Progress in the research of parasitic protozoan virus.
The virus parasitic in the parasite is parasitic virus. This phenomenon is hyper parasitism. Because of the presence of viruses, parasites change their invasions by carrying them. Some parasites increase the ability to infect the host, while some weaken the ability to infect the host. Some parasites also prolong the infection period because of the presence of viruses. There is not much of this kind of research at present. In this paper, the characteristics of parasitic protozoan virus, the influence of viruses on the infection of parasites and the use of parasitic protozoan viruses as vector are reviewed.