Consider the difference in size between some of the very tiniest and the very largest creatures on Earth. A small bacterium weighs as little as 0.00000000001 grams. A blue whale weighs about 100,000,000 grams. Yet a bacterium can kill a whale…Such is the adaptability and versatility of microorganisms as compared with humans and other so-called “higher” organisms, that they will doubtless continue to colonise and alter the face of the Earth long after we and the rest of our cohabitants have left the stage forever. Microbes, not macrobes, rule the world. – Bernard Dixon, 1994.
The Coming Plague by Laurie Garrett was a fantastic book to read, of all the books on microbes I have read so far, this is by far the most entertaining one. The book is written by a science journalist who clearly understands the science involved with her field, and clearly has a passion for science journalism. She covers epidemics, microbes, and public health policy with the detailed understanding of a scientist yet maintains the explanatory style of a journalist, which makes for an easy-to-read, rich in detail kind of book. If you are in search of a good book on epidemics, microbes, and the like, then I definitely recommend this book!
Here is a quick overview of some of the things I learned from the book: microbes spread in incredibly sophisticated and unpredictable ways, politics almost always intermingles with how we approach epidemics and microbes, and microbes are incredibly adaptive!
Complexity of Microbial Spread
Microbes can be spread by either humans or animals, and there are some extremely interesting methods for both! For animal spread, the most fascinating methods mentioned in the book were by rats and monkeys.
In Bolivia, there was a viral hemorrhagic fever (VHF) spreading amongst the inhabitants. What is a VHF?:
Viral hemorrhagic fevers (VHFs) are a group of illnesses caused by four families of viruses. These include the Ebola and Marburg, Lassa fever, and yellow fever viruses. VHFs have common features: they affect many organs, they damage the blood vessels, and they affect the body’s ability to regulate itself. Some VHFs cause mild disease, but some, like Ebola or Marburg, cause severe disease and death. (For more information: source).
In the case of Bolivia, the specific VHF that was spreading is called the Machupo Virus. When researchers were trying to identify the source of spread for the Machupo virus, they arrived at the following conclusion: when civil unrest in Bolivia during the 1950s happened, people began to struggle to survive. Food, money, and other resources became harder to come by. As a result, they began to cut down surrounding forests. In doing so, they destroyed the habitat of a Bolivian field mouse called Calomys. A field mouse that carried Machupo virus. When the field mouse habitat was destroyed, they began to migrate into villages for corn, which was a much superior food source for Calomys; and as a result of a much superior food source, they likewise experienced a population explosion. Put this all together, and what we have is virus carrying rodents that increased in population and that shared food with everyone in Bolivian villages!
Most remarkable, however, is the actual route in which the virus got to humans. Since the rodents were eating the corn of the Bolivian villagers, they were inside their houses: namely, their kitchens. While in their kitchens, the rodents would urinate on the dusty floors. And come morning time, when the Grandmothers of Bolivia swept the kitchen floors before serving breakfast, they would sweep the Machupo virus into the air. In other words, all the kitchens in Bolivian villages became covered in Machupo contaminated urine/dust particles that eventually found their way into the human body, all because the original habitat of the Calymos field mouse was destroyed years earlier!
And that supports a much grander claim made by microbiologists, epidemiologists, and the like: that is, deforestation leads to an increase in infectious diseases. There are many thousands, if not millions, of microbes hidden in the forests of the world, some of which can be deadly to humans.
Another prime example of this is HIV. When HIV first hit the scene, there was a scramble to find out where it came from. As expected, politicians blamed many other countries but their own. But as time went on, it is clear that probably everyone had some culpability in the spread of HIV, and that HIV was a zoonosis:
A zoonosis is an infectious disease that has jumped from a non-human animal to humans. Zoonotic pathogens may be bacterial, viral or parasitic, or may involve unconventional agents and can spread to humans through direct contact or through food, water or the environment. – (for more information: source)
Researchers reasoned that HIV likely had a natural reservoir in sooty mangabey. Not only did these monkeys spread the disease to other monkeys, but it also spread it to humans.
For example, when sooty mangabey and macaques were held in research facilities together, housed in the same room, the macaques also became HIV positive. In addition to that, researchers who handled macaques did indeed become HIV positive after receiving scratches and bites. Even furthermore, workers inside rubber plants near the habitats of sooty mangabeys had HIV positive results: nearly 10% of 944 workers were HIV positive. Hence why we think it was a zoonosis, one which came from us toiling with things inside the forest without precaution.
Compound all of that with amplification opportunities such as the following: international flight and much less strict protocols for shipping research monkeys internationally; an increase in the number of sexual partners per person for the gay and urban African heterosexual communities; the introduction of needles to the African continent, but with limited resupply, which lead to reuse of needles; heroin use, in conjunction with amphetamines and cocaine use, which suppressed immune systems and increased needle sharing; and the expansion of the blood and monkey research industries. It is quite easy to see why everyone is responsible for the spread of HIV, and how a single zoonosis can find many features of our human habitat to exploit!
