TLR4 and viral infectious disease: Well-known pathways related to viral infection have been identified in many vectors including A. aegypti and Culex quinquefasciatus and involves activation of Toll, Imd, JAK-STAT, and RNAi pathways, which serve as defense system for controlling the infection (Gruber et al., 2008; Souza-Neto et al., 2009; Kerpedjiev et al., 2015).