Causes of malaria disease

After an infected mosquito bite, malaria parasites enter the bloodstream and affect red blood cells. Symptoms may include [Fever](/symptoms/fever/), [Chills](/symptoms/chills/), sweating, headache, tiredness, nausea and [Muscle Aches](/symptoms/muscle-aches/). Different parasite types can cause illness with different timing and severity. Malaria does not spread through ordinary casual contact, but infection can rarely be passed through blood exposure or from a pregnant person to a baby.

Symptoms after visiting or living in a malaria-risk area should not be dismissed as a routine viral illness. A [Blood Test](/treatments/diagnostics-and-screening/blood-test/) can help check for the parasite, and treatment depends on the species, illness severity and travel history.

Tell a clinician about every country visited, travel dates, mosquito bites, preventive medicine and when symptoms started. Seek medical advice promptly for fever after travel, even if you used bite prevention. A [Travel Health Consultation](/treatments/occupational-and-travel-medicine/travel-health-consultation/) before future trips can review personal precautions, while [Malaria Prophylaxis](/treatments/occupational-and-travel-medicine/malaria-prophylaxis/) may be appropriate for some itineraries.

Seek urgent care for fever with confusion, severe weakness, breathing difficulty, seizures, fainting, repeated vomiting, yellowing of the skin, dark urine or inability to drink. Malaria can worsen quickly, and symptoms may appear after you have left the exposure area.

Ask whether your travel history warrants malaria testing, when results should be repeated if symptoms continue, which treatment is appropriate, and how to prevent infection on a future journey.