Lyme Disease Worstened by Climate Change Finds Yale Study

April 29, 2009

Scientists at Yale working in collaboration with other institutions have found that Lyme Disease could be made more severe in people by climate change. The researchers found that the cycle of feeding for each stage of a deer tick’s life is heavily affected by climate. In more moderate climates, larval deer ticks feed in the late summer after spring feeding of infected nymphs. The long gap in feeding times is why there are generally more cases of Lyme Disease in the Northeast than in areas such as the Midwest. “When there is a longer gap, the most persistent infections are more likely to survive,” explained Durland Fish, Professor of Epidemiology at Yale School of Public Health and co-author of the study in a media release. “These persistent bacterial strains cause more severe disease in humans, leading more people to seek medical attention and resulting in more case reports.” The clear implication of this research, say the researchers, is that as the planet warms, the Upper Midwest could find itself in the same situation as the Northeast–longer gaps between nymphal and larval feeding, and therefore stronger, more persistent strains of Lyme Disease. “Other diseases, such as malaria, have been projected to expand in response to climate change,” explains project leader Maria Diuk-Wasser, Assistant Professor of Epidemiology at Yale School of Public Health and senior author, “But this is the first study to show how the severity of disease can also be related to climate.” The findings are published in this month’s Applied and Environmental Microbiology.