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VIU professor researching how microbes can protect amphibians and oysters from disease

Biologist exploring the affect of small organisms on an animal’s ability to handle environmental challenges brought on by climate change
Vancouver Island University biology professor Andy Loudon is studying how good microbes can be used to make frogs and oysters more resistant to deadly pathogens. VANCOUVER ISLAND UNIVERSITY

A Vancouver Island University researcher is examining how bacteria can be used to protect frogs from a deadly pathogen and improve disease resistance in the Pacific oyster.

Andy Loudon, a professor of biology, received a $165,000 grant from the Natural Sciences and Engineering Research Council of Canada over five years to fund the research.

He is exploring how communities of microbes — all the small organisms that live in a habitat, such as bacteria — affect an animal’s ability to fight disease and handle environmental challenges brought on by climate change and what factors in a host affect what microbes are present.

While many people associate microbes with sickness and food-borne illnesses, Loudon said he’s studying “good microbes.”

He is studying a fungal pathogen called Batrachochytrium dendrobatidis that affects the skin of amphibians and can kill them. It’s one of many factors contributing to a decline in amphibians worldwide, he said.

Frogs are vital for keeping mosquito populations in check and maintaining ecological health. In tropical areas that have seen massive declines or local extinctions, there have been environmental consequences, such as different nutrients in streams that have lost frogs or too much algae, which affects the dynamics of the stream.

Amphibians have bacteria on their skin that can protect the animal from the pathogen, and each frog species generally has a unique bacteria that affect how susceptible they are to the pathogen.

“So, some become really sick and die. Others are fairly resistant,” Loudon said.

Working in collaboration with Brandon Sheafor, a biology professor at Carroll College in Montana, Loudon is exploring why there are different bacteria on different species and if there is something about a particular species that determines what microbes are dominant.

Columbia spotted frogs, which are found throughout most of B.C., are fairly resistant to the pathogen and have a simple bacterial community, with two types of bacteria making up about 80 per cent of those present on their skins, he said.

He is trying to determine if the immune system of the species influences the composition of bacteria on its skin and how that affects its resistance to disease.

That could aid in frog conservation by leading to selective breeding programs using the “winning equation” of which frog immune factors are needed to create frogs that are resistant to the pathogen, he said.

Loudon is working on similar research on microbes in oysters to determine how changing the microbiome in the early stages of an oyster’s life affect its health.

He and his collaborator, Canada Research Chair in shellfish health and genomics Timothy Green, are finding that oysters whose microbial communities are disturbed in the first 24 hours of life are more likely to die from disease caused by the Vibrio pathogen, which is responsible for high death rates in farmed Pacific oysters.

“The hope is that we do come up with what’s the right way to rear these oysters so that … you have healthy long-living oysters,” he said.

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