Association between gestational diabetes and cardiovascular disease within 24 months postpartum.

BACKGROUND: Cardiovascular disease is the leading cause of death among women in the United States. It is well established that gestational diabetes mellitus is associated with an overall lifetime increased risk of cardiometabolic disease, even among those without intercurrent type 2 diabetes. However, the association between gestational diabetes mellitus and short-term risk of cardiovascular disease is unclear. Establishing short-term risks of cardiovascular disease for patients with gestational diabetes mellitus has significant potential to inform early screening and targeted intervention strategies to reduce premature cardiovascular morbidity among women. OBJECTIVE: This study aimed to compare the risk of cardiovascular disease diagnosis in the first 24 months postpartum between patients with and without gestational diabetes mellitus. STUDY DESIGN: Our longitudinal population-based study included pregnant individuals with deliveries from 2007 to 2019 in the Maine Health Data Organization's All Payer Claims Database. We excluded records with gestational age <20 weeks, non-Maine residence, multifetal gestation, no insurance in the month of delivery or the 3 months before pregnancy, an implausibly short interval until next pregnancy (<60 days), pregestational diabetes mellitus, and any prepregnancy diagnosis of the cardiovascular conditions being examined postpartum. Gestational diabetes mellitus and cardiovascular disease (heart failure, ischemic heart disease, arrhythmia/cardiac arrest, cardiomyopathy, cerebrovascular disease/stroke, and new chronic hypertension) were identified by International Classification of Diseases 9/10 diagnosis codes. Cox proportional hazards models were used to estimate hazard ratios, adjusting for potential confounding factors. We assessed whether the association between gestational diabetes mellitus and chronic hypertension was mediated by intercurrent diabetes mellitus. RESULTS: Among the 84,746 pregnancies examined, the cumulative risk of cardiovascular disease within 24 months postpartum for those with vs without gestational diabetes mellitus was 0.13% vs 0.20% for heart failure, 0.16% vs 0.14% for ischemic heart disease, 0.60% vs 0.44% for cerebrovascular disease/stroke, 0.22% vs 0.16% for arrhythmia/cardiac arrest, 0.20% vs 0.20% for cardiomyopathy, and 4.19% vs 1.83% for new chronic hypertension. After adjusting for potential confounders, those with gestational diabetes had an increased risk of new chronic hypertension (adjusted hazard ratio, 1.56; 95% confidence interval, 1.32-1.86) within the first 24 months postpartum compared with those without gestational diabetes. There was no association between gestational diabetes and ischemic heart disease (adjusted hazard ratio, 0.75; 95% confidence interval, 0.34-1.65), cerebrovascular disease/stroke (adjusted hazard ratio, 1.13; 95% confidence interval, 0.78-1.66), arrhythmia/cardiac arrest (adjusted hazard ratio, 1.16; 95% confidence interval, 0.59-2.29), or cardiomyopathy (adjusted hazard ratio, 0.75; 95% confidence interval, 0.40-1.41) within the first 24 months postpartum. Those with gestational diabetes appeared to have a decreased risk of heart failure within 24 months postpartum (adjusted hazard ratio, 0.45; 95% confidence interval, 0.21-0.98). Our mediation analyses estimated that 28% of the effect of gestational diabetes on new chronic hypertension was mediated through intercurrent diabetes mellitus. CONCLUSION: Patients with gestational diabetes mellitus have a significantly increased risk of new chronic hypertension as early as 24 months postpartum. Most of this effect was not due to the development of diabetes mellitus. Our findings suggest that all women with gestational diabetes need careful monitoring and screening for new chronic hypertension in the first 2 years postpartum.

Pseudomonas Infection Outbreak Associated with a Hotel Swimming Pool - Maine, March 2023.

