One of the means we have developed is vaccination, which builds up the body's defenses against disease before the disease attacks the body. Vaccinations are particularly important for infants as they are more vulnerable to the harmful effects of a disease. Through vaccination campaigns, one major disease, smallpox , has been eradicated and another, polio , is expected to be eradicated by the year 2000. B ecause of these advances , it seemed for a while as if we might be winning the struggle against disease. But it was too early to celebrate.
Infectious diseases are back on the attack.
A host of new and re-emerging diseases are threatening the health of the world. Over the past two decades alone, at least 30 new infectious diseases have appeared or been identified. These include the HIV virus , which has affected millions of people all over the world and the Ebola virus which recently caused a major global health scare when early in 1995 it killed hundreds of people in Kikwit, Zaire, within weeks. Re-emerging diseases are those that had been subdued for a while but have suddenly returned. These diseases often return stronger than before and sometimes develop new strains that are resistant to the drugs previously used to combat them.