Variability in comorbidites and health services use across homeless typologies: multicenter data linkage between healthcare and homeless systems.

BACKGROUND: Homelessness is associated with substantial morbidity. Data linkages between homeless and health systems are important to understand unique needs across homeless populations, identify homeless individuals not registered in homeless databases, quantify the impact of housing services on health-system use, and motivate health systems and payers to contribute to housing solutions. METHODS: We performed a cross-sectional survey including six health systems and two Homeless Management Information Systems (HMIS) in Cook County, Illinois. We performed privacy-preserving record linkage to identify homelessness through HMIS or ICD-10 codes captured in electronic medical records. We measured the prevalence of health conditions and health-services use across the following typologies: housing-service utilizers stratified by service provided (stable, stable plus unstable, unstable) and non-utilizers (i.e., homelessness identified through diagnosis codes-without receipt of housing services). RESULTS: Among 11,447 homeless recipients of healthcare, nearly 1 in 5 were identified by ICD10 code alone without recorded homeless services (n = 2177; 19%). Almost half received homeless services that did not include stable housing (n = 5444; 48%), followed by stable housing (n = 3017; 26%), then receipt of both stable and unstable services (n = 809; 7%). Setting stable housing recipients as the referent group, we found a stepwise increase in behavioral-health conditions from stable housing to those known as homeless solely by health systems. Compared to those in stable housing, prevalence rate ratios (PRR) for those without homeless services were as follows: depression (PRR = 2.2; 95% CI 1.9 to 2.5), anxiety (PRR = 2.5; 95% CI 2.1 to 3.0), schizophrenia (PRR = 3.3; 95% CI 2.7 to 4.0), and alcohol-use disorder (PRR = 4.4; 95% CI 3.6 to 5.3). Homeless individuals who had not received housing services relied on emergency departments for healthcare-nearly 3 of 4 visited at least one and many (24%) visited multiple. CONCLUSIONS: Differences in behavioral-health conditions and health-system use across homeless typologies highlight the particularly high burden among homeless who are disconnected from homeless services. Fragmented and high use of emergency departments for care should motivate health systems and payers to promote housing solutions, especially those that incorporate substance use and mental health treatment.

Electronic Measurement of a Clinical Quality Measure for Inpatient Hypoglycemic Events: A Multicenter Validation Study.

BACKGROUND: Hypoglycemia related to antidiabetic drugs (ADDs) is important iatrogenic harm in hospitalized patients. Electronic identification of ADD-related hypoglycemia may be an efficient, reliable method to inform quality improvement. OBJECTIVE: Develop electronic queries of electronic health records for facility-wide and unit-specific inpatient hypoglycemia event rates and validate query findings with manual chart review. METHODS: Electronic queries were created to associate blood glucose (BG) values with ADD administration and inpatient location in 3 tertiary care hospitals with Patient-Centered Outcomes Research Network (PCORnet) databases. Queries were based on National Quality Forum criteria with hypoglycemia thresholds <40 and <54 mg/dL, and validated using a stratified random sample of 321 BG events. Sensitivity and specificity were calculated with manual chart review as the reference standard. RESULTS: The sensitivity and specificity of queries for hypoglycemia events were 97.3% [95% confidence interval (CI), 90.5%-99.7%] and 100.0% (95% CI, 92.6%-100.0%), respectively for BG <40 mg/dL, and 97.7% (95% CI, 93.3%-99.5%) and 100.0% (95% CI, 95.3%-100.0%), respectively for <54 mg/dL. The sensitivity and specificity of the query for identifying ADD days were 91.8% (95% CI, 89.2%-94.0%) and 99.0% (95% CI, 97.5%-99.7%). Of 48 events missed by the queries, 37 (77.1%) were due to incomplete identification of insulin administered by infusion. Facility-wide hypoglycemia rates were 0.4%-0.8% (BG <40 mg/dL) and 1.9%-3.0% (BG <54 mg/dL); rates varied by patient care unit. CONCLUSIONS: Electronic queries can accurately identify inpatient hypoglycemia. Implementation in non-PCORnet-participating facilities should be assessed, with particular attention to patient location and insulin infusions.

Lack of Transmission among Close Contacts of Patient with Case of Middle East Respiratory Syndrome Imported into the United States, 2014.

