Unexplained Deaths and Critical Illnesses (UNEX)   
Annual Summary of Reportable Diseases

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 by the MDH Public Health Lab (PHL) and the CDC Infectious Diseases Pathology Branch (IDPB). 

In 2022, 134 cases met UNEX criteria (120 deaths, 15 critical illnesses), compared to 206 cases in 2021. Of the 134, 123 (92%) were reported by providers and 11 deaths were found by death certificate review. Seventy-eight (57.4%) cases presented with respiratory symptoms; 31 (23.1%) with sudden unexpected death; 11 (8.2%) with neurologic symptoms; 8 (5.9%) with shock/sepsis; 5 (3.6%) with gastrointestinal symptoms; one (0.6%) with cardiac symptoms; one (0.6%) with hepatic symptoms; one (0.6%) with multiple symptoms. The age of cases ranged from newborn to 89 years, with a median age of 35.5 years. Fifty-seven percent resided in the 7-county metropolitan area, 63% were male, and 11% were non-MN residents who were either hospitalized in MN or investigated by a MN medical examiner. 

There were 376 MED-X cases in 2022; 120 of these also met UNEX criteria. The median age of the cases was 45 years, and 60% were male. There were 141 (38%) cases found through death certificate review and MEs reported 235 (62%) cases. The most common syndrome was pneumonia/upper respiratory infection (n=168 [45%]). There were 370 potential UNEX or MED-X cases that had specimens tested at the PHL and/or the IDPB. One hundred and eighty-one cases were determined to be non-infectious. Seventy-seven cases had pathogens identified as confirmed, probable, or possible cause of illness, including 67 UNEX deaths (Table 5). Among 53 unexplained deaths occurring in those <50 years of age without any immunocompromising conditions, were initially thought to have community acquired pneumonia. Autopsies revealed budding yeast in the lungs that was confirmed as Blastomyces dermatitidis in both decedents. The UNEX program also identified 35 deaths due to SARS-CoV-2 virus that UNEX helped to identify the pathogen(s) involved in 24 (45%) cases. MED-X surveillance detected an additional 50 cases with pathogens identified by MEs as the cause of death (Table 5). Cases with pathogens of public health importance detected included a 35 year old woman and a 52 year old male who occurred outside of traditional healthcare facilities, such as hospitals or congregate care settings. Due to the ongoing COVID-19 pandemic, the UNEX/MED-X team expanded surveillance testing to include swab autopsies that were performed on suspect infectious deaths that did not have an autopsy performed. Nasal pharyngeal swabs were collected from decedents at funeral homes and decedents’ homes. A total of 39 specimens were submitted to MDH and all decedents had known symptoms prior to death. Of those, 17 (43%) had potential pathogens detected, including SARS-CoV-2 (n=14), respiratory syncytial virus (n=1), bocavirus (n=1) and rhinovirus (n=1).

• For up to date information see: Unexplained Deaths and Critical Illnesses

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 by the MDH Public Health Lab (PHL) and the CDC Infectious Diseases Pathology Branch (IDPB). 

In 2021, 206 cases met UNEX criteria (191 deaths,15 critical illnesses), compared to 131 cases in 2020. Of the 206, 193 (94%) were reported by providers and 13 deaths were found by death certificate review. One hundred twenty-five (60.5%) cases presented with respiratory symptoms; 55 (27%) with sudden unexpected death; 14 (7%) with neurologic symptoms; 4 (2%) with shock/sepsis; 5 (2%) with gastrointestinal symptoms; 2 (1%) with cardiac symptoms; 1 (0.5%) with multiple symptoms. The age of cases ranged from 8 days to 89 years, with a median age of 47 years. Fifty-one percent resided in the 7-county metropolitan area, 64% were male, and 16% were non-MN residents who were either hospitalized in MN or investigated by a MN medical examiner. 

There were 554 MED-X cases in 2021; 191 of these also met UNEX criteria. The median age of the cases was 48.5 years, and 62% were male. There were 262 (47%) cases found through death certificate review and MEs reported 292 (53%) cases. The most common syndrome was pneumonia/upper respiratory infection (n=319 [58%]). There were 582 potential UNEX or MED-X cases that had specimens tested at the PHL and/or the IDPB. Two hundred and sixty-one cases were determined to be non-infectious. One hundred forty-five cases had pathogens identified as confirmed, probable, or possible cause of illness, including 139 UNEX deaths (Table 5). Among 49 unexplained deaths occurring in those <50 years of age without any immunocompromising conditions, UNEX helped to identify the pathogen(s) involved in 28 (57%) cases. MED-X surveillance detected an additional 129 cases with pathogens identified by MEs as the cause of death (Table 5). Cases with pathogens of public health importance detected included an 84-year-old male who developed neurologic symptoms 5 months after being bitten by a rabid bat and received appropriate rabies post exposure prophylaxis (PEP). An autopsy revealed meningoencephalitis consistent with rabies virus and postmortem samples submitted to IDPB and the CDC Rabies Branch confirmed the presence of rabies virus. This case represented the first documented rabies PEP failure since the introduction of modern cell-culture vaccines and was contributed to the patient having previously unrecognized impaired immunocompromising condition. The UNEX program also identified102 deaths due to SARS-CoV-2 virus that occurred outside of traditional healthcare facilities such as hospitals or congregate care settings. Due to the COVID-19 pandemic, the UNEX/MED-X team expanded surveillance testing to include swab autopsies that were performed on suspect infectious deaths that did not have an autopsy performed. Nasal pharyngeal swabs were collected from decedents at funeral homes, decedents’ homes and at long-term care facilities. A total of 52 specimens were submitted to MDH. 43 decedents had known symptoms prior to death. Of those, 25 (58%) had potential pathogens detected, including SARSCoV-2 (n=24) and influenza A (n=1).

