Demographic, social, and behavioral correlates of SARS-CoV-2 seropositivity in a representative, population-based study of Minnesota residents.

BACKGROUND: Monitoring COVID-19 infection risk in the general population is a public health priority. Few studies have measured seropositivity using representative, probability samples. The present study measured seropositivity in a representative population of Minnesota residents prior to vaccines and assess the characteristics, behaviors, and beliefs of the population at the outset of the pandemic and their association with subsequent infection. METHODS: Participants in the Minnesota COVID-19 Antibody Study (MCAS) were recruited from residents of Minnesota who participated in the COVID-19 Household Impact Survey (CIS), a population-based survey that collected data on physical health, mental health, and economic security information between April 20 and June 8 of 2020. This was followed by collection of antibody test results between December 29, 2020 and February 26, 2021. Demographic, behavioral, and attitudinal exposures were assessed for association with the outcome of interest, SARS-CoV-2 seroprevalence, using univariate and multivariate logistic regression. RESULTS: Of the 907 potential participants from the CIS, 585 respondents then consented to participate in the antibody testing (64.4% consent rate). Of these, results from 537 test kits were included in the final analytic sample, and 51 participants (9.5%) were seropositive. The overall weighted seroprevalence was calculated to be 11.81% (95% CI, 7.30%-16.32%) at of the time of test collection. In adjusted multivariate logistic regression models, significant associations between seroprevalence and the following were observed; being from 23-64 and 65+ age groups were both associated with higher odds of COVID-19 seropositivity compared to the 18-22 age group (17.8 [1.2-260.1] and 24.7 [1.5-404.4] respectively). When compared to a less than $30k annual income reference group, all higher income groups had significantly lower odds of seropositivity. Reporting practicing a number of 10 (median reported value in sample) or more of 19 potential COVID-19 mitigation factors (e.g. handwashing and mask wearing) was associated with lower odds of seropositivity (0.4 [0.1-0.99]) Finally, the presence of at least one household member in the age range of 6 to 17 years old was associated with higher odds of seropositivity (8.3 [1.2-57.0]). CONCLUSIONS: The adjusted odds ratio of SARS-CoV-2 seroprevalence was significantly positively associated with increasing age and having household member(s) in the 6-17 year age group, while increasing income levels and a mitigation score at or above the median were shown to be significantly protective factors.

COVID-19 Vaccine Hesitancy in a Population-Based Study of Minnesota Residents.

COVID-19 continues to be a public health concern in the United States. Although safe and effective vaccines have been developed, a significant proportion of the US population has not received a COVID-19 vaccine. This cross-sectional study aimed to describe the demographics and behaviors of Minnesota adults who have not received the primary series of the COVID-19 vaccine, or the booster shot using data from the Minnesota COVID-19 Antibody Study (MCAS) collected through a population-based sample between September and December 2021. Data were collected using a web-based survey sent to individuals that responded to a similar survey in 2020 and their adult household members. The sample was 51% female and 86% White/Non-Hispanic. A total of 9% of vaccine-eligible participants had not received the primary series and 23% of those eligible to receive a booster had not received it. Older age, higher education, better self-reported health, $75,000 to $100,000 annual household income, mask-wearing, and social distancing were associated with lower odds of hesitancy. Gender, race, and previous COVID-19 infection were not associated with hesitancy. The most frequently reported reason for not receiving a COVID-19 vaccination was safety concerns. Mask-wearing and being age 65 or older were the only strong predictors of lower odds of vaccine hesitancy for both the primary series and booster analyses.

Tackling the Lead Gremlins: A Response to Take-Home Lead Exposure in a Minnesota Industrial Facility, 2019.

Lead exposure that occurs from contamination inadvertently brought home from a workplace is known as take-home exposure. Take-home exposures are a public health hazard that adversely affects health equity for families and communities. This article describes coordinated action by agencies in Minnesota to curb lead exposure among children of workers at a facility that produces fishing sinkers and battery terminals. (Am J Public Health. 2022;112(S7):S655-S657. https://doi.org/10.2105/AJPH.2022.306982).

COVID-19 vaccine confidence and reasons for vaccination among health care workers and household members.

