Unexplained Critical Illnesses and Deaths of Possible Infectious Etiology (UNEX) and Medical Examiner Infectious Deaths Surveillance (MED-X), 2015

Surveillance for unexplained critical illnesses and deaths of possible infectious etiology (UNEX) began September 1995. Focus is given to cases <50 years of age with no significant underlying conditions; however, any case should be reported regardless of the patient’s age or underlying medical conditions to determine if further testing conducted or facilitated by MDH may be indicated. In addition to provider reporting, death certificates are reviewed for any deaths in persons <50 years of age with no apparent significant underlying conditions for possible unexplained infectious syndromes.

In 2006, MDH began Medical Examiner (ME) Infectious Deaths Surveillance (known as MED-X) to evaluate all ME cases for infectious-related deaths. MEs report explained and unexplained cases. Unexplained deaths in previously healthy individuals <50 years of age are included regardless of infectious hallmarks; this is predominantly represented by Sudden Unexplained Infant Deaths. In addition, we review death certificates, in which an autopsy was performed by an ME, with a potential infectious cause of death listed. Cases found through death certificate review are also considered for UNEX surveillance if they are <50 years of age and have no immunocompromising conditions.

Testing of pre-mortem and post-mortem specimens is conducted at the PHL and the CDC Infectious Diseases Pathology Branch. Cases are excluded from UNEX if they are determined to be explained by providers, are not critically ill, or have no infectious disease hallmarks.

Testing of pre-mortem and post-mortem specimens is conducted at the PHL and the CDC Infectious Diseases Pathology Branch (IDPB). Cases are excluded from UNEX if they are determined to be explained by providers, are not critically ill, or have no infectious disease hallmarks.

In 2015, 87 cases met UNEX criteria (71 deaths, 16 critical illnesses) in 2015, compared to 89 cases in 2014. Of the 87, 74 (85%) were reported by providers and 13 (15%) were found by death certificate review. Thirty-two (37%) cases presented with respiratory symptoms; 23 (26%) with sudden unexpected death; 17 (20%) with neurologic symptoms; 2 (2%) with shock/sepsis; 9 (10%) with gastrointestinal illness, 3 (4%) with cardiac symptoms and 1 (1%) with multiple symptoms. The age of cases ranged from newborn to 75 years. The median age was 15 years among 74 reported cases, and 50 years among 13 non-reported cases found through active surveillance. Fifty-two percent resided in the metropolitan area and 52% were male.

There were 272 MED-X cases in 2015; 71 of these also met UNEX criteria. The median age of the cases was 45 years, and 64% were male. There were 170 (63%) cases found through death certificate review; MEs reported 98 (36%) cases. The most common syndrome was respiratory disease (n=102 [37%]). Of the 272 cases, 67 (25%) were confirmed to have had an infectious cause, 160 (52%) had possible infectious causes, and 45 (17%) were non-infectious or unknown cause.

There were 146 cases that had specimens tested at the PHL and/or the IDPB. Forty-seven cases had pathogens identified as confirmed, probable, or possible cause of illness, including 45 UNEX cases (Table 5). Among 43 unexplained deaths occurring in those <50 years of age without any immunocompromising conditions, UNEX helped to identify the pathogen(s) involved in 24 (56%) cases. ME surveillance detected an additional 36 cases with pathogens identified by MEs as the cause of death (Table 5). Cases with pathogens of public health importance detected included a 59 year-old male with a 3-week history of fever, nausea, and vomiting who collapsed at home and was not able to be resuscitated. Pancarditis was noted on autopsy and a positive Western blot for Borrelia burgdorferi was reported 3 days after death. B. burgdorferi spirochetes were visualized in autopsied heart tissues at CDC documenting the first Lyme carditis death in Minnesota. UNEX laboratory testing detected lymphocytic choriomeningitis virus (LCMV) infection in a 15 year-old female. A home investigation was initiated and was found to have a rodent infestation with droppings that were positive for LCMV. Finally, UNEX surveillance was able to diagnose a case of Neisseria meningitidis Group C in a 47 year-old male linked to a multistate outbreak associated with men who have sex with men, the majority of whom were HIV-infected.

• For up to date information see>> Unexplained Deaths and Critical Illnesses
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2015