Treated recreational water venues (e.g., pools and hot tubs) located at hotels represent one third of sources of reported treated recreational water-associated outbreaks; when these outbreaks are caused by Pseudomonas aeruginosa, they predominantly occur during January-April. On March 8, 2023, the Maine Center for Disease Control and Prevention (Maine CDC) initiated an investigation in response to reports of illness among persons who had used a swimming pool at hotel A during March 4-5. A questionnaire was distributed to guests who were at hotel A during March 1-7. Among 35 guests who responded, 23 (66%) developed ear pain, rash, or pain or swelling in feet or hands within days of using the pool during March 4-5. P. aeruginosa, a chlorine-susceptible bacterium, was identified in cultures obtained from skin lesions of three patients; a difference of two single nucleotide polymorphisms was found between isolates from two patients' specimens, suggesting a common exposure. Hotel A management voluntarily closed the pool, and Maine CDC's Health Inspection Program identified multiple violations, including having no disinfectant feeder system, all of which had been identified during a previous inspection. Because chlorine had been added to the pool water after the pool was voluntary closed, environmental samples were not collected. The pool remained closed until violations were addressed. Health departments can play an important role in reducing the risk for outbreaks associated with hotel pools and hot tubs. This reduction in risk can be achieved by collaborating with operators to ensure compliance with public health codes, including maintaining chlorine concentration and otherwise vigilantly managing the pool, and by disseminating prevention messages to pool and hot tub users.

Responding to avian influenza A H5N1 detection on a hospital property in Maine-An interdisciplinary approach.

BACKGROUND: The risk of infection with avian influenza A viruses currently circulating in wild and domestic birds in the Americas is considered low for the general public; however, detections in humans have been reported and warning signs of increased zoonotic potential have been identified. In December 2022, two Canada geese residing on the grounds of an urban hospital in Maine tested positive for influenza A H5N1 clade 2.3.4.4b. AIMS: Given the opportunity for exposure to staff and hospital visitors through potentially infected faeces on the property, public health authorities determined mitigation efforts were needed to prevent the spread of disease. The ensuing response relied on collaboration between the public health and animal health agencies to guide the hospital through efforts in preventing possible zoonotic transmission to humans. MATERIALS AND METHODS: Mitigation efforts included staff communication and education, environmental cleaning and disinfection, enhanced illness surveillance among staff and patients, and exposure and source reduction. RESULTS: No human H5N1 cases were identified, and no additional detections in birds on the property occurred. Hospital staff identified barriers to preparedness resulting from a lack of understanding of avian influenza A viruses and transmission prevention methods, including avian influenza risk in resident wild bird populations and proper wildlife management methods. CONCLUSION: As this virus continues to circulate at the animal-human interface, this event and resulting response highlights the need for influenza A H5N1 risk awareness and guidance for facilities and groups not traditionally involved in avian influenza responses.

Factors associated with injury among Maine logging workers.

INTRODUCTION: Despite dramatic improvements in safety, logging remains one of the most dangerous industries in the United States. The purpose of this study was to explore longitudinal injury trends among Maine logging workers. METHODS: Loggers participated in seven quarterly surveys, over the course of 18 months. Categorical and free text data related to traumatic and acute injury, musculoskeletal disorders (MSD), and chronic pain were exported from REDCap into SAS 9.4, Excel, and NVivo, for quantitative and qualitative analysis, respectively. Time to injury was modeled using two different approaches: (1) time to the occurrence of first injury modeled by proportional hazard regression and (2) an intensity model for injury frequency. Two research team members also analyzed qualitative data using a content analysis approach. RESULTS: During the study, 204 injuries were reported. Of the 154 participants, 93 (60.4%) reported musculoskeletal pain on at least one survey. The majority of injuries were traumatic, including fractures, sprains, and strains. Lack of health insurance was found to be related to increased risk of first injury [HR = 1.41, 95% CI = 0.97-2.04, p = 0.069]. Variables found to be related to injury intensity at the univariate level were: (1) a lack of health insurance [HR = 1.51, 95% CI = 1.04-2.20, p = 0.030], (2) age [HR for 10-year age increase;= 1.12, 95% CI = 0.99-1.27, p = 0.082], and (3) years employed in logging industry [HR for 10-year increase = 1.12, 95% CI = 0.99-1.26, p = 0.052]. Seeking medical attention for injury was not a priority for this cohort, and narratives revealed a trend for self-assessment. A variety of barriers, including finances, prevented loggers from seeking medical attention. DISCUSSION: We found that loggers still experience serious, and sometimes disabling, injuries associated with their work. It was unsurprising that many injuries were due to slips, trips, and falls, along with contact with logging equipment and trees/logs. The narratives revealed various obstacles preventing loggers from achieving optimal health. Examples included geographic distance from healthcare, lack of time to access care, and entrenched values that prioritized independence and traditional masculinity. Financial considerations were also consistently cited as a primary barrier to adequate care. CONCLUSION: There is a continued need to emphasize occupational health and safety in the logging industry. Implementation of relevant safety programs is key, but it is likely that the benefits of these will not be fully realized until a cultural shift takes place within this industry.

