The Body: A Guide for Occupants

Throughout history, diseases have appeared without warning, gone through populations, then faded away and disappeared. Some have no known causative agent yet affect very young children, who aren’t suggestible, which rules out mass hysteria. Other diseases have known causes but strike at random. A new virus that appeared in Bourbon County, Kansas, in 2014—in the center of the U.S.—as of 2019, has killed seven people over a wide area, but the “Bourbon” virus otherwise has harmed no one. 

Sometimes a microbe infects large numbers of people but only generates symptoms in a small percentage of those affected. Now and then, an outbreak will be traced to a particular pathogen, and the pathogen is then attributed to mysterious outbreaks from years earlier. The bacterium that cause Legionnaire’s disease was first detected in the air conditioning ducts of a hotel in Philadelphia, where in 1976 participants at an American Legion convention became ill and many died. Epidemiologists then realized that a number of similar outbreaks from years earlier could be blamed on Legionella bacteria. It’s now known that about a dozen Legionella incidents occur every year in the U.S., sickening tens of thousands. 

A disease becomes an epidemic due to four factors: its lethality, contagiousness, ability to be contained, and susceptibility to vaccines. Frightening diseases, such as Ebola, often have limited lethal potential because they tend to knock down victims before they can spread the contagion, and because people tend to run away from an alarming outbreak. 

Successful pathogens tend to be non-lethal and easy to spread. The flu virus is a good example. The 1918 flu pandemic killed fewer than 3% of those infected, but the total was more than 100 million people. 

One major cause of disease, strangely, is agriculture. As farming developed, people began eating a narrow range of foods, causing dietary deficiencies. Furthermore, living in close quarters with domesticated animals permitted their diseases to jump into humans, so that an estimated 60% of infectious diseases are zoonotic, or animal sourced. 

Many dread diseases have been marginalized, but some still trouble the world. Diphtheria, a throat ailment that can spread to the rest of the body, sickened 200,000 Americans yearly, killing 15,000, until a vaccine slowed its course to the point where, in a recent 10-year period, only five people in the U.S. died of it. 

Typhoid fever affects 20 million people a year worldwide, killing 200,000 to 600,000; nearly 6,000 cases occur annually in the U.S. The first confirmed asymptomatic carrier of typhoid in the U.S. was an early-1900s cook dubbed Typhoid Mary, who may have infected dozens and caused the death of several. She refused to cooperate with authorities and was twice quarantined, the second time for 30 years until her death at age 69. 

One of the most vicious diseases was smallpox, which infected nearly everyone it touched and killed 30% of those infected, causing high fever and pustules that covered the skin. Smallpox was eradicated with a vaccine in 1980, “the first and so far only human disease to be made extinct” (327). Samples of the virus still exist, however, in a few labs around the world. 

Tuberculosis, a respiratory disease that causes people to cough up blood and waste away, killed half its victims until antibiotics became available. Today, it still kills nearly 2 million sufferers around the world each year. One-third of all humans carry the causative bacterium, but less than 10% develop the disease. 

A number of other scourges, called “neglected tropical diseases” (329), still plague the planet, including leishmaniasis, lymphatic filariasis—a parasite that disfigures 120 million people—and guinea worms, which grow up to three feet long inside a person, then burrow out through the legs. Many doctors died in the early 1900s while trying to learn about and cure diseases such as typhus, yellow fever, and trachoma. 

Genetic abnormalities also cause disease. Most are rare—less than one chance in 2,000 or better—but with 7,000 known types, these illnesses are suffered by 6% of Westerners. Some are well known, including multiple sclerosis, inflammatory bowel disease, and Huntington’s disease. Because each affliction is rare, little research money is allocated; 90% of genetic diseases have no treatment. 

An increasingly costly source of disease is lifestyle abnormalities. Lack of exercise, junk food, and too much eating have become so common that today 70% of the causes of mortality—including diabetes and heart disease—are preventable simply with changes in personal habits. 

One of the most dangerous diseases currently afflicting humankind is the flu, which mutates constantly to outwit immune systems. One version, called H5N1, rarely strikes humans but, when it does, it is lethal 50% to 90% of the time. Were this type of flu to mutate into a virus easily transmissible to humans, the results could be devastating.

A century ago, the diseases Americans feared most were diphtheria, smallpox, and tuberculosis. Today, it’s cancer. This preoccupation owes partly to the fact that “people in the past often didn’t live long enough to get cancer in great numbers” (335). In 1900, cancer was the eighth leading cause of death; today, it is second only to heart disease. More than 40% of people get cancer; three-fourths of men over 70 have prostate cancer. 

Cancers are genetic malfunctions that cause uncontrollable growth and spread of cells. To the body, these tumors appear normal and are symptomless until they press on a nerve or form a lump. They can become resistant to attacks by chemicals or grow dormant and hide as needed. 

