What it shows
Malaria is caused by a single-celled parasite, Plasmodium, that needs two hosts to complete its life: a human and a female Anopheles mosquito. This page draws the whole cycle as a loop, with the human side on the left and the mosquito side on the right. Tap a stage, or use Back and Next, to follow the parasite from one bite to the next:
- sporozoites enter with the mosquito’s saliva;
- they multiply in liver cells;
- merozoites invade red blood cells;
- the red blood cells burst together and release haemozoin: chills and high fever;
- some parasites become male and female gametocytes;
- a mosquito sucks them up with blood;
- the gametes fuse in the mosquito’s gut (fertilisation);
- the zygote forms an oocyst on the stomach wall, which makes thousands of sporozoites;
- the sporozoites move to the salivary glands, ready for the next bite.
A second card shows why the fever comes back in a rhythm: the red blood cells burst at about the same time, every 48 hours for P. vivax and every 72 hours for P. malariae.
It fits Class 12 Biology: human health and disease (common diseases in humans: malaria, the pathogen, its two hosts, symptoms and prevention). How the body fights back is in immune response timeline; the cells involved are drawn in cell explorer, and how a disease spreads through a whole town is in epidemic model.
How to use it
- Read stage 1, then press Next to move round the loop. The current stage turns red; its host and place are named under the picture.
- Tap any numbered circle to jump to it.
- In the fever card, switch between P. vivax and P. malariae and read the fever days.
Worked example
P. vivax: red blood cells burst every 48 hours. If the first attack of fever is on day 1, the next are 48, 96, 144 … hours later, so on days 1, 3, 5, 7, 9 and 11 in the first 12 days. That “every third day, counting the first” pattern is why it was called tertian fever. P. malariae bursts every 72 hours: days 1, 4, 7 and 10 (quartan fever).
Which host is which?
The parasite reproduces sexually (gametes fuse) only inside the mosquito, so the mosquito is the primary (definitive) host. In the human it only multiplies asexually, so the human is the secondary (intermediate) host.
Breaking the loop
Every stage is a chance to stop malaria: bed nets and repellents stop bites (stages 1 and 6), draining standing water and keeping fish that eat larvae (such as Gambusia) cut mosquito numbers, and treating patients removes the gametocytes that mosquitoes would pick up.
Check yourself
Five fresh questions: four on the cycle (chosen at random from a set) and one on the fever rhythm with new numbers. Nothing is saved.
FAQ
Do male mosquitoes spread malaria? No. Only females take blood meals, so only they pick up and pass on the parasite.
Is this medical advice? No. It is a simplified study diagram. Anyone with a fever in or after visiting a malaria area should see a doctor quickly.
Is this from my textbook? It covers the standard school topic with its own words and diagram. It is an independent study aid.
Where the numbers come from
- Standard school biology of malaria: the Plasmodium life cycle in humans (liver and red blood cell stages) and the female Anopheles mosquito (sexual stage), haemozoin and the fever rhythm (tertian 48 h for P. vivax, quartan 72 h for P. malariae). Written for fibub; no textbook text, figures or exercises are used; the diagram is drawn for fibub.
- A simplified teaching diagram, not medical advice. The fever rhythm days are checked by hand in the tests.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-09.