Infectious diseases have an incredible affect on humans directly through our own health as well as infections of agricultural crops. It is therefore necessary to understand what factors contribute to the spread of infectious diseases to improve human and agricultural health. The research of Dr. Lynda Delph and Dr. Curtis Lively, of Indiana University, does just that. Their combined theoretical and experimental approaches merge epidemiology with evolution in a way that provides insight into infectious diseases. By merging their interests, they can focus on a simple underlying theme: how does genetic diversity affect the spread of infectious disease in natural populations? Dr. Delph and Dr. Lively's laboratories are located side-by-side making collaboration easy. However, perhaps more unique, is that in addition to being collaborators, they are also married. Therefore, their career-long collaboration has supported innovative and rigorous scientific breakthroughs.

Using the plant, Silene latifolia, Dr. Delph looks at why males and females are so different from each other and why populations of this species also differ in many ways, including the extent to which they are infected by disease. Using a freshwater snail from New Zealand, Dr. Lively looks at why two different types of females, one that mates with males to produce genetically variable offspring, and asexual females that produce genetically identical clones of themselves, are able to coexist in nature when disease is present. The combination of their systems and studies allow this collaborative couple to understand various diseases. Dr. Lively has produced mathematical theory that combines epidemiological models with evolutionary models that makes specific predictions about how genetic diversity alters the spread of disease. The researchers plan to use both the plants and snails to experimentally test how having genetically diverse populations can slow or halt the spread of disease. The combination of using epidemiological and evolutionary frameworks to theoretically and experimentally investigate tractable systems is extremely rare and offers a new perspective to understanding disease spread.

Current research includes:

• Dr. Lively: Dr. Lively's research is focused on understanding what selects for genetic diversity in hosts and parasites. His research has suggested that increasing genetic diversity in hosts decreases the spread of disease. Therefore, his research has applications in human disease, crop plants, conservation biology, and dealing with inbred populations.   

• Dr. Delph: Dr. Delph has been working with plants throughout her career. She is interested in what environmental factors drive males and females to differ, including their susceptibility to disease, and how environmental factors work differently on the two sexes. Paired with the theoretical models prepared by Dr. Lively, Dr. Delph's experimental research will allow for incredible applications.

• Collaborative Work: Dr. Lively's mathematical theories paired with his and Dr. Delph's experimental research will allow the collaborative team to understand the ways in which diseases spread in plants and animals and why genetic diversity is an important factor when understanding the spread of disease. Therefore, their research may lead to applications in diseases that affect millions of people. For example Schistosomiasis, which affects 600 million people across the world, is a disease that humans contract through their interaction with snails. By understanding the snail system, Dr. Lively and Dr. Delph's research will give real insight into diseases such as this.