There was a time, in the 1960s and 1970s, when public health experts had high hopes that perhaps humanity had conquered infectious diseases.
It was an era when new, effective vaccines and antibiotics were being introduced. The ancient global scourge of smallpox was well on its way to being eradicated. Life expectancy was rising, in part because far fewer children were dying from infectious childhood diseases such as diphtheria.
We need only look at the current outbreak of swine flu to realize the tenacity of germs and their perpetual ability to outsmart us.
The influenza virus is trickier than most. It’s constantly mutating. Even though vaccines are available to protect against it, the formula must be updated every year to ensure it remains effective against whatever flu virus strains happen to be most prevalent.
Most of the time, this antigenic drift, or mutation, is not significant. But it has long been a fear of world health authorities that, sooner or later, a larger shift in the virus will take place, rendering current vaccine formulas mostly ineffective and leaving millions of people unprotected from the flu.
That’s what has happened with swine flu. It is a novel virus, a combination of human, avian and swine influenza that hasn’t been seen before, said Ann Stehn, director of Kandiyohi County Public Health.
"It’s a new and different strain," she said. "It is different from seasonal influenza."
At media briefings on Monday, state and local health officials were diligent about sharing as much information as they could. But there’s still much about the new flu virus that isn’t known, explained Dr. Ruth Lynfield, state epidemiologist with the Minnesota Department of Health.
Why, for instance, does swine flu appear to be hitting hardest among adults in their 20s, 30s and 40s? Is this really the case or is it a premature conclusion based on incomplete data?
Lynfield’s response: "We don’t know the answer to those questions but we are all looking carefully."
One point the health authorities made during their briefing on Monday: It’s more accurate to call this "North American flu." For one thing, the virus contains elements of human and avian influenza, not just swine flu. For another, although forms of swine flu do exist, this particular version has not previously been reported among pigs, nor is it spread by eating pork. It is believed to spread through human-to-human contact.
In the absence of any current effective vaccine, the best weapon, say health officials, is old-fashioned, low-tech prevention: hand washing, covering coughs and sneezes, and staying home if you are ill. None of these are expensive, they don’t involve any fancy equipment or technology, and they can be done by everyone. It’s the same message health authorities push during the normal flu season and during outbreaks of other infectious diseases. In other words, something we should be doing anyway, whether there’s a threat of pandemic influenza or not.
"People need to take responsibility for lessening the transmission of germs," Lynfield said.
Image: three-dimensional structure of an influenza virus photographed via electron tomography. Courtesy of NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases.