Mosquitoes are responsible each year for more than a million human deaths in tropical regions. To make matters worse, mosquitoes are gradually evolving a resistance to pesticides. Thus a new sense of urgency surrounds the need to combat the spread of malaria. On the scientific horizon are plans to create genetically altered mosquitoes that eliminate the microscopic parasites that cause malaria. The life cycle of the malaria parasite in mosquitoes and humans is well known.
Female mosquitoes require blood for egg development.
Faster than a human immune system can respond to the invasion, the parasites move quickly to the liver where they begin to rapidly multiply, producing millions within days. The parasites then invade the blood cells. Once in the blood, the malaria parasites produce structures that actually keep infected blood cells from passing through the spleen where they would be eliminated. Malaria causes anemia because the parasites can eventually occupy more than half of the blood cells, which are no longer effective at carrying oxygen or performing their other functions. The characteristic symptoms of fever and chills occur during another stage, when the parasites rupture the blood cells.