the infective stage of malarial parasite plasmodium that enters human body is
Plasmodium The life cycle of Plasmodium involves several distinct stages in the insect and vertebrate hosts. In infected mosquitoes, parasites in the salivary gland are called sporozoites. When the mosquito bites a vertebrate host, sporozoites are injected into the host with the saliva. From there, the sporozoites enter the bloodstream and are transported to the liver, where they invade and replicate within hepatocytes. At this point, some species of Plasmodium can form a long-lived dormant stage called a hypnozoite which can remain in the liver for many years.[2] The parasites that emerge from infected hepatocytes are called merozoites, and these return to the blood to infect red blood cells.
Trematode life cycle stages The life cycle of a typical trematode begins when the egg is immersed in water or from the adult worms in the definitive host. Some trematode eggs hatch in water, others are eaten by the first intermediate host and hatch within that host, so there are many different routes that a trematode could take to infect a host. Following this, the miracidium, which is free-swimming ciliated larva that a parasite moves from the egg to host stage, hatches which then also goes to find the mollusc host as the first intermediate host. This is where either a rediae or sporocyst will form depending on the host and if there is competition between the two. This eventually forms into a motile cercariae. The cercariae then either infects vertebrates through the skin of a host or is ingested and aims to locate the second intermediate host. When in the vertebrate host, the cercariae can then form into an adult, metacercariae or mesocercariae, depending on the life cycle, or is rejected through feces or urine. Then the metacercariae and second intermediate host has to be ingested by the definitive host for the life cycle to be completed.[1]