Wildlife Disease Behind Closed Trails

https://youtu.be/WPOk3m-9ZPg

Alexander Fernandez

Reporter, Life News Today

A closed trail or a barricaded viewing area may seem like a temporary inconvenience for visitors eager to explore America’s parks and wildlife areas. In many cases, however, those closures are not caused by damaged infrastructure or bad weather. They are implemented because wildlife officials are responding to disease outbreaks that can threaten animals, domestic pets and, in some cases, people. Behind the warning signs are veterinarians, biologists, laboratory specialists, park rangers and public-health officials working together to investigate illnesses, remove infected carcasses, monitor wildlife populations and determine when it is safe to reopen public areas.

A variety of diseases can trigger these restrictions depending on the species involved and the potential risk to visitors. Bird flu can spread through contact with infected animals or their droppings, rabies through bites or saliva, hantavirus through airborne rodent urine and feces, plague through infected fleas and tularemia through ticks, deer flies or direct contact with infected rabbits and rodents. Most visitors never encounter an infected animal, and the overall risk remains low. Health officials say exposure becomes more likely when someone touches wildlife, disturbs contaminated material, suffers a bite or allows a pet into an affected area.

Because each disease spreads differently, responses often require coordination among multiple agencies responsible for wildlife management, agriculture and public health. “CDC’s One Health Office is collaborating with DOI, USDA, and other partners across the government to bring together disease detectives, laboratorians, physicians, and veterinarians,” Casey Barton Behravesh, then director of the CDC’s One Health Office, said when the agencies released a joint zoonotic-disease report on May 6, 2019.

One recent example occurred in Pennsylvania. In February 2025, the Pennsylvania Game Commission closed the Willow Point Trail and parking lot, archery range, boat launch, White Oak Picnic Area and all lake shoreline access at Middle Creek Wildlife Management Area. Officials cited highly pathogenic avian influenza across Pennsylvania, warming temperatures and the expected arrival of migrating snow geese. “This decision was made out of an abundance of caution for human and domestic animal health,” the commission said. The visitor center and most hiking trails remained open. Instead, the restrictions focused on locations where visitors were more likely to encounter waterfowl, animal waste or potentially infected bird carcasses.

A year later, California faced a different wildlife emergency. California State Parks closed the elephant-seal viewing areas at Año Nuevo State Park and canceled guided tours for the remainder of the season after seven weaned pups tested positive for H5N1. The cases were California’s first confirmed H5N1 infections in marine mammals and the first detected in northern elephant seals. Researchers observed weakness, tremors and abnormal respiratory and neurological symptoms before collecting samples from sick and dead seals. Closing the viewing areas kept visitors and pets away while research teams monitored approximately 1,350 seals on the beach, tested additional animals and conducted drone surveys. “This is exceptionally rapid detection of an outbreak in free-ranging marine mammals,” Christine Johnson, director of the UC Davis Institute for Pandemic Insights, said Feb. 25, 2026, after federal testing confirmed the infections.

Wildlife agencies do not respond to every report of a sick or dead animal in the same manner. Officials evaluate where the animal was found, how the disease spreads, whether people or domestic animals may have been exposed and whether large numbers of sick or dead animals are present before deciding whether to restrict access or launch a larger investigation. “Responding to every report received from the public is neither logistically possible nor in the best interest of the wildlife, so incidents are prioritized,” Andrew Di Salvo, wildlife veterinarian for the Pennsylvania Game Commission, said in a Feb. 23, 2026, agency statement about sick and dead wild birds. Responding to a wildlife disease outbreak often extends far beyond posting warning signs. Wildlife veterinarians, biologists, park rangers, laboratory specialists and public-health officials may recover carcasses, collect and transport samples for testing, identify exposed visitors, monitor animal populations, install temporary barriers and determine when public access can safely resume.

