Plasmodium Vivax: Classification, Discovery, Morphology, Life Cycle, Treatment, and Prevention

Plasmodium Vivax: Classification, Discovery, Morphology, Life Cycle, Treatment, and Prevention


Phylum – Apicomplexa

Class – Sporozoa

Order – Haemosporidia

Genus – Plasmodium

Species – vivax


Malaria is caused by Plasmodium vivax, a human internal blood parasite. In Asia and Latin America, P. vivax is a serious infection. In 2006, it was projected that 3.3 billion people were in danger of contracting malaria, with at least 500 million infections and over a million deaths per year (WHO World Malaria Report, 2008). A person dies of malaria every 30 seconds on average. Currently, Africa accounts for almost 90% of all deaths, with young children being the most vulnerable.


Plasmodium was found in the blood of a malaria patient by Charles Laveran (1880). Ronald Ross, an Indian army doctor, found the Plasmodium oocyte in the gut of a female Anopheles mosquito in 1895.

Morphology of Plasmodium Vivax

In the peripheral smear, all the stages of the parasite are seen. These include the trophozoite form, shizoint form, and gametocyte form. The other developmental stages of the parasite occur in the endothelial lining of the venules in internal organs like the brain and kidneys.

The Ring form

A.The “Ring form” of an early trophozoite has reddish chromatin “dot” and a blue cytoplasm “ring.” It’s worth noting that infected red cells are larger than uninfected red cells. On the infected red cell membrane, Schuffner’s dots appear as small crimson spots.

(B) Growing trophozoite: “Amoeboid form” with “pseudopodia-like” cytoplasmic extension. Note infected red cell is larger than the uninfected red cell Schuffner’s dots appear as fine reddish dots on the infected red cell membrane

(C) Schizont

 (i) Immature schizont has 2-24 nuclei. Schuffner’s dots appear as fine reddish dots on the infected red cell membrane Infected red cells become irregular in shape and pale in color and enlarged

(ii) Mature schizont, containing 12-24 merozoites. Schuffner’s dots appear as fine reddish dots on the infected red cell membrane. Infected red cells become irregular in shape and pale in color and enlarged

D) Gametocyte form Gametocyte is round to oval in shape, cytoplasm in female is more bluish than that of male Female gametocyte has compact nucleus while in the male the nucleus is not compact.

Mode of Infection

When a female anopheles mosquito bites a healthy person to drink blood, the sporozoites (infectious stage) are injected into the human bloodstream along with the insect’s saliva. Thousands of sporozoites are introduced into human blood. Asporozoite is a sickle-shaped, tiny animalcule.

It has a body length of 14 inches and a width of 1 inch. A thin, elastic cuticle covers the body, giving it a distinct shape. In the absence of locomotory organelles, sporozoites glide. At the anterior ends, two secretory glands are thought to aid penetration into the cell.

Life Cycle

Plasmodium completes its life cycle inside the bodies of both male and female Anopheles mosquitoes. As a result, life follows a digenetic pattern. The major or definitive host is man, and the secondary or intermediate host or vector is the female anopheles mosquito.

To complete its life cycle, Plasmodium falciparum, the major pathogenic organism, requires both the Anopheles mosquito and humans. In the mosquito, the protozoan’s sexual cycle takes place. When a mosquito bites the skin to feed on man’s blood, the insect’s saliva contains immature sporozoites, which are passed to humans.

It is divided into 3 phases

(a) pre-erythrocytic schizogony,

(b) Exo-erythrocytic schizogony,

(c) Erythrocytic schizogony.

The infective stage is the sporozoite. An infected mosquito injects sporozoites into a man’s body while sucking blood. To continue pre- and exoerythrocytic schizogony, the sporozoites reach the liver.

The parasites enter the human body through the liver, reproduce, and then enter the bloodstream, where they attack red blood cells for their hemoglobin. The merozoites are released when red blood cells burst, allowing them to assault new red blood cells. When an RBC ruptures, a poison called haemozoin is released. This results in a high fever and a cold. A high number of merozoites are formed during these cycles. Every 48 hours, the erythrocytic cycle repeats, coinciding with the onset of malaria symptoms. The erythrocytic cycle produces certain merozoites that never assault fresh RBC. They are patiently waiting for the mosquito to be sucked. Some merozoites mature into sexually mature gametocytes, which are then passed on to another biting mosquito. The sexual cycle of the mosquito begins with gametocytes. Male and female gametocytes are the two types available. Inside the mosquito’s gut, they reproduce sexually.

In the body of a mosquito, the sexual phase of the life cycle takes place at a low temperature. The male or microgametocyte produces 4-8 microgametes after entering the mosquito’s stomach. Exflagellation is how this happens. Only one macrogamete is produced by the female or macrogametocyte. A zygote is formed when a microgamete and a macrogamete unite. The zygote produces an elongated ookinete that enters the mosquito’s gut wall. After that, the ookinete transforms into a spherical oocyst. To create sporoblasts, the oocyst splits. A huge number of sporozoites are produced by each sporoblast. This is referred to as sporogony. The sporozoites are injected along with the saliva when an infected mosquito bites a healthy male. The release of merozoites from red blood cells causes the fever cycles to occur every two or three days (Plasmodium falciparum) or three days (Plasmodium vivax).