• For up to date information see: Unexplained Deaths and Critical Illnesses

MDH conducts surveillance for unexplained deaths and critical illnesses to identify those that may have an infectious etiology. Surveillance is performed through two complementary surveillance systems, Unexplained Critical Illnesses and Deaths of Possible Infectious Etiology (UNEX), and Medical Examiner (ME) Infectious Deaths Surveillance (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 PHL and the CDC Infectious Diseases Pathology Branch (IDPB). 

In 2020, 131 cases met UNEX criteria (127 deaths, 4 critical illnesses), compared to 67 cases in 2019. Of the 131, 121 (92%) were reported by providers and 7 deaths were found by death certificate review. Eighty-four (64%) cases presented with respiratory symptoms; 25 (19%) with sudden unexpected death; 7 (5%) with neurologic symptoms; 7 (5%) with shock/sepsis; 5 (4%) with gastrointestinal symptoms; 2 (2%) with cardiac symptoms; and 1 (1%) with multiple symptoms. The age of cases ranged from 25 days to 88 years, the median age was 46.5 years. Fifty-nine percent resided in the metropolitan area, 69% were male, and 9% were non-Minnesota residents who were either hospitalized in Minnesota or investigated by a Minnesota medical examiner. 

There were 442 MED-X cases in 2020; 127 of these also met UNEX criteria. The median age of the cases was 52 years, and 64% were male. There were 203 (46%) cases found through death certificate review; MEs reported 239 (54%) cases. The most common syndrome was pneumonia/upper respiratory infection (n=239 [54%]). There were 458 potential UNEX or MED-X cases that had specimens tested at the PHL and/or the IDPB. Two hundred thirty-nine cases were determined to be non-infectious. Seventy-four cases had pathogens identified as confirmed, probable, or possible cause of illness, including 73 UNEX deaths (Table 5). Among 39 unexplained deaths occurring in those <50 years of age without any immunocompromising conditions, UNEX helped to identify the pathogen(s) involved in 16 (41%) cases. MED-X surveillance detected an additional 132 cases with pathogens identified by MEs as the cause of death (Table 5). Cases with pathogens of public health importance detected included 132 deaths due to SARS-CoV-2 virus that occurred outside of traditional healthcare facilities such as hospitals or congregate care settings. The UNEX/MED-X program provided key testing resources for MEs when COVID-19 healthcare testing resources were scarce.Due to the COVID-19 pandemic, the UNEX/MED-X team expanded surveillance testing to include swabs on suspect infectious deaths that did not have an autopsy performed. Nasal pharyngeal swabs were collected from decedents at funeral homes, decedents’ homes, and longterm care facilities. A total of 173 specimens were submitted to MDH. Eighty-five decedents had known symptoms prior to death. Of those, 39 (46%) had potential pathogens detected including SARS-CoV-2 (n=38) and influenza A (n=1).

• For up to date information see: Unexplained Deaths and Critical Illnesses

We conduct 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 premortem and post-mortem specimens is conducted at the PHL and the CDC Infectious Diseases Pathology Branch (IDPB).

In 2019, 67 cases met UNEX criteria (49 deaths, 18 critical illnesses), compared to 111 cases in 2018. Of the 67, all were reported by providers. Due to the COVID-19 response, no deaths were found by death certificate review as the review and testing is still under way. Thirty-one (46%) cases presented with respiratory symptoms; 15 (22%) with sudden unexpected death; 10 (15%) with neurologic symptoms; 10 15%) with shock/sepsis; and 1 (1%) with cardiac symptoms. The age of cases ranged from 4 days to 67 years, the median age was 30 years. Fifty-eight percent resided in the metropolitan area, 57% were male, and 12% were non-Minnesota residents who were either hospitalized in Minnesota or investigated by a Minnesota ME.

There were 207 MED-X cases in 2019; 49 of these also met UNEX criteria. The median age of the cases was 44 years, and 56% were male. There were 129 (62%) cases found through death certificate review; MEs reported 80 (39%) cases. The most common syndrome was pneumonia/upper respiratory infection (n=86 [42%]).

There were 166 potential UNEX or MED-X cases that had specimens tested at the PHL and/or the IDPB. Thirtyfive cases had pathogens identified as confirmed, probable, or possible cause of illness, including 35 UNEX deaths (Table 5). Seventy-one were determined to be non-infectious. Among 35 unexplained deaths occurring in those <50 years of age without any immunocompromising conditions, UNEX helped to identify the pathogen(s) involved in 20 (57%) cases. MED-X surveillance detected an additional 16 cases with pathogens identified by MEs as the cause of death (Table 5). Cases with pathogens of public health importance detected included a 64 year-old male who presented to an emergency department with sepsis-like syndrome. He had recently traveled to Texas and participating in a triathlon. Although initial leptospirosis serology was negative, CDC was able to detect Leptospira spp. DNA by PCR from a blood and urine leading to a public health investigation by Texas public health authorities. Repeated serology detected antibodies to L. interrogans sub. Bratislava. Finally, during the 2019 MDH response to E-cigarette or vaping product use-associated lung injury (EVALI), UNEX received reports from infectious disease clinicians and MEs of 8 possible EVALI cases including 6 that were later confirmed. Preexisting relationships allowed timely submission of autopsy specimens from MDH to CDC for pathologic review and toxicological testing, a process that contributed to the identification of vitamin E acetate within lung tissues, with vitamin E acetate determined to be the causitive agent of the national outbreak.

• For up to date information see: Unexplained Deaths and Critical Illnesses

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

• Archive of Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health
  Archive of past summaries (years prior to 2023 are available as PDFs).