Unexplained Critical Illnesses and Deaths of Possible Infectious Etiology (UNEX) and Medical Examiner Infectious Deaths Surveillance (MED-X), 2018

MDH conducts surveillance for unexplained deaths and critical illnesses in an effort to identify those that may have an infectious etiology. This surveillance is performed through two complementary surveillance systems, Unexplained Critical Illnesses and Deaths of Possible Infectious Etiology (known as UNEX), and Medical Examiner (ME) Infectious Deaths Surveillance (known as MED-X) which is not limited to deaths with infectious hallmarks. 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. Testing of pre-mortem and post-mortem specimens is conducted at the MDH PHL and the CDC Infectious Diseases Pathology Branch (IDPB).

In 2018, 111 cases met UNEX criteria (80 deaths, 31 critical illnesses), compared to 80 cases in 2017. Of the 111, 96 (86%) were reported by providers and 15 (14%) were found by death certificate review. Forty-one (37%) cases presented with respiratory symptoms; 27 (24%) with sudden unexpected death; 24 (22%) with neurologic symptoms; 7 (6%) with shock/sepsis; 6 (5%) with cardiac symptoms; 2 (2%) with gastrointestinal illness, 1 (1%) with hepatic symptoms, and 3 (3%) with multiple symptoms. The age of cases ranged from newborn to 72 years. The median age was 6 years among 96 reported cases, and 39 years among 15 non-reported cases found through active surveillance. Sixty-two percent resided in the metropolitan area, 50% were female, and 8% were non-Minnesota residents who were either hospitalized in Minnesota or investigated by a Minnesota ME.

There were 257 MED-X cases in 2018; 80 of these also met UNEX criteria. The median age of the cases was 44 years, and 57% were male. There were 155 (60%) cases found through death certificate review; MEs reported 97 (38%) cases. The most common syndrome was pneumonia/upper respiratory infection (n=94 [37%]).

There were 193 potential UNEX or MED-X cases that had specimens tested at the PHL and/or the IDPB. Fifty-four cases had pathogens identified as confirmed, probable, or possible cause of illness, including 43 UNEX deaths (Table 5). Fifty-five were determined to be non-infectious. Among 52 unexplained deaths occurring in those <50 years of age without any immunocompromising conditions, UNEX helped to identify the pathogen(s) involved in 29 (56%) cases. MED-X surveillance detected an additional 47 cases with pathogens identified by MEs as the cause of death (Table 5). Cases with pathogens of public health importance detected included a 57 year-old male who was found deceased in his home. He had recently traveled to Louisiana, and at the time of his death, his travel companion had been admitted with Legionella pneumonia. Although the ME had initially declined autopsy, the PHL was able to culture L. pneumonphila serogroup 1 from a blood sample collected for toxicology screening confirming the outbreak and leading to a public health investigation. UNEX testing detected coxsackievirus B5 in multiple specimens from a neonate and a 7 year-old who presented with myocarditis within days of each other to a tertiary care hospital. Finally, UNEX surveillance was able to diagnose Mycobacterium tuberculosis complex in a 55 year-old male who had succumbed to accidental head injuries. Granulomatous lesions in the lungs were noted on autopsy, and following the diagnosis at IDPB, a public health contact investigation was initiated. No secondary TB cases were identified.

Further investigation determined the man had a splenectomy from an earlier accident, and also was a dog owner. Finally, UNEX surveillance was able to diagnose a case of La Crosse encephalitis in a 14 year-old female. A public health investigation found that she lived near a private property with large numbers of used tires that were collecting rainwater.

• 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, 2018