Dr. William H. Stewart was the U.S. Surgeon General during 1965–1969. He is remembered primarily for his infamous statement: “It is time to close the book on infectious diseases, and declare the war against pestilence won.”

Reality check

In fact, there is some doubt whether Dr. Stewart ever made this claim, although many other distinguished scientists made similar statements around that period. Nevertheless, the passage of time has profoundly dashed those hopes.

For many millions of people around the world, be they in developing nations or in first world countries such as the United States or Europe, disease due to infectious microorganisms remains a constant threat. Despite extraordinary advances in understanding how bacteria cause disease and in the development of new vaccines, the war on infectious diseases is by no means won.

"Scientists are working to develop new, “smart” antibiotics that will get round the problems of resistance."

Firstly, antibiotics are just not as effective as they used to be. All around the world, including in the United States, bacteria have developed resistance to the antibiotics that Dr. Stewart thought would spell the end for most serious infectious diseases.

The World Health Organisation has identified this as a “major global threat” and in March of this year President Obama released details of his National Action Plan for Combating Antibiotic-Resistant Bacteria. The failure of antibiotics affects not only worldwide problems such as malaria and tuberculosis, but occurs every day in hospitals and clinics in New York, Paris and Beijing.

Re-emerging threats

The second challenge is that of emerging, and re-emerging, infectious diseases. We have just witnessed the terrible Ebola epidemic in West Africa that caused thousands of deaths. But the last 15 years also has seen a catalogue of infections that were either previously unknown (the worldwide outbreak of SARS in 2002, or the newly described MERS, Middle East Respiratory Syndrome) or else older diseases spreading to new areas (West Nile Fever spreading across the United States). Most of these new infections are viruses for which few if any treatment options exist at present, and with the ever-expanding rate of international travel, infections can rapidly be spread across the world.

But despite these concerns we should celebrate the huge advances that have been made. Improved public health infrastructure and the introduction of some new vaccines and drug therapies have helped to reduce the global burden of infection.

For the first time, chronic conditions such as cardiac disease or diabetes outnumber infections as the cause of death. And scientists are working to develop new, “smart” antibiotics that will get round the problems of resistance. For the moment we are just keeping ahead of the bacteria, but we cannot afford to take our eye off the ball; infectious diseases are likely to remain a real threat to our health for many years.