If you are traveling to almost any tropical country these days it is likely you will need to protect yourself against malaria. This is a disease which was supposed to have been eradicated by now but instead is on the increase. Resistant forms of malaria have now spread to most of the developing world.
Malaria is a disease spread by the bite of an anopheles mosquito.
These mosquitoes are more common in open, rural areas and usually bite at night. It goes through some reproductive stages and then emerges to invade the red blood corpuscles. These are soon destroyed by the parasites, leading to anemia and clogging up small blood vessels. Even if the body manages to destroy these parasites a new batch is forming in the liver, soon to be released to start the process all over again. Even weeks after a bout of malaria is successfully treated the parasites which have been hiding in the liver may emerge again.