Did COVID-19 ICU patient mortality risk increase as Colorado hospitals filled? A retrospective cohort study.

OBJECTIVES: To assess whether increasing levels of hospital stress-measured by intensive care unit (ICU) bed occupancy (primary), ventilators in use and emergency department (ED) overflow-were associated with decreasing COVID-19 ICU patient survival in Colorado ICUs during the pre-Delta, Delta and Omicron variant eras. DESIGN: A retrospective cohort study using discrete-time survival models, fit with generalised estimating equations. SETTING: 34 hospital systems in Colorado, USA, with the highest patient volume ICUs during the COVID-19 pandemic. PARTICIPANTS: 9196 non-paediatric SARS-CoV-2 patients in Colorado hospitals admitted once to an ICU between 1 August 2020 and 1 March 2022 and followed for 28 days. OUTCOME MEASURES: Death or discharge to hospice. RESULTS: For Delta-era COVID-19 ICU patients in Colorado, the odds of death were estimated to be 26% greater for patients exposed every day of their ICU admission to a facility experiencing its all-era 75th percentile ICU fullness or above, versus patients exposed for none of their days (OR: 1.26; 95% CI: 1.04 to 1.54; p=0.0102), adjusting for age, sex, length of ICU stay, vaccination status and hospital quality rating. For both Delta-era and Omicron-era patients, we also detected significantly increased mortality hazard associated with high ventilator utilisation rates and (in a subset of facilities) states of ED overflow. For pre-Delta-era patients, we estimated relatively null or even protective effects for the same fullness exposures, something which provides a meaningful contrast to previous studies that found increased hazards but were limited to pre-Delta study windows. CONCLUSIONS: Overall, and especially during the Delta era (when most Colorado facilities were at their fullest), increasing exposure to a fuller hospital was associated with an increasing mortality hazard for COVID-19 ICU patients.

Notes from the Field: Potential Outbreak of Extrapulmonary Mycobacterium abscessus subspecies massiliense Infections from Stem Cell Treatment Clinics in Mexico - Arizona and Colorado, 2022.

Mycobacterium abscessus is an intrinsically drug-resistant, rapidly growing, nontuberculous mycobacterium; extrapulmonary infections have been reported in association with medical tourism (1). During November-December 2022, two Colorado hospitals (hospitals A and B) treated patient A, a Colorado woman aged 30-39 years, for M. abscessus meningitis. In October 2022, she had received intrathecal donor embryonic stem cell injections in Baja California, Mexico to treat multiple sclerosis and subsequently experienced headaches and fevers, consistent with meningitis. Her cerebrospinal fluid revealed neutrophilic pleocytosis and grew M. abscessus in culture at hospital A. Hospital A's physicians consulted hospital B's infectious diseases (ID) physicians to co-manage this patient (2).

Acute Gastroenteritis Outbreak Among Colorado River Rafters and Backpackers in the Grand Canyon, 2022.

INTRODUCTION: From April 1 to May 31, 2022, Grand Canyon National Park received increased acute gastroenteritis reports. Pooled portable toilet specimens identified norovirus genogroups I and II. We sought to determine outbreak transmission contributors and individual risk factors while rafting or backpacking in the park. METHODS: Grand Canyon rafters and backpackers were surveyed online from June 13-July 8, 2022, and a Cox proportional hazards model was used to identify predictors associated with illness and adjusted for potential confounding factors. RESULTS: Among 762 surveys, 119 cases and 505 well persons submitted complete survey data. Illness among rafters was associated with interaction with ill persons during the trip (adjusted hazard ratio [adjHR] = 3.4 [95%CI 2.3-5.0]) and lack of any hand hygiene (1.2 [0.7-1.9]) or use of only sanitizer or water (1.6 [1.04-2.6]) before snacks. Younger rafters had higher illness rates compared to those ≥60 y (1.5 [1.2-1.8] for ages 40-59 and 2.2 [1.4-3.5] for ages <40 y). CONCLUSIONS: Person-to-person transmission likely accounted for the widespread outbreak. Future outbreak mitigation efforts on river trips could focus on symptom screening before the trip starts, prompt separation of ill and well passengers, strict adherence to hand hygiene with soap and water, minimizing social interactions among rafting groups, and widespread outbreak notices and education to all park users.

Involuntary displacement and self-reported health in a cross-sectional survey of people experiencing homelessness in Denver, Colorado, 2018-2019.

