The mutants will be created one day in a top-secret lab on one of the islands in the Carribean. Nobody knows much about the experiment except the scientists who participated in it. The mosquitos will then take over the entire island, making it their Hive and killing all of the scientists except for two.
Like an ordinary mosquito, but has the ability to suck up three times more blood than the average. They will also grow larger in size and have crab claws instead of front legs. However, they are 'allergic' to a special kind of antidote which has fortunately been experimented on the two scientists who survived. They aren't that smart. The Queen, however, is as smart as a teenager human and is gigantic.
The mosquitoes swarm the world, killing of many people until the scientists mass-produce the cure and insert it into many people. However, many more will have died before the remaining population of the world gets the antidote. This goes on for 4 months. Then it is discovered that the mosquitos share a collective mind.
A group of brave soldiers put together by all the nations of the world go to the Hive and kill the Queen. Out of the 200 soldiers sent, less than 50 managed to live to tell the tale. After the death of the Queen, all the mosquitos instantly died.