By Betsy Pisik, THE WASHINGTON TIMES
NEW YORK - Polio and tuberculosis are back. AIDS and malaria continue to infect and kill, and new ailments such as severe acute respiratory syndrome (SARS) and the human variant of mad cow disease keep appearing.
"There is a lot going on out there," said Dr. David L. Heymann, a specialist on communicable diseases at the World Health Organization.
Epidemiologists and public-health specialists say that diseases formerly thought nearly eradicated have gained a tenacious foothold in the early 21st century. This is occurring despite medical advances unimaginable in the Middle Ages, when smallpox or plague could decimate a population before exhausting itself.
The world never before has had so many medicines, vaccines or detailed knowledge about everything from rare disorders to sanitary food preparation. Investors are starting to fund the booming biotech industry, with its promises of new tests and treatments, and charitable foundations routinely make generous grants for basic medicine and fresh research.
So why are old killers such as tuberculosis and polio coming back? And why is it that every year seems to introduce a new killer microbe such as the highly contagious avian flu and the presence of West Nile virus in the Western Hemisphere?
A complex combination of factors have joined forces to "weaken the herd immunity," say public-health analysts.
The widespread use of antibiotics in medical treatment and meat production has weeded out the germs they were created to destroy, clearing the way for new microbes and super viruses, which are drug-resistant and deadly.
AIDS and malaria significantly weaken the immune system - making victims vulnerable to tuberculosis and other infections, and compromising society's general resistance to plague or other germs.
Humans are moving deeper into the forests and living closer to livestock, making it easier for viruses to jump between species and infect people through proximity, insect bites and food.
"All that, and we let down our guard," said Dr. Heymann, who is concentrating on polio eradication after running the WHO communicable-diseases program. "In the '70s and '80s, there were new antibiotics and new vaccines, and no one cared anymore."
"Now," he told The Washington Times, "the old diseases are back, and we're seeing new ones at a rate of one a year."
Public-health offices around the world are watching Southeast Asia with mounting worry, as wave after wave of infectious diseases are diagnosed. Countless civet cats, chickens and pigs have been slaughtered in recent weeks in efforts to control the new outbreaks. The exotic-bird markets are under scrutiny.
U.N. agencies overseeing human and animal health and food safety have issued a joint statement warning that avian influenza is "highly pathogenic" and a potentially dire public-health threat. Some fear that in the worst case, it could rival the influenza pandemic of 1918 that killed 21 million people worldwide. In the United States, 20 million Americans became infected and a half-million died.
The Centers for Disease Control and Prevention (CDC) in Atlanta has determined that existing flu vaccines and antibiotics are no match for the strain of avian flu that has spread to 10 nations. The CDC has advised U.S. health facilities to carefully screen patients who have returned from Asia with flu symptoms.
As of yesterday, 18 persons had died of avian flu - 13 in Vietnam and five in Thailand - Reuters reported. But up to 70 percent of people who have caught bird flu in the current Asian outbreak have died from the virus, about twice the level in the 1997 outbreak in Hong Kong, a doctor from the territory said.
"The data suggests [human fatalities from the bird flu are] in the range of 60 [percent] to 70 percent, so we are quite shocked by this," David Hui, specialist in respiratory medicine at the Chinese University of Hong Kong, told Reuters Television. "Last time [in 1997], the mortality rate was 30 percent."
Dr. Hui said there was little evidence that the virus was being spread by anything other than contact with sick poultry, but it is unclear why the H5N1 strain is proving more lethal this time or why only two countries have reported human deaths.
Indeed, after 8,000 SARS infections and 800 deaths, the medical community still has more questions than answers about the disease, which now appears to have both a weakened, almost asymptomatic form, as well as full-blown pneumonia-like respiratory symptoms. In November, American and Chinese researchers reported that SARS is twice as likely to kill patients in areas that have significant air pollution.
Dr. Heymann stresses that techniques honed on fighting old scourges are useful in diagnosing, isolating, treating and preventing new diseases. He is leading the World Health Organization's global effort to eradicate polio - a disease that was all but eliminated a few years ago. Today, a $3 billion global effort is jeopardized by the failure - or refusal - of a few governments to vaccinate their populations.
In northern Nigeria, for example, local officials since last year have refused to allow the WHO to vaccinate children against polio, wrongly convinced that the vaccine contains AIDS or will make women infertile. In the past year, children in eight African countries became infected with the Nigerian strain of poliovirus, and epidemiologists fear it could continue to spread. The capital of Nigeria, Lagos, already has been reinfected. Southeast Asia also is at risk, with cultural fears contributing to a collapse of vaccination programs in isolated regions.
In India, Muslim parents were afraid to present their children to Hindu vaccinators and hid them. In Pakistan, devout village women simply refused to open the door to male vaccinators. When Muslims were added to the public-health teams, or married couples were sent to perform the vaccinations, people's objections were overcome easily.
But in Afghanistan, which suffers from miserable sanitation conditions, polio has spread easily across the border.
"We have an opportunity now, but the longer it takes, the harder and more expensive it will be," said Dr. Heymann, who believes that his unit can wipe out polio this year. He says that polio, a slow-moving disease that cripples before it can be detected, offers lessons for how to deal with the new threats.
"Until we have a vaccine for SARS, the new flus, AIDS, and so on, our best hope ... will be early detection and treatment," Dr. Heymann said. "Until we know all the risk factors, and understand how [they] spread, we won't be able to do anything to stop it," he added.