Once-rare cases of malaria infection in Kenya's higher altitudes are becoming more common as temperature zones shift. "The good news in such areas is that most residents have not suffered from malaria; the bad news is the same. Because their bodies have never been exposed to the parasite, their immune systems respond too slowly to stop the infection during its early stages. And they, unlike lowland residents, usually lack two genetic traits that make people less susceptible to malaria. This genetic and immunological vulnerability mean that when malaria does hit highland residents, it hits harder..."