Turning the Tide Against Cholera
In its most severe forms, cholera is one of the most rapidly fatal illnesses known, but clean water and improved sanitation alone may not be able to eradicate it. A protective vaccine could be a major boon — and a team of scientists at Mass General and in Bangladesh is working on just that. Diarrheal diseases like cholera and dysentery — mainly attributable to contaminated water and food — kill and incapacitate more people than any of those other diseases. In fact, diarrheal disease is the third- leading cause of death among adults in the developing world, and the second-leading cause of death among children under five years of age, according to the World Health Organization (WHO).
With hundreds of millions of people contracting severe diarrheal diseases every year — and with more than 1.8 million deaths each year by WHO estimates— a collaborative clinical research team co-led by Stephen B. Calderwood, MD, chief of the Division of Infectious Diseases, Dr. Edward T. Ryan, MD, a member of the MGH Division of Infectious Diseases, and Firdausi Qadri, PhD, at the International Centre for Diarrhoeal Disease Research in Bangladesh (ICDDR,B) has made finding a solution for cholera a top priority.
In studies so far, the team has discovered that immunologic memory develops following cholera, and it is now studying how long this memory lasts and comparing development of memory after natural infection with what happens in the body after vaccination.
“Diarrheal disease is the third- leading cause of death among adults in the developing world, and the second-leading cause of death among children under five years of age.”
– World Health Organization
Currently, much of the work focuses on better understanding how the bacteria takes hold in the body, identifying proteins active in immune responses, characterizing the genetic factors that influence susceptibility to infection and determining how current vaccines can be made more effective.
Deployment of an effective cholera vaccine could provide a major health breakthrough for developing nations. It might preclude events like the 2008 and 2009 cholera outbreak in Zimbabwe, which claimed more than 4,000 lives. And during the war in Rwanda in 1994, 30,000 refugees living on a flood plain — 10 percent of the total that had fled there — died of cholera within three weeks of their arrival. In addition to improving approaches to cholera, the vaccine research could also play a role in improving vaccines for many other diarrheal diseases for which current vaccines do not exist or are ineffective.