BACKGROUND: The majority of healthcare workers (HCW) in the US report being fully vaccinated against COVID-19, yet little is known about vaccine decision-making for their household members, including children. METHODS: Cross-sectional survey July-August 2021 of HCW and their household members in Minnesota. RESULTS: 94 % of eligible participants were vaccinated with the most common reasons being wanting to protect oneself, family and loved ones. Safety concerns were the most commonly reported reasons for not being vaccinated; a significantly higher proportion of unvaccinated compared to vaccinated HCW (58 % vs 12 %, p = 0.0035) and household adults (25 % vs 5 %, p = 0.03) reported prior SARS-CoV-2 infection. Nearly half of unvaccinated adults and two-thirds of unvaccinated children would be vaccinated if a vaccine mandate were in place. CONCLUSIONS: Despite high COVID-19 vaccine acceptance among HCWs, more research is required to identify and address the needs and concerns of healthcare workers who decline COVID-19 vaccination despite availability.

SARS-CoV-2 seroprevalence among healthcare workers.

BACKGROUND: Monitoring COVID-19 infection risk among health care workers (HCWs) is a public health priority. We examined the seroprevalence of SARS-CoV-2 among HCWs following the fall infection surge in Minnesota, and before and after COVID-19 vaccination. Additionally, we assessed demographic and occupational risk factors for SARS-CoV-2 infection. METHODS: We conducted two rounds of seroprevalence testing among a cohort of HCWs: samples in round 1 were collected from 11/22/20-02/21/21 and in round 2 from 12/18/20-02/15/21. Demographic and occupational exposures assessed with logistic regression were age, sex, healthcare role and setting, and number of children in the household. The primary outcome was SARS-CoV-2 IgG seropositivity. A secondary outcome, SARS-CoV-2 infection, included both seropositivity and self-reported SARS-CoV-2 test positivity. RESULTS: In total, 459 HCWs were tested. 43/454 (9.47%) had a seropositive sample 1 and 75/423 (17.7%) had a seropositive sample 2. By time of sample 2 collection, 54% of participants had received at least one vaccine dose and seroprevalence was 13% among unvaccinated individuals. Relative to physicians, the odds of SARS-CoV-2 infection in other roles were increased (Nurse Practitioner: OR[95%CI] 1.93[0.57,6.53], Physician's Assistant: 1.69[0.38,7.52], Nurse: 2.33[0.94,5.78], Paramedic/EMTs: 3.86[0.78,19.0], other: 1.68[0.58,4.85]). The workplace setting was associated with SARS-CoV-2 infection (p = 0.04). SARS-CoV-2 seroprevalence among HCWs reporting duties in the ICU vs. those working in an ambulatory clinic was elevated: OR[95%CI] 2.17[1.01,4.68]. CONCLUSIONS: SARS-CoV-2 seroprevalence in HCW increased during our study period which was consistent with community infection rates. HCW role and setting-particularly working in the ICU-is associated with higher risk for SARS-CoV-2 infection.

Identification of Natural SARS-CoV-2 Infection in Seroprevalence Studies Among Vaccinated Populations.

Most SARS-CoV-2 antibody assays cannot distinguish between antibodies that developed after natural infection and those that developed after vaccination. We assessed the accuracy of a nucleocapsid-containing assay in identifying natural infection among vaccinated individuals. A longitudinal cohort composed of health care workers in the Minneapolis/St. Paul area was enrolled. Two rounds of seroprevalence studies separated by 1 month were conducted from November 2020 to January 2021 among 81 participants. Capillary blood from rounds 1 and 2 was tested for IgG antibodies against spike proteins by enzyme-linked immunosorbent assay (spike-only assay). During round 2, IgGs reactive to SARS-CoV-2 nucleocapsid protein (nucleocapsid-containing assay) were assessed. Vaccination status at round 2 was determined by self-report. Area under the curve was computed to determine the discriminatory ability of the nucleocapsid-containing assay for identification of recent infection. Participants had a mean age of 40 years (range, 23 to 66 years); 83% were female. Round 1 seroprevalence was 9.5%. Before round 2 testing, 46% reported vaccination. Among those not recently infected, in comparing vaccinated vs unvaccinated individuals, elevated levels of spike 1 (P<.001) and spike 2 (P=.01) were observed, whereas nucleocapsid levels were not statistically significantly different (P=.90). Among all participants, nucleocapsid response predicted recent infection with an area under the curve of 0.93 (95% CI, 0.88 to 0.99). Among individuals vaccinated more than 10 days before antibody testing, the specificity of the nucleocapsid-containing assay was 92%, whereas the specificity of the spike-only assay was 0%. An IgG assay identifying reactivity to nucleocapsid protein is an accurate predictor of natural infection among a partially vaccinated population, whereas a spike-only assay performed poorly.

