Silent Carriers: Wild Deer Spread a Fatal Disease Without Showing Symptoms

Chronic Wasting Disease Study in Wild Deer

According to НВ — Техно: On June 19 at 2:00 PM, researchers from the University of Calgary and international partners published findings on chronic wasting disease (CWD) in wild deer in the journal Science Advances. This prion-caused illness is always fatal and continues to expand across North America, including into Alberta. The study revealed that infected animals can be contagious long before visible signs emerge, shedding prions through urine and feces for months or even years before clinical symptoms appear.

Experiments and Their Results

In lab tests, scientists examined whether the disease could jump to other species. While most test subjects showed no illness, small amounts of prions were found in their tissues. When those tissue samples were transferred to different animal species, the recipients developed symptoms. This confirms that prions can mutate as they move between hosts, creating new strains.

As Hermann Schätzl noted, 'this shows we are not dealing with a single fixed pathogen,' but rather 'prion strains evolve, and this evolution influences how the disease develops.'

It is worth noting that no confirmed human infections have been recorded, despite a precedent for crossing species barriers-such as in bovine spongiform encephalopathy (mad cow disease). However, the risk remains significant given the disease's prevalence. Hermann Schätzl added that 'by the time clinical signs appear, the animal has often been contagious for a long time.'

The University of Calgary team is working on a CWD vaccine. Early experiments in mouse models showed promising results: vaccinated animals shed fewer infectious prions at both early and late stages of the disease and lived longer after exposure.

As Samia Hannaoui stated, 'if we can reduce prion shedding, we might also reduce disease transmission.'

This research opens new avenues for combating this dangerous illness.

The study underscores the serious threat CWD poses to wild deer and potentially other species. Understanding how prions spread and evolve is critical for developing effective control and prevention strategies. These findings could significantly impact wildlife management approaches and vaccine development efforts, potentially changing the fight against this disease in the future.