Malaria is a mosquito-borne disease caused by parasites of the plasmodium family. If left undiagnosed and untreated, malaria can be fatal.
Malaria parasites are carried in the saliva of female mosquitoes and are passed into the human bloodstream via a mosquito bite. Once in the bloodstream, parasites move toward the liver, where they grow and multiply in the liver cells. The parasites are then released back into the bloodstream in significantly higher numbers and continue to multiply inside the red blood cells until the cells explode. The parasites continue to invade the red blood cells, increasing in numbers as they do so.
It is the multiplication of parasites in the blood that causes symptoms of malaria. It is impossible to know if you have malaria immediately after being bitten by a mosquito, as it usually takes about 7 days for the parasites to begin rapidly multiplying in the blood.
According to the WHO, 216 million cases of malaria occurred in 2016, resulting in 443 000 deaths. These statistics do not take into account the many cases of malaria that go unrecorded.
There are five different types of malaria parasite. If you are travelling abroad and need to purchase antimalarial medication online, the type of medication you need will depend on which malarial parasite is prevalent in the areas you are visiting.
Plasmodium Falciparum is prevalent in sub-Saharan Africa and is the most dangerous malaria parasite. It is responsible for the majority of malaria deaths globally. The falciparum parasite has developed resistance to Chloroquine and, in some regions, Mefloquine. If travelling to these regions, you are advised to take Malarone instead.
Plasmodium vivax is the second most dangerous species and is particularly prevalent in Southeast Asia and Latin America. It is known for causing recurrent malaria, as it carries the added complication of a dormant liver stage which can be reactivated at any time.
Plasmodium ovale resides mainly in West Africa, but is also prevalent in the Philippines and Indonesia. It can also cause recurrent malaria for up to four years after the initial infection.
Plasmodium malariae is responsible for only a small proportion of infections and is less dangerous than the others. It is endemic to sub-Saharan Africa, Southeast Asia and parts of the West Pacific.
Plasmodium knowlesi primarily affects primates but has been known to lead to human malaria. It is prevalent in areas of Southeast Asia, including Malaysia, the Philippines and Indonesia.
Over 100 countries are classed as malaria hotspots. Malaria is particularly prevalent in:
The Middle East
Parts of Central and South America
It is vital to check with a doctor before buying antimalarial medication for travel to these areas, as different medications are more appropriate for different regions depending on the prevalent strain of parasite. Dr Felix offers a guide for malaria medication around the world.
It is important to be able to recognise the symptoms of malaria if you are travelling to areas where there is a high risk of contracting the disease. Initial symptoms of malaria tend to start 7 to 18 days after contracting the disease and include:
A high temperature of 38C or above
Feeling hot and shivery
Headaches and muscle pain
Vomiting and/or diarrhoea
Feeling generally unwell
Seek immediate medical attention if you develop any of these symptoms during or after a visit to a malaria zone. Symptoms can continue in bouts for months if left untreated. Some types of malaria parasites cause symptoms to occur in 48-hour cycles. With malarial parasites that can remain dormant in the liver, symptoms can take up to a year to develop.
The plasmodium falciparum parasite can act extremely quickly and lead to severe complications within days, or even hours, of infection. Complications of this type of malaria include:
Cerebral malaria (swelling of the brain)
Liver failure and jaundice
Swelling or rupturing of the spleen
Low blood sugar
Pulmonary oedema (a buildup of fluid in the lungs)
Sudden drop in blood pressure, resulting in shock
Acute respiratory distress syndrome (ARDS)
Symptoms of severe malaria need to be met with urgent medical attention and can include:
Yellowing of the skin and whites of the eyes
Blood in the urine
The WHO recommends that pregnant women avoid travelling to areas with a high risk of contracting malaria, as malaria of any strain can be dangerous for both mother and baby. Malaria during pregnancy can increase the risk of premature birth, low birth rate, restricted growth, stillbirth or miscarriage.
Malaria can be diagnosed with a blood test. If there is a possibility you have malaria, a blood test will be carried out immediately and the results processed on the same day.
Non-severe malaria can usually be treated at home with prescription-only antimalarials. The type of antimalarial used is dependent on the type of malaria, the severity of symptoms, where the malaria was caught, whether antimalarials were taken to prevent malaria and whether you are pregnant.
Severe malaria is treated in a hospital, as the patient will need to have their kidneys, lungs and blood sugar levels monitored. The standard treatment in the UK is a quinine injection into the bloodstream, followed by an antimalarial.
Before travelling to a region where malaria is known to be prevalent, it is important to be aware of the risk. You can take measures to avoid mosquito bites, including wearing long trousers and sleeves in the evenings and applying insect repellent to your skin. You can read up on how to avoid mosquito bites here.
Check with a doctor whether or not you need to take antimalarial medication and ensure you take them as instructed. Some preventative medications need to be started before your trip and continued after your return. Read more about the different types of antimalarial medication here.
NHS - Malaria: https://www.nhs.uk/conditions/malaria/
CDC - Malaria: https://www.cdc.gov/malaria/travelers/index.html
WHO - Malaria: http://www.who.int/ith/diseases/malaria/en/