Pest approach

Unconventional experiment provides

Researchers at the University of Stirling’s Institute of Aquaculture have developed an unlikely new method to better understand the bacteria that cause diseases of fish in aquaculture. However, this new technique has no need for fish – instead it relies on caterpillars of a moth species that is damaging bee populations worldwide.

Dr Andrew Desbois and PhD student Stuart McMillan found that the fish pathogen Vibrio anguillarum which causes vibriosis in fish could infect caterpillars of the greater wax moth. Crucially, the team found that the virulence of different strains of this bacterium were similar when injected into salmon and the caterpillar.

‘It may seem surprising to think that caterpillars can help us understand how bacteria infect and harm fish, but many innate immune system components are similar in fish and insect blood,’ said Dr Desbois.

‘As such, the environment to which the bacterium must adapt to cause infection is similar inside the insect as it is in a salmon or trout.’

The unconventional model is inexpensive to run, ethically more acceptable than studies on fish and safe because the insects are confined to the laboratory and disposed of with other contaminated waste to prevent inadvertent release into the environment.

Importantly, the new approach may help