We have now observed the Anopheles mosquito from egg to larva, through metamorphosis, and into adulthood. We’ve seen how she mates, feeds, and searches for the nutrients she needs to lay eggs. But when a female mosquito bites someone infected with malaria, the story takes on global public health significance.

This final article in the series summarises in a simplified manner how malaria parasites are picked up by mosquitoes, how they quietly develop inside them, and how transmission to humans occurs, thereby completing the deadly cycle.

Step one: The mosquito takes an infected blood meal

When a female Anopheles mosquito bites a person carrying the malaria parasite (Plasmodium), she may ingest parasite forms along with the blood. These parasites don’t harm the mosquito, but they begin a crucial transformation within her body. Not all mosquito species can support this process. Only certain types (as mentioned in the first article) can serve as malaria vectors, meaning they allow the parasite to survive and eventually become infectious.

The parasite gametocytes travel to her midgut, where they begin their own complex journey of development. During this step, the mosquito is not yet infectious.

Step two: What happens inside the mosquito?

Inside the mosquito’s midgut, the malaria parasites begin to develop. They multiply and mature slowly over the next 10 to 14 days inside the mosquito, depending on temperature and humidity,  to develop into sporozoites. Eventually, the infectious stage of the parasite travels to the mosquito’s salivary glands. Now, the mosquito is ready to transmit malaria with her next bite, even though she shows no signs of infection herself. But from that moment on, every blood meal she takes carries the risk of passing the parasite along to another person, and the disease with it.

Step three: Transmission to a new host

During her next blood meal, the mosquito injects a small amount of saliva into the skin to prevent clotting. It’s in this saliva that the parasites are delivered directly into the human bloodstream. From there, the malaria parasite begins its human phase, heading first to the liver, then re-entering the bloodstream to infect red blood cells. This is what causes the symptoms of malaria: fever, chills, sweating, and in some cases, severe complications or death. With that one single bite, the mosquito has done her part to keep malaria going, and she may do so again with every future meal.

Why this matters

Understanding the mosquito’s biology helps us understand how malaria spreads and, most importantly, how it can be prevented. Every step in the mosquito’s life offers a chance for intervention; from keeping water containers covered, to using bed nets, to targeting mosquitoes with insecticides. But it’s in this final stage, when a mosquito becomes infectious, that the stakes are highest. Because once the parasites are in her 'saliva', every bite becomes a risk. Every bite is a moment of transmission. Therefore, the best way to avoid getting malaria is to avoid being bitten. It takes one bite!

Here are some simple tips to reduce the risk:

• Stay indoors between dusk and dawn when mosquitoes are most active.
• If you need to go out at night, wear long-sleeved clothing.
• Avoid dark colours, as they attract mosquitoes.
• Use insect repellent on exposed skin (look for one with DEET or dimethyl phthalate).
• Stay in a solid, well-maintained building in the safest part of town.
• Make sure windows and doors are fitted with screens.
• Use mosquito sprays, insecticide dispensers, or burn mosquito coils at night.
• Sleep under insecticide-treated bed nets.

Taking prophylaxis when traveling to a malaria-endemic area is recommended. Ask your healthcare provider about the best options, but keep in mind that malaria can still be contracted even if you take these measures. Pregnant women and parents travelling with young children should carefully consider the risks before deciding to travel or bringing their children along.Ask your healthcare provider about the best options, but keep in mind that malaria can still be contracted even if you take these measures. Pregnant women and parents travelling with young children should carefully consider the risks before deciding to travel or bringing their children along.

Thank you for joining us on this journey through the remarkable and often underestimated life of the malaria mosquito. From its quiet beginnings on land, through its hidden development in water, and finally back to land as an airborne vector of disease, we’ve explored how each stage plays a role in the fight against malaria using control interventions. Hopefully this series has deepened your understanding of how one small bite can ripple into a major public health challenge, and why breaking that chain of infection matters now more than ever. In the next article series, we will learn more about the parasite life cycle in a similar fashion, tracing its path from human to mosquito and back again.

Click here to read the entire series.