1. Life cycle of malarial parasite
PLASMODIUM

2. Plasmodium is a genus, belonging to the parasitic group of
protozoa. At present, more than 200 species of this genus are
identified, out of which about 10 species infect humans. Among
several species, Plasmodium falciparum is reported to cause
maximum health complications and mortality in humans. Acute
plasmodium infections, if left untreated, can progress to life-
threatening conditions, whereas chronic infections can lead to
severe anemia. It also infects animals like rodents, monkeys as
well as birds. Plasmodium requires two hosts to complete its life
cycle, namely, a mosquito vector and a vertebrate host. Extensive
studies have been conducted on P. falciparum, as this protozoa
causes malaria. Let's discuss in brief about the life cycle of P.
falciparum.

3. The Vertebrate Stage: Initial Infection
There are two distinct phases within the
vertebrate stage; the hepatic phase and the
blood phase. When a mosquito carrying the
disease bites a host, sporozoites enter into the
bloodstream.
The Hepatic Phase
Sporozoites infect liver cells and mature into
capsules called schizonts. These eventually
rupture to release merozoites, which continue to
multiply in the liver.

4. The Blood Phase
Merozoites eventually infect red blood cells where
they become trophozoites. These will then mature
into schizonts that will rupture, releasing more
merozoites. This process will continue repeatedly.
Some trophozoites mature into gametocytes that will
eventually be ingested by a mosquito.

5. The Mosquito Stage: Infection
Within the mosquito, male and female gametocytes
combined to form zygotes. These mature into mobile
ookinetes that move to the mosquito's midgut and develop
into a oocysts. The oocysts than grow and
rupture, releasing sporozoites.
The Mosquito Stage: Transmission
The sporozoites travel to the mosquito's salivary
glands, where they will wait until the mosquito bites a
host. The sporozoites are transmitted to the host through
the mosquito's saliva, restarting the life cycle.