The current outbreak in northern Uganda once again finds the virus taking advantage of poor medical facilities and funeral practices. And, once again, classic public health efforts are in place to bring the epidemic under control. Like its predecessor in Zaire, this outbreak has come to world attention months after it began, and only when health care workers, including foreigners, have succumbed. The full scope of the epidemic, including evidence it may also be expanding in Sudan and southward towards Uganda's capital city, Kampala, has yet to be determined. Regardless of how large its scope may be, however, the same control measures will ultimately be effective.

In the two large Zaire outbreaks Ebola emerged in areas so remote that there was little, if any, threat of spread to other countries, including the U.S. Gulu, however, is connected to Uganda's capital by a paved highway, and flights from the now-prospering Kampala depart daily to London, Paris, Johannesburg, Nairobi and other African locales. The threat of spread in this case is a bit more real.

In Washington top national security leaders, both in the White House and at the Central Intelligence Agency, fret continuously about such things. There is genuine fear that the U.S. will be caught off guard by a dangerous microbe. After all, it's happened before; many times, most notably with HIV and hepatitis C. There is a tendency in such circles to seek high-tech solutions in the form of microbe sensors and automated early-warning systems.

But the reappearance of the Ebola virus does not signal such a need. Rather, it is warning us that we ignore the essential public health needs of the world's poorest nations at our own peril. Unless the wealthy world is prepared to assist in the development of strong infrastructures in the poor world, microbial diseases will remain a threat to us all. Investment need not be prohibitively massive. The good news is that most public health interventions are pretty cheap, and highly cost-effective.

But nobody in America ought to rest easy, thinking that Ebola, HIV, hepatitis C, malaria and other scourges that now claim record numbers of people worldwide are "over there"--not here. As long as health care workers "over there" are reusing non-sterile syringes and medical equipment, have no rapid way of contacting international or even national health authorities, lack basic laboratory diagnostic capacities and are overwhelmed by an astonishing array of background diseases that sap the time and intellectual stamina of their staff, nasty microbes will continue to break out. And, as happened with HIV, eventually something "over there" will find its way over here.

Laurie Garrett is a reporter for Newsday and the author of Betrayal of Trust: The Collapse of Global Public Health. She was awarded the Pulitzer Prize for coverage of the 1995 Ebola outbreak in Kikwit, Zaire.