BACKGROUND: The number of people experiencing unsheltered homelessness in the U.S. is increasing. Municipalities have responded with punitive responses such as involuntary displacement (i.e., encampment sweeps, move along orders), but little is known about the impact of involuntary displacement on health. The purpose of this study was to investigate the association between broadly defined experiences of involuntary displacement and self-reported health conditions among people experiencing homelessness. METHODS: We used logistic regression models to generate odds ratios using publicly available data from a cross-sectional sample of people experiencing homelessness in Denver, Colorado, during September 2018-February 2019. Hosmer-Lemeshow Goodness of Fit tests were used to assess model fit. RESULTS: Among 397 people experiencing homelessness, involuntary displacement was significantly associated with self-reported infectious diseases (adjusted odds ratio (aOR) 2.09, 95% CI 1.27, 3.41), substance and alcohol use (aOR 2.83; 95% CI 1.70, 4.73), climate-related conditions (aOR 2.27; 95% CI 1.35, 3.83), and worsening mental health (aOR 2.00; 95% CI 1.24, 3.24) after controlling for potential confounders. No statistically significant associations were identified between involuntary displacement and injuries, musculoskeletal issues, chronic conditions, and chronic mental and emotional issues. CONCLUSIONS: This research quantifies the association between involuntary displacement and multiple infectious and non-infectious health outcomes. While city officials attempt to grapple with increasing unsheltered homelessness, it is important to understand what harms are occurring that are associated with current policies. Our research adds to the growing body of literature that involuntary displacement is a harmful response to unsheltered homelessness. Alternative approaches focused on connections to housing and social services should be prioritized.

Lessons Learned from Cross-Systems Approach to COVID-19 Pandemic Response in Juvenile Justice System, Colorado, USA.

The global COVID-19 pandemic illustrates the importance of a close partnership between public health and juvenile justice systems when responding to communicable diseases. Many setting-specific obstacles must be navigated to respond effectively to limit disease transmission and negative health outcomes while maintaining necessary services for youth in confinement facilities. The response requires multidisciplinary expertise and collaboration to address unique considerations. Public health mitigation strategies must balance the risk for disease against the negative effects of restrictions. Key aspects of the COVID-19 response in the juvenile justice system of Colorado, USA, involved establishing robust communication and data reporting infrastructures, building a multidisciplinary response team, adapting existing infection prevention guidelines, and focusing on a whole-person health approach to infection prevention. We examine lessons learned and offer recommendations on pandemic emergency response planning and managing a statewide public health emergency in youth confinement settings that ensure ongoing readiness.

An examination of early socioeconomic status and neighborhood disadvantage as independent predictors of antisocial behavior: A longitudinal adoption study.

The present study examined early socioeconomic status (SES) and neighborhood disadvantage (ND) as independent predictors of antisocial behavior (ASB) and addressed the etiology of the associations (i.e., genes versus the environment) using a longitudinal adoption design. Prospective data from the Colorado Adoption Project (435 adoptees, 598 nonadopted children, 526 biological grandparents of adoptees, 481 adoptive parents, and 617 nonadoptive parents including biological parents of unrelated siblings of adoptees) were examined. SES and ND were assessed during infancy and ASB was evaluated from ages four through 16 using parent and teacher report. Associations between predictors and ASB were compared across adoptive and nonadoptive families and sex. Early SES was a nominally significant, independent predictor of antisocial ASB, such that lower SES predicted higher levels of ASB in nonadoptive families only. ND was not associated with ASB. Associations were consistent across aggression and delinquency, and neither SES nor ND was associated with change in ASB over time. Nominally significant associations did not remain significant after controlling for multiple testing. As such, despite nonsignificant differences in associations across sex or adoptive status, we were unable to make definitive conclusions regarding the genetic versus environmental etiology of or sex differences in the influence of SES and ND on ASB. Despite inconclusive findings, in nonadoptees, results were consistent-in effect size and direction-with previous studies in the literature indicating that lower SES is associated with increased risk for ASB.

Critical incidents in Colorado's opioid treatment programs: A comparison of the COVID-19 pandemic to previous years.

