Mosquitoes vector many dreadful human diseases. None has a greater impact on people than malaria. Among infectious diseases, malaria is the number one cause of death world wide killing over 2 million people every year, many of them young children. In some areas of the world, up to 40 percent of toddlers have died from malaria. Recently, a number of governments and NGOs have intensified programs to fight malaria.
Malaria is a plasmodium, a single cell eukaryotic organism, that reproduces in both mosquitoes and humans. To successfully reproduce, the plasmodium must evade detection by the host immune system. Humans can develop immune responses to protect against diseases by attacking and eliminating the disease organism. Our immune response works by immune cells that recognize proteins on the outside of the disease organism and recruit other immune cells to attack the foreign invader. Vaccinations work by challenging our immune system with proteins from the disease organism. Our immune system recognizes the protein as foreign and multiplies the number of immune cells that can recognize that foreign protein. If we do suffer an infection by the disease, our immune system is then primed to attack the disease agent and stop it.
The malaria plasmodium, however, is constantly changing the proteins on its coat. An immune system can develop a response to a protein on the plasmodium, however, that protein will undergo change so that the immune system no longer recognizes the plasmodium. Thus, the malaria plasmodium is able to escape detection by immune systems and cause disease. The rapid modification of coat protein makes developing a vaccine difficult. A vaccine that causes the immune system to recognize a protein will soon be out of date and no longer work because the protein will change and no longer be recognizable.Today, (Oct 18, 2011), results from trials of a new vaccine were reported. The vaccine is about 56 percent effective in preventing malaria. This is another tool to fight malaria, but ideally a vaccine would be over 90 percent effective. Reducing the incidence of malaria is important to eliminating the disease. Other measures to fight malaria such as bed nets to reduce transmission by mosquitoes and pesticide treatments to kill mosquitoes will continue to be important. Together, these measures will reduce the suffering caused by malaria and move forward our attempts to eliminate the disease.