Malaria is not contagious from person to person through casual contact, like touching or sharing food, nor is it sexually transmitted. Instead, its transmission relies on a specific biological vector.
How Malaria Spreads
Malaria spreads primarily through the bite of an infected female Anopheles mosquito. When a mosquito bites an infected person, it ingests Plasmodium parasites from their blood. These parasites then develop and multiply within the mosquito.
After about a week, the infected mosquito can transmit the parasites to another human during a blood meal. The parasites, called sporozoites, enter the bloodstream and travel to the liver. In liver cells, they mature and multiply, typically without causing symptoms during this initial phase.
These mature parasites, called merozoites, then leave the liver and invade red blood cells, where they multiply. This multiplication in red blood cells leads to malaria symptoms. While mosquito bites are the main route, malaria can also rarely be transmitted through blood transfusions, organ transplants, or from a mother to her unborn child during pregnancy or delivery.
Recognizing Malaria
Malaria symptoms often begin with a flu-like illness, including fever, headache, and chills. Other common signs include muscle aches, fatigue, nausea, vomiting, diarrhea, and abdominal pain. Some people experience cyclical “attacks” of shivering and chills followed by high fever and sweating.
Symptoms typically appear between 10 days and 4 weeks after the mosquito bite, though they can be delayed for months or even years, depending on the Plasmodium species. Early diagnosis is important because untreated malaria, especially that caused by Plasmodium falciparum, can rapidly progress to severe illness and death. If these symptoms develop, particularly after travel to a region where malaria is common, seek immediate medical attention. Diagnosis is confirmed through blood tests.
Protecting Against Malaria
Preventing mosquito bites is a primary method for protection against malaria. Using insecticide-treated bed nets while sleeping offers significant protection, especially where mosquitoes are active at night. Applying insect repellents containing DEET or picaridin to exposed skin is also effective. Wearing long-sleeved clothing and long pants, particularly from dusk to dawn when Anopheles mosquitoes are most active, adds another layer of defense.
For individuals traveling to high-risk malaria areas, antimalarial prophylactic medications are recommended. These medications, such as atovaquone-proguanil, doxycycline, or mefloquine, are taken before, during, and for a period after leaving the malaria-endemic region to prevent parasite multiplication. Malaria is a treatable disease, and early, appropriate treatment with antimalarial drugs is important to prevent complications.