In May 2014, a traveler from the Kingdom of Saudi Arabia was the first person identified with Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States. To evaluate transmission risk, we determined the type, duration, and frequency of patient contact among health care personnel (HCP), household, and community contacts by using standard questionnaires and, for HCP, global positioning system (GPS) tracer tag logs. Respiratory and serum samples from all contacts were tested for MERS-CoV. Of 61 identified contacts, 56 were interviewed. HCP exposures occurred most frequently in the emergency department (69%) and among nurses (47%); some HCP had contact with respiratory secretions. Household and community contacts had brief contact (e.g., hugging). All laboratory test results were negative for MERS-CoV. This contact investigation found no secondary cases, despite case-patient contact by 61 persons, and provides useful information about MERS-CoV transmission risk. Compared with GPS tracer tag recordings, self-reported contact may not be as accurate.

Meningococcal disease among men who have sex with men - United States, January 2012-June 2015.

Since 2012, three clusters of serogroup C meningococcal disease among men who have sex with men (MSM) have been reported in the United States. During 2012, 13 cases of meningococcal disease among MSM were reported by the New York City Department of Health and Mental Hygiene (1); over a 5-month period during 2012­2013, the Los Angeles County Department of Public Health reported four cases among MSM; and during May­June 2015, the Chicago Department of Public Health reported seven cases of meningococcal disease among MSM in the greater Chicago area. MSM have not previously been considered at increased risk for meningococcal disease. Determining outbreak thresholds* for special populations of unknown size (such as MSM) can be difficult. The New York City health department declared an outbreak based on an estimated increased risk for meningococcal infection in 2012 among MSM and human immunodeficiency virus (HIV)­infected MSM compared with city residents who were not MSM or for whom MSM status was unknown (1). The Chicago Department of Public Health also declared an outbreak based on an increase in case counts and thresholds calculated using population estimates of MSM and HIV-infected MSM. Local public health response included increasing awareness among MSM, conducting contact tracing and providing chemoprophylaxis to close contacts, and offering vaccination to the population at risk (1­3). To better understand the epidemiology and burden of meningococcal disease in MSM populations in the United States and to inform recommendations, CDC analyzed data from a retrospective review of reported cases from January 2012 through June 2015.

First confirmed cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States, updated information on the epidemiology of MERS-CoV infection, and guidance for the public, clinicians, and public health authorities - May 2014.

Since mid-March 2014, the frequency with which cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection have been reported has increased, with the majority of recent cases reported from Saudi Arabia and United Arab Emirates (UAE). In addition, the frequency with which travel-associated MERS cases have been reported and the number of countries that have reported them to the World Health Organization (WHO) have also increased. The first case of MERS in the United States, identified in a traveler recently returned from Saudi Arabia, was reported to CDC by the Indiana State Department of Health on May 1, 2014, and confirmed by CDC on May 2. A second imported case of MERS in the United States, identified in a traveler from Saudi Arabia having no connection with the first case, was reported to CDC by the Florida Department of Health on May 11, 2014. The purpose of this report is to alert clinicians, health officials, and others to increase awareness of the need to consider MERS-CoV infection in persons who have recently traveled from countries in or near the Arabian Peninsula. This report summarizes recent epidemiologic information, provides preliminary descriptions of the cases reported from Indiana and Florida, and updates CDC guidance about patient evaluation, home care and isolation, specimen collection, and travel as of May 13, 2014.

New Delhi metallo-ß-lactamase-producing carbapenem-resistant Escherichia coli associated with exposure to duodenoscopes.

IMPORTANCE: Carbapenem-resistant Enterobacteriaceae (CRE) producing the New Delhi metallo-ß-lactamase (NDM) are rare in the United States, but have the potential to add to the increasing CRE burden. Previous NDM-producing CRE clusters have been attributed to person-to-person transmission in health care facilities. OBJECTIVE: To identify a source for, and interrupt transmission of, NDM-producing CRE in a northeastern Illinois hospital. DESIGN, SETTING, AND PARTICIPANTS: Outbreak investigation among 39 case patients at a tertiary care hospital in northeastern Illinois, including a case-control study, infection control assessment, and collection of environmental and device cultures; patient and environmental isolate relatedness was evaluated with pulsed-field gel electrophoresis (PFGE). Following identification of a likely source, targeted patient notification and CRE screening cultures were performed. MAIN OUTCOMES AND MEASURES: Association between exposure and acquisition of NDM-producing CRE; results of environmental cultures and organism typing. RESULTS: In total, 39 case patients were identified from January 2013 through December 2013, 35 with duodenoscope exposure in 1 hospital. No lapses in duodenoscope reprocessing were identified; however, NDM-producing Escherichia coli was recovered from a reprocessed duodenoscope and shared more than 92% similarity to all case patient isolates by PFGE. Based on the case-control study, case patients had significantly higher odds of being exposed to a duodenoscope (odds ratio [OR], 78 [95% CI, 6.0-1008], P < .001). After the hospital changed its reprocessing procedure from automated high-level disinfection with ortho-phthalaldehyde to gas sterilization with ethylene oxide, no additional case patients were identified. CONCLUSIONS AND RELEVANCE: In this investigation, exposure to duodenoscopes with bacterial contamination was associated with apparent transmission of NDM-producing E coli among patients at 1 hospital. Bacterial contamination of duodenoscopes appeared to persist despite the absence of recognized reprocessing lapses. Facilities should be aware of the potential for transmission of bacteria including antimicrobial-resistant organisms via this route and should conduct regular reviews of their duodenoscope reprocessing procedures to ensure optimal manual cleaning and disinfection.

