In the time of Moses, Egypt was struck by a number of plagues. Among them was their river turning to blood:

... and all the waters that were in the river turned to blood. And the fish that were in the river died; and the river stank, and the Egyptians could not drink of the water of the river; and there was blood throughout all of the land of Egypt.
- Exodus 7:20-21

Of course we now know that the river water did not turn into that slick red liquid that flows through our veins. These two verses are of utmost importance, however, because they are the first documentation of red tide happening in the world.

Red tide is caused by a type of algae called dinoflagellates¹. When conditions were favourable, they bloomed in a mighty explosion of red, killing millions of fish and fish-eating birds. People were not spared - toxins from these creatures were so potent that mere inhalation of their vapours could cause sickness and neurological damage. Affected fishermen developed open wounds that would not heal. People over time learned to dread the phosphorescent glow of the tides by night.

Everything in this world has a Yin and Yang, a good and bad side. Everyone has a black sheep or two in the family. Likewise, despite all the good micro-organisms that have helped life on Earth, there are a number of bad ones that wreak havoc and generally give the family a bad name.

This is the story we are all familiar with. Every other day, some newspaper somewhere blares out the headlines, 'mystery flu kills thousands'. Every winter, children way up north or down south fall victim to chicken pox or measles. Food that we have accidentally left on the kitchen table spoils and infuses the house with a putrid smell. Dentists prosper as the incidence of dental decay rises. Clearly, there are some very nasty bugs at play here.

Microbes as the Cause of Disease

If you were to stop any stranger on the street and ask him the role microbes play in our lives, chances are that he'd tell you that they were the cause of debilitating infectious disease.

He wouldn't be far wrong. While micro-organisms are not the sole cause of illness and disease, they are nevertheless the sole cause of infectious disease. Half of Athens was razed by plague in 430 BC². The bubonic plague that ravaged Europe in the Middle Ages - and had previously swept across India and China - was brought to Egypt by merchants fleeing the warring Crimea, where the Tartar army had been hurling the corpses of plague victims over the walls of Kaffa. New diseases such as ebola and AIDS have claimed just as many lives since their discovery. Old diseases such as tuberculosis, once thought to be controlled, are again on the rise, not only in 'third world' countries, but also in developed nations.

Humans are not the only creatures susceptible to disease. Plants are regularly infected by pathogenic³ fungi, one of the most notorious being Phytophthora infestans, which, in 1845, ravaged Ireland's staple food - the potato. In fact, plants can be infected by almost anything you can name, from viruses to worms. Animals are no exception either, and the ticks that are responsible for spreading bubonic plague to rats and humans are themselves victims of the plague bacillus - Yersinia pestis. The ticks are driven to frenzied hunger and madness because any blood that they suck is broken down by the bacteria for their own nutrition.

Because of micro-organisms' ability to adapt to any environment, we now have a whole host of them that can be transmitted by air, water, food, bodily fluids and even bodily contact. A number of them have even evolved to take advantage of modern technology, a good example being the legionnaires' disease bacillus, which is spread by water droplets from air-conditioning cooling towers. Some have even developed ways to cross the species and family barriers. What 'mad cow disease' (bovine spongiform encephalopathy) is to cows, Creutzfeld-Jacob disease is to humans. What once was thought to be a human disease, Hepatitis B, has recently been discovered to be transmissible to squirrels via mosquitoes. Parasites of amoebae can become parasites of man.

What makes things worse is that not only are many microbe-caused diseases contagious, but the one place we go to for healing and sanctuary from disease happens to be a reservoir for some of the worst diseases found on the face of this planet. 'Nosocomial' infections are those contracted in a hospital or other places of medical treatment. Day in, day out, hospitals receive hundreds and thousands of sick people. It is inevitable, therefore, that some of these patients may harbour pathogens that inadvertently get spread around before medical treatment can wipe them out of the patient's system. Other patients, whose immune systems are already weakened by whatever illness they are plagued with, are the perfect hosts for these pathogens. Incomplete cures or medications that fail to eliminate all of the infectious agents tend to select the hardy ones, those that are resistant to the medicine. When this happens, you get horror microbes such as methicillin-resistant Staphylococcus aureus (MRSA), multiple-drug-resistant tubercle bacilli and the titan of nosocomial horrors, Pseudomonas aeruginosa, that resist any attempt to kill them off.

