Fresh Meat by Maeve Sleibhin

When Lola gets kicked off her professional soccer team due to excessive violence, she turns up at the door of her best friend, Jeremy, who is working at a health clinic in Old San Juan, Puerto Rico. She soon discovers that the town is being plagued by vampires who prey on the homeless, and Jeremy, along with the scantily-clad, crucifix-wearing, supervising physician, Lucia, have taken it upon themselves to stop them. As it turns out, Lola's blood is irresistible to both the mosquitos and the vampires that plague the island.