Search the fly to find the blue tongue vector

Staff at the Vector Surveillance Center of the Dutch Food and Consumer Product Safety Authority placed fly traps on Tuesday at a dairy and sheep farm in Vinkeveen, Utrecht. They want to know which species of midges spread the bluetongue virus.

The center was founded more than ten years ago, in part due to a previous case of bluetongue. Research is being conducted on native and invasive species that can transmit diseases, such as ticks, midges and mosquitoes.

The Vector Control Center conducts fly monitoring every year to get a good idea of ​​which mosquitoes are present where and in what quantities. In the case of a bluetongue outbreak, additional measurements are taken to determine which midges are responsible for the outbreak.

inside and outside

For example, six insect traps were set up on this farm, four in the stable and two outside. These remain for a week, during which the insects and midges captured are collected daily for examination.

Midges are separated by type, location, trap and moment of capture. The midges that carry the bluetongue virus are then examined. The tests are being carried out by Wageningen Bioveterinary Research (WBVR) in Lelystad, Flevoland.

The other alternative

“We know that in the previous outbreak, seven out of forty midge species found in the Netherlands were responsible for the spread. This is another variant of bluetongue. We don’t know if it is possible,” says veterinary microbiologist and veterinarian Mathilde Ouerwijk. It is spread by the same species of fleas.

The vet expects the results of the examination in the spring. “At WBVR, they are now busy discovering bluetongue in animals.”

Preference for midges

The research results show which species of midges prefer a particular host. “For these species, it’s often a cow or a sheep, and it’s probably a different species than what’s found in the swamps,” says Ouerwijk.

When the distributor is known, it also becomes clear where the midges lay their eggs. ‘With this species, this is often all over the farm, such as in manure, silage residue and in wet areas. For example, cleaning up that residue or fixing a leaky faucet may limit the spread of disease. “There’s not much you can do about the midges themselves,” the vet says.

Uiterwijk predicts that as the cold nights approach, the midges will become less active and will no longer reproduce. “But they become active again in March or April, when the weather gets warmer. She fears that they can then spread the virus further.