PROTOCOL FOR HUMAN EXPOSURE TO OPIOIDS AND CONCENTRATED MEDETOMIDINE USED IN FIELD APPLICATIONS.

Wildlife professionals routinely use potent sedatives and anesthetics when chemically immobilizing wildlife and zoo species in remote environments. Accidental exposure to these prescription veterinary drugs is rare but could be rapidly fatal. Commonly used agents include opioids and α2 adrenoreceptor agonists. These drugs can be reversed with specific antagonists; however, they are often not approved for human use. The protocol created here can be used by wildlife health professionals in a field setting with basic human emergency medical response training in coordination with local Emergency Medical Services (EMS). Key components include, building local relationships between EMS and wildlife professionals, focused EMS training, administering opioid and α2 adrenergic antagonists off label, and local evacuation procedures. This framework could allow wildlife management agencies or zoos to mitigate the risk of human exposures to these commonly used drugs, significantly improving occupational safety in an otherwise high-risk environment.

Predicting climate-change induced heat-related illness risk in Grand Canyon National Park visitors.

BACKGROUND: The climate crisis is the greatest public health threat of the 21st century. Excessive heat is responsible for more deaths than any other extreme weather event, and the frequency, intensity, and duration of extreme heat events are increasing globally due to climate change. Exposure to excessive heat can result in heat related illnesses (HRIs) and long-term poor health outcomes. Physical exertion, sudden exposure to excessive heat, and the lack of physical or behavioral adaptation resources are all associated with greater HRI risk, which is expected to increase for visitors to Grand Canyon National Park (GCNP) and other public lands as climate change worsens. OBJECTIVES: Our objectives were to understand 1) the relationship between weather and HRI in GCNP visitors, 2) how future HRI rates may change, and 3) how land management agencies can update risk mitigation strategies to match changing risk and better manage an increased HRI burden. METHODS: We utilized previously published data on HRI in GCNP visitors, and records of daily visitation, temperatures, and maximum and minimum daily humidity from the same study period to develop a model estimate for HRI risk. We then used future climate projections from the World Climate Research Programme's Coupled Model Intercomparison Project phase 5 multi-model dataset to model future HRI risk under different climate scenarios. RESULTS: The incidence of HRI was significantly associated with maximum daily temperature and minimum relative humidity, and was more common in the shoulder season months. We estimated that HRI will increase 29%-137% over 2004-2009 levels through 2100, assuming no change in visitation. DISCUSSION: Climate change will continue to increase HRI risk for GCNP visitors and poses risks to public land managers' mission to provide for safe recreation experiences for the benefit of this and future generations in places like GCNP. Excessive risk during the shoulder season months presents an opportunity to increase preventative search and rescue and education efforts to mitigate increased risk.

Deer management generally reduces densities of nymphal Ixodes scapularis, but not prevalence of infection with Borrelia burgdorferi sensu stricto.

Human Lyme disease-primarily caused by the bacterium Borrelia burgdorferi sensu stricto (s.s.) in North America-is the most common vector-borne disease in the United States. Research on risk mitigation strategies during the last three decades has emphasized methods to reduce densities of the primary vector in eastern North America, the blacklegged tick (Ixodes scapularis). Controlling white-tailed deer populations has been considered a potential method for reducing tick densities, as white-tailed deer are important hosts for blacklegged tick reproduction. However, the feasibility and efficacy of white-tailed deer management to impact acarological risk of encountering infected ticks (namely, density of host-seeking infected nymphs; DIN) is unclear. We investigated the effect of white-tailed deer density and management on the density of host-seeking nymphs and B. burgdorferi s.s. infection prevalence using surveillance data from eight national parks and park regions in the eastern United States from 2014-2022. We found that deer density was significantly positively correlated with the density of nymphs (nymph density increased by 49% with a 1 standard deviation increase in deer density) but was not strongly correlated with the prevalence of B. burgdorferi s.s. infection in nymphal ticks. Further, while white-tailed deer reduction efforts were followed by a decrease in the density of I. scapularis nymphs in parks, deer removal had variable effects on B. burgdorferi s.s. infection prevalence, with some parks experiencing slight declines and others slight increases in prevalence. Our findings suggest that managing white-tailed deer densities alone may not be effective in reducing DIN in all situations but may be a useful tool when implemented in integrated management regimes.

Patterns and Ecological Mechanisms of Tick-Borne Disease Exposure Risk in Acadia National Park, Mount Desert Island, Maine, United States.

National parks are unique and significant vector-borne pathogen transmission settings, engaging over 300 million people in outdoor recreation per year. In this study, we integrated vector surveys and ecological habitat feature data in spatial models to characterize tick-borne disease exposure risk in Acadia National Park (ANP), Maine. To determine the broad-scale patterns of blacklegged tick Ixodes scapularis Say (Acari: Ixodidae) densities in ANP, we conducted host-seeking tick collections at 114 sites across the park over two years. Using these tick survey data and geospatial landscape feature data (i.e., land cover, elevation, forest patch size, and aspect) we developed a random forest model of nymphal tick density. We found that host-seeking tick density varies significantly across the park and is particularly high in areas characterized by deciduous forest cover and relatively low elevation. To explore potential fine-scale ecological drivers of tick density spatial patterns, we quantified microclimate conditions, host activity, and vegetation characteristics at a subset of 19 sites. We identified significant differences in microclimate conditions but not host activity or vegetation metrics across broad-scale landscape feature classes. Mean temperature and mean humidity were correlated to nymphal densities and therefore may provide a mechanistic link between landscape features and blacklegged tick densities. Finally, we detected multiple tick-borne pathogens in both ticks and small mammals sampled in ANP, including Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum. Our findings demonstrate the value of using ecological metrics to estimate vector-borne disease exposure risk and provide insight into habitat characteristics that may drive tick-borne disease exposure risk.

A comparison of Mini-FLOTAC and McMaster techniques, overdispersion and prevalence of parasites in naturally infected North American bison (Bison bison) in the USA.

Several quantitative diagnostic techniques are available to estimate gastrointestinal parasite counts in the feces of ruminants. Comparing egg and oocyst magnitudes in naturally infected samples has been a recommended approach to rank fecal techniques. In this study, we compared the Mini-FLOTAC (sensitivity of 5 eggs per gram (EPG)/oocysts per gram (OPG)) and different averaged replicates of the modified McMaster techniques (sensitivity of 33.33 EPG/OPG) in 387 fecal samples from 10 herds of naturally infected North American bison in the Central Great Plains region of the USA. Both techniques were performed with fecal slurries homogenized in a fill-FLOTAC device. In the study population, prevalence of strongyle eggs, Eimeria spp. oocysts, Moniezia spp. eggs and Trichuris spp. eggs was 81.4%, 73.9%, 7.5%, and 3.1%, respectively. Counts of strongyle eggs and Eimeria spp. oocysts obtained from 1 to 3 averaged technical replicates of the modified McMaster technique were compared to a single replicate of the Mini-FLOTAC. Correlation between the two techniques increased with an increase in the number of averaged technical replicates of the modified McMaster technique used to calculate EGP/OPG. The correlation for Moniezia spp. EPG when averaged triplicates of the modified McMaster technique were compared to a single replicate of the Mini-FLOTAC count was high; however, the correlation for Trichuris spp. eggs was low. Additionally, we used averaged counts from both techniques to show the overdispersion of parasites in bison herds.

Southwestern national park service employee risk, knowledge, and concern for triatomine exposure: A qualitative analysis using a novel knowledge, attitudes, and practices survey.