So, animals can spread microbes to us in ways that we only are able to predict after the fact, in many cases. But humans also have very interesting and tough to predict ways of spreading microbes amongst one another.
In 1980, Don Francis, an American epidemiologist, was dealing with a new hepatitis B strain. The spread of the new hepatitis B strain was linked to drug usage amongst affluent sons and daughters in North Carolina. The wealthier children were adopting a fad of shooting cocaine rather than snorting it.
Now, because cocaine is a more expensive drug, it was usually a drug abused by wealthier individuals. However, shooting cocaine means a user requires less of the drug to feel the effects, and thus, can effectively lower the price of each high. Once that was discovered, the fad of shooting cocaine soon spread to adolescents of other socioeconomic classes, which led to needle sharing and then the spread of hepatitis B.
Similarly, amongst heroin users, the spread of microbes was extremely high. Not only did they share syringes, but heroin also has some deleterious effects on the immune system. Throw into the picture the living conditions of the average heroin user, and we have an environment ripe for microbial spread: dirty alleys, humid temperatures, poor diet, use of additional intoxicants that negatively impact the immune system, and shared drug equipment. So, an increase in drug users can lead to a massive increase in microbial spread.
Another interesting cluster bomb of events that lead to massive malaria outbreaks in asian countries relates to war, civil unrest, drug abuse, and gem mining. When Cambodia and Vietnam experienced war, this led to millions of people being uprooted. Many people moved, and they also moved ecologies with them. In addition to that, the human population grew, which required expanding further into the forests. As well, mining for gems was quite popular, which was essentially people digging through mud that was soaked in rain water with little to no equipment. And alongside all of that, there were bomb craters and rain-filled army vehicles. All of these conditions created ideal breeding conditions for mosquitoes seeking new habitats.
Now, once the mosquitoes became a problem, people began to abuse malaria drugs and use them ineffectively. People would take chloroquine injections from non-medical professionals, and parents would buy malaria drugs from the black market, which they used ineffectively; in part because physicians were paid 5USD a month. The spread of drug resistance malaria was inevitable, given the conditions. And that is exactly what happened:
“In 1983 the combined use of mefloquine and Fansidar cured 96.7 percent of all malaria in the gem-mining areas. By 1990 the same drug combination cured less than 21 percent of all cases. In practical terms, malaria acquired in the region was incurable” – The Coming Plague, pg. 455
The last form of spread caused by humans that I want to share relates to global warming. This form of spread I found most interesting, so much so, that I want to quote it at length:
“Another feature of global warming would be an increased dependence in wealthier nations on air conditioning. In order to conserve energy, buildings in the industrialized world had specifically been designed to minimize outward and inward air flow. It was much cheaper to heat or cool the same air repeatedly in a sealed room than to pump in fresh air from the outside, alter its temperature, circulate it through a structure, and at the same time expel old air. As the numbers of hot days per year increased, necessitating longer periods of reliance upon air conditioning, the economic pressures to recirculate old air repeatedly, to the limits of reasonable oxygen depletion, could be expected. Such practices for winter heat conservation in large office buildings had already been linked to workplace transmission of influenza and common cold viruses. Spread of Legionnaires’ Disease and other airborne microbes was expected to increase with global warming.” The Coming Plague, pg. 568
So, deforestation can cause an increase in infectious diseases, but also our current building practices, in conjunction with global warming, can cause an increase in infectious diseases! The spread of microbes comes in many ways and forms, most of which can only be discovered through hindsight!
Politicization of Medicine
Another topic the book covers quite well is the relationships between politics and medicine. Far from being what we would expect to see in an epidemic or even pandemic, politicians hoard resources, ignore warnings, or outrightly disregard epidemiologists and virologists. In some cases, they even implement policies that do more harm than good, based on personal whim rather than science.
As one example demonstrates, during the early outbreak of HIV/AIDs the CDC experienced budget cuts because politicians believed the age of plague had passed. In addition to that, when researchers were citing the alarming amount of HIV/AIDS cases emerging, which would suggest a pandemic is soon to come, they were ignored. One researcher’s response to the issue was as follows: “You gotta steal resources”. Of course, he meant stealing resources from other parts of the CDC, since researchers could not raise funding to deal with the HIV/AIDs outbreak.
Under the Reagan administration, HIV/AIDs was actually called GRID, which meant Gay Related Immunodeficiency. It was believed to be caused by activities associated with homosexuality, both in lifestyle and in partner choice. And as a result, when the CDC pleaded for federal assistance to handle the outbreak, since it was believed to be a strictly homosexual disease, they were ignored.