Hepatitis C Virus Cascade of Care Among Perinatal Patients in Maine Diagnosed With Opioid Use Disorder, 2015-2020.

OBJECTIVE: This is a quality improvement project to determine the best process to identify and address gaps in care for perinatal patients in receiving appropriate hepatitis C virus (HCV) testing and treatment across the largest health system in Maine. STUDY DESIGN: We reviewed electronic medical record data between October 1, 2015, and February 1, 2020, to investigate rates of HCV testing and treatment among 916 perinatal patients with opioid use disorder across 8 hospitals using a "cascade of care" framework, a model used previously to identify gaps in care and treatment of chronic diseases. MAIN OUTCOME MEASURE: We examined HCV testing and treatment rates along the cascade of care and patient characteristics associated with HCV antibody testing and treatment, separately, using log binomial regression models. Models were adjusted for age, residential distance to medical center, psychiatric diagnosis, and opioid agonist therapy at delivery. RESULTS: Of pregnant patients eligible for screening, 64% (582/916) received HCV antibody testing. Of 136 patients with active HCV infection, 32% (n = 43) received a referral for treatment, 21% (n = 28) were treated, and 13% (n = 18) achieved sustained virologic response. In the adjusted regression models, only opioid agonist therapy was associated with HCV antibody testing (adjusted risk ratio, 1.31; 95% confidence interval, 1.18-1.46), and no factors were significantly associated with receipt of treatment among HCV viremic patients. CONCLUSION: Low referral and treatment rates signify the need for quality improvement interventions to improve coordination of care between multiple disciplines and practice settings to increase access to HCV treatment.

Provision of Postpartum Contraception Before and After the Start of the COVID-19 Pandemic in Maine.

OBJECTIVE: Preliminary findings from selected health systems revealed interruptions in reproductive health care services due to the COVID-19 pandemic. We estimated changes in postpartum contraceptive provision associated with the start of the COVID-19 pandemic in Maine. METHODS: We used the Maine Health Data Organization's All Payer Claims Database for deliveries from October 2015 through March 2021 (n = 45 916). Using an interrupted time-series analysis design, we estimated changes in provision rates of long-acting reversible contraception (LARC), permanent contraception, and moderately effective contraception within 3 and 60 days of delivery after the start of the COVID-19 pandemic. We performed 6- and 12-month analyses (April 2020-September 2020, April 2020-March 2021) as compared with the reference period (October 2015-March 2020). We used Poisson regression models to calculate level-change rate ratios (RRs) and 95% CIs. RESULTS: The 6-month analysis found that provision of LARC (RR = 1.89; 95% CI, 1.76-2.02) and moderately effective contraception (RR = 1.51; 95% CI, 1.33-1.72) within 3 days of delivery increased at the start of the COVID-19 pandemic, while provision of LARC (RR = 0.95; 95% CI, 0.93-0.97) and moderately effective contraception (RR = 1.08; 95% CI, 1.05-1.11) within 60 days of delivery was stable. Rates of provision of permanent contraception within 3 days (RR = 0.70; 95% CI, 0.63-0.78) and 60 days (RR = 0.71; 95% CI, 0.63-0.80) decreased. RRs from the 12-month analysis were generally attenuated. CONCLUSION: Disruptions in postpartum provision of permanent contraception occurred at the beginning of the COVID-19 pandemic in Maine. Public health policies should include guidance for contraceptive provision during public health emergencies and consider designating permanent contraception as a nonelective procedure.

Modeling Opioid Abuse: A Case Study of the Opioid Crisis in New England.

