Will the midges that spread the bluetongue virus in the Netherlands disappear this winter? Or will they still be present in stables, for example? The Dutch Food and Consumer Product Safety Authority (NVWA) has started an investigation to get an answer to this.
To know how to do something about the spread of the virus, it is important to find out which midge species spread bluetongue. In the Netherlands there are forty species of midges that suck blood and can transmit pathogens. The NVWA expects that only a small part of these are involved in this bluetongue outbreak.
It is not known exactly which species spread this bluetongue variant. That is why the NVWA went to ten affected companies in recent weeks to catch midges. In the lab, insect experts look at tens of thousands of animals through a microscope to see which species fell into the trap. Scientists in the laboratory of Wageningen Bioveterinary Research then investigate which species carry the bluetongue virus.
Yesterday, the NVWA started placing new traps to monitor the numbers of midges in the near future. Traps occur at about five farms: one outside in the yard and one inside the stable.
The real solution to this outbreak is a vaccine, experts say. But the NVWA hopes that this research can slow the spread somewhat. “Some midge species reproduce in the manure, other species do so in the soil,” says NVWA entomologist Arjan Stroo. If you know where the virus spreaders breed, you may be able to reduce the numbers.
“We also want to know whether those midges occur as much indoors as outdoors,” says veterinary microbiologist Uiterwijk. “Does it make sense to bring livestock inside, or do the same species of midges occur there in the same quantities and is there therefore not much point?”
Farmers’ organization LTO Netherlands is not looking forward to the research. “Scientifically it will be very useful, but we have other priorities at the moment,” responds Saskia Duives, chair of the sheep farming department of the trade association. “For me, this research is not necessary. A vaccine must be available quickly, and the minister must allocate money for that.”
When placing and emptying the traps, the NVWA researchers already noticed that the total number of midges has decreased in recent weeks and experts expect that the cold will reduce the number of infections with bluetongue. The knowledge gained from the research will therefore make the biggest difference in the spring, when temperatures rise and the midges become more active.