Defining the transmission parameters of lumpy skin disease virus by the three model insect vector species Aedes aegypti, Stomoxys calcitrans and Culicoides nubeculosus reveals important differences in their likely role in transmission

Lumpy skin disease virus (LSDV) is a poxvirus that can cause severe, systemic disease in cattle. By far the most important route of transmission of LSDV is mechanical transmission via haematophagous arthropod vectors. However we lack detailed information on this process including the likelihood of transmission by different vector species. This study used an experimental bovine model of LSDV transmission to quantify the transmission of LSDV from an infected donor to a naive recipient calf. Three species of Diptera representing different vector groups were included (Stomoxys calcitrans, Aedes aegypti and Culicoides nubeculosus, respectively a large biting fly, a mosquito and a midge), and the clinical, virological and immunological outcomes in the recipient calves studied. The ability of Ae. aegypti to mechanically transmit LSDV following feeding on an artificial membrane feeding system was also examined. Both Ae. aegypti and S. calcitrans were able to transmit LSDV, resulting in disease in recipient calves. Bites from virus-positive C. nubeculosus did not result in disease in recipient calves, though the presence of neutralising antibodies in these recipients indicated exposure to virus or virus components. Ae. aegypti successfully transmitted LSDV following feeding on LSDV-spiked blood through an artificial membrane feeding system, validating this laboratory model as a future replacement for donor cattle. Mathematical models of the data were generated and predicted S. calcitrans to be the most efficient vector of LSDV of the insects tested with a reproduction number (R0) of 5.8. Impact statementLumpy skin disease virus (LSDV) is a neglected, rapidly emerging pathogen of cattle that has spread into Europe and throughout the Middle East and Asia over the past ten years. Lack of understanding of the mechanism of transmission of LSDV has hampered efforts to control its rapid spread. This study compares the ability of three model species of Diptera (Stomoxys calcitrans, Aedes aegypti and Culicoides nubeculosus) to mechanically transmit the virus to cattle, generating high quality quantitative data to facilitate mathematical modelling of virus transmission. S. calcitrans was identified as a potential driver of LSDV transmission with a R0 of 5.8. This work provides new insights into the vector transmission of LSDV that can be used to design more targeted and effective disease control programmes.