For the past two decades, the USA has been embroiled in a growing prescription drug epidemic. The ripples of this epidemic have been especially apparent in the state of Maine, which has fought hard to mitigate the damage caused by addiction to pharmaceutical and illicit opioids. In this study, we construct a mathematical model of the opioid epidemic incorporating novel features important to better understanding opioid abuse dynamics. These features include demographic differences in population susceptibility, general transmission expressions, and combined consideration of pharmaceutical opioid and heroin abuse. We demonstrate the usefulness of this model by calibrating it with data for the state of Maine. Model calibration is accompanied by sensitivity and uncertainty analysis to quantify potential error in parameter estimates and forecasts. The model is analyzed to determine the mechanisms most influential to the number of opioid abusers and to find effective ways of controlling opioid abuse prevalence. We found that the mechanisms most influential to the overall number of abusers in Maine are those involved in illicit pharmaceutical opioid abuse transmission. Consequently, preventative strategies that controlled for illicit transmission were more effective over alternative approaches, such as treatment. These results are presented with the hope of helping to inform public policy as to the most effective means of intervention.

Risk and Protective Factors for Vaping and Smoking Among High School Students in Maine.

INTRODUCTION: Vaping rates are rising among adolescents across the country, and smoking rates remain high. Understanding risk and protective factors associated with vaping and smoking can guide public health interventions. This study examined risk and protective factors associated with vaping and smoking among high school students in Maine. METHODS: We used 2019 Maine Integrated Youth Health Survey (MIYHS) data to examine risk and protective factors for vaping and smoking among Maine high school students. Our analytic sample consisted of 17,651 Maine high school students. In addition to bivariate analyses, we used unadjusted and adjusted logistic regression models to assess risk and protective factors. RESULTS: Factors with the greatest effect on students' likelihood to vape, smoke, or do both were parental attitude toward adolescent smoking and depressive symptoms. Students who reported their parents feel it is a little wrong or not wrong at all if they smoked had 4.9 times higher adjusted odds of smoking and 4.6 times higher adjusted odds of vaping and smoking compared with students who said their parents feel it would be wrong or very wrong if they smoked. Students who reported depressive symptoms had 2.1 times higher adjusted odds of vaping, 2.7 times higher adjusted odds of smoking, and 3.0 times higher adjusted odds of vaping and smoking compared with students who did not report depressive symptoms. CONCLUSION: Understanding risk and protective factors for smoking and vaping among high school students can help tailor adolescent-focused vaping and smoking public health interventions to increase effectiveness.

Implementation of Universal School Meals during COVID-19 and beyond: Challenges and Benefits for School Meals Programs in Maine.

School meals play a major role in supporting children's diets and food security, and policies for universal school meals (USM) have the potential to contribute to positive child health outcomes. During the COVID-19 pandemic, schools provided free school meals to all students in the United States, but this national USM policy ended in school year (SY) 2022-2023; however, a few states have adopted policies to continue USM statewide for SY 2022-2023. Research examining the challenges and strategies for successful continuation of USM is essential, along with studying pandemic-related challenges that are likely to persist in schools. Therefore, we conducted a study in Maine (with a USM policy) to evaluate the impact of COVID-19 and the concurrent implementation of USM, as well as examine differences in implementation by school characteristics, throughout the state. A total of n = 43 school food authorities (SFAs) throughout Maine completed surveys. SFAs reported multiple benefits of USM including increased school meal participation; reductions in the perceived stigma for students from lower-income households and their families; and no longer experiencing unpaid meal charges and debt. SFAs also experienced challenges due to the COVID-19 pandemic, particularly regarding costs. When considering future challenges, most respondents were concerned with obtaining income information from families, product and ingredient availability, and the costs/financial sustainability of the school meal programs. Overall, USM may have multiple important benefits for students and schools, and other states should consider implementation of a USM policy.

Jamestown Canyon Virus in Collected Mosquitoes, Maine, United States, 2017-2019.

Jamestown Canyon virus (JCV) is a mosquito-borne arbovirus that circulates in North America. We detected JCV in 4 pools of mosquitoes collected from midcoastal Maine, USA, during 2017-2019. Phylogenetic analysis of a JCV sequence obtained from Aedes cantator mosquitoes clustered within clade A, which also circulates in Connecticut, USA.

