In the future, farmers may have a tiny, invisible ally in the fight against bovine respiratory disease.
BRD, or shipping fever, is a pneumonia bacterial disease that rears up when an animal’s immune system is weak, usually during times of stress. It costs producers money in drug treatments, reduced feed efficiency and weight gain and dead cattle. In Canada, BRD costs are estimated to be in the hundreds of millions of dollars.
Baljit Singh, a professor at the University of Saskatchewan’s veterinary biomedical sciences program, is working on a novel approach to fighting the disease.
Read Also
August rain welcome, but offered limited relief
Increased precipitation in August aids farmers prior to harvest in southern prairies of Canada.
“We want to use compounds developed through nanotechnology to treat respiratory diseases of cattle and horses,” Singh said.
“Respiratory diseases such as shipping fever and feedlot pneumonia in cattle cause millions of dollars in losses every year, and we still don’t have any effective treatments for that.”
At the root of Singh’s research is the bovine immune system’s response to the bacteria. When a cow’s natural defenses respond to BRD, it sends out white blood cells, or leukocytes, to destroy the bacteria.
“Now we understand that although it’s good for the leukocytes to come and kill the bacteria … the same leukocytes also kill the body’s normal cells, so it becomes a double-edged sword,” he said.
“Do you kill an ant with a bazooka? That’s what the major effort is, in understanding how much response (is necessary).”
This is where nanotechnology comes in. Using nanoparticles designed at the National Institute for Nanotechnology in Edmonton, Singh is trying to regulate the amount of leukocytes released during pneumonic infections.
The microscopic particles, called nanotubes, are artificially created protein fragments. They bind to the proteins that help the leukocytes leave the blood stream to combat the infection.
“At certain points in the infection, we should be able to inject the tubes into the animal to reduce the number of leukocytes coming to where the infection is to have a calibrated immune response.”
So far, Singh has run tests on blood samples and lab mice.
In the blood sample experiments, blood cells are infected with bacteria. Nanotubes are released into some of the blood samples and Singh measures how the samples with nanotubes fare compared to those without. So far, he said, the experiments show that the nanotubes are effective in controlling the release of leukocytes.
The tests with mice are to find out if the nanoparticles have nasty side effects.
“None of the mice died at a very high dose (of nanotubes). Although there may have been a bit of inflammation in the lungs, generally (the nanotubes) were very well tolerated.”
Questions remain. Nanotechnology is a relatively new field and the effects nanoparticles may have after entering the food chain are still largely unexplored.
Singh said the challenge facing the scientific community and governments is to make sure nanoproducts released into the environment are rigorously tested for side effects.
“If a society is expecting to create magic bullets which will have no side effects, then I don’t think those are expectations that can be fulfilled,” he said.
“For us, the challenge is going to be the balance. At some stage, we’re going to have to say, ‘OK, this product is going to have these positive effects with some negative effects. Can we live with it?’ “
