An appraisal of current and new techniques intended to protect bulls against Culicoides and other haematophagous nematocera: the case of Schmergow, Brandenburg, Germany

Abstract

The outbreak of bluetongue (BTV-8) in many parts of north-western Europe led to efforts to curb the spread of the disease, particularly in farms with valuable livestock, as on a stud bull farm in Schmergow, Brandenburg, Germany. In the abundance of the putative BT vectors, Palaearctic Culicoides species, several vector control methods were applied in the hope for a reduction of the target insect populations. Insecticide-impregnated ear tags and regular treatments at 6-week intervals of all bulls with deltamethrin pour on were expected to achieve the desired control of the biting midges. Additionally, insecticide-treated mosquito fences circumventing much of the pens were tried for the first time against Culicoides. Two suction black-light traps (BioGents(R) sentinel traps) helped to monitor the densities of Culicoides and other haematophagous nematocera during the trial period from July to December 2007. Despite all efforts, the densities of Culicoides were not distinctly reduced. Several thousand midges were repeatedly recorded during one-night catches. Examinations of midges and other haematophagous nematocera (Aedes and Anopheles species) revealed high percentages of successful feedings between 10% and 35% for Culicoides and more than 50% for Aedes and Anopheles species. Since all insects were caught inside the pens, the concept of endophily vs exophily or endophagy vs exophagy for some Culicoides species needs to be revised accordingly. Also, stabling of valuable livestock does not reduce the host-vector interface and, hence, the risk of transmission of BT.

Bluetongue disease in Germany (2007–2008): monitoring of entomological aspects

“…The detailed results of the monitoring in the different German regions are presented in the ten papers following this introducing overview in the present volume of the journal Kiehl et al 2009;Vorsprach et al 2009;Balczun et al 2009;Kiel et al 2009; Clausen Bartsch et al 2009;Stephan et al 2009;Bauer et al 2009;Hörbrand and Geier 2009). However, the common features can be summarized as follows:…”

“…The 10 papers following this introducing overview in the present volume of the journal Vorsprach et al 2009;Balczun et al 2009;Kiel et al 2009;Kiehl et al 2009;Bartsch et al 2009;Clausen et al 2009;Stephan et al 2009;Bauer et al 2009;Hörbrand and Geier 2009) describe the results obtained during this monitoring program, which ran from the end of March 2007 until the end of May 2008.…”

“…Evaluating these main results of the entomological monitoring and the fact that many wild ruminants have also been infected with BTV, it becomes evident that bluetongue disease has become endemic in Central Europe, and that only constant effort including vaccination and perhaps also insecticidal protection of cattle and sheep will keep the economical losses at a reasonable level. The following papers (1-10) in this journal will contribute more details obtained from this worldwide unique entomological monitoring: Bartsch et al 2009;Bauer et al 2009;Clausen et al 2009;Hörbrand and Geier 2009;Kiehl et al 2009;Mehlhorn et al 2009;Kiel et al 2009;Vorsprach et al 2009;Balczun et al 2009.…”

Culicoides biting midge density in relation to the position and substrate temperature in a cattle dung heap

“…Although not studied in detail, Culicoides species in temperate climate zones are expected to hibernate in a late larval stage (Szadziewsi et al 1997). Moreover, vector surveillance studies in Northern Europe indicated very low but regular activity of adult Culicoides also in winter (Losson et al 2007;Bauer et al 2009;Clausen et al 2009;Hoffmann et al 2009;Kiel et al 2009;Mehlhorn et al 2009). These findings raised a discussion whether or not these individuals represent an overwintering adult population or newly emerged imagines (Losson et al 2007).…”

A review on Schmallenberg virus infection: a newly emerging disease of cattle, sheep and goats

“…The treatment of livestock and animal housing with pyrethroid insecticide combined with the use of midge-proofed housing for viraemic or high-value animals and reduction of local breeding sites are the best options currently available (Carpenter et al 2008). However, application of pour-on insecticides has been unsuccessful with no noticeable reduction in the density of biting midges in highly-challenged areas (Bauer et al 2009). Control of midges is unlikely to be effective given that they are extremely widespread, and appear to be very effective at spreading SBV.…”