Malaria spreads through the bite of an infected mosquito

You get malaria when a female mosquito carrying the malaria parasite bites you and injects the parasite into your bloodstream. Not all mosquitoes carry malaria—only certain species of Anopheles mosquitoes do, and only if they have previously bitten someone with malaria. The mosquito must be infected for you to contract the disease; you cannot get malaria from touching, breathing near, or sharing food with an infected person.

The parasite travels from the mosquito's saliva into your blood during the bite. Once inside your body, the parasite multiplies in your liver and then in your red blood cells, which is when symptoms begin. The entire process from bite to first symptoms typically takes 7 to 30 days, though in some cases it can take longer.

Key Takeaways

  • Malaria is transmitted only through bites from infected female Anopheles mosquitoes, not through person-to-person contact or contaminated food and water.
  • The mosquitoes that carry malaria are most active during dusk and nighttime hours and breed in standing water.
  • Malaria is found in tropical and subtropical regions, particularly in parts of Africa, Southeast Asia, and Central and South America.
  • Symptoms appear 7 to 30 days after infection and include fever, chills, headache, and muscle aches that may come and go in cycles.
  • Preventing mosquito bites through nets, insect repellent, and protective clothing reduces your risk significantly in areas where malaria occurs.

Where malaria-carrying mosquitoes live

Anopheles mosquitoes thrive in warm, humid climates and are found mainly in tropical and subtropical regions. Malaria is endemic—meaning it occurs regularly—in parts of sub-Saharan Africa, Southeast Asia, the Indian subcontinent, Central America, and South America. The risk varies by country, region, and even by season within a region.

These mosquitoes breed in standing water: marshes, swamps, rice paddies, slow-moving rivers, and even small collections of water in containers or plant leaves. They are most active during dusk and nighttime, which is when bites most commonly occur. During the day, infected mosquitoes rest in dark, humid places like caves, dense vegetation, or inside buildings.

How the parasite develops inside the mosquito

A mosquito becomes infected when it bites a person who has malaria parasites in their blood. The parasite enters the mosquito's stomach and begins to multiply. This process takes 7 to 14 days inside the mosquito, depending on the temperature and the type of parasite.

Once the parasite has multiplied enough, it moves to the mosquito's salivary glands. At this point, the mosquito can transmit malaria to the next person it bites. A single infected mosquito can bite multiple people over its lifetime, spreading the parasite to each one. The mosquito itself is not harmed by carrying the parasite and can remain infected for months.

Why only female mosquitoes transmit malaria

Only female Anopheles mosquitoes bite humans. Males feed on plant nectar and do not take blood meals, so they cannot become infected with malaria or transmit it. Female mosquitoes need blood protein to develop their eggs, which is why they seek out humans and animals to bite.

A female mosquito may bite multiple people during her lifetime, and each bite is an opportunity to pick up the parasite if she bites someone with malaria, or to transmit it if she is already infected. This is why controlling female mosquito populations is central to malaria prevention efforts in affected regions.

Risk factors that increase your chances of infection

Your risk of getting malaria depends on where you are, when you are there, and what precautions you take. People who live in or travel to malaria-endemic areas without protection face the highest risk. Infants, young children, and pregnant women are more vulnerable to severe malaria if infected. People with HIV or other conditions that weaken immunity also face higher risk of serious illness.

Spending time outdoors at dawn and dusk, sleeping without a bed net, wearing minimal clothing, and staying in accommodations without screens or air conditioning all increase your exposure to mosquito bites. Travelers from malaria-free regions who visit endemic areas have no immunity and face significant risk if they do not take preventive measures.

Rare transmission routes besides mosquito bites

Malaria can spread through routes other than mosquito bites, though these are uncommon. Blood transfusion from an infected donor, sharing needles with an infected person, or organ transplant from an infected donor can all transmit malaria. Pregnant women can pass malaria to their unborn child.

These non-mosquito routes account for a very small fraction of malaria cases worldwide. In countries with screened blood supplies and sterile needle programs, the risk from these routes is minimal. The overwhelming majority of malaria transmission occurs through mosquito bites in tropical regions where the disease is endemic.

What happens after infection

After a mosquito injects the parasite, it travels to your liver and multiplies for several days before entering your bloodstream and infecting red blood cells. This is when you develop symptoms: fever, chills, headache, muscle aches, and fatigue. Symptoms may come in cycles, with fever spiking and then dropping over hours or days.

Without treatment, malaria can cause severe complications including organ failure, severe anemia, and brain damage. The risk of death is highest in young children and pregnant women. Treatment with antimalarial medications is effective if started early, which is why recognizing symptoms and seeking medical care quickly matters.

Frequently Asked Questions

Can you get malaria from mosquitoes in the United States?

Malaria does not occur naturally in the United States. Anopheles mosquitoes that could carry malaria do not live in the U.S. climate. Rare cases have occurred in travelers returning from endemic regions, but these are isolated and do not lead to local spread.

How long does it take to get sick after a mosquito bite?

Symptoms typically appear 7 to 30 days after infection, though the range can extend to several months in some cases. This delay occurs because the parasite must multiply in your liver before entering your bloodstream. If you traveled to a malaria area and develop fever weeks later, mention the travel to your doctor.

Can you catch malaria twice?

Yes. Malaria infection does not create permanent immunity. People living in endemic areas may develop partial immunity over time, which reduces symptom severity, but they can still become reinfected. Travelers who have had malaria can contract it again if bitten by an infected mosquito.

Do bed nets really prevent malaria?

Bed nets, especially those treated with insecticide, significantly reduce the risk of mosquito bites during sleep when Anopheles mosquitoes are most active. Studies show they reduce malaria cases by 50 percent or more in areas where they are used consistently. They work best when tucked in properly and used every night.

What should you do if you think you have malaria?

Seek medical care immediately and tell your doctor about any recent travel to malaria-endemic areas. A blood test can confirm malaria within hours. Early treatment with antimalarial drugs is highly effective and prevents serious complications. Do not wait for symptoms to worsen.