In a longstanding dispute between environmentalists and agriculture, two environmental groups are attempting to link a disease that affects ruminants with COVID-19.
Western Watershed Project (WWP) and the Resource Renewal Institute served notice earlier in May to the National Park Service, citing the current public health crisis and Johne’s disease, which affects cattle, and noting the disease’s potential spread to visitors to the park.
In the letter, the groups expressed concern the potential of zoonotic diseases are not “adequately addressed” in the environmental impact statement (EIS) for the general management plan (GMP) set to govern leasing by private livestock operations of National Park Service (NPS) lands on Point Reyes National Seashore and Golden Gate National Recreation Area (collectively, “the Parks”).
The groups state NPS has a responsibility to protect the human health and safety of the 3 million visitors who recreate at the Parks each year, and “should not assume the legal liabilities of putting the public at risk for zoonotic disease transmission to extend the questionable benefit of commercial beef and dairy operations within the Parks.”
Deborah Moskowitz, president of Resource Renewal Institute, a local conservation group, stated, “When we dug deeper into the science, we discovered that Johne’s disease bacterium wasn’t just a major problem for Tule elk, but also a human health risk.”
COVID-19, which is believed to be a zoonotic disease, caused the groups to investigate the bacteria Mycobacterium avium subsp. paratuberculosis (MAP), which causes Johne’s disease, and whether it poses a human health risk. The groups assert the MAP bacterium is closely related to Crohn’s disease in humans.
Citing several studies in their letter, the groups state that MAP is “potentially a zoonotic disease, and has been implicated as a potential cause of Crohn’s disease, multiple sclerosis, irritable bowel disease, Type 1 diabetes, and colorectal cancer.”
The groups argue because MAP is potentially a zoonotic disease and “livestock present a grave risk for transmission of this bacterium to humans,” there are several pathways it could be transmitted to humans.
First, they state, “cattle, particularly in high concentrations, contaminate surface waters with which the public may come in direct contact.” The groups cite a previous investigative report showing high concentrations of E. coli in Kehoe Creek and the potential of MAP.
Second, NPS allows livestock operations to liquify untreated manure and spread it on the lands of Point Reyes National Seashore. Lastly, “meat and dairy products potentially contaminated with M. a. paratuberculosis are sold throughout the surrounding region,” the groups said.
A study published in March 2020 by the University of Sydney found an “absence of conclusive scientific evidence in the causal association” between the bacteria that causes Johne’s disease and that of the small subset of people with MAP-positive Crohn’s disease.
Johne’s disease
Johne’s disease is a highly contagious chronic wasting disease that predominantly affects sheep and cattle, with dairy cattle the most at risk.
According to the University of Wisconsin, Johne’s Information Center (JTC), an estimated 68 percent of dairy herds and 8 percent of beef herds in the U.S. contain at least one infected animal.
MAP is typically identified in cattle beginning at 4 to 7 years of age. Signs and symptoms are possible after 1 to 2 years of age. Afflicted “unthrifty” animals show signs of intestinal inflammation such as diarrhea, gradual and continuous weight loss despite not being off-feed, and having a normal body temperature.
Thickening of the intestinal walls of affected animals shows low absorption of protein, leading to muscle wasting, possible “bottle jaw,” and decreased milk production.
Prevention is based on management protocols to avoid infection by the bacterium. Vaccines for Johne’s disease focus on reducing the shedding of the bacteria, which does not prevent initial infection.
Johne’s disease has been found to have high morbidity within elk and other cervids, including different species of deer. Unlike the chronic progressive infection of cattle, Johne’s disease within populations of elk as young as 8 months tends to progress rapidly to the development of the clinical condition and appears in the form of an outbreak.
According to the NPS, Johne’s disease was first documented in five of 10 dairy herds at the Point Reyes National Seashore in 1979. The disease was documented in tule elk at Tomales Point Elk Reserve in 1980. Park staff have worked with the JTC to test elk fecal samples from the Drakes Beach and Limantour tule elk herds beginning in 2014. A small number of bull elk from the Drakes Beach herd tested positive for the bacterium.
Tule elk
Tule elk is the smallest of elk species found in North America. Biologists estimate that in 1850, there were around 500,000 tule elk in California. By the 1870s, they had been hunted to the point that less than 30 remained on a single ranch near Bakersfield.
In 1978, NPS moved 10 elk from the San Luis National Wildlife Refuge, in California’s Central Valley, to a 2,600-acre fenced “reserve” on Tomales Point, the seashore’s northernmost tip. The herd grew fast. Within 10 years, it had a population of 93.
In 1998, in response to concerns over the herd’s increasing population, the NPS moved 28 elk to a wilderness area in the southern portion of the seashore. It set the herd’s population limit at 350—not the number of elk the landscape could sustain, but the number of elk the NPS felt could be “successfully maintained, monitored, studied, and as necessary, controlled.”
In the letter, the groups assert, “Cattle can be completely eliminated from the Parks, thereby eliminating public health threats to park visitors.” Previously during an open comment period on the EIS for the GMP, environmentalists proposed relocating cattle to private land.
Ranching in the Parks
During the Great Depression, ranchers struggled to make ends meet. It was not uncommon for ranchers to augment their incomes with expanded livestock production, such as beef cattle, chickens, and eggs. After the opening of the Golden Gate Bridge in 1937, Marin County saw expanded growth. With the influx of new residents, many of them affluent, dairies feared the loss of the quality of life as much as declining profitability.
To secure their place at Point Reyes, the dairy and cattle ranchers formed an uneasy alliance with the Sierra Club in hopes of preserving their ranches and west Marin open space. The compromise provided for the retention of the ranches in a designated pastoral zone, with ranchers signing 25- to 30-year reservations of use and occupancy leases, and exclusive use permits for cattle grazing. Over a 10-year period beginning in the late 1970s, the NPS acquired the 17 remaining operating ranches and the property of the abandoned ranches. — Charles Wallace, WLJ correspondent