Microbes as the Agents of Spoilage and Destruction

Next to disease, spoilage is what we dread most. There is nothing more distasteful than going into the kitchen first thing in the morning to discover that the garbage you'd forgotten to take outside the night before is now exuding a wonderfully malodorous stink that has permeated everything in your house. Or, for that matter, biting into a slice of Cheddar cheese only to discover that mould has already claimed the territory.

Because micro-organisms are everywhere and have an incredibly diverse appetite, everything has potential to spoil. Meat spoils the fastest, as bacteria do not differentiate between dead organic matter to be recycled and food we eat, turning both to sticky, smelly mush that is unpalatable to anyone but themselves. Confections such as ice-cream and chocolate can spoil if proper care is not taken to keep contaminants out of the way. Likewise, good wine, fermented by choice microbes, can turn sour if Pediococcus damnosus manages to sneak into it. Spoiled food is a nuisance, especially if one accidentally eats food that is spoiled and becomes sick as a result. It seems that the only way of getting around food spoilage and subsequent food poisoning is by cooking the food very thoroughly - lovers of rare steak, despair - and eating it immediately. Any spoiled food should be tossed straight into the garbage bin.

But we'd have little to worry about if micro-organisms were content to spoil only food. Microbial offenders have done quite a lot to make life miserable, including complicating the use of medical implants such as pacemakers, and clogging up industrial pipelines, thus impeding the flow of water and oil. They accelerate the corrosion of pipes and initiate degradation of submerged objects, such as off-shore oil rigs, boats and shoreline installations. And - to the dismay of the confection-lover - acid-producing bacteria are the cause of breakdown in dental health.

In 1992, a paper from the Defence Research Establishment in Novo Scotia, Canada, described an interesting case of microbes⁴ ruining the turbines of a gas-powered turbine ship, costing the Canadian Navy quite a big lump of currency. This incident no doubt embarrassed the Navy, especially as the crew assigned to the ship had been much more familiar with steam propulsion, and the ship's new home port lacked expertise in the maintenance of gas-powered turbines.

Microbes as Economic Hazards

Anything that causes damage to commodities is a potential economic threat. The Guatemalans surely suffered loss when, in 1996, their raspberry crops were devastated by rogue microbes, just as the Irish did when their potatoes were destroyed in 1844-5. About a million poor Irish folk died of starvation in winter, or were claimed by typhoid fever and dysentery; two million more emigrated to Australia and the New World. Likewise, when pig farmers in Negeri Sembilan, Malaysia came down with a mystery disease⁵ that turned their brains to mush, thousands of infected pigs were culled, seriously denting the pork industry - not just by reducing supply, but by instilling fear in the locals that the pork they were eating was infected. The situation was not helped by the government, which had been circulating the wrong information to the masses, and providing vaccination for the wrong disease, although admittedly, this was not done deliberately. If not for the sharp eye of scientists Professor Lam Sai Kit - who went on to win one of the three internationally coveted Prince Mahidol awards - and Dr Chua Kaw Bing, people might still have believed that the disease was caused by the Japanese encephalitis virus, and many more people may have died.