SARS-CoV-2 Seroprevalence Survey in Grocery Store Workers-Minnesota, 2020-2021.

Grocery workers were essential to the workforce and exempt from lockdown requirements as per Minnesota Executive Order 20-20. The risk of COVID-19 transmission in grocery settings is not well documented. This study aimed to determine which factors influenced seropositivity among grocery workers. We conducted a cross-sectional study of Minnesota grocery workers aged 18 and older using a convenience sample. Participants were recruited using a flyer disseminated electronically via e-mail, social media, and newspaper advertising. Participants were directed to an electronic survey and were asked to self-collect capillary blood for IgG antibody testing. Data were analyzed using logistic regression and adjusted for urbanicity, which confounded the relationship between number of job responsibilities in a store and seropositivity. Of 861 Minnesota grocery workers surveyed, 706 (82%) were tested as part of this study, of which 56 (7.9%) tested positive for IgG antibodies. Participants aged 65-74 years had the highest percent positivity. Having multiple job responsibilities in a store was significantly associated with seropositivity in our adjusted model (OR: 1.14 95% CI: 1.01-1.27). Workplace factors influenced seropositivity among Minnesota grocery workers. Future research will examine other potential factors (e.g., in-store preventive measures and access to PPE) that may contribute to increased seropositivity.

Severe Acute Respiratory Syndrome Coronavirus 2 Seroprevalence and Reported Coronavirus Disease 2019 Cases in US Children, August 2020-May 2021.

BACKGROUND: Case-based surveillance of pediatric coronavirus disease 2019 (COVID-19) cases underestimates the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among children and adolescents. Our objectives were to estimate monthly SARS-CoV-2 antibody seroprevalence and calculate ratios of SARS-CoV-2 infections to reported COVID-19 cases among children and adolescents in 8 US states. METHODS: Using data from the Nationwide Commercial Laboratory Seroprevalence Survey, we estimated monthly SARS-CoV-2 antibody seroprevalence among children aged 0-17 years from August 2020 through May 2021. We calculated and compared cumulative incidence of SARS-CoV-2 infection extrapolated from population-standardized seroprevalence of antibodies to SARS-CoV-2, cumulative COVID-19 case reports since March 2020, and infection-to-case ratios among persons of all ages and children aged 0-17 years for each state. RESULTS: Of 41 583 residual serum specimens tested, children aged 0-4, 5-11, and 12-17 years accounted for 1619 (3.9%), 10 507 (25.3%), and 29 457 (70.8%), respectively. Median SARS-CoV-2 antibody seroprevalence among children increased from 8% (range, 6%-20%) in August 2020 to 37% (range, 26%-44%) in May 2021. Estimated ratios of SARS-CoV-2 infections to reported COVID-19 cases in May 2021 ranged by state from 4.7-8.9 among children and adolescents to 2.2-3.9 for all ages combined. CONCLUSIONS: Through May 2021 in selected states, the majority of children with serum specimens included in serosurveys did not have evidence of prior SARS-CoV-2 infection. Case-based surveillance underestimated the number of children infected with SARS-CoV-2 more than among all ages. Continued monitoring of pediatric SARS-CoV-2 antibody seroprevalence should inform prevention and vaccination strategies.

Identification of natural SARS-CoV-2 infection in seroprevalence studies among vaccinated populations.

