Malaria spreads through the bite of an infected mosquito, not through contact with a sick person

You catch malaria when a female Anopheles mosquito bites you and injects parasites into your bloodstream. The mosquito must be infected with the parasite already—she picked it up from biting someone else who had malaria. The parasite then travels to your liver, multiplies, and eventually enters your red blood cells, where it causes the fever and chills you recognize as malaria.

This is why malaria does not spread person-to-person through coughing, touching, or sharing food. You cannot catch it from someone sitting next to you on a bus or from a family member in the same house. The mosquito is the only bridge between an infected person and a new person who gets sick.

Not all mosquitoes carry malaria. Only certain species of Anopheles mosquitoes—and only the females—bite humans and can transmit the parasite. These mosquitoes are found in tropical and subtropical regions, mainly in Africa, Southeast Asia, and parts of South America and the Pacific.

Key Takeaways

  • Malaria spreads only through the bite of an infected female Anopheles mosquito, never through contact with a sick person.
  • The mosquito must already carry the parasite before she bites you; she acquired it from biting someone else with malaria.
  • Anopheles mosquitoes are most active at dusk and during the night, which is when most malaria transmission happens.
  • You are at highest risk in areas where malaria is common, and risk depends on which parasite species is circulating there.
  • Preventing mosquito bites through nets, screens, and insect repellent is the most direct way to avoid infection.

Why only female mosquitoes transmit malaria

Female Anopheles mosquitoes bite because they need blood protein to develop their eggs. Males do not bite at all—they feed only on plant nectar. When a female bites a person who has malaria, she ingests parasites along with the blood. The parasites survive in her gut and eventually reach her salivary glands, where they wait to be injected into the next person she bites.

This process takes 7 to 30 days inside the mosquito, depending on the temperature and which parasite species it is. During this time, the mosquito is infected but shows no sign of illness. She simply goes on biting other people, passing the parasite along.

Once a female mosquito is infected, she stays infected for life. She can transmit malaria to every person she bites from that point forward.

When and where mosquitoes bite

Anopheles mosquitoes are most active between dusk and dawn. They rest during the day in dark, humid places—inside houses, in vegetation, or in animal shelters. This nighttime feeding pattern is why sleeping under a bed net is one of the most effective ways to prevent malaria in areas where the disease is common.

The mosquitoes that transmit malaria live in warm climates. They thrive in standing water—marshes, rice paddies, slow-moving streams, and even small pools that collect after rain. In cooler regions or during winter months, the parasite cannot complete its development inside the mosquito, so transmission stops.

This is why malaria is concentrated in Africa (which accounts for the majority of cases worldwide), parts of Asia, and parts of Central and South America. Travelers from these regions carry the parasite in their blood, but they cannot transmit it in places where Anopheles mosquitoes do not live.

How the parasite develops inside you

When an infected mosquito bites you, she injects parasites called sporozoites directly into your bloodstream. These parasites are microscopic and travel quickly to your liver, where they hide and multiply for 7 to 30 days. During this time, you feel nothing—you have no symptoms.

After multiplying in the liver, the parasites burst out and invade your red blood cells. This is when symptoms begin: fever, chills, headache, and muscle aches. The fever spikes as parasites break out of cells in waves, which is why malaria fever often comes and goes in cycles.

If the infection is not treated, the parasites can damage your organs, especially your brain and kidneys. In severe cases, malaria can be fatal. Treatment with antimalarial drugs kills the parasites at different stages of this cycle, depending on which drug is used.

Risk factors that increase your chances of infection

Your risk of catching malaria depends on where you are and how long you stay there. People who live in areas where malaria is common are bitten repeatedly and may develop partial immunity over time, though they can still get sick. Travelers from malaria-free regions have no immunity and face higher risk even during short visits.

Pregnancy increases risk of severe malaria, and malaria in pregnancy can harm the developing baby. Young children under five are also at higher risk of severe disease. People with HIV or other conditions that weaken immunity face worse outcomes if they catch malaria.

The specific parasite species circulating in an area also matters. Plasmodium falciparum causes the most severe disease and is responsible for most malaria deaths. Plasmodium vivax and Plasmodium ovale can cause relapses months or years later if not treated completely. The type of mosquito and parasite present varies by region.

How mosquito behavior affects transmission

Some Anopheles mosquitoes bite indoors and rest indoors after feeding—these are called endophilic. Others prefer to bite outdoors and rest outdoors—these are exophilic. This behavior matters for prevention: bed nets work well against endophilic mosquitoes but are less effective if the mosquitoes in your area bite outside.

Mosquito behavior also changes with the season and with rainfall. In dry seasons, mosquitoes may disappear entirely because standing water dries up. In rainy seasons, populations explode. This is why malaria transmission is seasonal in some regions and year-round in others.

Insecticide resistance is also changing transmission patterns. In some areas, mosquitoes have developed resistance to the insecticides used on bed nets and in indoor spraying, making them harder to control. This is an ongoing challenge for malaria prevention programs.

Frequently Asked Questions

Can you catch malaria from someone's blood or saliva?

No. Malaria parasites cannot survive outside the mosquito and human body. You cannot catch malaria from touching blood, sharing utensils, or any other direct contact with a sick person. The only way the parasite reaches your bloodstream is through a mosquito bite.

How long after a mosquito bite do symptoms appear?

Symptoms usually appear 7 to 30 days after infection, though in some cases it can take months. During this time, you may feel fine and have no idea you are infected. This is why travelers from malaria regions are sometimes screened for the parasite even if they feel well.

Can you catch malaria twice?

Yes. Catching malaria once does not make you immune for life. People in malaria-endemic areas can be infected multiple times. However, repeated infections do build partial immunity, which is why children who grow up in these areas tend to have less severe disease as adults.

What if a mosquito bites you but is not infected?

You will not catch malaria. The mosquito must already carry the parasite for transmission to happen. A bite from an uninfected mosquito causes only the normal itching and swelling, with no risk of malaria.

Can malaria spread through pregnancy or breastfeeding?

Malaria parasites can cross the placenta and infect a developing baby, but this is not the same as the baby catching malaria from the mother through normal contact. Breastfeeding does not transmit malaria. The main risk is that pregnancy weakens immunity and allows the infection to become more severe in the mother.