INTRODUCTION: In response to the COVID-19 pandemic, Substance Abuse and Mental Health Services Administration (SAMHSA) guidance allowed opioid treatment programs (OTPs) greater flexibility to provide take-home medication doses to patients. This study aims to characterize trends in the rates of critical incidents-safety events occurring in OTPs that are reportable to regulatory entities-across all Colorado OTPs during the COVID-19 pandemic. METHODS: This study is a retrospective review of critical incidents (CIs) for patients enrolled in Colorado OTPs between the years 2017 to 2022, as recorded in Colorado Behavioral Health Administration's (BHA) Opioid Treatment Program Critical Incident Repository Dataset. March 15, 2020 was considered the start of the COVID-19 pandemic in Colorado, so only incidents which occurred from March 15-December 31 of each year were included. CI rate per 100 patients was calculated by dividing CI annual count between March 15-December 31 by the census of enrolled patients at the calendar midpoint of this period, which is August 7. Means comparison tests assessed differences in CI rates. RESULTS: OTP patient enrollment in Colorado increased from 4377 in 2017 to 7327 in 2022. Overall, Medication Diversion accounted for 70 % of CIs, followed by Death (14 %), and Other (5 %). There was a significant increase in the overall rate of CIs from 2017 to 2022 (1.1 % to 3.4 %). The average post-COVID CI rate was higher than pre-COVID (4.0 % vs. 2.4 %). There was no difference, however, in the post-COVID rate of CIs when exclusively compared to 2019 (4.0 % vs. 4.1 %). Post-pandemic years had significantly more CIs per month than pre-pandemic years (27.6 ± 5.6 vs 15.8 ± 3.5). There was no difference in mean monthly CIs between 2019 and post-pandemic (28.5 ± 5.3 vs 27.6 ± 5.6). CONCLUSIONS: There was no increase in the rate of reportable CIs in Colorado OTPs following the SAMHSA COVID-19 guidance increasing take-home doses when comparing 2019 to post-pandemic years. The notable increase in CI incidence occurred from 2018 to 2019, predating the pandemic. These data offer a measure of reassurance for the safety of increased take-home methadone doses. There should be further consideration of how a greater number of take-home doses might benefit both patients and OTPs.

Provider-Reported Barriers in Sexual Health Care Services for Women With Upstream Barriers: The Case of Syphilis and Congenital Syphilis in Southern Colorado, 2022.

BACKGROUND: Syphilis and congenital syphilis rates have increased sharply in Colorado in the past 5 years. Congenital syphilis is passed during pregnancy in utero and can cause lifelong physical, developmental, and neurologic problems for the child, or can lead to miscarriage, stillbirth, or early infant death. Congenital syphilis is easily prevented if the mother receives timely testing, treatment, and prenatal care. Providers can play a key role in preventing congenital syphilis for women with social vulnerabilities, who have a higher likelihood of syphilis and/or congenital syphilis infection. METHODS: We surveyed 23 and interviewed 4 health care providers in southern Colorado in 2022 to record their experiences in providing sexual health care services. We asked providers with direct care experience about perceived barriers in effectively treating syphilis. RESULTS: The most significant barriers reported in the survey were the cost of treatment (26%) and the loss to follow-up (22%). Interviews revealed further challenges, including discretionary testing procedures, delays in screening results, treatment referral issues, and stigma around substance use and sexual activity. CONCLUSIONS: Elevated syphilis and congenital syphilis rates pose significant public health challenges. Coordinated interventions are necessary to effectively reduce the transmission of syphilis and congenital syphilis among women with upstream barriers. Potential care solutions include expanding rapid, point-of care testing and treatment options, supporting bicillin delivery or web-based inventory systems, offering anti-stigma training for providers, offering mental and behavioral health resources at providers' clinics, and expanding partnerships with syringe access programs.

Evaluating the sensitivity of mortality attributable to pollution to modeling Choices: A case study for Colorado.