Chagas disease (CD), caused by the parasite Trypanosoma cruzi, is a neglected parasitic infection in the United States (US). In the Southwestern US, National Park Service (NPS) employees are a unique population with potential exposure to CD. This population lives in close contact with several species of sylvatic triatomine bugs, the vectors of T. cruzi, that may enter residential buildings at night. Despite the higher potential risk of CD transmission for southwestern NPS employees, the socio-cultural factors that impact autochthonous CD transmission in the US remain unknown. To address this gap, we investigated how NPS employee knowledge and attitudes impact their triatomine preventive behaviors. We distributed a 42-item online questionnaire to NPS employees at four national parks in Arizona and Texas. We detected high self-reported bite exposure in NPS housing, despite moderate- to high-frequency of prevention behaviors. Specific behaviors, such as often or always repairing window screens, were associated with a decreased risk of putative triatomine bug exposure. Additionally, NPS employees had low knowledge of CD. For those with greater knowledge of CD, it was not associated with increased frequency of prevention behavior. We found that increased CD anxiety was associated with increased personal agency to reduce the risk of CD. These results demonstrate the influence of knowledge and attitudes regarding CD on triatomine prevention behavior within a potential high-risk population in the US, and the importance of utilizing strategies beyond provision of education to influence behaviors.

Rabies as a Potential Cause of Mass Mortality Events in North American Bat Species.

Rabies-association bat mortality events are rarely reported, suggesting that rabies is not a significant cause of bat mass mortality. Three bat die-offs in National Park Service units were attributed to rabies, highlighting the value of including rabies, and rabies virus strain spillover events, as a differential in mass mortality events.

Lake Michigan insights from island studies: the roles of chipmunks and coyotes in maintaining Ixodes scapularis and Borrelia burgdorferi in the absence of white-tailed deer.

Deer management (e.g., reduction) has been proposed as a tool to reduce the acarological risk of Lyme disease. There have been few opportunities to investigate Ixodes scapularis (blacklegged tick) and Borrelia burgdorferi sensu stricto dynamics in the absence of white-tailed deer (Odocoileus virginianus) in midwestern North America. A pair of islands in Lake Michigan presented a unique opportunity to study the role of alternative hosts for the adult stage of the blacklegged tick for maintaining a tick population as a deer herd exists on North Manitou Island but not on South Manitou Island, where coyotes (Canis latrans) and hares (Lepus americanus) are the dominant medium mammals. Additionally, we were able to investigate the maintenance of I. scapularis and B. burgdorferi in small mammal communities on both islands, which were dominated by eastern chipmunks (Tamias striatus). From 2011 to 2015, we surveyed both islands for blacklegged ticks by drag cloth sampling, bird mist netting, and small and medium-sized mammal trapping. We assayed questing ticks, on-host ticks, and mammal biopsies for the Lyme disease pathogen, B. burgdorferi. We detected all three life stages of the blacklegged tick on both islands. Of the medium mammals sampled, no snowshoe hares (Lepus americanus, 0/23) were parasitized by adult blacklegged ticks, but 2/2 coyotes (Canis latrans) sampled on South Manitou Island in 2014 were parasitized by adult blacklegged ticks, suggesting that coyotes played a role in maintaining the tick population in the absence of deer. We also detected I. scapularis ticks on passerine birds from both islands, providing support that birds contribute to maintaining as well as introducing blacklegged ticks and B. burgdorferi to the islands. We observed higher questing adult and nymphal tick densities, and higher B. burgdorferi infection prevalence in small mammals and in adult ticks on the island with deer as compared to the deer-free island. On the islands, we also found that 25% more chipmunks were tick-infested than mice, fed more larvae and nymphs relative to their proportional abundance compared to mice, and thus may play a larger role compared to mice in the maintenance of B. burgdorferi. Our investigation demonstrated that alternative hosts could maintain a local population of blacklegged ticks and an enzootic cycle of the Lyme disease bacterium in the absence of white-tailed deer. Thus, alternative adult blacklegged tick hosts should be considered when investigating deer-targeted management tools for reducing tick-borne disease risk, especially when the alternative host community may be abundant and diverse.

Long-Term Rodent Surveillance after Outbreak of Hantavirus Infection, Yosemite National Park, California, USA, 2012.

