"Mathematical modeling has long been used to study complex biological processes such as the spread of infectious diseases through particular populations," said Arek Goetz, associate professor of mathematics and one of Maxey's thesis advisers. "But it is only recently that models are being used to design the best strategies for controlling outbreaks of global proportion."

A 1997 WHO report concluded that an estimated 5.9 million people worldwide had become blind due to trachoma. Medical authorities estimated in 2005 that 84 million people in 55 endemic countries suffered from active infection caused by Chlamydia trachomatis, which is easily spread via hands, clothing and even flies. The infection causes raised scarring under the eyelid. After repeated infection the thickening scars turn the eyelid inward to such a degree that eyelashes scratch and destroy the cornea, leading to blindness.

Maxey's research was conducted in collaboration with Thomas Lietman, M.D., an associate professor at the Proctor Foundation, an ophthalmology research center at University of California, San Francisco. They developed baseline data by measuring the rate of infection and recovery from earlier data collected in Ethiopia's Guraghe zone. Dr. Lietman then took swabbed samples of moisture from the eyes of 100 children in 16 Ethiopian villages. The same groups were sampled again after two and six months.

Once the samples were analyzed, Maxey developed a mathematical model to predict the future rate of infection in Ethiopian communities undergoing mass antibiotic treatments. After running 1,000 mathematical simulations, the model proved that eliminating the infection locally is possible and that average prevalence will continue to decrease with appropriate antibiotic use.

Though an effective vaccine does not exist, trachoma is currently treated in undeveloped countries with mass doses of an antibiotic. The treatment is given to all individuals in infected communities whether they have contracted the disease or not. Maxey's calculations will help health agencies to develop a more precise timetable and less expensive treatment regime to stop the spread of trachoma.

Maxey said that the inspiration for her thesis was a biostatistics course. She credits her advisers -- Goetz and Mathematics Professor Mohammad Kafai -- for their support during the process.

"One of the reasons I chose to pursue my master's in math at SFSU is because the professors here really put their students first," Maxey said.

Maxey will continue her work as a staff research associate at the Proctor Foundation and plans to build a career as a mathematician in medical research.

"I like the idea of entering a messy situation and using math to make some sense of something," Maxey said. "And this work allows me to make a difference."

-- Denize Springer