Legionnaires' Disease Outbreak Associated With a Hot Tub Display at the North Carolina Mountain State Fair, September 2019.

OBJECTIVES: On September 23, 2019, the North Carolina Division of Public Health identified a legionellosis increase in western North Carolina; most patients had recently attended the North Carolina Mountain State Fair. We conducted a source investigation. METHODS: Cases were fair attendees with laboratory-confirmed legionellosis and symptom onset within 2 to 14 days (Legionnaires' disease) or ≤3 days (Pontiac fever). We conducted a case-control study matching cases to non-ill fair attendees as control participants and an environmental investigation, and we performed laboratory testing (Legionella bacteria culture and polymerase chain reaction) of 27 environmental samples from fairgrounds and hot tubs and 14 specimens from case patients. We used multivariable unconditional logistic regression models to calculate adjusted odds ratios for potential Legionella exposure sources and risk factors. RESULTS: Of 136 people identified with fair-associated legionellosis, 98 (72%) were hospitalized and 4 (3%) died. Case patients were more likely than control participants to report walking by hot tub displays (adjusted odds ratio = 10.0; 95% CI, 4.2-24.1). Complete hot tub water treatment records were not kept, precluding evaluation of water maintenance conducted on display hot tubs. Legionella pneumophila sequence types (STs) were consistent among 10 typed clinical specimens (ST224) but distinct from the only positive environmental sample from the fair (ST7 and ST8). CONCLUSIONS: Hot tub displays were identified as the most likely outbreak source, making this the largest hot tub-associated Legionnaires' disease outbreak worldwide. Following the investigation, the North Carolina Division of Public Health and the Centers for Disease Control and Prevention released guidance on mitigating risk of Legionella exposure from hot tub displays. Results highlight the importance of properly maintaining equipment that aerosolizes water, including hot tubs intended for display purposes only.

Gastroenteritis outbreak associated with unpasteurized tempeh, North Carolina, USA.

During an investigation of an outbreak of gastroenteritis caused by Salmonella enterica serovar Paratyphi B variant L(+) tartrate(+), we identified unpasteurized tempeh as a novel food vehicle and Rhizopus spp. starter culture as the source of the contamination. Safe handling of uncooked, unpasteurized tempeh should be emphasized for prevention of foodborne illnesses.

Group A Streptococcus outbreak among residents and employees of two skilled nursing facilities: North Carolina, 2017.

In this report, we summarize the results of surveillance, on-site assessments, and molecular analysis conducted as part of a group A Streptococcus outbreak investigation in 2 skilled nursing facilities. We identified cases in 24 individuals (6 deaths) and infection prevention deficiencies. Isolates from 14 individuals represented the globally emergent clade 3 emm89 strain. Molecular analysis suggests that the 2 outbreaks were related. Wound care practices and 1 symptomatic shared employee may have facilitated transmission. Strict adherence to infection prevention practices is needed to prevent group A Streptococcus transmission.

Creation of a Geospatially Explicit, Agent-based Model of a Regional Healthcare Network with Application to Clostridioides difficile Infection.

Agent-based models (ABMs) describe and simulate complex systems comprising unique agents, or individuals, while accounting for geospatial and temporal variability among dynamic processes. ABMs are increasingly used to study healthcare-associated infections (ie, infections acquired during admission to a healthcare facility), including Clostridioides difficile infection, currently the most common healthcare-associated infection in the United States. The overall burden and transmission dynamics of healthcare-associated infections, including C difficile infection, may be influenced by community sources and movement of people among healthcare facilities and communities. These complex dynamics warrant geospatially explicit ABMs that extend beyond single healthcare facilities to include entire systems (eg, hospitals, nursing homes and extended care facilities, the community). The agents in ABMs can be built on a synthetic population, a model-generated representation of the actual population with associated spatial (eg, home residence), temporal (eg, change in location over time), and nonspatial (eg, sociodemographic features) attributes. We describe our methods to create a geospatially explicit ABM of a major regional healthcare network using a synthetic population as microdata input. We illustrate agent movement in the healthcare network and the community, informed by patient-level medical records, aggregate hospital discharge data, healthcare facility licensing data, and published literature. We apply the ABM output to visualize agent movement in the healthcare network and the community served by the network. We provide an application example of the ABM to C difficile infection using a natural history submodel. We discuss the ABM's potential to detect network areas where disease risk is high; simulate and evaluate interventions to protect public health; adapt to other geographic locations and healthcare-associated infections, including emerging pathogens; and meaningfully translate results to public health practitioners, healthcare providers, and policymakers.

Syndromic surveillance for emerging infections in office practice using billing data.

