Medical and Veterinary Entomology (2009) 23, 367-378

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G.J. Venter, I.M. Wright, T.C. Van Der Linde and J.T. Paweska (2009)
The oral susceptibility of South African field populations of Culicoides to African horse sickness virus
Medical and Veterinary Entomology 23 (4), 367-378
Abstract: Twenty-two isolates of African horse sickness virus (AHSV), representing its distinct serotypes, geographical and historical origins, were fed to three populations of South African livestock-associated Culicoides spp. (Diptera, Ceratopogonidae). Infective blood meals included 12 recent isolates, nine historical reference strains and one live attenuated vaccine strain serotype 7 (AHSV-7) of the virus. Field-collected midges were fed through a chicken-skin membrane on sheep blood spiked with one of the viruses, which concentrations ranged from 5.4 to 8.8 log10TCID50/mL of blood. After 10 days incubation at 23.5°C, AHSV was isolated from 11 Culicoides species. Standard in vitro passaging of AHSV-7, used for the preparation of live attenuated vaccine, did not reduce its ability to infect Culicoides species. Virus recovery rates in orally infected Culicoides midges differed significantly between species and populations, serotypes, isolates and seasons. Significant variations in oral susceptibility recorded in this study emphasize a complex inter-relationship between virus and vector, which is further influenced by multiple intrinsic and extrinsic factors. As it is not possible to standardize all these factors under laboratory conditions, conclusive assessment of the role of field-collected Culicoides midges in the transmission of orbiviruses remains problematic. Nevertheless, results of this study suggest the potential for multi-vector transmission of AHSV virus in South Africa.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Gert J. Venter, Janusz T. Paweska

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Culicoides (genus) South Africa