Most cancers arise among epithelial cells—the skin or the inner linings and ducts of organs that divide rapidly—and are called carcinomas. One percent of cancers originate in connective tissues like bone, cartilage, and muscle, or tissues like blood vessels. 

Older people are much more likely to get cancer than the young. Lifestyles affect people’s chances, too, causing half of all cases. Smoking and heavy alcohol consumption are primary culprits along with being overweight, though why excess poundage worsens the odds is unclear. 

Toxins in the environment also cause cancers. The first type reported, in 1775, was scrotal cancer among chimney sweeps, caused by accumulated soot that often wasn’t washed off for weeks. Of 80,000 chemical products generated by industry, only four—radon, carbon monoxide, tobacco smoke, and asbestos—have been studied extensively for toxic effects. As much as 20% of cancers come from air pollution. 

Microbes can also cause cancer. Viral infections are responsible for 6% of cancers in industrialized nations and 22% elsewhere. Other microbe-induced cancers include those of the cervix and certain types of liver and lymphatic malignancies. Some cancers, 10% to 15% of the total, develop in people with no risk factors at all. 

In the past, cancer was usually a death sentence. Sometimes, surgeries were attempted without anesthesia or sterilization, and usually without success. In 1810, English novelist Fanny Burney endured an agonizing 17-minute surgery to remove a cancerous breast, later describing it as “a terror that surpasses all description” (341); fortunately, she survived and lived another 30 years. 

Breast cancers tended to become open, weeping, odorous sores that caused victims to banish themselves from society. In 1894, American surgeon William Halsted—noted for his improvement of surgical technique and invention of the surgical glove—introduced the radical mastectomy, a severely disfiguring process that removed a breast and surrounding tissue but added many months, without exile, to the lives of patients. It became the standard of care until scientists realized that breast cancer doesn’t spread so much as it migrates to other parts of the body.  

Early in the 1900s, doctors believed radiation was beneficial; radium was added to some medicines, with deadly results. Glowing radium was painted onto watch hands by workers, mostly women, who achieved nice points on their paintbrushes by licking them; many became sick and some died. X-rays were tried on cancer patients with poor results. 

Ernest Lawrence, in 1937, used a cyclotron, a device he invented that hurls subatomic particles into targets at tremendous speed, on his cancer-stricken mother, who suffered great pain from it but her cancer retreated and she survived another 22 years. This advance marked the beginning of radiation treatment for the malady. An accidental release of outlawed mustard gas during World War II caused many victims’ white blood cell count to decline, the first hint that chemicals could treat certain cancers. 

Childhood cancers account for only two percent of the total, but most leukemias occur in the young, and until 1968 the survival rate was 0.1%. That year, a U.S. doctor tried attacking the rogue cells with full doses of chemotherapy and radiation, which vastly improved survival; today, children have a 90% chance of pulling through. The process damages the body, though, and some children die from the treatments. 

Cancer therapies can make hair fall out, damage internal organs, and cause fertility problems. Still, survival rates have increased, and 2.4 million Americans, and millions of others around the world, have been saved over the past 30 years. The dream is to detect cancers earlier and cure them before they become lethal. 

Bacteria come in two main types based on the thickness of their cell walls. One type, called Gram-positive, can be killed by penicillin, but many diseases are caused by the other type, Gram-negative. In 1943, a Rutgers University student, Albert Schatz, discovered a new antibiotic, streptomycin, that kills Gram-negative bacteria, which cause many deadly scourges like tuberculosis and plague. 

Schatz ceded his patent rights to his school, Rutgers University, but his supervisor, Selman Waksman, kept his own rights. Schatz sued and won royalties, but Waksman refused ever to give him credit; Schatz was ostracized by the science community and languished in obscurity, while Waksman won a Nobel Prize for the discovery. 

Despite such incidents, medicine in the 20th century advanced so much that life expectancy improved more than during all of the previous 8,000 years. Worldwide, men in 1950 lived an average of 48 years; today, they average 70 years. During that same time, women’s life spans have risen from an average of 53 to 76 years. Two dozen countries boast a life expectancy past 80. 

Half of deaths in 1900 were due to infections, while today infections cause only 3% of deaths. Heart disease, cancer, and accidents crowd the top ranks of killers today mainly because so many infectious diseases have been greatly minimized, some to a fraction of a percent of what they were in the past, as with diphtheria, polio, and other once-dreaded scourges. Today’s leading causes of death, however, often are exacerbated by persistent lifestyle problems such as smoking, drug use, and poor diets. 

One factor that dragged down average life spans in the past was infant mortality, which once took more than a fifth of all children but today claims only 4%. Antibiotics and vaccines have saved countless lives; before they were introduced, however, deaths from diseases had already begun to decrease, possibly due to improvements in sanitation and better food supplies. 