Triple-reassortant swine influenza A (H1) in humans in the United States, 2005-2009.

BACKGROUND: Triple-reassortant swine influenza A (H1) viruses--containing genes from avian, human, and swine influenza viruses--emerged and became enzootic among pig herds in North America during the late 1990s. METHODS: We report the clinical features of the first 11 sporadic cases of infection of humans with triple-reassortant swine influenza A (H1) viruses reported to the Centers for Disease Control and Prevention, occurring from December 2005 through February 2009, until just before the current epidemic of swine-origin influenza A (H1N1) among humans. These data were obtained from routine national influenza surveillance reports and from joint case investigations by public and animal health agencies. RESULTS: The median age of the 11 patients was 10 years (range, 16 months to 48 years), and 4 had underlying health conditions. Nine of the patients had had exposure to pigs, five through direct contact and four through visits to a location where pigs were present but without contact. In another patient, human-to-human transmission was suspected. The range of the incubation period, from the last known exposure to the onset of symptoms, was 3 to 9 days. Among the 10 patients with known clinical symptoms, symptoms included fever (in 90%), cough (in 100%), headache (in 60%), and diarrhea (in 30%). Complete blood counts were available for four patients, revealing leukopenia in two, lymphopenia in one, and thrombocytopenia in another. Four patients were hospitalized, two of whom underwent invasive mechanical ventilation. Four patients received oseltamivir, and all 11 recovered from their illness. CONCLUSIONS: From December 2005 until just before the current human epidemic of swine-origin influenza viruses, there was sporadic infection with triple-reassortant swine influenza A (H1) viruses in persons with exposure to pigs in the United States. Although all the patients recovered, severe illness of the lower respiratory tract and unusual influenza signs such as diarrhea were observed in some patients, including those who had been previously healthy.

National outbreak of Acanthamoeba keratitis associated with use of a contact lens solution, United States.

An outbreak of Acanthamoeba keratitis, a rare, potentially blinding, corneal infection, was detected in the United States in 2007; cases had been increasing since 2004. A case-control study was conducted to investigate the outbreak. We interviewed 105 case-patients from 30 states and 184 controls matched geographically and by contact lens use. Available contact lenses, cases, solutions, and corneal specimens from case-patients were cultured and tested by molecular methods. In multivariate analyses, case-patients had significantly greater odds of having used Advanced Medical Optics Complete Moisture Plus (AMOCMP) solution (odds ratio 16.9, 95% confidence interval 4.8-59.5). AMOCMP manufacturing lot information was available for 22 case-patients, but none of the lots were identical. Three unopened bottles of AMOCMP tested negative for Acanthamoeba spp. Our findings suggest that the solution was not intrinsically contaminated and that its anti-Acanthamoeba efficacy was likely insufficient. Premarket standardized testing of contact lens solutions for activity against Acanthamoeba spp. is warranted.

Outbreak of human adenovirus type 3 infection in a pediatric long-term care facility--Illinois, 2005.