Modeling the impact of the COVID-19 pandemic on speeding at rural roadway facilities in Maine using short-term speed and traffic count data.

The COVID-19 pandemic caused a significant change in traffic operations and safety. For instance, various U.S. states reported an increase in the rate of fatal and severe injury crashes over this duration. In April and May of 2020, comprehensive stay-at-home orders were issued across the country, including in Maine. These orders resulted in drastic reductions in traffic volume. Additionally, there is anecdotal evidence that speed enforcement had been reduced during pandemic. Drivers responded to these changes by increasing their speed. More importantly, data show that speeding continues to occur, even one year after the onset of the pandemic. This study develops statistical models to quantify the impact of the pandemic on speeding in Maine. We developed models for three rural facility types (i.e., major collectors, minor arterials, and principal arterials) using a mixed effect Binomial regression model and short duration speed and traffic count data collected at continuous count stations in Maine. Our results show that the odds of speeding by more than 15 mph increased by 34% for rural major collectors, 32% for rural minor arterials, and 51% for rural principal arterials (non-Interstates) during the stay-at-home order in April and May of 2020 compared to the same months in 2019. In addition, the odds of speeding by more than 15 mph, in April and May of 2021, one year after the order, were still 27% higher on rural major collectors and 17% higher on rural principal arterials compared to the same months in 2019.

The Impact of COVID-19 on Northeast and Appalachian Loggers.

OBJECTIVE: The Northeast Center for Occupational Health and Safety conducted a survey in December 2020 to understand the impact of the coronavirus disease 2019 (COVID-19) and the Androscoggin Mill explosion among loggers in six states: Maine, New Hampshire, Vermont, New York, Pennsylvania, and West Virginia. METHODS: Logger mailing addresses were aggregated with the assistance of state logging organizations. A paper survey, including a self-addressed return envelope was mailed to the loggers in December 2020. RESULTS: The mailed survey had a response rate of 13.3% and captured data on 484 loggers. The majority knew someone (including themselves) who tested positive for COVID-19 (71.9%). Less than half (43%) received employer training about COVID-19 prevention measures, though 73% received some form of COVID-19 personal protective equipment from their employers. The health department, Centers for Disease Control and Prevention (CDC), and health care providers were the most trusted sources of health information. Nearly half acknowledged significant change in their home lives and work responsibilities due to the pandemic. The explosion of the Androscoggin Mill affected the business of 80% of Maine loggers, and 18% of loggers that resided outside Maine. CONCLUSION: The lessons learned can be used to enhance trust in public health institutions and future public health response to this unique occupational group.

Relationship Analysis of Injured Workers' Average Weekly Wages and Workers' Compensation Indemnity Claims in Maine, US: 1998 to 2017.

OBJECTIVE: Explore the relationship between injured workers' average weekly wages (AWW) and their workers' compensation (WC) claims outcomes in Maine, US. METHODS: A total of 29,668 indemnity (lost-time) claims categorized into three wage-based percentile groups from a 20-year period (5-year intervals) were analyzed. WC outcomes included medical costs, number of indemnity checks, claim's duration, and claim settlements. RESULTS: Generally, claims within the lower percentile group were less likely to have high medical costs, but were more likely to have an elevated number of indemnity checks when compared to those in the middle percentile group. An inverse relationship was observed for those claims within the higher percentile group. CONCLUSIONS: Generalizations about low wage earners' claims being longer-lasting and more expensive or early return to work always reducing the medical cost of claims should be avoided.

Not Quite Out of the Woods: Overall Health and Chronic Disease Risk Factors among Maine Logging Workers.

OBJECTIVE: This research reports on the health status, including chronic disease risk factors, among Maine loggers. METHODS: Loggers completed a survey and health screenings were held across Maine, collecting data on a variety of health endpoints. RESULTS: Seventy-five loggers participated. The majority were men (97.1%) with a median age of 46, and a mean BMI of 30.6 kg/m2 (SD 4.9). Nearly half of those screened (45.9%) had blood pressure at the level of stage II hypertension. Loggers with at least a single joint abnormality were 38.4%. The health screening cohort was similar to the non-health screening cohort for many attributes. CONCLUSIONS: Future research should focus on tailored interventions to improve cardiovascular and musculoskeletal risk factors among loggers.

