Midges' role in Bluetongue spread clarified
A team from Oxford University have demonstrated that midges which spread Bluetongue across Europe in the 2006 epidemic were not blown by the wind but spread the disease while under their own power. It was previously thought that the midges were 'passengers' blown on the wind and carrying the disease to wherever they ended up. However, the scientific team have demonstrated after analysing the 2006 outbreak that the active movement of midges was responsible for around 40% of the spread of the disease.
The analysis concentrated on Northern Europe – Germany, Luxembourg, the Netherlands, Belgium and France. Approximately 40% of the midges's movements during the outbreak were downwind or random movements attributed to the midges' own activity, with the remainder attributed to the combination of upwind, downwind and random movement.
“For the first time we can say that midges, under their own power, travel upwind as well as downwind during this kind of epidemic. This has very important implications for the control of future epidemics as previously efforts had been targeted at preventing downwind infection.” said Dr Luigi Sedda of the University’s Department of Zoology. Dr Sedda led the research with Professor David Rogers.
“Our model can explain 94 per cent of the over 2,000 farm outbreaks of bluetongue in Northern Europe in 2006. While some infected farms were the source of infections for up to 15 other farms, 70 per cent of all the infected farms were transmission ‘dead ends’ – that is they did not infect other farms.” Dr Sedda added.
Defra has published guidance for the vet sector ahead of a proposed UK-EU Sanitary and Phytosanitary agreement.