Those responsibilities have coincided with changes in National Park Service staffing. The Park Service had the equivalent of 19,722 full-time workers in fiscal year 2016. By fiscal year 2025, that figure had fallen to 18,541, a decline of about 6%. The figures measure total hours worked, not the exact number of permanent, seasonal or part-time employees. Park Service staffing declined between 2017 and 2020, recovered somewhat over the following four years and then declined again in 2025. According to the agency, the latest reduction resulted from early retirements, deferred resignations, other voluntary departures and the transfer of some work to the Department of the Interior. At the same time, hiring restrictions made it more difficult to replace departing employees, while high housing costs and challenges recruiting seasonal workers for remote or lower-paying positions continued to complicate staffing efforts.

Although the Park Service’s budget increased from approximately $3.38 billion in 2016 to $4.65 billion in 2025, an increase of roughly 38% before inflation, much of that additional funding could not be used to hire rangers, biologists or veterinarians. Federal law dedicated much of the money to construction projects, deferred maintenance, land acquisition, historic preservation, grants, trails, campgrounds, visitor facilities and transportation improvements. Sam Peterson, a former National Park Service ranger at Lake Roosevelt National Recreation Area, warned about the potential effects of staffing reductions after he lost his position. “The existing staff will be stretched thin, safety issues will arise,” Peterson said during a February 2025 press conference. During a May 2025 congressional hearing, Sen. Patty Murray of Washington also emphasized the range of specialists parks depend on. “We need trail guides and biologists,” Murray said. “We need EMTs and geologists.”

Neither statement establishes that staffing reductions caused wildlife outbreaks or delayed any specific response. Likewise, National Park Service public records do not identify an outbreak investigation, carcass removal, visitor warning or reopening that took longer because fewer employees were available. Wildlife-related closures vary widely depending on the disease involved. Some restrictions last only a few weeks, while others remain in place for years. Middle Creek reopened after 32 days because officials received relatively few reports of sick or dead birds and recorded limited H5N1 detections both on the property and in the surrounding area, even though the broader national outbreak continued. Other closures have remained in effect far longer. Great Smoky Mountains National Park has kept its caves and mine shafts closed since 2009 to prevent visitors from carrying the fungus responsible for white-nose syndrome between bat habitats. Although the disease does not infect humans, contaminated clothing and equipment can transport the fungus into previously unaffected caves. White-nose syndrome has killed millions of North American bats and eliminated as much as 99% of some colonies.

Federal scientists continue to document the spread of avian influenza across North America. A U.S. Geological Survey study found that the current H5N1 strain entered North America through migratory bird routes in late 2021 before spreading widely among wild birds and mammals. The agency’s National Wildlife Health Center later reported 241 wild-bird mortality events involving more than 126,000 birds in 28 states between September 2025 and January 2026. H5N1 was confirmed or suspected in 123 of those events.  The U.S. Geological Survey also maintains the Wildlife Health Information Sharing Partnership, or WHISPers, a national database used by wildlife agencies to monitor mortality events and emerging diseases across North America. The system allows wildlife managers to identify outbreaks, coordinate investigations and track disease trends over time. When disease investigations occur within national parks or other public lands, the response often requires confirming diagnoses, coordinating with the Centers for Disease Control and Prevention and state or local health departments, interviewing potentially exposed visitors, testing wildlife and environmental samples, implementing control measures and communicating findings to the public.

Closing a trail is rarely a simple or routine decision. Before access is restricted, wildlife veterinarians, biologists, park rangers, laboratory specialists and public-health officials must investigate reports of sick or dead animals, collect and analyze samples, assess potential risks to people and domestic animals, coordinate with state and federal agencies, and determine whether limiting public access is necessary. Ignoring those closures can expose visitors and their pets to hazards that are often invisible, including contaminated environments or infected wildlife. At the same time, much of this work is being carried out by a National Park Service workforce that is smaller than it was a decade ago, requiring fewer employees to balance disease surveillance, visitor safety and the many other responsibilities involved in managing America's public lands. While available records do not show that staffing reductions delayed any specific wildlife-disease response, they do underscore the growing demands placed on the professionals responsible for protecting both wildlife and the millions of people who visit the nation's parks each year.