What Is Malaria?
A potentially fatal mosquito-borne disease caused by Plasmodium parasites.
Pathogen: Plasmodium falciparum, P. vivax, P. ovale, P. malariae, P. knowlesi (protozoan parasites)
Type: Parasite
Transmission
Bite of infected female Anopheles mosquitoes, mainly between dusk and dawn. Can also be transmitted via blood transfusion, organ transplant, or from mother to baby.
Vector: Anopheles mosquitoes (most active between dusk and dawn)
Symptoms
Initial symptoms include fever, chills, sweats, headache, muscle pain, nausea, and fatigue. Can progress to severe anaemia, respiratory distress, cerebral malaria (seizures, coma), organ failure, and death if untreated.
Incubation period: 7 – 30 days
P. vivax and P. ovale can relapse months or years later from dormant liver stages (hypnozoites). P. falciparum typically 9-14 days; P. vivax 12-17 days.
Timeline: Symptoms typically appear 7-30 days after an infective bite. P. falciparum can progress to severe disease within 24-48 hours of symptom onset.
Case fatality rate: P. falciparum: <0.5% with prompt treatment, up to 20% if untreated or treatment delayed. Other species rarely fatal.
Diagnosis & Treatment
Diagnosis: Thick and thin blood films (gold standard), rapid diagnostic tests (RDTs). Blood films should be repeated every 12-24 hours if initially negative and malaria is suspected.
Treatment: Artemisinin-based combination therapy (ACT) for P. falciparum. Chloroquine for P. vivax in sensitive areas. Primaquine for P. vivax/ovale radical cure to eliminate liver hypnozoites. IV artesunate for severe malaria.
Prevention
- Antimalarial prophylaxis (atovaquone-proguanil, doxycycline, or mefloquine)
- DEET-based insect repellent (20-50% concentration)
- Insecticide-treated bed nets
- Long sleeves and pants at dusk and dawn
- Mosquito coils and plug-in repellents
- Avoid outdoor exposure between dusk and dawn where possible
💉 Vaccine Status
There is currently no vaccine available for Malaria in Australia for travellers. Prevention relies on avoiding exposure.
Post-Exposure
Any fever during or after travel to a malaria-endemic area (even up to 12 months later) requires urgent medical assessment including malaria blood films. Tell the doctor about your travel history immediately.
Long-Term Effects
P. vivax can cause recurrent episodes for years if not treated with primaquine. Cerebral malaria survivors may have persistent neurological deficits. Chronic infection can cause severe anaemia and splenomegaly.
📋 Malaria is a nationally notifiable disease in Australia. Approximately 400-500 cases are notified annually, almost all acquired overseas.
Frequently Asked Questions
Can you get malaria in Bali?
Malaria risk in Bali is negligible. The main tourist areas of Bali, including Kuta, Seminyak, Ubud, and the Gili Islands, are considered malaria-free. However, malaria is present in some eastern Indonesian provinces including Papua and Nusa Tenggara. Antimalarial prophylaxis is generally not needed for Bali but should be discussed with a travel doctor if visiting rural eastern Indonesia.
Do I need malaria tablets for Thailand?
Most tourist areas in Thailand, including Bangkok, Chiang Mai city, Phuket, and Koh Samui, are malaria-free. Antimalarial prophylaxis is recommended only for travellers visiting forested border areas with Myanmar, Cambodia, or Laos, particularly in Tak, Trat, and other border provinces. Consult a travel doctor for your specific itinerary.
What are the first symptoms of malaria?
The first symptoms are often non-specific and can be mistaken for the flu: fever, chills, sweats, headache, muscle aches, nausea, and tiredness. Symptoms may come and go in cycles. Any fever within 12 months of returning from a malaria-risk area should be treated as a medical emergency until malaria is ruled out by blood tests.
How long after being bitten do malaria symptoms appear?
Symptoms typically appear 7-30 days after an infective mosquito bite, though the most dangerous species (P. falciparum) usually causes symptoms within 9-14 days. P. vivax can remain dormant in the liver and cause symptoms months or even years after exposure.
Is there a malaria vaccine?
The RTS,S/AS01 (Mosquirix) vaccine was recommended by the WHO in 2021 for children in high-transmission areas of sub-Saharan Africa. A newer vaccine, R21/Matrix-M, was prequalified by WHO in 2024. However, these vaccines are designed for young children in endemic regions and are not currently available or recommended for adult travellers. Antimalarial tablets remain the primary prevention for travellers.
Which antimalarial is best for me?
The three main options are atovaquone-proguanil (Malarone), doxycycline, and mefloquine. Malarone is well-tolerated with few side effects but more expensive. Doxycycline is affordable but causes sun sensitivity. Mefloquine is taken weekly but can cause neuropsychiatric side effects in some people. A travel doctor will recommend the best option based on your destination, trip length, medical history, and budget.
Can I still get malaria if I take antimalarial tablets?
Antimalarial prophylaxis significantly reduces your risk but is not 100% effective. You must combine tablets with bite-prevention measures: DEET repellent, treated bed nets, and covering up at dusk and dawn. If you develop a fever during or after your trip, seek medical attention immediately and mention your travel history, even if you took prophylaxis.
Do I need malaria prevention for Kenya or Tanzania?
Yes. Malaria is widespread in Kenya and Tanzania, including in popular safari areas and coastal regions like Mombasa, Zanzibar, and the Serengeti. Antimalarial prophylaxis is strongly recommended for all travellers to these countries. Nairobi has low risk due to its altitude but brief transits aside, prophylaxis is still generally advised.
Sources & References
Last updated: April 2026