The benefits of medicine are distributed unequally, even in industrialized countries. Glasgow East End males live shorter lives than men in India; young black men in Harlem have shorter life expectancies than Bangladeshi men. Well-off Western people can expect to live into their late 80s, but people who are identical in exercise, diet, and sleep patterns but have much less money will likely die in their 70s. 

Despite spending more than any other nation on health care, Americans from all socioeconomic levels have shorter life spans than their counterparts in most other wealthy countries and are 31st in life expectancy worldwide. Several reasons are at play: Americans tend to eat more, exercise less, and suffer much higher death rates from car crashes and gunfire than in most advanced countries. 

Ironically, screenings to catch cancer and other ailments early can produce false positive results and lead to unnecessary surgeries and other procedures. Both breast and prostate screenings save only about one in 1,000 people tested. 

Fear of litigation and the opportunity to make more money motivate doctors to overtreat patients. Pharmaceutical companies spend tens of billions of dollars, enticing doctors with pay and gifts to prescribe their drugs. Some modern medicines do exactly what they’re designed to do but have no effect on outcomes—lowering blood pressure, for example, but not reducing heart attacks or deaths—while other medications create side effects that the companies cover up. Fines in the billions of dollars have little effect if the corporations have already reaped much more in profits from dubious meds. 

Experimental drugs must first be tested on animals, which have different metabolisms and body chemistries from humans; this inefficiency leads to a lot of dead ends when the drugs then fail in people. Drug testers avoid subjects who are on other medications that might complicate results, but patients in real life often take multiple prescriptions, so their outcomes receive no scrutiny before the meds are approved. 

Some medical practices of long standing turn out to have no effect or adverse ones. Low-dose aspirin, for example, apparently provides no protection against cancer or heart attacks for most people who take it regularly but does present a risk of internal bleeding. 

On the other hand, simple patient-care skills can make a big difference. Severe complications among diabetes patients drop by 40% when they’re “treated by doctors rated high for compassion” (366). 

People today are more at risk from their own bad health habits than they are from communicable diseases. Humans are also living longer into old age—90% of the developed world reaches age 65 in decent health—and 60% of deaths follow long declines. Among people over 50, more than half struggle with disability or chronic pain. 

The elderly consume a high proportion of medical resources but also live many more years past retirement than previous generations, so that societies have more trouble paying for their health care. 

Scientists don’t yet understand why people age. Of hundreds of theories, three stand out: genetic mutations, wear and tear, and waste buildup in cells. Telomeres, the chemical clasps that keep the ends of chromosomes from unravelling, shorten over time until their cells fail; gerontologists thought this might explain aging, but further study showed that telomeres cause only 4% of human death risk after age 60. Another theory, that antioxidants such as Vitamins C and E prevent the accumulation of damaging free radicals and therefore might postpone aging, has sold millions of pills but done virtually nothing to slow the death rate. 

Aging has its own symptoms: The bladder stiffens and holds less, skin loses elasticity and bruises more easily, the immune system weakens, subcutaneous fat gets thinner, and the heart pumps less blood to the body. Only a few dozen people are older than 110 at any one time. The oldest person on record was a woman who reached 122. 

Long lifespans are more likely with long-lived parents, but people also tend to live longer if they have strong social connections. Women have always, for unknown reasons, tended to live several years longer than men. Some gerontologists believe people commonly will live well into the 100s through medical advances.

Humans are one of only four mammals that go through menopause. Why it occurs remains a mystery, though some scientists think it allows older women to focus on caring for their grandchildren. 

About two-thirds of senility cases are due to Alzheimer’s disease—the third most-common cause of death among the elderly—which makes minds deteriorate until victims lose their memories, tempers, and inhibitions, and finally can no longer function or even breathe properly. Tangles and plaques of protein fragments are found in their brains. As yet, there is no cure. People with good health habits are less likely to develop Alzheimer’s, and some people, especially educated and inquisitive ones, accumulate the protein buildups without losing brain function. 

Other common forms of dementia are caused by Lewy body dementia (similar to Alzheimer’s), frontotemporal dementia (often from strokes that cause victims to lose all inhibitions), and Korsakoff’s syndrome (from alcoholism). One-third of people over 65 will suffer some form of dementia. 

Fewer than one in 100 people die in a given year, but this adds up to over 60 million people. Eighty percent of deaths occur in people 65 or older. More than half of terminally ill people report intense yet comforting dreams about dying. At the end, trouble swallowing or breathing can cause rasping sounds: death rattles and agonal breathing. 

At death, blood drains from the face, leaving a ghostly pallor, but collects at the bottom of the body, giving it the purple of livor mortis. Brain cells begin to deteriorate within minutes, but muscle and skin can last up to a day. Gut and other bacteria begin to devour the body, releasing putrid gases that become awful within a couple of days but fade as body tissues are consumed. A body buried in a coffin can take decades to decompose fully. Cremation, increasingly popular, will leave a pile of ashes that weigh about five pounds.