Which term describes a mosquito species that transmits disease from infected birds to mammals (e.g., humans or horses)?

• A. Reservoir Host
• B. Pathogen
• C. Vector
• D. Bridge Vector

Answer: (D)

A bridge vector is the mosquito that transmits a pathogen from a reservoir host to a different host group, enabling spillover to mammals. Here, birds harbor the virus in nature (the reservoir), and certain mosquitoes feed on birds and then bite humans or horses, effectively moving the pathogen from birds to mammals. The term 'reservoir host' would refer to the birds themselves as the hosts that maintain the pathogen; 'pathogen' is the virus or agent; 'vector' is any organism that transmits the pathogen, but it doesn’t specify cross-species transfer. Therefore, describing this mosquito as a bridge vector best captures its role in linking bird reservoirs to mammalian hosts.