autumn 2002