We evaluated the sensitivity of estimated PM2.5 and NO2 health impacts to varying key input parameters and assumptions including: 1) the spatial scale at which impacts are estimated, 2) using either a single concentration-response function (CRF) or using racial/ethnic group specific CRFs from the same epidemiologic study, 3) assigning exposure to residents based on home, instead of home and work locations for the state of Colorado. We found that the spatial scale of the analysis influences the magnitude of NO2, but not PM2.5, attributable deaths. Using county-level predictions instead of 1 km2 predictions of NO2 resulted in a lower estimate of mortality attributable to NO2 by âˆ¼ 50 % for all of Colorado for each year between 2000 and 2020. Using an all-population CRF instead of racial/ethnic group specific CRFs results in a 130 % higher estimate of annual mortality attributable for the white population and a 40 % and 80 % lower estimate of mortality attributable to PM2.5 for Black and Hispanic residents, respectively. Using racial/ethnic group specific CRFs did not result in a different estimation of NO2 attributable mortality for white residents, but led to âˆ¼ 50 % lower estimates of mortality for Black residents, and 290 % lower estimate for Hispanic residents. Using NO2 based on home instead of home and workplace locations results in a smaller estimate of annual mortality attributable to NO2 for all of Colorado by 2 % each year and 0.3 % for PM2.5. Our results should be interpreted as an exercise to make methodological recommendations for future health impact assessments of pollution.

Multimodal Surveillance Model for Enterovirus D68 Respiratory Disease and Acute Flaccid Myelitis among Children in Colorado, USA, 2022.

Surveillance for emerging pathogens is critical for developing early warning systems to guide preparedness efforts for future outbreaks of associated disease. To better define the epidemiology and burden of associated respiratory disease and acute flaccid myelitis (AFM), as well as to provide actionable data for public health interventions, we developed a multimodal surveillance program in Colorado, USA, for enterovirus D68 (EV-D68). Timely local, state, and national public health outreach was possible because prospective syndromic surveillance for AFM and asthma-like respiratory illness, prospective clinical laboratory surveillance for EV-D68 among children hospitalized with respiratory illness, and retrospective wastewater surveillance led to early detection of the 2022 outbreak of EV-D68 among Colorado children. The lessons learned from developing the individual layers of this multimodal surveillance program and how they complemented and informed the other layers of surveillance for EV-D68 and AFM could be applied to other emerging pathogens and their associated diseases.

For Some Patients, Better Health Starts With Finding A Home.

As the US homeless population grows older and sicker, new programs in Denver, Colorado, and elsewhere link care, services, and housing.

Colorado drugged driving prevalence and impaired driving conviction rates: Effects of impaired driving definitions and a 5-nanogram limit for delta-9 tetrahydrocannabinol.

Objectives: How prevalent is drugged driving among Colorado drivers convicted of Driving Under the Influence (DUI)? What are the conviction rates of Colorado drivers charged with DUI, including impairment by marijuana's delta-9 tetrahydrocannabinol (THC)? Is Colorado's THC permissible inference law effective? To answer these questions, this report analyzes data published primarily in appendices of Colorado drugged driving reports.Methods: In 2017 Colorado began requiring annual analyses of Driving Under the Influence (DUI) offenses, including causes and judicial consequences of DUI offenses. These analyses are performed by the Division of Criminal Justice's Office of Research and Statistics (ORS) within the Department of Public Safety. Each analysis requires ORS to link toxicology and court data bases. Data linking enables reporting of charges and convictions by categories including alcohol only, THC only, and polydrug use (two or more drugs simultaneously). Reports have been published annually for 5 years, the latest published in 2023 which covers case filings for 2020.Results: A rough estimate of one-half of the state's DUI filings were attributed to drug use and half were attributed to alcohol only. The largest component of drugged driving was polydrug impairment, rather than impairment by a single drug like THC. Conviction rates in 2020 were 91% for alcohol only, 90% for polydrug cases, and 72% for THC only. Blood drug levels and law structure (per se, permissible inference, DUI definition) affected conviction rates significantly by defendant subsets. THC conviction rates in 2020 ranged from 11% to 100%, depending on blood drug levels and the legal charges.Conclusions: Efforts to educate the public about the dangers of drugged driving should emphasize polydrug impairment, not simply THC impairment. States should analyze data on causes and consequences of DUI arrests to understand what their drugged driving problems are and what they are not. Non-zero drug per se levels and defining DUI as "incapable of safe driving" can severely reduce the effectiveness of DUI laws.

Improving occupational health surveillance for enteric infections.

