Malaria

Malaria – life cycle

Malaria is caused by a parasite – a protozoan called Plasmodium. The parasite is carried by a vector – a species of mosquito called Anopheles.

When an infected mosquito bites, saliva containing Plasmodium enters the body. Plasmodium are carried in the bloodstream to the liver, where they invade liver cells and reproduce asexually. At about eight days after infection, the liver cells burst, releasing millions of Plasmodium into the bloodstream where they invade the red blood cells.

Malaria – life cycle

Plasmodium reproduces asexually inside the red blood cells.

Plasmodium make you ill about 10-15 days after infection, when they burst out of the red blood cells and release a chemical that causes fever.

The Plasmodium is then free to invade more red blood cells. A person may have many bouts of malaria fever.

Malaria – life cycle

If the person gets bitten by another mosquito, the mosquito takes up the infected blood.

In the mosquito’s stomach and the male Plasmodium gametes fertilise the female gametes to produce zygotes (sexual reproduction).

The zygotes invade the mosquito’s gut wall and reproduce asexually. Their life cycle begins again, when they are injected into another human host.

Malaria - drugs

Prophylactics are drugs that you can take to prevent malaria, and will stop you from getting it, even if you are infected with Plasmodium.

These drugs are variations of the drug, quinine. The most common prophylactics were chloroquine and proguanil, but many Plasmodium are now resistant to these. These days, mefloquine (Larium)or Malarone are used.

Malaria - prevention

Nine people in the UK died of malaria in 2002, and 16 in 2003. This is because they did not think about malaria before they went on holiday and took no precautions!

Precautions include; taking prophylactics, sleeping under a mosquito net, wearing insect repellent containing DEET (an insecticide), wearing long sleeved tops, wearing long skirts or trousers.