In 2012, a total of 9 cases of hantavirus infection occurred in overnight visitors to Yosemite Valley, Yosemite National Park, California, USA. In the 6 years after the initial outbreak investigation, the California Department of Public Health conducted 11 rodent trapping events in developed areas of Yosemite Valley and 6 in Tuolumne Meadows to monitor the relative abundance of deer mice (Peromyscus maniculatus) and seroprevalence of Sin Nombre orthohantavirus, the causative agent of hantavirus pulmonary syndrome. Deer mouse trap success in Yosemite Valley remained lower than that observed during the 2012 outbreak investigation. Seroprevalence of Sin Nombre orthohantavirus in deer mice during 2013-2018 was also lower than during the outbreak, but the difference was not statistically significant (p = 0.02). The decreased relative abundance of Peromyscus spp. mice in developed areas of Yosemite Valley after the outbreak is probably associated with increased rodent exclusion efforts and decreased peridomestic habitat.

Evaluating the public health response to a mass bat exposure-Wyoming, 2017.

Mass bat exposures (MBEs) occur when multiple people are exposed to a bat or a bat colony, often over an extended period. In August 2017, a public health investigation was started in response to an MBE that occurred during May-August 2017 at a national park research station in Wyoming. We identified 176 people who had slept primarily in two lodges (Lodges A and B) at the research station, and successfully contacted 165 (93.8%) of these individuals. Risk assessments (RAs) were administered to all 165 individuals to determine degree and type of exposures to bats (e.g., biting or scratching). Exposure status for research station guests was classified as "non-exposed," "low risk" or "high risk," and counselling was provided to guide post-exposure prophylaxis (PEP) recommendations. Prior to public health notification and intervention, 19 persons made the decision to pursue PEP. The healthcare-seeking behaviours of this group were taken to represent outcomes in the absence of public health intervention. (These persons received a RA, and their risk classification was retrospectively assigned.) Approximately 1-2 weeks after conducting the RAs, we conducted a follow-up survey to determine whether recommendations regarding PEP were ultimately followed. The proportion of individuals that unnecessarily pursued PEP was higher among the 19 individuals that sought health care prior to receiving the RA (p < 0.00001). Among those receiving the RA first, all persons classified as high risk followed public health guidance to seek PEP treatment. Despite this, upon re-interview, only 21/79 (26.6%) of guests could accurately recall their risk classification, with most people (55.7%) overestimating their risk. Study findings demonstrate that early public health interventions such as RAs can reduce unnecessary use of PEP and that messaging used during rabies counselling should be clear.

Tularemia (Francisella tularensis) in a Black-Tailed Prairie Dog (Cynomys ludovicianus) Colony.

Tularemia is a bacterial zoonosis caused by Francisella tularensis. We conducted a serosurvey of black-tailed prairie dogs (Cynomys ludovicianus) in Devils Tower National Monument, Wyoming, US, following an epizootic in voles ( Microtus spp.) due to F. tularensis. Only 1 of 44 (2%) sampled prairie dogs was seropositive for F. tularensis, providing evidence of survival and potentially limited spread among free-ranging prairie dogs.

Characteristics of animal-related motor vehicle crashes in select National Park Service units-United States, 1990-2013.

OBJECTIVES: Nationally, animal-motor vehicle crashes (AVCs) account for 4.4% of all types of motor vehicle crashes (MVCs). AVCs are a safety risk for drivers and animals and many National Park Service (NPS) units (e.g., national park, national monument, or national parkway) have known AVC risk factors, including rural locations and substantial animal densities. We sought to describe conditions and circumstances involving AVCs to guide traffic and wildlife management for prevention of AVCs in select NPS units. METHODS: We conducted an analysis using NPS law enforcement MVC data. An MVC is a collision involving an in-transit motor vehicle that occurred or began on a public roadway. An AVC is characterized as a collision between a motor vehicle and an animal. A non-AVC is a crash between a motor vehicle and any object other than an animal or noncollision event (e.g., rollover crash). The final data for analysis included 54,068 records from 51 NPS units during 1990-2013. Counts and proportions were calculated for categorical variables and medians and ranges were calculated for continuous variables. We used Pearson's chi-square to compare circumstances of AVCs and non-AVCs. Data were compiled at the park regional level; NPS parks are assigned to 1 of 7 regions based on the park's location. RESULTS: AVCs accounted for 10.4% (5,643 of 54,068) of all MVCs from 51 NPS units. The Northeast (2,021 of 5,643; 35.8%) and Intermountain (1,180 of 5,643; 20.9%) regions had the largest percentage of the total AVC burden. November was the peak month for AVCs across all regions (881 of 5,643; 15.6%); however, seasonality varied by park geographic regions. The highest counts of AVCs were reported during fall for the National Capital, Northeast/Southeast, and Northeast regions; winter for the Southeast region; and summer for Intermountain and Pacific West regions. CONCLUSIONS: AVCs represent a public health and wildlife safety concern for NPS units. AVCs in select NPS units were approximately 2-fold higher than the national percentage for AVCs. The peak season for AVCs varied by NPS region. Knowledge of region-specific seasonality patterns for AVCs can help NPS staff develop mitigation strategies for use primarily during peak AVC months. Improving AVC data collection might provide NPS with a more complete understanding of risk factors and seasonal trends for specific NPS units. By collecting information concerning the animal species hit, park managers can better understand the impacts of AVC to wildlife population health.

