Egg study gives insights into bluetongue control
The researchers used a protein found in egg white to track the movements of Culicoides biting midges.
The spread of Bluetongue virus (BTV) could be controlled through the use of a protein found in egg, according to new research.
Previously, scientists used ovalbumin - a protein found in egg white - to record and assess crop pests. The method is sensitive enough to show if even a single insect has been exposed and enables marking without the need for collection.
In a new study, researchers at The Pirbright Institute explored whether they could use the technique to track Culicoides biting midges, which are responsible for the spread of Bluetongue.
Published in the Journal of Applied Ecology, the research is the first to measure how midges might travel between farms. Experts say that it could help bluetongue-affected countries respond faster in the event of an outbreak.
“The outcomes of this research will provide governments with crucial insight to enable them to put control measures in place for these diseases more quickly, saving animals’ lives and helping reduce the losses to farmers,” said lead researcher Dr Chris Sanders.
In the study, researchers sprayed ovalbumin on to dung and straw in a barn. This ensured the insects would pick up the protein marker when they emerged or landed on it.
The team set traps for the midges at various distances from the barn to measure how far they had travelled. They conducted five trials, collecting 9,000 midges in total. 600 midges tested positive for the protein and had travelled up to 3.1km from the treated barn.
“By combining this data with information from on-site weather stations, we found that the Culicoides midges had flown upwind and downwind towards the traps, and we think that a significant number are actively moving between farms,” explained Dr Sanders.
He continued: “Midges are too small to track by eye or with cameras or radar technology. People have tried capture-mark-recapture, but this is very hard work for small insects because so few marked insects are usually recovered.
“This research means we now have a much better understanding of the movement of the Culicoides midge species that transmits BTV and have the data we need to estimate the likely spread of the disease between farms more accurately.”
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