Forskning i vektorbårne dyresygdomme

Research on midges and vector-borne diseases

Knowledge about the small mosquitoes called midges is important as midges through their bites can spread diseases such as bluetongue and Schmallenberg. Therefore, the National Veterinary Institute conducts research in order to elucidate the midges’ behavior and thus their ability to spread diseases. This enables the researchers to predict and prevent outbreaks of midge-borne diseases.

Monitoring of disease-carrying mosquitoes

Small mosquitoes called midges (genus Culicoides) are carriers of livestock diseases such as bluetongue and Schmallenberg. Through their bites, they may transfer the viruses to cattle, sheep, goats, deer, and other ruminants.

In the summer, the researchers in the Section for Epidemiology at the National Veterinary Institute perform field studies in different parts of Denmark. Here they measure, where and when the midges occur in greatest numbers.

The samples collected in the summer are analyzed during the winter, and the data is used to build behavioral models. Subsequently, these models are used to build other models that predict the spread of bluetongue during an outbreak.

One of the behavioral parameters that are currently being investigated is the density of the midges around the host animal (sheep, cattle, etc.) in connection to their breeding sites. It is also being investigated, which meteorological parameters are influencing the flight activity of the midges. Greater knowledge of distribution and outbreaks may help reduce or prevent outbreaks of midge-borne diseases that undetected may have major economic consequences for farmers in terms of lost export and destruction of animals.

Bluetongue is no longer present in Denmark after an extensive vaccination campaign. But in 2011 a new virus called Schmallenberg emerged in Germany and spread to Denmark, where it was discovered in midges collected by the National Veterinary Institute. As a result, in the spring of 2012 the first birth defects in newborn calves were observed in Denmark. Midges collected in late summer 2012 showed an extensive spread of Schmallenberg virus in many parts of the country.

Dispersal model Nord Risk

The dispersal model Nord Risk, developed with support from the Nordic Council of Ministers, shows the risk of infection in Scandinavia. With this model, it is possible to forecast the influence from the climate and the environment on the spread of vector-borne diseases and to model the effects for humans, livestock, pets, and wild animals. The model is also able to predict the infection/transmission that takes place between animals and humans. The model is important in relation to the principle of ‘One Health’, which combines research on animals, humans and the environment.

In Denmark, we are doing surveys on the prevalence of mosquitoes. Seasonal variation and geographic differences are mapped by collecting mosquitos in gardens, recreational areas, and around livestock. This basic knowledge will be used in dispersion models to model infections spread by mosquitoes and the risk of new mosquito-borne diseases that may be introduced to Denmark in the coming years due to increasing temperatures.

See www.nordrisk.dk

In the Section for Epidemiology we are working with several models of how the climate and environment affect the spread of infection. The Section’s expertise is among other things used to develop monitoring systems for Scandinavia and Europe. Read more about the work with dispersion models here.

The section is also leader of the project 'Vector-borne Infections: risk-based and cost effective surveillance system'.

Postdoc

Carsten Thure Kirkeby
Postdoc
DTU Vet
+45 35 88 63 36

Epidemiologist

Rene Bødker
Epidemiologist
DTU Vet
+45 35 88 63 66