Vector and host interactions underlying hemorrhagic disease transmission: what can network analysis uncover?

AGUSTÍN IE. QUAGLIA; MCGREGOR, BETHANY L.; SAYLER, KATHERINE; WISELY, SAMANTHA M.; BURKETT-CADENA, NATHAN D.

Saint Augustine, FL

Conferencia; 67th Annual International Wildlife Disease Association Conference; 2018

Bluetongue virus (BTV) and Epizootic hemorrhagic disease virus (EHDV) cause hemorrhagic disease in manyruminant species worldwide, both wild and farmed, with important ecologic, economic and social impacts.Various Culicoides species transmit these viruses between infected and uninfected ruminants. As the vector‐host interaction is necessary for arbovirus maintenance in this system, a network analysis framework could highlight actors and processes masked by the complex nature of the disease system. Here we show how blood feeding behavior, through the structure and composition of Culicoides‐vertebrate interactions, sets the transmission scenario for EHDV and BTV with implications for management activities for protecting ruminants. We built Culicoides‐vertebrate network projections and calculated network, node and edge measurements from a blood engorged Culicoides dataset of a deer ranch in northwest Florida. The network dataset comprised 1,684 blood feeding interactions from 14 Culicoides species and 25 vertebrate species, where only 20% of the possible interactions were realized. The structure showed an isolated specialist compartment and another generalist blood feeding compartment with a high level of nestedeness. Culicoides stellifer, C. biguttatus and C. venustus fed on 68%, 40% and 36% of the available vertebrates, respectively, although 86% of the interactions came from C. stellifer. A noticeably over‐connected ruminant compartment and a moderately sparse bird‐mammal community emerged in the vertebrate projection. The high level of generalization in host use on exotic, domestic and wild ruminants set up a permissive scenario for EHDV and BTV transmission. Therefore, preventive and control activities might best be focused on the entire ruminant community and not only the clinically susceptible species. In the future this network intervention approach needs to be validated and improved by taking into consideration the temporal and spatial changes in the host use by midges.