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A large fraction of the population of Dhaka, Bangladesh, has no access to clean water sources and can be exposed to the cholera pathogen through water bodies such as this pond, photographed during the city's dry season.
Enter HHMI investigator Mercedes Pascual at the University of Michigan. A marine and theoretical ecologist by training, with a gift for computational analysis, Pascual bridges the worlds of climate and infectious disease research. Her quantitative models—developed with collaborators in meteorology, epidemiology, and other fields—have generated convincing evidence that complex climate patterns influence infectious disease epidemics and their distribution.
Pascual's research has shown that cholera epidemics in Bangladesh vary in accordance with sea-surface temperatures 10,000 miles away in the Eastern Pacific Ocean. More recently, her models have revealed heightened risks for malaria in African highlands, accelerated by long-term warming trends that favor reproduction of the disease-carrying mosquitoes that were once less abundant in this region.
With global warming threatening major changes in how humans interact with infectious agents, Pascual's studies have taken on new urgency.
Born in Uruguay, Pascual had a nomadic childhood, living in four Latin American countries while her father, a chemical engineer, moved from job to job. From an early age, she developed a love of the ocean that influenced her academic choices and career. An avid sailor, she was a crew member on yachts that traveled long-distance passages up and down the South American coast. And as an undergraduate at the University of Buenos Aires, she spent a summer studying dolphin ecology in Tierra del Fuego, just 600 miles from Antarctica.
Pascual's early interests revolved around marine ecology, but, as her academic career evolved, she found mathematics increasingly appealing. She says she was captivated by how complex dynamics in nature could be described in mathematical terms. “I liked how you could reduce observable patterns in population dynamics to numbers and equations,” she explains. “And I liked that even messy data sets had patterns that might give you clues to their behavior in the real world, even though they might not be obvious at first.”
When her studies took her to the United States in 1985, a meeting with Simon Levin, a pioneer in theoretical ecology at Cornell University (now at Princeton), helped Pascual realize she could combine her interests in math and ecology. After completing a master's degree in mathematics from New Mexico State University in 1989, she migrated east for a Ph.D. at the Woods Hole Oceanographic Institute to study with theoretical ecologist Hal Caswell.
Photo: Mercedes Pascual