Examination of multiple drug arrests reported to the Maine Diversion Alert Program.

PURPOSE: Much of the responsibility for the increasing drug overdoses in the US has been attributed to opioids but most opioid overdoses also involve another drug. The objective of this study was to identify the drugs involved in polysubstance arrests. The substances that were more likely to be found in conjunction with other substances, using the drug arrests reported to Maine's Diversion Alert Program (DAP) were examined. METHODS: Single and multiple drug arrests were quantified (N = 9,216). Multiple drug arrest percentages were compared to single drug arrest percentages to create a Multiple-to-Single Ratio (MSR) specific to each drug family and each drug to identify over (MSR > 1) and under-representation (MSR < 1). RESULTS: Over three-fifths (63.8%) of all arrests involved a single drug. Opioids accounted for over-half (53.5%) of single arrests, followed by stimulants (27.7%) and hallucinogens (7.7%). Similarly, nearly two-fifths (39.6%) of multiple arrests were for opioids, followed by stimulants (30.8%) and miscellaneous (13.0%). Miscellaneous psychoactive prescription substances (e.g. clonidine, gabapentin, cyclobenzaprine, hydroxyzine) had the highest (1.51) MSR of any drug family. Conversely, stimulants (0.63), opioids (0.42), and hallucinogens (0.35) were significantly underrepresented in polysubstance arrests. Carisoprodol (8.80), amitriptyline (6.34), and quetiapine (4.69) had the highest MSR. Bath-salts (0.34), methamphetamine (0.44), and oxycodone (0.54) had the lowest MSR. CONCLUSION: The misuse of opioids, both alone and in conjunction with another drug, deserves continued surveillance. In addition, common prescription drugs with less appreciated misuse potential, especially carisoprodol, amitriptyline, and quetiapine, require greater attention for their ability to enhance the effects of other drugs.

Exclusion of SARS-COV-2 From Two Maine Overnight Camps July-August 2020.

OBJECTIVES: Summer camp can positively affect self-esteem and social skills. Most United States summer camps did not open during 2020 because of concerns about severe acute respiratory syndrome coronavirus 2 (SARS-COV-2). Our objective is to describe exclusion strategies successfully used by 2 summer camps in Maine. METHODS: Before camp arrival, all attendees were asked to quarantine at home for 14 d and perform a daily symptom checklist. Salivary specimens were submitted by mail for SARS-COV-2 PCR testing 4 d before arrival, and again 4 d after arrival. At camp, multiple layers of nonpharmaceutical interventions (NPIs) were used. RESULTS: A total of 717 (96.7%) prospective attendees underwent remotely supervised saliva collection; 4 were positive and did not come to camp. Among the 20 who did not submit a sample, 3 did not come to camp; the other 17 underwent screening and a rapid antigen test for SARS-COV-2 immediately upon arrival and before reporting to communal living spaces; all were negative. All campers and staff were re-tested by salivary polymerase chain reaction 4 d after arrival, and all were negative. CONCLUSIONS: We demonstrate that it is possible to safely operate overnight camps during a pandemic, thus supporting the continued physical and socioemotional growth of children, using multiple layers of NPIs.

Barriers and facilitators associated with establishment of emergency department-initiated buprenorphine for opioid use disorder in rural Maine.

PURPOSE: The opioid epidemic in the United States continues to grow, particularly impacting rural communities served by critical access hospitals (CAHs) in Maine. Buprenorphine is an effective medication for the treatment of opioid use disorder (OUD) that can be successfully initiated in the emergency department (ED). However, many EDs have not implemented programs to initiate buprenorphine. This study sought to identify barriers and facilitators to successful implementation of buprenorphine programs inCAH EDs. METHODS: Semistructured interviews were conducted with ED directors of Maine CAHs regarding barriers and facilitators to developing programs for ED-initiated buprenorphine. Seventeen Maine CAH EDs exist and 11 of their directors agreed to participate and completed interviews, which were audio-recorded, transcribed, and analyzed using a thematic approach. RESULTS: Four themes and 11 subthemes were identified, including (1) compelled to act-directors' personal experiences with patients facilitated the development of buprenorphine programs in their EDs; (2) leadership and mentorship-peer mentorship from other CAH ED directors facilitated, and senior hospital administrators facilitated, or created a barrier in some cases; (3) stigma-fear that EDs would be overcrowded by drug-seeking patients was a common barrier; and (4) follow-up-finding appropriate outpatient follow-up for OUD patients created the greatest logistical barrier. DISCUSSION: ED directors' clinical experience with OUD patients, supportive hospital leadership, and peer mentorship facilitated ED-initiated buprenorphine programs in rural Maine CAH EDs. Overcoming stigma, developing community outreach, and appropriate follow-up were the greatest barriers. Future research should focus on enhancing peer mentorship, administrative support, community outreach, and staff education.