IMPORTANCE: Identification of SARS-CoV-2 infection via antibody assays is important for monitoring natural infection rates. Most antibody assays cannot distinguish natural infection from vaccination. OBJECTIVE: To assess the accuracy of a nucleocapsid-containing assay in identifying natural infection among vaccinated individuals. DESIGN: A longitudinal cohort comprised of healthcare workers (HCW) in the Minneapolis/St. Paul metropolitan area was enrolled. Two rounds of seroprevalence studies separated by one month were conducted from 11/2020-1/2021. Capillary blood from round 1 and 2 was tested for IgG antibodies against SARS-CoV-2 spike proteins with a qualitative chemiluminescent ELISA (spike-only assay). In a subsample of participants (n=82) at round 2, a second assay was performed that measured IgGs reactive to SARS-CoV-2 nucleocapsid protein (nucleocapsid-containing assay). Round 1 biospecimen collections occurred prior to vaccination in all participants. Vaccination status at round 2 was determined via self-report. SETTING: The Minneapolis/St. Paul, Minnesota metropolitan area. PARTICIPANTS: HCW age 18-80 years. EXPOSURES: Round 1 recent SARS-CoV-2 infection assessed via a spike-only assay and participant self-report. OUTCOMES: Round 2 SARS-CoV-2 infection assessed via the nucleocapsid-containing assay. Area under the curve (AUC) was computed to determine the discriminatory ability of round 2 IgG reactivity to nucleocapsid for identification of recent infection determined during round 1. RESULTS: Participants had a mean age of 40 (range=23-66) years, 83% were female, 46% reported vaccination prior to the round 2 testing. Round 1 seroprevalence was 9.5%. Among those not recently infected, when comparing vaccinated vs. unvaccinated individuals, elevated levels of spike 1 (p<0.001) and spike 2 (p=0.01) were observed while nucleocapsid levels were not statistically significantly different (p=0.90). Among all participants, nucleocapsid response predicted recent infection with an AUC(95%CI) of 0.93(0.88,0.99). Among individuals vaccinated >10 days prior to antibody testing, the specificity of the nucleocapsid-containing assay was 92% and while the specificity of the spike-only assay was 0%. CONCLUSIONS AND RELEVANCE: An IgG assay identifying reactivity to nucleocapsid protein is an accurate predictor of natural infection among vaccinated individuals while a spike-only assay performed poorly. In the era of SARS-CoV-2 vaccination, seroprevalence studies monitoring natural infection will require assays that do not rely on spike-protein response alone.

Seroprevalence of Antibodies to SARS-CoV-2 in 10 Sites in the United States, March 23-May 12, 2020.

IMPORTANCE: Reported cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection likely underestimate the prevalence of infection in affected communities. Large-scale seroprevalence studies provide better estimates of the proportion of the population previously infected. OBJECTIVE: To estimate prevalence of SARS-CoV-2 antibodies in convenience samples from several geographic sites in the US. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study performed serologic testing on a convenience sample of residual sera obtained from persons of all ages. The serum was collected from March 23 through May 12, 2020, for routine clinical testing by 2 commercial laboratory companies. Sites of collection were San Francisco Bay area, California; Connecticut; south Florida; Louisiana; Minneapolis-St Paul-St Cloud metro area, Minnesota; Missouri; New York City metro area, New York; Philadelphia metro area, Pennsylvania; Utah; and western Washington State. EXPOSURES: Infection with SARS-CoV-2. MAIN OUTCOMES AND MEASURES: The presence of antibodies to SARS-CoV-2 spike protein was estimated using an enzyme-linked immunosorbent assay, and estimates were standardized to the site populations by age and sex. Estimates were adjusted for test performance characteristics (96.0% sensitivity and 99.3% specificity). The number of infections in each site was estimated by extrapolating seroprevalence to site populations; estimated infections were compared with the number of reported coronavirus disease 2019 (COVID-19) cases as of last specimen collection date. RESULTS: Serum samples were tested from 16 025 persons, 8853 (55.2%) of whom were women; 1205 (7.5%) were 18 years or younger and 5845 (36.2%) were 65 years or older. Most specimens from each site had no evidence of antibodies to SARS-CoV-2. Adjusted estimates of the proportion of persons seroreactive to the SARS-CoV-2 spike protein antibodies ranged from 1.0% in the San Francisco Bay area (collected April 23-27) to 6.9% of persons in New York City (collected March 23-April 1). The estimated number of infections ranged from 6 to 24 times the number of reported cases; for 7 sites (Connecticut, Florida, Louisiana, Missouri, New York City metro area, Utah, and western Washington State), an estimated greater than 10 times more SARS-CoV-2 infections occurred than the number of reported cases. CONCLUSIONS AND RELEVANCE: During March to early May 2020, most persons in 10 diverse geographic sites in the US had not been infected with SARS-CoV-2 virus. The estimated number of infections, however, was much greater than the number of reported cases in all sites. The findings may reflect the number of persons who had mild or no illness or who did not seek medical care or undergo testing but who still may have contributed to ongoing virus transmission in the population.