Many CDC researchers attempted to convince the Reagan administration that it was not a disease strictly linked to homosexuality, but they would not listen. In addition to that, the Reagan administration ensured that the issue was never handled federally and that funding for research was minimal, since they did not like the idea of many Americans engaging in homosexual behavior as being true.
In other words, the beginning of the HIV/AIDs problem that the entire world faced was blundered because of politics. Once politicians believed one thing, it didn’t matter what science had to say about the topic.
A terrific example of this happened in Haiti. In Haiti a significant amount of the GRID patients were females, yet western countries continued to insist that Haitian males were in denial about homosexual behavior instead.
Another fascinating part of the political aspects of medicine comes from inequality. In 1993, the World Bank estimated that poor countries required a minimum of $8.00 per capita expenditure for medicine. Yet they couldn’t afford more than $2.00 to $3.00 per person every year on total healthcare. In comparison, Japan spent $412 per person on medicine each year, and America spent $192 per person on medicine each year. But that isn’t what is most interesting.
Only %20, at the time, of pharmaceutical companies sold to the third world, and most drug resistant strains emerged in first world nations. So, the misuse of medicine in first world nations negatively impacted the third world, since they could not manufacture their own medicine nor could they receive medicine that worked efficiently; because many of the medicines no longer worked against resistant strains.
The last thing I want to share from the book on the topic of politics and medicine is another quote, of which should be shared in length:
“In November 1987 the president of the German Federal Court of Justice, Gerd Pfeiffer, announced that in the absence of an HIV vaccine it might soon prove necessary to tattoo and quarantine people who were infected with the virus” – The Coming Plague, Pg. 466
There is a problem with drugs running into microbes that can withstand their use. In other words, our medicines become less effective. The reason why is because the microbes that cause so many of our infections can adapt to the medicines we use against them. And when we engage in bad health policy, they adapt even quicker.
In Indonesia, many mild (ARI) Acute Respiratory Infections were treated with antibiotics that were not required, and many of the paramedics in villages were neither trained nor had the equipment to identify whether an infection was viral or bacterial. As a result, overuse was rampant and that led to drug resistant pneumococcal strains to appear all over the world. Physicians ran into strains that were resistant to six different classes of antibiotics simultaneously!
In Southeast Asia, drug resistant gonorrhea emerged. Those who recently travelled to Southeast Asia in 1992 and contracted gonorrhea would likely have a drug resistant strain, because the misuse of antibiotics in the black markets inside Southeast Asia was likewise rampant. Not taking the antibiotic for a long enough duration, or simply not getting a large enough dose, was common. These drugs were not handed out by physicians, after all, but street vendors.
In America, an outbreak of resistant microbes came as a result of destroying equilibriums. Some microbes don’t spread and mutate because there are other microbes in their ecology fighting for resources, but when we disturb that ecology by wiping out a natural competitor to another microbe, the other microbe takes advantage.
For example, in American hospitals “the emergence of a super-enterococci was facilitated by practices that allowed the organism to instantly spread from one susceptible human to another: electronic thermometers, catheters and surgical instruments, intravenous lines, mechanical ventilation, and over-use of cephalosporin-type antibiotics”. Importantly, cephalosporin-type antibiotics had no effect on enterococcal bacteria, it only served to devastate rival colonies of microbes.
Similarly, when we began to give antibiotics to animals, salmonella strains resistant to antibiotics began to emerge, because not only did we provide antibiotics to billions of humans but likewise billions of animals.
Strains of salmonella resistant to antibiotics were found in chicken meat and eggs, of which could only be killed by high-heat cooking. And in the case of livestock, another resistant strain emerged because farmers were giving illegal doses to their cows. As we know, if we do not use enough antibiotics to kill an infection, the infection can not only come back stronger, but it can also adapt to the medicine. And some farmers, to save money, were giving low-dose antibiotics to their livestock to save on money. The result was the emergence of a salmonella strain resistant to antibiotics.
Compound this with the fact that many who then ate the meat from those cows were already on antibiotics, and you have a recipe for disaster: a drug resistant microbe going into an ecology where their natural competitors are already wiped-out.
Drug resistance is a very serious problem, and much of it is linked to bad policy rather than a lack of technology. As a close-off of this section, I want to leave you with another good quote from the CDC about chlorine resistance:
“Evidence suggests that a substantial proportion of non-outbreak-related diarrheal illness may be associated with consumption of water that meets all current water quality standards”.
There are so many more topics inside this book that I left unmentioned, such as international health data sharing, the tricky classification of viruses that are different but cause the same symptoms, or even the sheer amount of conspiratorial thinking that goes on amongst politicians and ordinary people when it comes to medicine – especially as it relates to vaccines. The book is jam packed with data and insights!
If you are looking for a book which covers the general nature of epidemiology, virology, and health policy, then this book is the one to go for!