Use of Cervid Serosurveys to Monitor Eastern Equine Encephalitis Virus Activity in Northern New England, United States, 2009-2017.

Vertebrate surveillance for eastern equine encephalitis virus (EEEV) activity usually focuses on three types of vertebrates: horses, passerine birds, and sentinel chicken flocks. However, there is a variety of wild vertebrates that are exposed to EEEV infections and can be used to track EEEV activity. In 2009, we initiated a pilot study in northern New England, United States, to evaluate the effectiveness of using wild cervids (free-ranging white-tailed deer and moose) as spatial sentinels for EEEV activity. In Maine, New Hampshire, and Vermont during 2009-2017, we collected blood samples from hunter-harvested cervids at tagging stations and obtained harvest location information from hunters. U.S. Centers for Disease Control and Prevention processed the samples for EEEV antibodies using plaque reduction neutralization tests (PRNTs). We detected EEEV antibodies in 6 to 17% of cervid samples in the different states and mapped cervid EEEV seropositivity in northern New England. EEEV antibody-positive cervids were the first detections of EEEV activity in the state of Vermont, in northern Maine, and northern New Hampshire. Our key result was the detection of the antibodies in areas far outside the extent of documented wild bird, mosquito, human case, or veterinary case reports of EEEV activity in Maine, New Hampshire, and Vermont. These findings showed that cervid (deer and moose) serosurveys can be used to characterize the geographic extent of EEEV activity, especially in areas with low EEEV activity or with little or no EEEV surveillance. Cervid EEEV serosurveys can be a useful tool for mapping EEEV activity in areas of North America in addition to northern New England.

Microclimate conditions alter Ixodes scapularis (Acari: Ixodidae) overwinter survival across climate gradients in Maine, United States.

The incidence and geographic range of vector-borne diseases have been expanding in recent decades, attributed in part to global climate change. Blacklegged ticks (Ixodes scapularis), the primary vector for multiple tick-borne pathogens in North America, are spreading rapidly beyond their historic post-colonial range and are thought to be constrained mainly by winter temperature at northern latitudes. Our research explored whether winter climate currently limits the distribution of blacklegged ticks and the pathogens they transmit in Maine, U.S.A., by contributing to overwinter mortality of nymphs. We experimentally tested tick overwinter survival across large-scale temperature and snowfall gradients and assessed factors contributing to winter mortality in locations where blacklegged tick populations are currently established and locations where the blacklegged tick has not yet been detected. We also tested the hypothesis that insulation in the tick microhabitat (i.e., by leaf litter and snowpack) can facilitate winter survival of blacklegged tick nymphs despite inhospitable ambient conditions. Overwinter survival was not significantly different in coastal southern compared to coastal and inland northern Maine, most likely due to sufficient snowpack that protected against low ambient temperatures at high latitudes. Snow cover and leaf litter contributed significantly to overwinter survival at sites in both southern and northern Maine. To further assess whether the current distribution of blacklegged ticks in Maine aligns with patterns of overwinter survival, we systematically searched for and collected ticks at seven sites along latitudinal and coastal-inland climate gradients across the state. We found higher densities of blacklegged ticks in coastal southern Maine (90.2 ticks/1000 m2) than inland central Maine (17.8 ticks/1000 m2) and no blacklegged ticks in inland northern Maine. Our results suggest that overwinter survival is not the sole constraint on the blacklegged tick distribution even under extremely cold ambient conditions and additional mechanisms may limit the continued northward expansion of ticks.