Does yearly and seasonal variation of blood feeding in Culicoides drive Bluetongue virus and Epizootic hemorrhagic disease virus circulation?

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

Yosemite, CA

Conferencia; 48th ANNUAL CONFERENCE OF SOCIETY FOR VECTOR ECOLOGY; 2018

Biting midges of the genus Culicoides (Ceratopogonidae: Culicoides) are vectors of Bluetongue virus (BTV) and Epizootic hemorrhagic diseases virus (EHDV) worldwide (Reoviridae: Orbivirus). These viruses have impacted the livestock industry and constrain t

Biting midges of the genus Culicoides (Ceratopogonidae: Culicoides) are vectors of Bluetongue virus (BTV) and Epizootic hemorrhagic diseases virus (EHDV) worldwide (Reoviridae: Orbivirus). These viruses have impacted the livestock industry and constrain the development of hunting activities. Blood feeding behavior of Culicoides is expected to change seasonally and therefore virus transmission may follow this pattern. As the vector-host interaction is necessary for arbovirus maintenance in this system, a community network analysis framework could highlight temporal change in the host use. Here, we show the variation in blood feeding behavior between the summer and fall when BTV and EHDV activity is expected to increase. Culicoides? host preference structure will be more modular during the fall, and the host composition of this modules will rely on ruminants. We built Culicoides-vertebrate networks from blood engorged midges collected during two consecutive summers and falls from a deer ranch in northwest Florida. Structure and composition of modules where used to explore the compartmentalization in blood feeding behavior and species roles as a measure of the relevance for a given Culicoides spp to cohesion among and along modules. Proportion of the viremic White-tailed deer (RT-PCR) was used as proxy for Orbivirus activity. Bluetongue virus activity was greater in fall than summer for both years, although this transition demonstrated dependence of the year for EHDV?s activity. The degree of compartmentalization observed was different from that expected when Culicoides follow a neutral host use pattern. Additionally, the blood meal network structure showed seasonal and yearly variation. For instance, modularity increased from summer to fall and modules? host composition were more diverse in summer when Culicoides fed in close modules of wild ruminants during fall, supporting that Culicoides host feeding preference might be tighter during peaks in arbovirus transmission. Finally, Culicoides debilipalpis Lutz, Culicoides venustus Hoffman and Culicoides stellifer (Coquillet) displayed greater temporal variability in their network role. Thus, the novel network framework proposed it may show that the host feeding behavior phenology in Culicoides is in accordance with the host preference phenology in vectored mosquitoes? arbovirus and their seasonal transmission. These findings further incriminate Cu. stellifer, Cu. debilipalpis and Cu. venustus as vectors of EHDV and BTV in Florida. Finally, the timing in roles pictured should be used to program vector control interventions.