Humans versus Microbes

Posted on | May 4, 2009 | Comments Off on Humans versus Microbes

Infectious microbes – tiny organisms that include bacteria and viruses – are alive and well and continue to give us a run for our money. We find them pretty scary, and we are quick to panic, especially since a number of popular movies have been replete with the pandemic theme.

What are the facts? Microbes reproduce about every 30 minutes. When they reproduce, they can mutate, or change their genetic structure in a way that protects them from our medicines. We call that "resistance." So our scientists keep their eyes open worldwide, with constant testing and surveillance, and are always trying to come up with something new: the latest vaccine, anti-viral, or antibiotic to fight them off.^1,2

We develop antimicrobials in order to control symptoms, to destroy organisms, and to seek to eradicate diseases. With the development of new classes of antimicrobials in the 1950s and 60s, the scientific community prematurely thought they could claim victory over the microbes. In fact, in the late 1960s, Surgeon General William H. Stewart stated it was “time to close the book on infectious diseases, declare the war against pestilence won, and shift national resources to such chronic problems as cancer and heart disease”.^1,2

But here we are, a half century later, in a full blown panic over the swine flu that has spread outwards from Mexico. Clearly, there is still a lot of work to be done in infectious disease prevention. Here’s a quick list of five challenges:

1. We continue to struggle with highly recognizable foes like malaria, tuberculosis and HIV, especially in the developing world.⁴

2. Studies increasingly show a link between infections and the development of chronic diseases like stomach ulcers and heart attacks.^5,6,7

3. Drug-resistant microbes are a big problem in humans and animals.^1,2

4. New infections continue to appear out of nowhere.⁴

5. Bioterrorism. Remember anthrax? We don’t like to think of it, but these bugs in the wrong hands can be very dangerous.²

With so many sources for trouble, it is little wonder that infectious diseases remain a dominant cause of worldwide mortality. In 2002, infectious diseases caused 26 percent of global deaths. Four million deaths were attributed to respiratory infections; 2.8 million to HIV/AIDS; 1.8 million to diarrhea; 1.6 million to TB; and 1.3 million to malaria.²

Several factors have coalesced to make this an ideal time for an emergence of infectious diseases. First off, the microbes themselves have demonstrated truly remarkable genetic and biologic flexibility. We are also seeing changes in our physical environment, with global warming and weather patterns being favorable to microbes. In addition, social, political, and economic factors, compounded by war and famine, have led to a breakdown in public health measures. Human behavior and activities bring people into contact with species of animals that harbor transmittable diseases. And finally, high speed travel and the threat of terrorism have the world on edge.³

But I believe that humans are up to the challenge. Since the outbreak of SARS and concerns over bird flu, we are more organized worldwide and doing a better job of monitoring surveillance, sharing of information, and stock piling adequate supplies of medicines. Bottom line: microbes will never go away so we must always stay one step ahead of them.

For Health Commentary, I’m Mike Magee.

References

1.World Health Organization. WHO Report on Global Surveillance of Epidemic-prone Infectious Disease. Geneva: WHO, 2003.

2.Emerging Crisis in Infectious Diseases: Challenges for the 21^st Century. The Pfizer Journal. 2004; 5:2.

3.Institutes of Medicine. Microbial Threats to Health: Emergence, Detection, and Response. Washington, D.C.: The National Academies Press, 2003.

4.American Society for Microbiology. New and Reemerging Infectious Diseases: A Global Crisis and Immediate Threat to the Nation’s Health, The Role of Research. Washington, D.C.: ASM, 1997.

5.Volume 70: Epstein-Barr virus and Kaposi’s sarcoma herpesvirus/human herpesvirus

6. IARC monographs on the Evaluation of Carcinogenic Risks to Humans. 1997. Emerging Crisis in Infectious Diseases.

7.Bahrmand AR, et al. Chlamydia pneumonia DNA is more frequent in advanced than in mild atherosclerosis lesions. Scand J Infect Dis. 2004; 36:119-123. Emerging Crisis in Infectious Diseases.

7.Kindhauser MK. Communicable diseases 2002; Global Defence Against the Infectious Disease Threat. Geneva: WHO, 2003. Emerging Crisis in Infectious Diseases.