BACKGROUND: Human adenovirus type 3 (HAdV-3) causes severe respiratory illness in children, but outbreaks in long-term care facilities have not been frequently reported. We describe an outbreak of HAdV-3 infection in a long-term care facility for children with severe neurologic impairment, where only 3 of 63 residents were ambulatory. METHODS: A clinical case of HAdV-3 was defined as fever (temperature, > or = 38.0 degrees C) and either a worsening of respiratory symptoms or conjunctivitis in a resident, with illness onset from June through August 2005. We reviewed medical records; conducted surveillance for fever, conjunctivitis, and respiratory symptoms; and collected nasopharyngeal and conjunctival specimens from symptomatic residents. Specimens were cultured in HAdV-permissive cell lines or were analyzed by HAdV-specific polymerase chain reaction assay. RESULTS: Thirty-five (56%) of 63 residents had illnesses that met the case definition; 17 patients (49%) were admitted to intensive care units, and 2 (6%) died. Patients were hospitalized in the intensive care unit for a total of 233 patient-days. Illness onset dates ranged from 1 June through 24 August 2005. Thirty-two patients (91%) had respiratory infection, and 3 (9%) had conjunctivitis. HAdV was identified by culture or PCR in 20 patients. Nine isolates were characterized as HAdV-3 genome type a2. CONCLUSIONS: Considering the limited mobility of residents and their reliance on respiratory care, transmission of HAdV-3 infection during this outbreak likely occurred through respiratory care provided by staff. In environments where patients with susceptible underlying conditions reside, HAdV infection should be considered when patients are identified with worsening respiratory disease, and rapid diagnostic tests for HAdV infection should be readily available to help identify and curtail the spread of this pathogen.

Outbreak of Pantoea agglomerans Bloodstream Infections at an Oncology Clinic-Illinois, 2012-2013.

OBJECTIVE To determine the source of a healthcare-associated outbreak of Pantoea agglomerans bloodstream infections. DESIGN Epidemiologic investigation of the outbreak. SETTING Oncology clinic (clinic A). METHODS Cases were defined as Pantoea isolation from blood or catheter tip cultures of clinic A patients during July 2012-May 2013. Clinic A medical charts and laboratory records were reviewed; infection prevention practices and the facility's water system were evaluated. Environmental samples were collected for culture. Clinical and environmental P. agglomerans isolates were compared using pulsed-field gel electrophoresis. RESULTS Twelve cases were identified; median (range) age was 65 (41-78) years. All patients had malignant tumors and had received infusions at clinic A. Deficiencies in parenteral medication preparation and handling were identified (eg, placing infusates near sinks with potential for splash-back contamination). Facility inspection revealed substantial dead-end water piping and inadequate chlorine residual in tap water from multiple sinks, including the pharmacy clean room sink. P. agglomerans was isolated from composite surface swabs of 7 sinks and an ice machine; the pharmacy clean room sink isolate was indistinguishable by pulsed-field gel electrophoresis from 7 of 9 available patient isolates. CONCLUSIONS Exposure of locally prepared infusates to a contaminated pharmacy sink caused the outbreak. Improvements in parenteral medication preparation, including moving chemotherapy preparation offsite, along with terminal sink cleaning and water system remediation ended the outbreak. Greater awareness of recommended medication preparation and handling practices as well as further efforts to better define the contribution of contaminated sinks and plumbing deficiencies to healthcare-associated infections are needed. Infect Control Hosp Epidemiol 2017;38:314-319.

Measles Outbreak in a Child Care Center, Cook County, Illinois, 2015.

BACKGROUND: During January-February 2015, Cook County Department of Public Health led an investigation of a measles outbreak predominantly affecting infants at a child care center who were too young for routine immunization with measles-mumps-rubella (MMR) vaccine. METHODS: Measles cases and contacts were investigated by Illinois public health officials. Cases were isolated for 4 days after rash onset. Exposed healthcare workers and child care center staff were required to provide documentation of receipt of 2 doses of MMR vaccine or laboratory evidence of immunity to return to work. Susceptible contacts were actively monitored for 21 days after exposure and provided postexposure prophylaxis (PEP) if certain criteria were met. RESULTS: Fifteen confirmed measles cases were identified; 12 (80%) occurred in infants who were attendees of a child care center. Clinical misdiagnosis of 1 case allowed for continued transmission within the center. Twelve (86%) of 14 exposed infants at the child care center were diagnosed with measles; no other attendees or staff were infected. Five cases visited outpatient pediatric clinics during their infectious period, exposing 33 infants. Six exposed child care center staff and 3 healthcare workers did not have documentation of immunity available and were excluded from work until this was obtained. No healthcare-associated transmission was identified. Ninety-one contacts were actively monitored and 20 received PEP. CONCLUSIONS: This outbreak underscores the vulnerability of infants to measles, the need for early consideration of measles in susceptible patients presenting with a febrile rash illness, and the importance of immunity among individuals working closely with infants.

Epidemic diarrhea due to enterotoxigenic Escherichia coli.