Screening for Elevated Blood Lead Levels: False-Positive Rates of Tests on Capillary Samples, Minnesota, 2011-2017.

CONTEXT: A typical strategy for identifying children with elevated blood lead levels (BLL) is to use a test on a capillary sample as a screening tool and then perform a confirmatory test on a venous sample following an elevated capillary screen. However, tests on capillary samples are prone to false-positive results, which affect surveillance estimates of the prevalence of elevated BLL. OBJECTIVE: We sought to measure the prevalence and risk of false-positive results in elevated tests on capillary samples based on various potential predictors. DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME MEASURES: We analyzed blood lead results for children aged 0 to 6 years tested during 2011 to 2017 in Minnesota. A false positive was defined as a test on a capillary sample of at least 5 µg/dL, followed by a test result on a venous sample less than 5 µg/dL within 90 days. Binomial regression was used to estimate the probability of false-positive results dependent on the initial test result and the time between initial and confirmatory tests. RESULTS: Results from 3898 children were included in analyses. Of these, 2330 (60%) had confirmatory results below 5 µg/dL and were classified as false positives. The proportion of false positives varied with time between tests, dependent on the initial result. Extrapolating the model to zero days between tests, without time for any change in the child's true BLL, we predicted 55% false positives in this study group (95% confidence interval: 53%-57%). CONCLUSION: Caution is warranted when interpreting elevated tests on capillary samples without confirmatory tests on venous samples. Providers should be encouraged to follow up all elevated capillary screens with confirmatory tests on venous samples.

Response to the US FDA LeadCare Testing Systems Recall and CDC Health Alert.

On May 17, 2017, the Food and Drug Administration issued a safety recall for the Magellan Diagnostics' LeadCare Testing Systems due to the potential for inaccurately low blood lead test results when used with venous blood samples. Concurrently, the Centers for Disease Control and Prevention (CDC) issued a health alert with retesting recommendations for specific high-risk populations. The purpose of the CDC retesting recommendations was to help identify high-risk individuals so that those potentially impacted by falsely low test results could be retested and receive appropriate follow-up care. The CDC's Lead Poisoning Prevention Program sought to understand how the recall and recommendations impacted state and local public health agencies. Childhood lead poisoning prevention programs (CLPPPs) in state and local public health agencies collect blood lead test results for children and had a lead role in identifying children for retesting. Case studies are presented that highlight the experiences of 4 state CLPPPs in responding to the recall and recommendations. Collectively, the case studies point to several lessons learned, including the importance of (1) having a well-functioning surveillance system in place prior to a serious incident; (2) having a clear understanding of the roles partners play in the continuum of care for children potentially exposed to lead; and (3) ensuring effective communications with all staff, both internal and external, to public health agencies that have a role in responding to a serious incident. The ability to respond to public health emergencies or other serious incidents takes the combined effort of federal, state, and local public health agencies as well as others in the health care delivery system. The CDC will continue to support state and local lead poisoning prevention programs so that they have the information and tools they need to address and prevent the health effects of lead exposures in communities.

Lead Exposure Among Workers at a Shipyard-Wisconsin, 2015 to 2016.

OBJECTIVE: In March 2016, the state health departments of Wisconsin and Minnesota learned of three shipyard workers with blood lead levels (BLLs) more than 40 µg/dL. An investigation was conducted to determine the extent of and risk factors for the exposure. METHODS: We defined a case as an elevated BLL more than or equal to 5 µg/dL in a shipyard worker. Workers were interviewed regarding their symptoms and personal protective equipment (PPE) use. RESULTS: Of 357 workers, 65.0% had received more than or equal to 1 BLL test. Among tested workers, 171 (73.7%) had BLLmax more than or equal to 5 µg/dL. Workers who received respirator training or fit testing had a median BLLmax of 18.0 µg/dL, similar to the median BLLmax of workers who did not receive such training (22.6 µg/dL, P = 0.20). CONCLUSIONS: Our findings emphasize the importance of adequate provision and use of PPE to prevent occupational lead exposure.