Francisella tularensis Exposure Among National Park Service Employees During an Epizootic: Devils Tower National Monument, Wyoming, 2015.

Introduction: Tularemia is a zoonotic infection caused by the highly infectious bacterium Francisella tularensis. Persons having outdoor professions are more likely than others to be exposed to F. tularensis through increased contact with arthropods, infected animals, and contaminated aerosols. Materials and Methods: After a tularemia epizootic during July and August 2015 at Devils Tower National Monument and an associated tularemia infection in a park employee, we assessed seroprevalence of F. tularensis antibodies, risk factors for F. tularensis seropositivity, and use of protective measures among park employees. Results: Seroprevalence among participating employees was 13% (3/23). Seropositive employees reported multiple risk factors for F. tularensis exposure through both job-related and recreational activities. Activities reported by more seropositive than seronegative employees included using a power blower (67% vs. 5%, p = 0.03), collecting animal carcasses (100% vs. 30%, p = 0.047), and hunting prairie dogs recreationally (67% vs. 5%, p = 0.03). Seropositive employees reported exposure to more ticks (median 30, range 25-35) than seronegative employees (median 6, range 0-25, p = 0.001). Most employees used protective measures (e.g., insect repellent) inconsistently but increased use after receiving educational materials. Conclusions: Educating and enabling at-risk employees to use protective measures consistently, both at work and during recreational activities, can reduce exposure during epizootics.

Risk-enhancing behaviors associated with human injuries from bison encounters at Yellowstone National Park, 2000-2015.

Yellowstone National Park is home to the largest bison population on public land in the United States. Although Yellowstone regulations require visitors to remain at least 23 m from bison, since 1980, bison have injured more visitors to Yellowstone than any other animal. We examined a series of bison-related injuries at Yellowstone to evaluate the circumstances of these injuries and to identify common risk-enhancing behaviors that lead to injury. To do this, we analyzed narrative case incident records from law enforcement regarding bison-human encounters in Yellowstone during 2000-2015. Data regarding demographics, preencounter activities, number of persons involved, type of injury, and acknowledgement of appropriate viewing distance were extracted from the records. Bison encounters resulted in injury to 25 persons (21 visitors and 4 employees). Age range for injured persons was 7-68 years (median: 49 years), and 13 were female. All injuries occurred in areas of high visitor concentration. Mean visitor distance from bison before injury was 3.4 m (range: 0.3-6.1 m). Twenty persons (80%) actively approached bison before their injuries; 5 (20%) failed to retreat when bison approached. Fifteen persons (60%) were injured when in a group of ≥3 persons approaching bison. Twelve persons (48%) sustained injuries while photographing bison. Six persons (24%) acknowledged they were too close to bison. Education alone might not be sufficient to reduce bison-related injuries. Effective injury prevention campaigns for national parks require an understanding of the behaviors and motivations of persons who approach bison. Including behavioral science and behavior change techniques in bison injury prevention campaigns might reduce injuries at Yellowstone.