BACKGROUND: In June 1998, we investigated one of the largest foodborne outbreaks of enterotoxigenic Escherichia coli gastroenteritis reported in the United States. METHODS: We conducted cohort studies of 11 catered events to determine risk factors for illness. We used stool cultures, polymerase chain reaction, and serologic tests to determine the etiologic agent, and we conducted an environmental inspection to identify predisposing conditions and practices at the implicated establishment. RESULTS: During 5-7 June, the implicated delicatessen catered 539 events attended by >16,000 people. Our epidemiological study of 11 events included a total of 612 attendees. By applying the median prevalence of illness (20%) among events with ill attendees to the total number of events with any ill attendees, we estimate that at least 3300 persons may have developed gastroenteritis during this outbreak. Multiple food items (potato salad, macaroni salad, egg salad, and watermelon) were associated with illness, all of which required extensive handling during preparation. Enterotoxigenic Escherichia coli serotype O6:H16 producing heat-labile and heat-stable toxins was isolated from the stool specimens from 11 patients. Eight patients with positive stool culture results, 11 (58%) of 19 other symptomatic attendees, and 0 (0%) of 17 control subjects had elevated serum antibody titers to E. coli O6 lipopolysaccharide. The delicatessen had inadequate hand-washing supplies, inadequate protection against back siphonage of wastewater in the potable water system, a poorly draining kitchen sink, and improper food storage and transportation practices. CONCLUSIONS: In the United States, where enterotoxigenic Escherichia coli is an emerging cause of foodborne disease, enterotoxigenic Escherichia coli should be suspected in outbreaks of gastroenteritis when common bacterial or viral enteric pathogens are not identified.

Outbreak of bloodstream infection with the mold Phialemonium among patients receiving dialysis at a hemodialysis unit.

BACKGROUND: Molds are a rare cause of disseminated infection among dialysis patients. OBJECTIVE: We evaluated a cluster of intravascular infections with the mold Phialemonium among patients receiving hemodialysis at the same facility in order to identify possible environmental sources and prevent further infection. DESIGN: Environmental assessment and case-control study. SETTING: A hemodialysis center affiliated with a tertiary care hospital. METHODS: We reviewed surveillance and clinical microbiology records and performed a blood culture survey for all patients. The following data for case patients were compared with those for control patients: underlying illness, dialysis characteristics, medications, and other possible exposure for 120 days prior to infection. Environmental assessment of water treatment, dialysis facilities, and heating, ventilation, and air-conditioning (HVAC) systems of the current and previous locations of the dialysis center was performed. Samples were cultured for fungus; Phialemonium isolates were confirmed by sequencing of DNA. Investigators observed dialysis access site disinfection technique. RESULTS: Four patients were confirmed as case patients, defined as a patient having intravascular infection with Phialemonium species; 3 presented with fungemia, and 1 presented with an intravascular graft infection. All case patients used a fistula or graft for dialysis access, as did 12 (75%) of 16 of control patients (P=.54). Case and control patients did not differ in other dialysis characteristics, medications received, physiologic findings, or demographic factors. Phialemonium species were not recovered from samples of water or dialysis machines, but were recovered from the condensation drip pans under the blowers of the HVAC system that supplied air to the dialysis center. Observational study of 21 patients detected suboptimal contact time with antiseptic agents used to prepare dialysis access sites. CONCLUSION: The report of this outbreak adds to previous published reports of Phialemonium infection occurring in immunocompromised patients who likely acquired infection in the healthcare setting. Recovery of this mold from blood culture should be considered indicative of infection until proven otherwise. Furthermore, an investigation into possible healthcare-related environmental reservoirs should be considered.

Two outbreaks of occupationally acquired histoplasmosis: more than workers at risk.

OBJECTIVE: The objective of this study was to determine the etiology and risk factors for acute histoplasmosis in two outbreaks in Illinois among laborers at a landfill in 2001 and at a bridge reconstruction site in 2003. DESIGN: We performed environmental investigations during both outbreaks and also performed an analytic cohort study among bridge workers. PARTICIPANTS: Workers at the landfill during May 2001 and those at the bridge site during August 2003 participated in the study. At the landfill, workers moved topsoil from an area that previously housed a barn; at the bridge, workers observed bat guano on bridge beams. EVALUATIONS/MEASUREMENTS: We defined a case by positive immunodiffusion serology, a > or = 4-fold titer rise in complement fixation between acute and convalescent sera, or positive urinary Histoplasma capsulatum (HC) antigen. Relative risks (RR) for disease among bridge workers were calculated using bivariate analysis. RESULTS: Eight of 11 landfill workers (73%) and 6 of 12 bridge workers (50%) were laboratory-confirmed histoplasmosis cases. Three bridge workers had positive urinary HC antigen. At the bridge, seeing or having contact with bats [RR = 7.0; 95% confidence interval (CI), 1.1-43.0], jack-hammering (RR = 4.0; 95% CI, 1.2-13.3), and waste disposal (RR = 4.0; 95% CI, 1.2-13.3) were the most significant job-related risk factors for acquiring histoplasmosis. CONCLUSIONS: Workers performing activities that aerosolized topsoil and dust were at increased risk for acquiring histoplasmosis. Relevance to professional and clinical practice: Employees should wear personal protective equipment and use dust-suppression techniques when working in areas potentially contaminated with bird or bat droppings. Urinary HC antigen testing was important in rapidly identifying disease in the 2003 outbreak.

