Today's intersection: chronic wasting disease and toxoplasmosis

There is research underway and much discussion about how best to control chronic wasting disease in cervids like elk and deer while protecting big cats like cougars and lynx while reintroducing wolves to historic habitats. 

Scavengers like American crows can move CWD from gut pile to gut pile which can remain in soils for years yet transmission of the pathogen to other species including humans is very rare.

Only 2% of the chronic wasting disease prions that go into a bobcat’s mouth can be detected in the bobcat’s poop. And that’s day one. By day two there’s less than 1%, and by day three there’s none at all. In 2021, a team of researchers conducted a similar study on two captive mountain lions and found that while there were infectious prions in their poop, it was only about 3% of what they consumed. That meant 97% of the prions that went in could not be detected when they came out. It’s partly why Jennifer Malmberg, an adjunct UW veterinary sciences professor who led the project, decided to look at bobcats. No one knows for sure what happens on the insides of a lion or bobcat that seems to neutralize a prion that requires lye, bleach or high temperatures to destroy. Malmberg’s best guess is the prions bind to something inside the cats that renders them no longer detectable. [Carnivores and scavengers could help reduce CWD]

CWD is surging in Midwest states like Iowa and Minnesota but Wyoming and Colorado are seeing spikes, too. According to Wyoming Game and Fish, the disease, which occurs mainly in male cervids like wapiti, moose and deer, is found in 34 of the state's 37 mule deer herds and in 15 of the state’s 36 elk herd units. In parts of Canada 85% of male mule deer and 35% of females are infected. Colorado Parks and Wildlife's mandatory testing revealed increases in CWD in three of the state's mule deer herds. 

So, kill off apex predators like grizzlies, wolves and cougars, spray atrazine, neonicotinoids and glyphosate on everything then wonder why cervids like deer and wapiti contract a prion contagion like chronic wasting disease? 

Toxoplasma gondii is a parasite that reproduces in cat species, whether domestic, feral or wild. 

Infected mice lose the fear of cat urine and are more likely to be preyed upon spreading the parasite over significant distances. Toxoplasmosis has been linked to risky behavior in wolves after they ingested cougar scat while living in and around Yellowstone National Park and while the parasite infection can be treated it is never completely eliminated.

A warming climate is blamed for part of increased transmission rates but researchers say the federal government's feeding of elk, especially in Wyoming, in close proximity is also a factor. Hay fed to those animals is likely contaminated with Roundup® and other pesticides. 

ip images.