Plasmodium is a parasite protozoan which causes malaria in human beings. The primar host of it is female Anopheles mosquito Technically the primary host of a parasite bean sexual cycle of the parasite and secondary host bears asexual cycle of the parasite. So, sexual cycle of Plasmodium is taken place in mosquito (i.e., primary host) and asexual cycle is completed in man (i.e. secondary host).