The emergence of west nile virus during a large outbreak in Illinois in 2002.

In 2002, the world's largest outbreak of neuroinvasive West Nile virus (WNV) disease occurred. Illinois reported 21% of the total cases in the United States, the most among all states. The epidemiology of WNV in Illinois in 2002 was examined to determine factors associated with severe disease and death. A total of 884 cases were identified and there were 66 deaths. The overall attack rate of WNV infection was 7.1 per 100,000 population and this increased with age. The median ages of patients and patients who died were 56 and 78 years, respectively. Among patients who died, 91% were diagnosed with encephalitis and the case-fatality rate for patients with encephalitis was 18.6%. Patients more than 50 years old had a significantly higher risk of being reported with encephalitis (relative risk [RR] = 3.3, 95% confidence interval [CI] = 2.6-4.3%) and death (RR = 22.3, 95% CI = 5.5-90.4%). Clinicians evaluating elderly patients with WNV infection should assess patients closely for progression of disease.

Severe respiratory illness associated with a nationwide outbreak of enterovirus D68 in the USA (2014): a descriptive epidemiological investigation.

BACKGROUND: Enterovirus D68 (EV-D68) has been infrequently reported historically, and is typically associated with isolated cases or small clusters of respiratory illness. Beginning in August, 2014, increases in severe respiratory illness associated with EV-D68 were reported across the USA. We aimed to describe the clinical, epidemiological, and laboratory features of this outbreak, and to better understand the role of EV-D68 in severe respiratory illness. METHODS: We collected regional syndromic surveillance data for epidemiological weeks 23 to 44, 2014, (June 1 to Nov 1, 2014) and hospital admissions data for epidemiological weeks 27 to 44, 2014, (June 29 to Nov 1, 2014) from three states: Missouri, Illinois and Colorado. Data were also collected for the same time period of 2013 and 2012. Respiratory specimens from severely ill patients nationwide, who were rhinovirus-positive or enterovirus-positive in hospital testing, were submitted between Aug 1, and Oct 31, 2014, and typed by molecular sequencing. We collected basic clinical and epidemiological characteristics of EV-D68 cases with a standard data collection form submitted with each specimen. We compared patients requiring intensive care with those who did not, and patients requiring ventilator support with those who did not. Mantel-Haenszel χ(2) tests were used to test for statistical significance. FINDINGS: Regional and hospital-level data from Missouri, Illinois, and Colorado showed increases in respiratory illness between August and September, 2014, compared with in 2013 and 2012. Nationwide, 699 (46%) of 1529 patients tested were confirmed as EV-D68. Among the 614 EV-D68-positive patients admitted to hospital, age ranged from 3 days to 92 years (median 5 years). Common symptoms included dyspnoea (n=513 [84%]), cough (n=500 [81%]), and wheezing (n=427 [70%]); 294 (48%) patients had fever. 338 [59%] of 574 were admitted to intensive care units, and 145 (28%) of 511 received ventilator support; 322 (52%) of 614 had a history of asthma or reactive airway disease; 200 (66%) of 304 patients with a history of asthma or reactive airway disease required intensive care compared with 138 (51%) of 270 with no history of asthma or reactive airway disease (p=0·0004). Similarly, 89 (32%) of 276 patients with a history of asthma or reactive airway disease required ventilator support compared with 56 (24%) of 235 patients with no history of asthma or reactive airway disease (p=0·039). INTERPRETATION: In 2014, EV-D68 caused widespread severe respiratory illness across the USA, disproportionately affecting those with asthma. This unexpected event underscores the need for robust surveillance of enterovirus types, enabling improved understanding of virus circulation and disease burden. FUNDING: None.