Culicoides vector species on three South American camelid farms seropositive for bluetongue virus serotype 8 in Germany 2008/2009.
Palearctic species of Culicoides (Diptera, Ceratopogonidae), in particular of the Obsoletus and Pulicaris complexes, were identified as putative vectors of bluetongue virus serotype 8 (BTV-8) on ruminant farms during the epizootic in Germany from 2006 to 2009. BTV may cause severe morbidity and mortality in ruminants and sporadically in South American camelids (SAC). However, the fauna of Culicoides spp. on SAC farms has not been investigated. Therefore, the ceratopogonid fauna was monitored on three farms with BTV-seropositive SAC in Germany. Black-light traps were set up on pastures and in stables from summer 2008 to autumn 2009. Additionally, ceratopogonids were caught in emergence traps mounted on llama dung and dung-free pasture from spring to autumn 2009. After morphological identification, selected Culicoides samples were analysed for BTV-RNA by real-time RT-PCR. The effects of the variables 'location', 'temperature' and 'humidity' on the number of Culicoides caught in black-light traps were modelled using multivariable Poisson regression. In total, 26 species of Culicoides and six other genera of biting midges were identified. The most abundant Culicoides spp. collected both outdoors and indoors with black-light traps belonged to the Obsoletus (77.4%) and Pulicaris (16.0%) complexes. The number of Culicoides peaked in summer, while no biting midges were caught during the winter months. Daily collections of Culicoides were mainly influenced by the location and depended on the interaction of temperature and humidity. In the emergence traps, species of the Obsoletus complex predominated the collections. In summary, the absence of BTV-RNA in any of the analysed Culicoides midges and in the BTV-seropositive SAC on the three farms together with the differences in the pathogenesis of BTV-8 in SAC compared to ruminants suggests a negligible role of SAC in the spread of the virus. Although SAC farms may provide similar suitable habitats for putative Culicoides vectors than ruminant farms, the results suggest that geographic and meteorological factors had a stronger influence on Culicoides abundance than the animal species.
Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany; BFS, Institute of Parasitology, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
Claudia
C
Schulz
Workgroup Biomathematics, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
Mario
M
Ziller
Institute of Infectology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
Helge
H
Kampen
Department of Animal Science, Livestock Production Group, Georg August University Göttingen, Albrecht-Thaer-Weg 3, 37075 Göttingen, Germany.
Matthias
M
Gauly
Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
Martin
M
Beer
BFS, Institute of Parasitology, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
Christoph G
CG
Grevelding
Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
Bernd
B
Hoffmann
BFS, Institute of Parasitology, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
Christian
C
Bauer
Leibniz Centre for Agricultural Landscape Research, Eberswalder Str. 84, 15374 Müncheberg, Germany. Electronic address: dwerner@zalf.de.
Doreen
D
Werner
D000818:Animals; D044822:Biodiversity; D001819:Bluetongue / Q000097:blood / Q000635:transmission; D001820:Bluetongue virus / Q000502:physiology*; D002161:Camelids, New World / Q000821:virology; D002519:Ceratopogonidae / Q000033:anatomy & histology / Q000145:classification* / Q000821:virology; D005243:Feces / Q000469:parasitology; D005260:Female; D005858:Germany; D006813:Humidity; D007300:Insect Control / Q000295:instrumentation; D007303:Insect Vectors / Q000033:anatomy & histology / Q000145:classification* / Q000821:virology; D008297:Male; D012367:RNA, Viral / Q000032:analysis; D012044:Regression Analysis; D012621:Seasons; D013696:Temperature
D012367:RNA, Viral
Alpaca; Bluetongue virus serotype 8; Culicoides; Germany; Llama; Vector