Malaria is one of the most dangerous tropical diseases and although it's not a threat everywhere, it's a potentially very risky disease for people who are travelling into a malaria area such as parts of Africa, Asia, Central America and South America. Provided a person takes preventative treatments and in general aims to avoid bites, it's highly unlikely that malaria transmission will occur, however it's important to understand the risks involved.
The Anopheles mosquito is one of the most common methods of malaria transmission, however, because the malaria parasite is present in red blood cells, it can also be transmitted via blood transfusion, organ transplant or through the sharing of needles, though this is much less likely to occur.
There is also the possibility of malaria transmission from a mother to her child during birth, something which is known as congenital malaria, but this is also much rarer than malaria transmission via mosquito bite from the Anopheles mosquito.
Generally a mosquito will bite a person that has a malaria parasite present in their red blood cells, thereby becoming infected with the parasite.
The malaria life cycle starts as soon as an infected Anopheles mosquito injects a person with one of the four types of plasmodium parasites that cause malaria. As soon as malaria transmission has occurred, the parasite enters the blood stream and travels to the liver, where it matures and starts infecting red blood cells, eventually causing them to burst, leading to a fever, chills and other flu-like symptoms associated with a malaria infection.
When the malaria parasite is in the red blood cells, it’s possible for the malaria parasite to be picked up by a parasite-free Anopheles mosquito, which means that the malaria transmission life cycle continues. Once inside the mosquito, the parasite matures and starts infecting the insect’s saliva glands, which becomes the primary way in which the malaria parasite is transmitted.
Ideally malaria transmission shouldn’t occur if you’ve taken the correct precautions but if transmission does occur, it’s important to seek treatment early on in the malaria life cycle, as certain parasites can cause serious complications.
After malaria transmission has occurred, a person isn’t likely to feel ill straight away. As part of the plasmodium parasite’s life cycle, it needs to mature before it’s likely to make a person feel ill. Malaria symptoms could start to appear as early as seven days after malaria transmission or it can take many years for the parasite to start making you feel unwell. However, it’s more likely to cause symptoms a couple of days or weeks after malaria transmission has taken place. The most serious type of plasmodium parasite, namely plasmodium falciparum, will usually start to cause symptoms within a week after transmission.