AIMS: Enteric pathogens with a livestock reservoir pose a unique risk to people in occupations with regular contact with animals. However, public health surveillance of occupational exposures is inadequate, with surveillance for occupation typically focusing on the risk of transmission and the need for worker exclusion, rather than workplace exposures. To improve surveillance for occupational zoonoses, the Colorado Integrated Food Safety Center of Excellence convened a group of subject matter experts who developed a set of variables on occupation, industry, and exposures, which were integrated into Colorado's surveillance system in 2017. We evaluated the quality and completeness of these new occupational fields for interviewed cases with laboratory-confirmed zoonotic infections and compared occupations to cases with a non-zoonotic infection (Shigella) and to employment data from the Bureau of Labor Statistics. METHODS AND RESULTS: From March 2017 through December 2019, 3668 domestically acquired, laboratory-confirmed sporadic infections of Campylobacter, Cryptosporidium, Shiga toxin-producing Escherichia coli, and non-typhoidal Salmonella among individuals ≥14 years of age were interviewed by public health. We found asking explicitly about occupational exposure risks and focusing on animal exposures, improved data quality and accuracy. Of the cases who stated that they were employed, 262 (13%) reported working in an occupation with regular animal exposure, and 254 (14%) reported an industry with regular animal exposure. Cases with an animal exposure occupation were more likely to be male and live in a rural or frontier county compared to other occupations. All occupations with regular animal contact were reported at a higher frequency than among Shigella cases or the general population. CONCLUSIONS: Public health efforts, both in occupational health and communicable disease sectors, should be made to improve surveillance for enteric zoonoses and identify opportunities for prevention strategies.

Short Interpregnancy Intervals Among Women Experiencing Homelessness in Colorado.

Importance: Short interpregnancy intervals (SIPIs) are associated with increased risk of adverse maternal and neonatal outcomes. Disparities exist across socioeconomic status, but there is little information on SIPIs among women experiencing homelessness. Objective: To investigate (1) differences in rates and characteristics of SIPIs between women experiencing homelessness and domiciled women, (2) whether the association of homelessness with SIPIs differs across races and ethnicities, and (3) whether the association between SIPIs of less than 6 months (very short interpregnancy interval [VSIPIs]) and maternal and neonatal outcomes differs between participant groups. Design, Setting, and Participants: This cohort study used a Colorado statewide database linking the Colorado All Payer Claims Database, Homeless Management Information System, death records, and infant birth records. Participants included all women who gave birth between January 1, 2016, and December 31, 2021. Data were analyzed from September 1, 2022, to May 10, 2023. Exposures: Homelessness and race and ethnicity. Main Outcomes and Measures: The primary outcome consisted of SIPI, a binary variable indicating whether the interval between delivery and conception of the subsequent pregnancy was shorter than 18 months. The association of VSIPI with maternal and neonatal outcomes was also tested. Results: A total of 77 494 women (mean [SD] age, 30.7 [5.3] years) were included in the analyses, of whom 636 (0.8%) were women experiencing homelessness. The mean (SD) age was 29.5 (5.4) years for women experiencing homelessness and 30.7 (5.3) years for domiciled women. In terms of race and ethnicity, 39.3% were Hispanic, 7.3% were non-Hispanic Black, and 48.4% were non-Hispanic White. Associations between homelessness and higher odds of SIPI (adjusted odds ratio [AOR], 1.23 [95% CI, 1.04-1.46]) were found. Smaller associations between homelessness and SIPI were found among non-Hispanic Black (AOR, 0.59 [95% CI, 0.37-0.96]) and non-Hispanic White (AOR, 0.57 [95% CI, 0.39-0.84]) women compared with Hispanic women. A greater association of VSIPI with emergency department visits and low birth weight was found among women experiencing homelessness compared with domiciled women, although no significant differences were detected. Conclusions and Relevance: In this cohort study of women who gave birth from 2016 to 2021, an association between homelessness and higher odds of SIPIs was found. These findings highlight the importance of conception management among women experiencing homelessness. Racial and ethnic disparities should be considered when designing interventions.

Associations between Adolescent Marijuana Use, Driving after Marijuana Use and Recreational Retail Sale in Colorado, USA.

