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Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Key concept
Malaria is caused by the protoctist Plasmodium, transmitted by the bite of an infected female Anopheles mosquito. The mosquito is the vector, not the pathogen. Plasmodium infects red blood cells and liver cells, causing recurring fevers. Prevention targets the mosquito vector through nets, insecticides and draining breeding sites.
Malaria is a named disease in the syllabus and a frequent exam topic. The most important distinction is between the pathogen (Plasmodium) and the vector (the mosquito). Many students lose marks by calling the mosquito the cause of malaria.
The transmission cycle
A female Anopheles mosquito bites an infected person and takes up Plasmodium parasites along with the blood meal. The parasites develop inside the mosquito. When the mosquito bites another person, it injects saliva containing Plasmodium into the blood.
In the human host, Plasmodium first multiplies in liver cells, then enters and reproduces inside red blood cells. The infected red blood cells eventually burst, releasing more parasites and toxins into the blood, causing the characteristic recurring fever and chills. The cycle repeats as new red blood cells are invaded.
Prevention strategies
Method
How it works
Insecticide-treated bed nets
Physical barrier prevents mosquito bites during sleep; insecticide kills mosquitoes on contact
Insecticide spraying
Kills adult mosquitoes in homes and surrounding areas
Draining stagnant water
Removes mosquito breeding sites where larvae develop
Antimalarial drugs
Kill Plasmodium in the body; used for treatment and short-term prevention for travellers
Biological control
Introducing fish that eat mosquito larvae into water bodies
Why malaria is difficult to eliminate
Malaria remains a major global health challenge because the parasite has a complex life cycle involving two hosts, making a single intervention insufficient. Plasmodium hides inside red blood cells, where antibodies cannot reach it easily. The parasite also changes its surface antigens, making vaccine development difficult.
Mosquitoes can develop resistance to insecticides, and Plasmodium can develop resistance to antimalarial drugs. Effective control requires a combination of strategies applied consistently over long periods, along with investment in healthcare infrastructure in affected regions.
Try a focused question (3 marks)
Describe the role of the mosquito in the transmission of malaria.
Show the answer and marking guidance
The female Anopheles mosquito acts as the vector, carrying the Plasmodium pathogen between human hosts.
It picks up Plasmodium when it feeds on the blood of an infected person.
It transmits Plasmodium when it bites and injects saliva into another person.
Original Cambridge-style practice written for this site. It is not an official Cambridge past-paper question.
Common mix-ups to avoid
Check these points against your own answer before moving on.
Calling the mosquito the pathogen: the mosquito is the vector; Plasmodium is the pathogen.
Saying malaria is caused by a virus or bacterium: it is caused by a protoctist.
Describing malaria as transmitted by any mosquito: only the female Anopheles species is the vector.
Forgetting that prevention includes draining standing water to remove breeding sites.