|MadSci Network: General Biology|
It looks like the second part of your question got chopped off, so I'll just answer the first part. I looked in a variety of texts, and most were very unhelpful, merely stating that mosquitos inject saliva. "The Science of Entomology", by Romoser and Stoffolano, 1998, went a bit further. The major problems mosquitos face are blood coagulation, platelet aggregation, and vessel constriction. They have produced a variety of salivary secretions to overcome these host responses. The book mentioned only a few, including prostaglandins and nitrovasodilators to keep blood vessels open, and an enzyme called salivary apyrase to prevent platelet aggregation. Interestingly, some disease organisms interfere with this system for their own benefit. The critter that rides inside mosquitos and carries bird malaria reduces the mosquito's production of apyrase. This causes the mosquito to bite a bird longer, giving the parasite a better chance of moving from the mosquito to the bird!
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