BANFF, ALTA. — There are many things scientists do not know about chronic wasting disease, but recent research has shown this fatal prion can spread in blood, saliva and from mother to offspring.
Figuring out how this rogue protein causes disease and is transmitted could lead to live tests and treat-ment.
Various projects are examining CWD found in deer, elk and moose in 22 American states, two Canadian provinces, Mexico and South Korea.
It causes the body to waste away and spurs behaviour changes like staring, skittishness and heavy salivation. Since studying wild animals is difficult, many tests have been conducted with captive animals as well as transgenic mice created to develop the disease.
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They know it is transmitted in body fluids like blood, urine, saliva and many tissues including the alimentary tract, tonsils and lymph nodes, said researchers Davin Henderson and Edward Hoover of Colorado State University at the Alberta Prion Research Institute conference held recently in Banff.
They also believe positive animals do not need to have direct contact to get it.
“It is likely the dissemination of this disease in this population is due to the proliferation of prions and the shedding of prions in the environment. That is an interesting thing for prions to do — come from a central nervous system type of setting and spread through the body and then end up in the environment,” said Henderson.
Jeffery Christiansen is studying moose and has found the disease was identical to that found in mule deer. Five cases in the wild were found in Colorado, Wyoming and Alberta.
“Moose are susceptible to CWD from mule deer. We are interested in investigating if the reverse is also true where CWD can be passed back to deer and elk,” he said.
The Colorado State scientists have also detected two different strains of CWD. Type one has a short incubation period while type two has a longer period with an asymmetrical distribution pattern of disease in the brain.
Candace Mathiason, also of Colorado State, may have answered the question of whether the disease can be passed from mother to offspring.
She wanted to know if there was a possibility of transmission during pregnancy in the colostrum, milk or contact with saliva among deer.
They infected 12 Reeve’s Muntjac deer that subsequently produced 14 offspring. They stayed with their mothers until weaning and all the fawns went on to develop CWD at 28 to 58 months of age. One is still alive.
Eight died at birth and although they appeared physically normal, two had positive tissue samples. They also examined three fetuses and found all had at least one positive tissue.
The university plans to continue with further experiments.
