From an infection control perspective, it is important to recognize that cryptic transmission cycles of tick-borne pathogens maintained by nidicolous ticks have substantial human and veterinary health risk implications when sympatric exophilic tick vectors act as a bridge to potentiate human or livestock infections.
Rather, people acquire the disease when some other mosquito, known as a bridge vector, bites an infected bird and then bites a person.
Furthermore, this finding could support the ability of Ae. albopictus mosquito to serve as a bridge vector, capable of mediating the spillover of a virus from rural-cycle to urban-cycle, role already suggested for this species in regard to other viruses, including WNV [34], [35].
This finding suggests that this species may act as a bridge vector for exchange between forest and peridomestic habitats.
Although Cs. melanura mosquitoes feed infrequently on mammals (10, 12, 15 ), their ability to serve as a bridge vector may be offset by a much higher prevalence of EEEV infection in this species.
At least one species of flea ectoparasite (Orchopeas howardii) of flying squirrels is known to opportunistically bite humans and could serve as a bridge vector for transmission from flying squirrel to human.
This finding suggests that Oc. canadensis mosquitoes may be a bridge vector in Connecticut, but its relative contribution appears to be minor when virus titers in field-collected mosquito pools are considered.
Fonseca et al. [ 4] have shown that hybrids between two different forms in the Culex pipiens complex, probably introduced in the United States at two different moments, may act as a bridge vector between birds and humans of the West Nile virus, contributing to the current epidemics.
Mosquitoes that feed on both birds and mammals are referred to as bridge vectors for WNV because they act as a "bridge" between an infected reservoir (birds) and mammalian incidental hosts which do not develop sufficiently high viremia to support transmission to mosquitoes [ 110, 111].
In the first step, a bridge PCR is performed to produce a long fragment fusing the insert of choice with the desired vector.
