Global health

Monday 19 July 2010 8:39AM (view full episode)

Dr Rita Colwell is Distinguished University Professor at the University of Maryland and at Johns Hopkins University Bloomberg School of Public Health. She specialises in global infectious diseases, water and health and is developing an international network to address emerging infectious diseases and water issues, including safe drinking water. Norman Swan talks with her about these issues.

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Norman Swan: 30 years ago medical researchers were predicting the end of infectious diseases because vaccines and antibiotics seemed to be triumphant. Well, HIV, Ebola, Japanese encephalitis, E Coli food poisoning and many other bugs have put an end to that thinking. But all of these so called new and emerging infections came from animals, their routes to humans made easier by global change.

That's why leading researchers are now calling for new thinking under an umbrella named One Health, meaning we're all in it together. One of the leaders of this movement is Professor Rita Colwell of the University of Maryland and Johns Hopkins School of Public Health in Baltimore.

Professor Colwell is one of the most respected biologists in the United States who years ago, ironically in the light of current events in the Gulf of Mexico, exposed the risk of cholera in the United States from environmental changes on the Louisiana coastline.

Rita Colwell: One Health is a very important concept of bringing together veterinary medicine, human medicine and the ecological sciences so that we have a totally multi-dimensional perspective of the various factors that are influencing infectious diseases, their incidence, their distribution and how they attack and cause disease.

Norman Swan: So give me some examples of why we need that?

Rita Colwell: It's very important with modern medicine to be able to deal with these epidemics that sweep across the world. SARS is a perfect example, it cost $40 or $50 billion in economic and trade as well as health of course. When you consider the West Nile virus and its problems, the emergence of the various influenza strains and how they moved rapidly through populations clearly we need to be able to address these epidemics, these pandemics quickly to be able to provide vaccines but also to understand how they are transmitted and to be able to block them in their natural transmission mode.

Norman Swan: The concept being that we humans are not alone on the planet.

Rita Colwell: We humans certainly are not the only ones on the planet, we are interactive with the animals that we've domesticated, the animals we have not domesticated and we are also part of the life system of the earth. If we think that we can simply eradicate all infectious diseases I'm afraid we are mistaken. There are many, many micro-organisms that provide beneficial effects for us. In our very gut we carry bacteria that produce vitamins that we utilise, so it's understanding how we interact with our fellow humans but more importantly with our environment, with nature and how important conservation of nature is for our own health and well- being.

Norman Swan: Now organisations throughout the world already, you know they have chicken sentinel stations using animals as advance warning of viruses coming in, watching what's happening with domesticated pigs even in remote developing countries. What more could occur that isn't happening now?

Rita Colwell: I would have to answer that from my most favourite theme and that is if we could provide safe drinking water for ourselves and animals that we domesticate we would do far more to curbing infectious disease than any other action that we could take.

Norman Swan: That concept alone is a new one which is safe water for animals.

Rita Colwell: Indeed, those domesticated animals that we depend on for food stuff, particularly chickens, cattle, we find that with ducks and chickens we have transmitted very readily and in very large numbers various infectious agents. I think understanding how these infectious agents accumulate and transmit within the animal population would be an eye opener for us. I would also like to take the opportunity to point out that we're learning with these new tools of DNA, understanding that infectious diseases are really not always caused by a single infectious agent. It's now becoming understood, at least from some of the early research results, that when you come down with salmonella you might have a few other infectious agents especially in the developing world.

In the developing world a child that comes down with let's say cholera probably is carrying at least four or five other infectious disease, giardia, probably salmonella as well as E. coli and as well as shigella. In other words more than one single pathogen and I think we have to understand this in order to be able to understand infectious diseases. How these pathogens interact and how they are transmitted as a package so to speak.

Norman Swan: But you actually are arguing that some of the solutions may be quite simple.

Rita Colwell: Some of the solutions indeed are simple, safe drinking water, washing hands after using rest rooms, being very careful in preparing foods, not to have the same cutting board that you put the raw chicken on, the cooked chicken that you're going to put on the table. These kinds of simple steps go a long way to preventing infectious disease and transmission of the disease.

Norman Swan: And surveillance - what more could we be doing because you're arguing that vets should be much more integral to the process.

Rita Colwell: Understanding the transmission is critical. I feel very strongly that we need to work very hard to provide mechanisms for very rapid identification of pathogens. It is not helpful in surveillance to have to wait a week for a culture to grow with the new DNA tools, the nucleic acid detection tools we can make identifications within minutes and this is critical, especially if we can do this in devices that can be used in developing countries we can be able to detect, surround and prevent infectious diseases very quickly, very rapidly and save untold numbers of lives.

Norman Swan: And who's going to pay for it?

Rita Colwell: Fortunately these devices can be developed. I'm working on doing just that and just as we've got cell phones everywhere in the world, a cell phone sized identification device can be used anywhere and the information transmitted by cell phone and this would provide a surveillance system that would be enormously effective and enormously powerful.

Norman Swan: It looks at the whole biological system not just the human population.

Rita Colwell: Absolutely, it can be used to identify insects, flowers, whatever.

Norman Swan: Professor Rita Colwell is at the University of Maryland and Johns Hopkins School of Public Health in Baltimore.


Dr Rita Colwell
Distinguished University Professor,
University of Maryland and Johns Hopkins University,
Bloomberg School of Public Health


Dr Norman Swan
Brigitte Seega

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