Economic collapses, social disorders, wars, famines, floods, or earthquakes can easily leave great masses of people helpless before microbes do.

Cholera's resurgence shows the fragility of our barriers against epidemics!

Even during brief disruptions of the ecology; such as, water and wastes going untreated, diseases-carrying insects multiplying uncontrolled, garbage brings scavengers and vermin, children not being immunized, and malnutrition all help sicken the healthy and kill the sick.

These things are taking place somewhere in the world every year. Recently typhus, typhoid, yellow fever, malaria, dysentery, cholera, hepatitis, pneumonia, and other ills (old and new) have struck in starving Ethiopia, in war-torn Somalia and Rwanda and Afghanistan, and in chaotic former republics of the Soviet Union.

It is not only in developing nations that epidemics rise from social and natural disruptions. In 1994, an earthquake in California stirred fungal spores in the soil and caused an outbreak of valley fever (air borne coccidioidomycosis).

In the previous year, drought followed by heavy rains provoked a hantavirus epidemic in the Four Corners region of the Southwest.

Where did new diseases come from and why are so many arriving now?

The answer is that their arrival is an ancient, natural process. It has risen to crisis proportions whenever people have made radical changes in their lifestyle and environment in order to live in greater plenty.

The current wave of diseases came about with the acceleration of travel, technology, and social and environmental changes in the past half-century.

The twenty-first century will bring a savage test. Infectious diseases remain the world's leading cause of death; they will remain so for a long time to come.

We will probably see more zoonoses, more mutated and drug-resistant germs, new microbe carriers, more environment degradation and population pressures.

Neither we nor our pathogens would exist today without a huge capacity of mutual adaptation. We and they have survived cataclysmic changes before. We have seen diseases arrive; we have seen them also become less deadly or disappear.

The pace of change is faster than ever, but our tools for responding are better. We cure and control more diseases, and we are learning at a terrific pace about germs, genes, and immunity.

We know that we cannot flee disease by moving to a suburb or even a wilderness. There is no magic city encased in a protective bubble, nor will there ever be.

Our most troubling vulnerability is our spotty record of serving our own best interests. Ignorance, greed, and shortsightedness often keep us from using the tools we have.

Perhaps the prospect of global sickness will move us to protect ourselves better. Or maybe we can rouse the same determination to deal with infectious disease that has informed recent efforts to curb pollution, environmental ruin, and harmful behavior. Then it just might be possible that individuals and governments will be able to keep up with the great wheel of change.

Now we have another scary germ

The bacterial infection that killed a New York City student, panicked many parents, and sent school officials in many states into a frenzy of cleaning and disinfecting is only the latest manifestation of a very dangerous problem: the development of bacterial strains that are resistant to many antibiotics.

The pathogen now generating fear; known as methicillin-resistant Staphylococcus aureus, or MRSA, has long been infecting sick patients in hospitals and nursing homes.

In the past decade, it has developed into a major public health problem, sickening otherwise healthy individuals in the general community.

Right now, the vast majority of cases involve only a skin eruption, perhaps a reddish pimple or a small boil that is easily treated.

In some cases, the pathogen can invade the blood stream and internal organs, causing severe illness and even death.

A recent government study concluded that the serious and invasive infections are a lot more widespread than previously thought: striking 94,360 people in the United States in 2005 and contributing to the deaths of 18,650 of them, more than the number that died from AIDS that year.

The vast majority of serious infections (some 85 percent) were attributed to exposure in health care institutions, while only 15 percent stemmed from infection in the community, often at schools, gyms, or other places where people come into close contact.

The community form may be more virulent than the hospital-acquired form, but it is treatable with a wider range of antibiotics and caused only eight percent of the deaths.

There is now no known vaccine to prevent the disease. To prevent the spread of the pathogen where it is detected, health authorities recommend frequent hand-washing (with soap), cleaning and covering cuts and scrapes; avoiding contact with other people's wounds or bandages; and not sharing personal items; such as, towels or razors.

It also makes sense to clean surfaces that come into contact with the skin of people, but most experts dismiss the idea that schools have to be scrubbed top to bottom, or even closed, if a case is found.

The discovery that MRSA is more prevalent than anyone thought reinforces the need for an aggressive, multi-pronged approach to curb the growing number of antibiotic-resistant bacteria.

Hospitals need to improve their infection control procedures and should probably screen high-risk patients or even all patients for dangerous germs, as many now do.

In the case of MRSA, American farmers, or government officials, may also need to test pigs, which have been found to harbor the infection in other countries.

Of great importance, the indiscriminate use of antibiotics in medicine and agriculture needs to be limited so that resistant strains take longer to emerge.

Back to: Diseases and Plagues in History and in Our Modern Times Part 1 of 4.