As long as people lived in small isolated groups, epidemics were sporadic and limited. As people began clustering in cities, they shared water and food supplies, handled unwashed food, and were exposed to primitive communal garbage and toilet facilities. Epidemics have occurred since man began living in communities. There are many communicable diseases that can turn into epidemics. Among the most devastating are bubonic plague, influenza, smallpox, typhus, cholera, and tuberculosis.
Black Death (Bubonic Plague)
In AD 1347, the bubonic plague, also known as Black Death, swept through Europe, killing at least one-third of the population. During the Middle Ages, an average of 8 to 13 million people died annually worldwide. The mortality rate for those afflicted ranged from 30 to 75 percent. In this disease, victims develop fever with temperatures ranging from 101 to 105°F, headaches, nausea, vomiting muscle aches, and inflamed lymph nodes (called buboes), particularly in the groin, armpits, and neck. Buboes become swollen and tender and can be as large as an egg. They can break open and discharge foul-smelling pus.
There are two other less common forms of the plague: pneumonic and septicemic. The pneumonic (lung) form has a mortality rate as high as 95 percent; it can occur from inhaling infected droplets from infected patients and from spread of bubonic plague through the bloodstream to the lungs. The septicemia (blood stream) form is the least common form, but it has a mortality rate approaching 100 percent. For both the bubonic and septicemic forms of the plague, there is bleeding and multiple system failure followed by death three to seven days from the onset of illness.
Plague is caused by the bacterium Yersinia pestis. It is spread to humans by fleas that live on rodents, including rats, prairie dogs, squirrels, and mice. The disease is particularly likely to occur in areas of famine and social disintegration where garbage and sewage collect, allowing rats to breed extensively.
The Great Plague of England (1665)
London’s population was decimated during the Great Plague of 1665. That year the city had experienced a very hot summer. Sanitation facilities were almost nonexistent. Garbage and human waste were thrown out into the streets. The black rat population exploded.
The disease spread with frightening speed. Those who could left London for the comparative safety of the countryside. The first victims of the plague lived in the slum areas of London. There the population density was high, and people could not avoid contact with either rats or infected humans. Families that had one member diagnosed with the plague were quarantined in their homes for forty days and nights. A red cross was painted on the door to warn others to stay away.
Searchers were hired to find dead bodies or plague victims who were yet to be found by the authorities. The collected bodies were then put on carts and transported to mass burial pits. The plague was at its peak in September 1665 until the onset of colder weather slowed the spread of the disease. The worst had passed by the end of 1665, but the plague did not end until September 2, 1666, when the Great Fire of London devastated the filthy city areas where rats had thrived.
Today bubonic plague is still endemic in certain areas. Madagascar, Tanzania, Brazil, Peru, Burma, and Vietnam have experienced cases almost every year since the last pandemic in 1880. Prairie dogs in the southwestern United States still carry the disease, and an occasional case has been reported there in humans.
Influenza
Hippocrates was the first to record an influenza pandemic in the year 412 BC. Since 1580, there have been thirty-one additional flu pandemics recorded. Influenza is caused by a virus that is readily spread by aerosol droplets from the mouths and noses of infected persons. Symptoms include a sudden onset of fever, chills, headache, sore throat, cough, muscle aches, and sometimes a feeling of exhaustion. In the northern hemisphere, the disease usually peaks from December to March.
The mortality rate from the milder strains of influenza is usually less than 0.1 percent, but because the number of patients infected is so high, there is a significant number of deaths, usually due to pneumonia or other pulmonary complications. In a typical year in the United States, twenty thousand people die of bacterial pneumonia as a secondary infection to flu. During heavy epidemics caused by a more virulent strain of the virus, the mortality figures can rise significantly.
The 1918 Influenza Pandemic
The influenza pandemic of 1918 hit in three waves. The first wave began in March 1918 and spread through the United States, Europe, and Asia over the next six months. Death rates during the first wave were not unusually high. The second wave, in the fall of 1918, spread across the globe and was highly fatal. The third wave occurred from February to April 1919. Both the fall and winter waves had a much higher frequency of cases complicated by severe pneumonia. It has been postulated that the virus underwent spontaneous changes in its genetic makeup between the first and second waves, accounting for the increased severity of the disease in the succeeding waves. The mortality pattern of this influenza epidemic was noteworthy in that in addition to the usual high mortality rate in infants, young children, and the elderly, there was an unusually high death rate among persons under thirty-five years of age.
The death toll due to the influenza pandemic in the United States was 650,000. At its height, mortality rates were 15.8 percent in Philadelphia, 14.8 percent in Baltimore, and 10.9 percent in Washington, DC. The rest of the world did not fare well either. Mexico had 500,000 deaths, Russia 450,000, Italy 375,000, and Britain 228,000. There were 44,000 deaths in Canada. Millions died in the Asian subcontinent.
World War I had already claimed 9 million lives in its four-year duration. On the morning of March 11, 1918, Albert Mitchell, a company cook at Camp Funston (now Fort Riley), Kansas, reported to the infirmary complaining of a low-grade fever, sore throat, headache, and muscle aches. By noon that day, 107 soldiers exhibited similar symptoms. Within two days, a total of 522 people were sick. Some were close to death with severe pneumonia. Other military bases reported similar figures almost immediately. By April, French soldiers and civilians were infected. Within two weeks, the disease had spread to China and Japan. By May, it had spread to Africa and South America. This first wave was more deadly than the typical flu but was still far from what it was yet to be. The second wave was more virulent. Deaths from pneumonia were unusually high. Both military and civilian populations were decimated. The flu was a major determinant on the outcome of some battles. Many soldiers were too sick to engage in the fighting.
The 1918 influenza epidemic turned out to be the most lethal in human history. An estimated one-third of the world’s population of 1.5 billion (about 500 million people) was infected. Total deaths were estimated at 50 million though the toll may have been as high as 100 million.