Adult Blood Lead Levels in Minnesota: Rates and Trends, 2005-2012.

Lead exposure is associated with a number of adverse health events including peripheral neuropathy, anemia, renal damage and cognitive impairment. The vast majority of adult lead exposures occur in the workplace. By statute, all results from blood lead level (BLL) tests performed in Minnesota are submitted to the Minnesota Department of Health for surveillance purposes. We analyzed that data to examine lead exposure trends from 2005 through 2012. We found that an average of 548 persons 16 years of age and older had a BLL greater than 10 µg/dL each year during that period. Analysis of the prevalence rate of elevated BLLs among adults for the years 2005-2012 showed a modest, nonsignificant decline among those with BLLs greater than 1O µg/dL. Much has been done to reduce exposures and BLLs among young children. However, the policies and standards that protect workers have not been similarly adjusted, and many workers remain at risk of exposure. Although OSHA is responsible for developing and implementing policies and standards to protect workers, health care providers can play a critical role in identifying cases of lead exposure by asking patients about their occupation and industry. Those working in high-risk industries should be tested to determine whether they have been exposed and intervention is warranted.

Colorado tick fever in the United States, 2002-2012.

BACKGROUND: Colorado tick fever (CTF) is an acute systemic febrile illness caused by the CTF virus (CTFV). The last national summary of CTF cases in the United States included cases reported through 2001. This study summarizes national surveillance data for CTF from 2002 through 2012 and examines trends in the epidemiology and testing of identified CTF cases. METHODS: Because CTF is not nationally notifiable, we identified CTF cases through solicited reports from state health departments and diagnostic laboratory records. For all cases, we collected data on age, sex, county of residence, travel history, symptom onset date, laboratory testing, and clinical outcome. Poisson regression was used to examine trends over time in case counts, and simple linear regression and logistic regression were used to examine trends in case characteristics. RESULTS: From 2002 through 2012, 75 CTF cases were identified with a median of five cases per year (range 3-14). Forty-seven (63%) cases occurred in males and 49 (65%) occurred in people aged ≥40 years. The majority (80%) of cases had onset of illness during May through July. Cases occurred in residents of 14 states but the infections were acquired in six western states. Wyoming had the highest annual incidence of CTF among residents (3.4 cases per million population), followed by Montana (1.5 per million), and Utah (0.5 per million). Over the 11 years, there was an increase in the proportion of cases diagnosed by RT-PCR testing and in the proportion of cases among travelers to another state. CONCLUSIONS: CTF cases continue to occur annually among residents and visitors to the western United States. Public health prevention messages about decreasing tick exposure should be targeted to residents and travelers who will spend time outdoors in an endemic region during the spring and summer months.

Outbreak of Francisella novicida bacteremia among inmates at a louisiana correctional facility.

BACKGROUND: Francisella novicida is a rare cause of human illness despite its close genetic relationship to Francisella tularensis, the agent of tularemia. During April-July 2011, 3 inmates at a Louisiana correctional facility developed F. novicida bacteremia; 1 inmate died acutely. METHODS: We interviewed surviving inmates; reviewed laboratory, medical, and housing records; and conducted an environmental investigation. Clinical and environmental samples were tested by culture, real-time polymerase chain reaction (PCR), and multigene sequencing. Isolates were typed by pulsed-field gel electrophoresis (PFGE). RESULTS: Clinical isolates were identified as F. novicida based on sequence analyses of the 16S ribosomal RNA, pgm, and pdpD genes. PmeI PFGE patterns for the clinical isolates were indistinguishable. Source patients were aged 40-56 years, male, and African American, and all were immunocompromised. Two patients presented with signs of bacterial peritonitis; the third had pyomyositis of the thigh. The 3 inmates had no contact with one another; their only shared exposures were consumption of municipal water and of ice that was mass-produced at the prison in an unenclosed building. Swabs from one set of ice machines and associated ice scoops yielded evidence of F. novicida by PCR and sequencing. All other environmental specimens tested negative. CONCLUSIONS: To our knowledge, this is the first reported common-source outbreak of F. novicida infections in humans. Epidemiological and laboratory evidence implicate contaminated ice as the likely vehicle of transmission; liver disease may be a predisposing factor. Clinicians, laboratorians, and public health officials should be aware of the potential for misidentification of F. novicida as F. tularensis.