Edward Thomas Ryan

Early career

In 1990, Ryan published a study of patients with Hirschsprung's disease and discovered that first-born children have a lower incidence of the condition. During the same year he also estimated that 22% of children with Hirschsprung's disease have other conditions of the gastrointestinal, cardiovascular, neurologic or genitourinary systems, including such disorders as Down syndrome, tetralogy of Fallot, and Dandy-Walker syndrome.

The Edward T. Ryan Laboratory at Massachusetts General Hospital studies host-bacteria interactions and aims to develop vaccines to prevent enteric bacterial illnesses. He discovered that Vibrio cholera secretes Clostridium difficile toxin A, the action which causes E. coli.

Later career

In 2000, he and Stephen Calderwood have discovered that while United States have phenol-inactivated vaccine against cholera, the rest of the world already developed subunit vaccine which based off cholera toxin which can orally kill the whole cholera-infected cell such as Vibrio cholerae. He also discovered that the vaccine protects a person for 6 months and is effective 80%–85% of the time against serotype O1 but is still not effective against O139.

In 2005 he and colleagues have collected human feces and vomit and discover that the environment in which V. cholerae gene is expresses in humans is different than in vitro models of pathogenesis. The same year, he also proved that people with blood type O are less vulnerable against V. cholerae.

In 2006 he completed recording on diarrhea patients after the floods in Dhaka, Bangladesh which occurred in 1988, 1998, and 2004 respectively.

A year later, he along with his colleagues used Rhesus macaque which they infected with various Bartonella species and discovered that B. bacilliformis is the main agent which causes Carrion's disease.

Ryan was named a Fellow of the American Society of Tropical Medicine and Hygiene with the first class of fellows in 2011.