We live in fear of global warming, economic disaster and nuclear war, though not necessarily in that order.
What we should be afraid of – and what can wipe us off the planet in a matter of weeks – are the smallest things; the bacteria and viruses that multiply unseen in our midst, their spread enhanced by rising temperatures and rising populations. The newest alert comes from Johannesburg , South Africa , where health officials report that an illness similar to hemorrhagic fever but still unknown has killed three people so far.
The lifespan of a microbe is 24 hours. In two days, it can produce offspring that have adapted, or evolved, to overcome all our sanitary precautions and our most potent medicines. In the months it takes scientists to develop newer and more potent antibiotics, these microbes will be 100 generations into a metamorphosis that allows them, not only to survive our clinical advances unharmed, but in rare cases to actually convert the medicine to food. Fortunately, these soil bacteria have so far not crossed the barrier to afflict mankind.
Our old weapons – antibiotics, antimicrobials, antifungals – are no longer adequate to protect us from these stealthy, invisible enemies, and we need the time and money to create new ones. The time that elapses between phase I animal trials and human use can be as much as six years and cost millions of dollars, but as often as not new drugs also become obsolete because their very use promotes bacterial resistance and mutations. Even totally synthetic drugs, like quinolones, derived from nalidixic acid, and the cutting-edge vancomycins (used to treat flesh-eating bacteria) are currently failing in their effectiveness.
The threats come from everywhere. Not only do we have supposedly eradicated diseases like tuberculosis re-emerging on a global scale, but we have animal-borne diseases migrating to humans.
In the first category – returning diseases – tuberculosis, which was virtually absent in 1985, has returned with a vengeance in the new millennium as humans move from third world countries to places like Great Britain. There, by 2006, more than 14 people out of every 100,000 had the disease, compared to two cases per 100,000 three decades earlier, and that’s not counting the unreported cases, since tuberculosis symptoms often don’t appear until the disease has progressed to the active stage.
Another re-emerging disease is rickets, and it occurs primarily among children in northern climates, where malnutrition, a lack of calcium and a lack of Vitamin D from sunlight cause abnormal bone growth, skeletal deformities, softening of the bones of the skull and dental problems, among other symptoms.
Other re-emerging diseases include diphtheria, pertussis (whooping cough), measles, typhoid fever, dysentery and syphilis. The first three, largely eradicated in the 20th century in Western nations by a regimen of vaccinations beginning in infancy, are returning because of the fear that the vaccines cause autism. Typhoid fever and dysentery are largely tropical or subtropical in origin, but in a warming world both have moved north with growing populations and a subsequent decline in the ability of health care agencies to meet existing needs. Opportunistic to the core, these bacteria, viruses and amoeba may eventually adapt to colder climates, putting more and more people at risk. Another contributing factor is the failure of existing medications to work as effectively as they once did.
In the latter category of transgenic diseases (passing from animals to humans) we not have deadly AIDS, which originated in African monkeys, but also bird flu and severe acute respiratory syndrome (SARS), among others. These diseases are caused, first, by increasing populations which put humans and both wild and domestic animals in close proximity, and, second, by the worldwide international trade in exotic pets such as monkeys, crocodiles, sugar gliders, parrots, parakeets, iguanas and species of rodents like guinea pigs.
According to Dorothy Crawford, Professor of Medical Microbiology at the University of Edinburgh, this trade must be curtailed to prevent the spread of zoonoses (animal-borne microbes) and their eventual spread, via either contagion or mutation, to humans.
Diseases in the past, like the 1918 Spanish Flu, wiped out an estimated 100 million people or more. This, at a time when the world’s population was a mere 1.8 billion. Now, with more than three times as many people occupying the same space, a recurrence of such a sweeping pandemic becomes even more likely as international travel and animal sales, an ineffective and outdated pharmacopeia, and global warming urge our smallest enemies to proliferate unchecked.
We do have two new weapons in the battle, however. One, a recent discovery that bacteria have a special chemical language that they use to communicate, has led UK researchers toward a Rosetta stone for decoding that language. Knowing that bacteria communicate via a method known as "quorum sensing" allows scientists to develop compounds to disrupt this signaling process, which will provide new treatments for formerly antibiotic-resistant bacteria.
Another weapon is worldwide communication. In 1918, health officials didn’t know the extent of the disaster until a year after it was over. Using modern communications tools like the Internet and cellphones, health specialists can instantaneously alert one another at great distances of an emerging health threat. These 21st century weapons work well, not only for controlling inadvertently spread diseases, but also in the advent of a biological attack.
We are not helpless, and the current economic crisis – by limiting both local and international travel – may actually have a beneficial aspect. In spite of that, none of us can afford to be complacent. With new diseases manifesting every month, and world tensions at a level not seen since the 1960s, we would all be advised to limit our exposure to public venues, avoid impulse purchases of "cute" foreign pets, foods or toys, and stock food, water and medicines enough for 30 days. Where possible, we should also have an alternate source for generating electricity.
The best weapon against the unthinkable is still planning, and every individual and family should have a disaster mitigation strategy in place.