There are many types of mosquitoes but all of them are dangerous to man. There are a number of mosquitoes that can cause diseases such as dengue, malaria, chikungunya etc. in humans. They are simply vectors of the disease since they carry the parasite inside themselves without being affected by it. When they bite an infected human, the parasite enters their body and is then released into the next human they bite. The parasite enters the human, and multiples within him/her. This leads to different symptoms such as fever and shivering if it is malaria or joint pain if it is chikungunya.