An ABM of biting midge dynamics to understand Bluetongue outbreaks

Abstract

AO_SCPLOWBSTRACTC_SCPLOWBluetongue (BT) is a well-known vector-borne disease that infects ruminants such as sheep, cattle, and deer with high mortality rates. Recent outbreaks in Europe highlight the importance of understanding vector-host dynamics and potential courses of action to mitigate the damage that can be done by BT. We present an agent-based model (ABM), entitled MidgePy, that focuses on the movement of individual Culicoides spp. biting midges and their interactions with ruminants to understand their role as vectors in BT outbreaks, especially in regions that do not regularly experience outbreaks. Sensitivity analysis is performed and results indicate that midge survival rate has a significant impact on the probability of a BTV outbreak as well as its severity. Parameter regions where outbreaks are more likely to occur are determined, with an increase in environmental temperature corresponding with an increased probability of outbreak, where midge flight activity is used as a proxy for temperature. This suggests that future methods to control BT spread could combine large-scale vaccination programs with biting midge population control measures such as the use of pesticides. Spatial heterogeneity in the environment is also explored to give insight on optimal farm layouts to reduce the potential for BT outbreaks.