Microbes as the Cause of Misery

In terms of victim number, the top three ranking plagues in the world are:

• The Black Plague (bubonic plague)
• The White Plague (tuberculosis)
• Acne⁶

Many pathogenic micro-organisms are responsible for severely debilitating disease. There is, however, a small minority that causes relatively mild symptoms, but creates debilitating embarrassment for the victim, who is at the very least attempting to live a socially normal life. The wonderful red bloom of acne is one of the things that plagues teenagers who have just started high school and are trying to fit in with the rest of the kids. Smelly feet - brevibacteria nestling between toes produce the cheesy-smelling methanethiol - and body odour - caused by the action of micro-organisms on the secretions of the apocrine glands - are two other high school worst-case scenarios. And even without the necessity to appear cool at school, it would be somewhat discomfiting to be squished into a bus with someone plagued with this at the end of the day. Pity the soldiers who are forced to march the whole day, and share tents by night.

What We Can Do to Minimise Damage and Risk

It is imperative that, when dealing with the enemy, we should familiarise ourselves with the enemy and strike at its weakest point instead of blindly lashing out or giving it weapons with which to strike back with us. Here is a list of suggestions on how you can protect yourself, or at least minimise the risk of winding up alone in a dark alley with a bad microbe:

• Wash your hands properly with soap before handling food, after engaging in activity that will dirty your hands, and after using the washroom. Many pathogens spread through contact with contaminated material and are often harboured in faeces and other wastes, which are all too easily transferred to our hands. Rinsing your hands under tapwater will not get rid of pathogenic microbes; a good old scrubbing with soap will.

• Get vaccinated for infections that you are likely to contract, such as measles, mumps, rubella, chicken pox, hepatitis and tuberculosis. Make sure you follow through with the vaccination programme. Also bear in mind that no vaccination is 100% effective, so avoid areas or people harbouring these diseases.

• Don't abuse antibiotics. It's fine if your doctor prescribes them⁷ for bacterial infection - antibiotics do not work for viral infections - but don't get too smart and prescribe them to yourself without medical advice. Chances are you will not only fail to heal yourself, but will encourage antibiotic-resistant micro-organisms to thrive. Don't give them to your livestock either. And if you are prescribed antibiotics, make sure you finish the whole course; otherwise you will again be left with antibiotic-resistant bacteria.

• Forget about antibiotic mattresses and antibiotic paint. The only rooms that should be painted with antibiotic paint are in hospitals, where sterility is a must. You, on the other hand, do not need bacteria-free walls; not when there are micro-organisms everywhere else in the house. Once again, you will be promoting the proliferation of antibiotic-resistant bacteria.

• Avoid staying in an enclosed room with somebody with an airborne contagious disease, say the common cold.

• If you are living in the tropics, avoid letting water stagnate anywhere around or inside your house. Stagnant waters are the most popular breeding ground for mosquitoes, which, more often than not, are the vectors of disease.

• Brush your teeth after you eat breakfast, not before. Swallowing bacteria that have been growing as plaque on your teeth won't hurt you - your digestive juices will eliminate them. Leaving food on your teeth after a meal for them to act upon is not sensible - rather like using toilet paper on yourself before you use the commode.

Above all, find out more about these microbes on your own. Visit reliable websites such as the Centres for Disease Control (CDC) to get the latest news about the latest outbreaks. Don't rely on word-of mouth or tabloid articles - a lot of facts can be distorted along the way. And don't panic unnecessarily:

A pastor met the devil on the road. He asked the devil, 'Where are you going?'

The devil replied, 'I'm going to Europe to kill a thousand.'

Some time later the pastor met the devil again. He said, 'The last time we met, you said you were off to Europe to kill a thousand. How is it that two thousand died?'

The devil replied, 'I only killed one thousand. Fear killed the rest.'

- Edward A Alcamo

Further Reading

• Are microbes really at fault for the misery they cause the human race?

• Barker, R, 1997. And the Waters Turned to Blood. Simon and Schuster, New York.

• Brookesmith, P, 1997. Future Plagues: Biohazard, Disease and Pestilence. Universal International Pty Ltd, Australia.

• Dixon, B, 1994. Power Unseen: How Microbes Rule the World. WH Freeman and Company Limited, New York.

• Madigan, MT, JM Martinko and J Parker. 1997. Brock Biology of Microorganisms, 8th ed Prentice-Hall International, Inc, New Jersey.