Malaria affects mammals other than humans, including bats, rats, and primates, as well as birds and reptiles. Female Anopheles mosquitos are the only ones that feed on blood and hence transmit malaria. Males are unable to pass the sickness on to their female partners.


Malaria is characterized by a patient’s intermittent fever, chills, and rigors. The patient’s liver and spleen may be enlarged. Sporozoa of the genus Plasmodium, which cause malaria in humans, are amoeboid parasites that produce pigment. They can be found in red blood cells as well as hepatocytes. The parasite is spread through the bite of an infected female anopheles mosquito.

Genus Plasmodium: There are four species

(a) Plasmodium vivax

(b) Plasmodium falciparum

(c) Plasmodium ovale

(d) Plasmodium malariae

Types of Malaria:

Human malaria is caused by four Plasmodium species. Each species has its incubation period, recurrence period, and host-harming effects.

Benign Tertian Malaria

Malaria of the third stage is also known as tertian malaria. It’s known as Vivax malaria since it’s caused by P. vivax. In this case, the incubation period is 14 days, and the fever recurs every 48 hours or every third day. The death rate is minimal in this kind of malaria. The disease is found all across the world, however, it is most prevalent in temperate areas. In India, this is the most frequent kind of malaria.

Quartan Malaria

P. malaria is the cause of subclinical malaria. The incubation period, in this case, is 28 days, and the fever recurs every 72 hours or every fourth day. It is usually not lethal, and those who are left untreated can live a long and healthy life. It is widespread in tropical Africa, Sri Lanka, and Burma, but not so much in India.

Mild Tertian Malaria

P. ovale causes it, it’s also known as ovale malaria. Malaria of this sort is similar to tertian malaria. The incubation time is 14 days in this case, and the fever comes back every 48 hours or third day. Malaria is a rare disease that is mostly found in tropical Africa.

Malignant Tertian Malaria

Pernicious malaria, also known as Aestivo-automnal malaria, is caused by Plasmodium falciparum. The incubation period is 12 days, and the fever recurs every 48 hours or every third day. The death rate is higher in this case because the fever causes a variety of complications. Quotidian Malaria is a disease in which the fever recurs virtually every day due to several or mixed infections by more than one species of Plasmodium.


Malaria is resistant to vaccines and inoculations because the parasite does not generate antibodies or antitoxins in human blood. Quinine was formerly regarded to be a great antimalaria drug for eliminating schizonts, but it had a lot of disadvantages. Later, Atebrin and camoquin were used in Germany. Chloroquine, paludrine, plasmochin, resochin, and Daraprim are some of the most effective antimalaria drugs now available.


Malaria can be avoided by taking the following steps:

Use of drugs

Healthy people who live in disease-prone areas should take preventative medicines in tiny dosages regularly (Atebrine 0.1 gm per day, Chloroquine 0.15 gm once a week).

(i) Mosquito bite protection:

(a) Mosquito nets should be worn at all times of the day and night.

(b) Houses should be built on high, dry ground, away from marshy areas, with a strong drainage system.

(c) Mosquito repellants, mustard oil, and dimethyl carbamate should be administered to exposed areas with anti-mosquito cream (e.g. Odomus).

(d) Infection susceptibility can be reduced by eating well and limiting exposure to harmful environments.

Control Measures:

In India, malaria kills a considerable number of people each year.

 A. Nationwide initiative called NMEP (National Malaria Eradication Program) was initiated to control and eradicate malaria. Insecticides such as DDT, Gammaxene, Flit, Pyrethrum, and others are sprayed on adult Anopheles mosquitos to combat malaria.

(b) Mosquitoes can be driven out of the house or killed by fumigation, which involves the burning of sulfur, pyrethrum, tarcomphor, and other naptha derivatives to release poisonous fumes. The TIFA machine generates emissions in municipal areas.

c) In stagnant water, mosquito larvae and pupae develop. To eliminate breeding grounds, flooded regions, marshes, and stagnant water should be cleared. Clear the brush and shrubbery around the house.

(d) Killing aquatic larvae is less difficult than killing winged adults. By cleaning sewers, streams, and ditches, the larvae in stagnant waters are stopped from growing.

(e) The larvae population can be controlled by introducing mosquito larvae-eating ducks in ponds, ditches, and tanks, such as Gambusia, Goldfish, Sticklebacks, Minnows, Trouts, and so on. Biological control is the term for it.

(f) Mosquito larvae can be killed by spraying oil solutions or emulsions containing DDT, DDD, or Benzene hexachloride.


Question: Which class belongs to Plasmodium?

Ans: Sporozoa

Question: Which disease causes Plasmodium?

Ans: Malaria

Question: What is the Common name of Plasmodium Vivax?

Ans: Malaria parasite

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