Malaria is caused by a parasite called Plasmodium. This small single-cell organism invades the liver and metamorphoses so that it can burrow into red blood cells. The parasite then multiplies until the red blood cells burst, causing the host body (human or animal) to be assaulted by waves of fever as the body attempts to destroy the parasite. In some cases, the infected red blood cells become stuck in the arteries and veins of the head, leading to death. In the early 20th century, Robert Ross used Koch’s Postulates to prove that bird malaria was transmitted from bird to bird by mosquitoes. The next year, a team of Italian scientists showed that human malaria was also spread by mosquitoes, paving the way for a series of simple measures to interrupt the transmission of the disease, such as the use of bed nets and insecticides. But because the malaria parasite metamorphoses as it moves from the liver to the red blood cells, it has been difficult to develop a vaccine that will stimulate the host’s immune system into recognizing the two different forms of the parasite.
Even though scientists have not yet been able to develop a malaria vaccine, animal research has played an important part in developing drugs to treat malaria and helps scientists understand how to develop a vaccine for a parasite with two different forms. Dr. Nirbhay Kumar, professor in the Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, has been studying malaria using several animal model systems including chicken and rodent models of malaria, even though these animal malaria parasites cannot infect humans. Results from the research on these animal models allow him to understand how the parasite infects liver