[avium]

Not my area of expertise at all, but mosquitoes seem unique in nature in that they can pick up diseases from one animal and spread them to another by direct blood transfusion. I've long wondered if this might confer some kind of advantage to the animals being bit, perhaps along the lines of how vaccines work.

[zimpenfish]

Possibly also leeches - https://www.ncbi.nlm.nih.gov/pubmed/8073013

"many fish leeches directly transmit several blood parasites" "Consequently, the leech is a potential vector of many pathogens, especially in regions with an endemic spread of human and/or animal pathogens."