OBJECTIVE: We investigated associations between the retail distribution of recreational marijuana in Colorado and (i) past 30-day marijuana use and (ii) driving after marijuana use (DAMU) among a representative sample of public high school students using four waves of data from a state surveillance system. METHODS: Past 30-day marijuana use was assessed among all sampled students (n = 85,336). DAMU was assessed among students 15 years or older who indicated driving (n = 47,518). Modified Poisson regression with robust variance estimates was used to estimate prevalence ratios (PR) comparing the pre-distribution (2013) and post-distribution (2015, 2017, 2019) periods for marijuana-related behaviors. Frequency of behavioral engagement was assessed using a multinomial approach. RESULTS: An estimated 20.3% of students engaged in past 30-day marijuana use and 10.5% of student drivers engaged in DAMU. Retail distribution of recreational marijuana was not significantly associated with the prevalence of any marijuana use or DAMU. However, it was associated with 1.16 (95% CI: 1.04-1.29) times the prevalence of using marijuana one or two times in the last 30 days, 1.27 (1.03, 1.55) times the prevalence of DAMU one time, and 0.82 (0.69, 0.98) times the prevalence of DAMU six or more times. No significant associations were observed for the remaining frequency categories. CONCLUSIONS: Approximately 1 in 10 students who drive reported DAMU. Varying prevalence in the frequency of past 30-day marijuana use and DAMU was observed following the retail distribution of recreational marijuana in Colorado. Care should be taken to properly educate adolescent drivers regarding the dangers of DAMU.

Surveillance for Avian Bornavirus in Colorado and Wyoming, USA, Raptor Populations.

Avian bornavirus (ABV) is known to infect at least 80 avian species and is associated with avian bornaviral ganglioneuritis (ABG). Avian bornaviral ganglioneuritis is characterized by a lymphoplasmacytic infiltration of the nervous tissue, mainly affecting the nerves that supply the gastrointestinal tract of birds. This disease is diagnosed commonly in psittacines under human care and has been demonstrated in wild bird species; however, its occurrence in raptors is largely unknown. Because of the commonality of ABV in the pet bird population, there is concern about the spread of this virus to other companion avian species, such as falconry birds, as well as wildlife. This prospective study used reverse-transcription quantitative PCR (RT-qPCR) to survey free-ranging Colorado and Wyoming, US, raptor populations for ABV. Quantitative PCR was performed on mixed conjunctival-choanal-cloacal swabs collected from live birds (n=139). In dead birds, a combination of mixed swabs (n=265) and tissue samples of the brain (n=258), heart (n=162), adrenal glands (n=162), liver (n=162), kidney (n=139), spinal cord (n=139), and brachial plexus (n=139) were evaluated. All 1,565 swab and tissue samples RT-qPCR results from the 404 birds evaluated were negative. Based on these results and a lack of clinical signs suggestive of ABG, ABV is likely not a prevalent pathogen in Colorado and Wyoming raptor populations at this time.

SARS-CoV-2 surveillance in a veterinary health system provides insight into transmission risks.

OBJECTIVE: To investigate the prevalence and seropositivity of SARS-CoV-2 in companion and exotic animals in a veterinary healthcare system. SAMPLE: A total of 341 animals were sampled by a combination of oral and nasal swabs. Serum from whole blood was collected from a subset of animals (86 canines, 25 felines, and 6 exotic animals). METHODS: After informed owner consent, convenience samples from client-owned animals and the pets of students and staff members associated with Colorado State University's Veterinary Health System were collected between May 2021 and September 2022. Study samples were collected by trained veterinarians, Veterinary Health System staff, and veterinary students. RESULTS: SARS-CoV-2 RNA was detected by reverse transcription PCR in 1.6% (95% CI, 0.5% to 4.6%) of domestic canines and 1.1% (95% CI, 0.2% to 6.1%) of domestic felines. No RNA was detected in any of the exotic animal species tested (n = 66). Plaque reduction neutralization tests indicated that 12.8% (95% CI, 7.3% to 21.5%) of canines and 12.0% (95% CI, 4.2% to 30.0%) of felines had neutralizing antibodies against SARS-CoV-2. CLINICAL RELEVANCE: This study provides insight regarding SARS-CoV-2 spillover in domestic companion and exotic animals and contributes to our understanding of transmission risk in the veterinary setting.

Recovery of multireassortant bluetongue virus serotype 6 sequences from a mule deer (Odocoileus hemionus) and Dorset sheep (Ovis aries) in Colorado.

We report the discovery of two bluetongue virus serotype 6 (BTV-6) reassortants recovered from a domestic sheep and a free-ranging mule deer in northern Colorado. At the time of this publication, whole-genome sequencing of BTV-6 isolates in the Western U.S. have not been undertaken. These findings reflect the incursive movement of geographically distinct BTV serotypes into important agricultural areas of the U.S. and demonstrate reassortment with regionally circulating serotypes.