Soil Type Could Affect Infectivity of CWD Prions

Humic acid, found in highly organic soils, degrades the CWD prion proteins and makes them less infective.
Humic acid, found in highly organic soils, degrades the CWD prion proteins and makes them less infective.
(John Maday)

Prions, the misshapen proteins associated with transmissible spongiform encephalopathies such as BSE and Chronic Wasting Disease (CWD) have a dangerous ability to persist and remain infective in spite of environmental exposure. In the case of CWD, the prions, shed through saliva, feces or decomposition of a dead animal, can survive exposure to air, sunlight and temperature extremes, allowing them to persist in soils and spread to other grazing animals.  

This ability, however, might depend on soil composition. Researchers at the University of Alberta in Edmonton have found that humic acid, found in highly organic soils, degrades the prion proteins and makes them less infective.

Previous research has shown that CWD prions can bind to particles of certain soil minerals such as quartz, kaolinite and montmorillonite, resulting in long-term stability and persistence in the soil. This new research indicates that organic soils containing high levels of humic acid could have the opposite effect.

In this study, the researchers first exposed infected elk brain tissue to one, 2.5 and 25 grams per liter of commercially produced humic acid, and let it incubate overnight. They found that higher concentrations of humic acid reduced chemical signatures left by the infectious prions by as much as 95 %. They note similar results when using humic acid extracted from soil samples from around western Canada.

In another part of the study, the scientists injected a mixture of humic acid and CWD-infected elk brain tissue into the brains of lab mice, while injecting other mice with a noninfected mixture as a control group. Due to the slow incubation period for prion diseases, they monitored the mice for 280 days, and found that about half of the mice injected with infected tissue and humic acid did not show any signs of CWD.

Researchers believe these results could lead to a soil treatment on deer farms or other areas where deer congregate, or to map areas of high or low risk for CWD based on humic acid levels in soils. The researchers plan to conduct further study on the effects of humic acid on prions in soil samples.

The report, titled “Soil humic acids degrade CWD prions and reduce infectivity,” is published in the journal PLOS Pathogens.

 

 

Latest News

New Regulations Proposed by FDA for Animal Drug Labeling
New Regulations Proposed by FDA for Animal Drug Labeling

New rules would provide animal drug sponsors with predictable requirements for the labeling of prescription and over-the-counter new animal drugs, as well as new animal drugs for use in animal feeds

Calf-Raising Success is All in the Details
Calf-Raising Success is All in the Details

Raising a heifer from newborn up to 20-plus months until she becomes a productive milk cow is more important than ever. Dairy producers are increasingly looking to heifer growers to lend a helping hand with the process.

Who “Nose” When a Calf is Getting Sick?
Who “Nose” When a Calf is Getting Sick?

If you want to stay ahead of calf health and catch sickness in its earliest stage, University of Minnesota Graduate Student Abbigail Prins offers a handy detection tip.

7 Ways To Prioritize Employee Retention
7 Ways To Prioritize Employee Retention

Want to keep your valued team players? Learning how to avoid these frustrating and deal-breaking mistakes can help.

Aggie Serves As Houston Livestock Show And Rodeo Veterinarian For 21st Year
Aggie Serves As Houston Livestock Show And Rodeo Veterinarian For 21st Year

Professor at Texas A&M's Large Animal Teaching Hospital leads a team of volunteers in caring for the 18,000 livestock animals at the annual event.

DT_Dairy_Udder_Parlor_Teats
NMC Webinar Addresses Feeding Trace Minerals to Enhance Udder Health

By participating in this educational offer, you can gain a better understanding of the role trace minerals play in immunity and udder health.