Echinococcus spp. Tapeworms in North America.

Alveolar and cystic echinococcosis are emerging and reemerging in Europe, Africa, and Asia. The expansion of Echinococcus spp. tapeworms in wildlife host reservoirs appears to be driving this emergence in some areas. Recent studies suggest a similar phenomenon may be occurring in North America. We describe the context of Echinococcus spp. research in North America, with a specific focus on the contiguous United States. Although studies were conducted in the United States throughout the 1900s on various sylvatic and domestic Echinococcus spp. tapeworm cycles, data are lacking for the past ≈30 years. We review previous research, provide analysis of more recent focal studies, and suggest that Echinococcus spp. tapeworms, in particular E. canadensis, may be underrecognized. As a result, we suggest that additional research and surveillance be conducted for these tapeworms in wildlife host reservoirs across the United States.

GREEN TREE FROG ( HYLA CINEREA) AND GROUND SQUIRREL ( XEROSPERMOPHILUS SPILOSOMA) MORTALITY ATTRIBUTED TO INLAND BREVETOXIN TRANSPORT AT PADRE ISLAND NATIONAL SEASHORE, TEXAS, USA, 2015.

: On 16 September 2015, a red tide ( Karenia brevis) bloom impacted coastal areas of Padre Island National Seashore Park, Texas, US. Two days later and about 0.9 km inland, 30-40 adult green tree frogs ( Hyla cinerea) were found dead after displaying tremors, weakness, labored breathing, and other signs of neurologic impairment. A rainstorm accompanied by high winds, rough surf, and high tides, which could have aerosolized brevetoxin, occurred on the morning of the mortality event. Frog carcasses were in good body condition but contained significant brevetoxin in tissues. Tissue brevetoxin was also found in two dead or dying spotted ground squirrels ( Xerospermophilus spilosoma) and a coyote ( Canis latrans) found in the area. Rainwater collected from the location of the mortality event contained brevetoxin. Green tree frog and ground squirrel mortality has not been previously attributed to brevetoxin exposure and such mortality suggested that inland toxin transport, possibly through aerosols, rainfall, or insects, may have important implications for coastal species.

Exposure Characteristics of Hantavirus Pulmonary Syndrome Patients, United States, 1993-2015.

Those at highest risk are persons in occupations with potential for rodent exposure and American Indian women 40--64 years of age.

Prevalence and Diversity of Tick-Borne Pathogens in Nymphal Ixodes scapularis (Acari: Ixodidae) in Eastern National Parks.

Tick-borne pathogens transmitted by Ixodes scapularis Say (Acari: Ixodidae), also known as the deer tick or blacklegged tick, are increasing in incidence and geographic distribution in the United States. We examined the risk of tick-borne disease exposure in 9 national parks across six Northeastern and Mid-Atlantic States and the District of Columbia in 2014 and 2015. To assess the recreational risk to park visitors, we sampled for ticks along frequently used trails and calculated the density of I. scapularis nymphs (DON) and the density of infected nymphs (DIN). We determined the nymphal infection prevalence of I. scapularis with a suite of tick-borne pathogens including Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia microti. Ixodes scapularis nymphs were found in all national park units; DON ranged from 0.40 to 13.73 nymphs per 100 m2. Borrelia burgdorferi, the causative agent of Lyme disease, was found at all sites where I. scapularis was documented; DIN with B. burgdorferi ranged from 0.06 to 5.71 nymphs per 100 m2. Borrelia miyamotoi and A. phagocytophilum were documented at 60% and 70% of the parks, respectively, while Ba. microti occurred at just 20% of the parks. Ixodes scapularis is well established across much of the Northeastern and Mid-Atlantic States, and our results are generally consistent with previous studies conducted near the areas we sampled. Newly established I. scapularis populations were documented in two locations: Washington, D.C. (Rock Creek Park) and Greene County, Virginia (Shenandoah National Park). This research demonstrates the potential risk of tick-borne pathogen exposure in national parks and can be used to educate park visitors about the importance of preventative actions to minimize tick exposure.