By BEN NEARY
NMWF Conservation Director
ALBUQUERQUE — A scientist who tracks chronic wasting and other animal diseases around the state will be the featured speaker at the New Mexico Wildlife Federation’s Wildlife Wednesday event in July.
Dr. Kerry Mower, animal health specialist with the New Mexico Department of Game and Fish, has been tracking chronic wasting disease since it first turned up in some southern New Mexico herds in 2002.
These days, Mower also has been tracking the recent outbreak of rabbit hemorrhagic fever and serves on a state/federal task force on the lookout for signs that the coronavirus now sweeping the world as a global pandemic is spreading to wildlife populations.
Mower’s Wildlife Wednesday presentation about his work on animal diseases will be livestreamed on Zoom starting at 5:30 p.m., July 8. To join the meeting, use this LINK. Meeting ID: 924 3162 5461.
Mower, who started working with the game department as a contract employee 30 years ago, holds a Ph.D. from Ohio State in animal science. In addition to tracking wildlife diseases, he typically gets involved when the department captures wildlife for transplanting or other reasons.
Chronic wasting, a contagious neurological disease that affects deer, elk and moose, was first discovered in New Mexico in the foothills of the Organ Mountains, near Las Cruces. Since then, it’s spread to some areas of the Sacramento Mountains.
“Most of the cases right now are in Unit 28, which is the McGregor Range, the southern foothills of the Sacramento Mountains,” Mower said. “So it doesn’t seem to be spreading quickly, but the presence seems to be remaining fairly high, and consistently high on the McGregor Range.”
In New Mexico, CWD primarily turns up in free-ranging mule deer, Mower said. He said it also occurs in elk, but said the state has never detected it among animals in any of the roughly 25 private game farms in the state.
Scientists believe that the most common mode of transmission of chronic wasting among animals is nose-to-nose contact.
“And in some areas, if we have a high density, they can pick it up from the ground,” Mower said. “They can pick it up with contact from urine and fecal matter on the ground. There’s some evidence that it might be uptaken in plants, and that the infective agent may bind to the soil, and they can pick it up from the soil. But probably most common is nose-to-nose contact and ingestion of the agents that way.”
Most scientists think it’s unlikely hunters could contract CWD through handling, field dressing and processing an infected animal and eating its meat, Mower said.
“They say that based on the fact that there’s no known human case of transmission with this disease to humans. And we do know that large numbers of these infected animals have been consumed by humans probably since the 1960s,” Mower said. “Furthermore, there’s a disease in domestic sheep that is very similar, and there’s no known transmission of that disease to humans, with humans in contact with and eating sheep for over 400 years.”
It probably would be possible to infect a human with CWD experimentally through a radical procedure such as injecting it into the person’s brain, Mower said. “And experimentally with this disease, they can move it from one species to another by injecting either the agent directly, or sometimes other forms of the infected agent. But it seems unlikely given the history that it could happen through casual contact. But then, like most things in biology and science, I’m never going to say never.”
To keep CWD from spreading, the game department has implemented carcass removal restrictions in areas where the disease occurs. Hunters are required to leave high-risk tissues such as the brain and spinal cord and bones in the field.
“So, when they leave, we’d like them to take the meat, but leave behind the tissues that are most likely to be contaminants in a new area,” Mower said. “We ask them really just to take skeletal muscle, the meat, out with them. They can take the skin, they can take antlers they can take the ivories out of elk. But if they take the skull cap, we’d like it cleaned out so that they’re removing just the antlers with the skull cap, leaving behind the rest of the skull and the brain.”
The prevalence of CWD doesn’t seem to be high enough anywhere in New Mexico to merit the removal of whole animal herd, Mower said. “On the McGregor Range, that might be an exception, but it would require probably removal of a large portion of those deer and it seems to be one of the more sought-after places to hunt,” he said.
Especially when an animal is in the early stages of suffering from CWD, it’s not obvious to hunters that they have the disease.
“It will look just like the next one,” Mower said of an infected animal. “And most of the cases that we’ve dealt with that have come from hunters have been exactly that: no critical manifestations at all. But then we do make it a practice in our management that whenever we find a sick deer or elk, and we euthanize it, we test every one of them. So occasionally we do pick up an animal with the disease and it is obviously sick.”
During rifle hunting seasons, the NMGF keeps collection stations in the field in areas where the disease is known to occur.
“Hunters can take a head, where the brainstem is not damaged, and we’ll take those tissues and we’ll test all of them for hunters,” Mower said. “Alternatively, any hunter can take a head and present it at one of our area offices. We’ll take the head and test it. Beyond that, hunters can contact laboratory officials or their veterinarian, and have it done completely privately if they’d rather do that.”
The field test stations are only in game management units 34, 28 and 19, Mower said. “And I get a total number of tests every year that numbers around 400, and those are primarily voluntary. Out of all the tests I run, I get between two and four positive cases in any given year.”
Over all of the years of testing, Mower said the game department has found about 65 cases of the disease, of which all were in deer except for about seven or eight in elk.
The federal Centers for Disease Control CDC offers hunters tips to avoid CWD exposure. It advises that hunters shouldn’t shoot, handle or eat meat from an animal that looks sick or is acting strangely, or that’s found dead such as a roadkill.
When field-dressing an animal and handling the meat, the CDC advises hunters to wear latex or rubber gloves and to minimize handling the organs of the animal, particularly the brain or spinal cord tissues. It advises not to use household knives or other kitchen utensils for field dressing.
In addition to discussing CWD, Mower’s talk will address the recent occurrence of Rabbit Hemorrhagic Disease, which was discovered for the first time in wild rabbit populations this spring when wild rabbits started turning up dead in New Mexico.
People previously believed that the disease only occurred in domestic rabbits, Mower said. Since its discovery in New Mexico, it’s been discovered in Arizona, California, Colorado, Nevada and Texas, he said.
Mower also serves on a group of state and federal officials that focuses on the risk of COVID-19 spreading to wildlife. Other agencies involved in tracking the disease behind the ongoing worldwide pandemic include the federal Centers for Disease Control, the U.S. Geological Survey and U.S. Department of Agricultural, as well as livestock and wildlife agencies from New Mexico and other states.
The group is particularly concerned that COVD-19 could spread to bats in North America, Mower said. “We don’t know that it has, but it would be bad if, all of a sudden, we had our North American bats serving as our reservoir for the virus to reinfect humans at a later time,” he said.
So far, COVID-19 has been found in various places to have infected domestic cats, as well as in a lion and tiger in a zoo, Mower said. “There are cases in the Netherlands of the virus moving into mink on mink ranches,” he said.
“The single thing that we have done here in New Mexico is we have declared a halt on all research and wildlife rehabilitation involving bats,” Mower said. “So we have tried from a regulatory standpoint to prevent human contact with bats, all except for one research project that was proposed and funded and that was to capture bats and monitor specifically for the sign of COVID virus in New Mexico populations.”
The New Mexico Wildlife Federation has staged its Wildlife Wednesday events at Marble Brewery’s Northeast Heights location before the pandemic forced it to go to online presentations earlier this year.