The Baltimore Zoo is located in Druid Hill Park, a green oasis in the midst of a concrete desert. But the large colony of penguins living at the zoo must cope with a bloodthirsty adversary capable of transforming this oasis into an intensive care unit: the plasmodium-laden mosquitoes that infest the park and transmit a deadly strain of malaria. “This is a problem in zoos throughout North America,” says Dr. Thaddeus Graczyk, Associate Research Professor in the Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health. “This is a huge problem for the zoo because there is very high mortality among the newly hatched and juvenile penguins.” The penguins hatch in winter and are still young and vulnerable in May or June, when the mosquitoes in Baltimore begin to bite. “We’ve captured a few of the mosquitoes and have seen that they all carry the parasite,” says Graczyk. But malaria is not just a problem for penguins in zoos. Malaria is also becoming a problem for wild populations, such as African penguins. African penguins are particularly vulnerable to the malaria parasite because they are a “naive” population; they have never encountered malaria before. African penguins are found on islands off the coast of South Africa, in a harsh climate where at one time there were no mosquitoes or malaria. But human development brought mosquitoes, and African penguins are now catching malaria, just like the Baltimore Zoo penguins. The penguins of the Baltimore Zoo have become an important ally in the quest to develop a malaria vaccine for African penguins and even people. If a penguin survives the first time it becomes infected with malaria, it is much more likely to survive a second bout. By studying the Baltimore penguins, Graczyk and his colleagues have identified antibodies created by the penguins’ immune systems that attack the malaria parasite and help them survive the disease. By identifying antibodies against malaria, this may help develop a malaria vaccine for penguins. Because of the similarities between malaria in penguins and humans, this development may also lead to a malaria vaccine for people.