PURPOSE: We wanted to evaluate the feasibility of conducting syndromic surveillance in a primary care office using billing data. METHODS: A 1-year study was conducted in a primary care practice; comparison data were obtained from emergency department records of visits by county residents. Within the practice, a computer program converted billing data into de-identified daily summaries of International Classification of Diseases, Ninth Revision (ICD-9) codes by sex and age-group; and a staff member generated daily summaries and e-mailed them to the analysis team. For both the practice and the emergency departments, infection-related syndromes and practice-specific thresholds were calculated using the category 1 syndrome codes and an analytical method based upon the Early Aberration Reporting System of the Centers for Disease Control and Prevention. RESULTS: A mean of 253 ICD-9 codes per day was reported. The most frequently recorded syndromes were respiratory illness, gastrointestinal illness, and fever. Syndromes most commonly exceeding the threshold of 2 standard deviations for the practice were lymphadenitis, rash, and fever. Generating a daily summary took 1 to 2 minutes; the program was written by the software vendor for a fee of dollar 1,500. During the 2003-2004 influenza season, trend line patterns of the emergency department visits reflected a pattern consistent with that of the state, whereas the trend line in primary case practice cases was less consistent, reflecting the variation expected in data from a single clinic. Still, spikes of activity that occurred in the practice before the emergency department suggest the practice may have seen patients with influenza earlier. CONCLUSIONS: This preliminary study showed the feasibility of implementing syndromic surveillance in an office setting at a low cost and with minimal staff effort. Although many implementation issues remain, further development of syndromic surveillance systems should include primary care offices.

Lessons learned from a norovirus outbreak in a locked pediatric inpatient psychiatric unit.

We report an outbreak of norovirus in a locked pediatric inpatient psychiatric unit with attack rates of 75% among 4 patients and 26% among 38 staff. Factors contributing to the outbreak included environmental contamination, close staff-patient contact including sharing meals, and inability to confine the index patient with the use of contact precautions.

Outbreak of late-onset group B Streptococcus in a neonatal intensive care unit.

BACKGROUND: In September 2007, the Tennessee Department of Health was notified of a cluster of late-onset group B streptococcal (GBS) infections in a neonatal intensive care unit (NICU). Outbreaks of late-onset GBS are rare. METHODS: A case was defined as culture-confirmed invasive GBS infection in a neonate aged > or =7 days, identified in hospital A during August 23 to September 6, 2007. We reviewed medical records; examined NICU microbiology reports; and performed serotyping, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) on invasive isolates. Maternal GBS screening, prophylaxis, and infection control policies were reviewed and staff practices observed. RESULTS: Five cases of late-onset GBS were identified. None of the mothers of the infants received optimal GBS prophylaxis. Patient isolates were of 2 serotypes, 3 PFGE patterns, and 2 MLST patterns. Three isolates were indistinguishable on subtyping. These 3 cases were clustered in time. No common health care providers were identified. Infection control deviations in the NICU were observed. CONCLUSION: We identified a multiclonal cluster of 5 late-onset GBS cases. Multiple factors likely contributed to the outbreak, including nosocomial transmission of GBS. Further efforts to prevent late-onset GBS disease are necessary.

Acute selenium toxicity associated with a dietary supplement.

BACKGROUND: Selenium is an element necessary for normal cellular function, but it can have toxic effects at high doses. We investigated an outbreak of acute selenium poisoning. METHODS: A case was defined as the onset of symptoms of selenium toxicity in a person within 2 weeks after ingesting a dietary supplement manufactured by "Company A," purchased after January 1, 2008. We conducted case finding, administered initial and 90-day follow-up questionnaires to affected persons, and obtained laboratory data where available. RESULTS: The source of the outbreak was identified as a liquid dietary supplement that contained 200 times the labeled concentration of selenium. Of 201 cases identified in 10 states, 1 person was hospitalized. The median estimated dose of selenium consumed was 41 749 microg/d (recommended dietary allowance is 55 microg/d). Frequently reported symptoms included diarrhea (78%), fatigue (75%), hair loss (72%), joint pain (70%), nail discoloration or brittleness (61%), and nausea (58%). Symptoms persisting 90 days or longer included fingernail discoloration and loss (52%), fatigue (35%), and hair loss (29%). The mean initial serum selenium concentration of 8 patients was 751 microg/L (reference range, < or =125 microg/L). The mean initial urine selenium concentration of 7 patients was 166 microg/24 h (reference range, < or =55 microg/24 h). CONCLUSIONS: Toxic concentrations of selenium in a liquid dietary supplement resulted in a widespread outbreak. Had the manufacturers been held to standards used in the pharmaceutical industry, it may have been prevented.