12,000 B.C.: American Mammal Pandemic?
North and South America rifted away from the rest of the world’s landmasses (Pangaea) by 100 million years ago. For millions of years the animals of the Americas had no contact with those on the rest of the planet. About 13,000 year ago connection with Asia was re-established via the Bering Land Bridge, which led to the extinction of many large mammals in the Americas during the subsequent 2000 years. Those animals included mammoths, giant ground sloths, single-hump camels, horses, 300-pound giant beavers, and saber-toothed cats. What happened to them? There are three controversial theories. First is that the climate was changing swiftly as warming temperatures melted ice age glaciers and altered habitats for many species. Second, mammals (including humans) that came from Asia into the Americas probably brought diseases that American animals had never been exposed to and had no immunity against. Third, and most sensational, is that a wave of hungry proto-Indians hunted to extinction many species of large mammals. As in many controversies with some evidence to support each alternative, probably all three proposed causes contributed, but we don’t know yet if one was vastly more important than the others. If infection by new diseases eliminated tens of millions of animals over just a few thousand years that would be a huge pandemic.
“The Midwestern United States 16,000 Years Ago.” Illinois State Museum. Accessed May 24, 2017. http://exhibits.museum.state.il.us/exhibits/larson/lp_extinction.html
Image from Wikipedia.
| 430-427 B.C.: Plague of Athens
Intellectually, Athens was the most important city of the ancient world. Its philosophers, dramatists, logicians, architects, politicians and scientists profoundly affected western civilization. Yet Athens was often immersed in warfare and during the Peloponnesian War an unfamiliar contagious disease killed perhaps a quarter of Athens’ population when the city was surrounded by enemies. The famous historian Thucydides described it as a new disease, unseen before in Greece. Modern physicians have been unable to decipher which disease caused the attack, but believe it was not the plague, for Thucydides didn’t list the characteristic buboes as a symptom. Despite modern DNA analysis of victims’ teeth there is no certainty of what the disease was, although smallpox and measles fit many of the symptoms. Athens ultimately lost the Peloponnesian War, and the decimation of its population by the epidemic undoubtedly played a role.
Epidemics and Pandemics – Their Impacts on Human History – J.N. Hayes, 2005 (Ch. 1). Image of Thucydides from Wikipedia.
| 1492-1600 A.D.: Biggest Human Pandemic of All
Columbus and the thousands of Europeans who came to the western hemisphere over the following 100 years brought many infectious diseases that the Indians had no prior exposure to. Smallpox, measles, typhus, influenza and other deadly diseases swept through Indian villages, ultimately killing millions; some estimates go as high as 90% all Native Americans. Cortés’ conquest of the Aztecs of Mexico was aided by an enormous number of deaths caused by the rapid spread of smallpox, introduced inadvertently by the Spaniards. Similar disease outbreaks decimated the Indians of the Eastern seaboard of North America, aiding colonialists in their conquest.
Image of Cortés and Aztec king from Wikipedia.
| 1665: Great Plague of London
The plague has plagued humans since at least Roman times. It is spread by rats and similar small mammals whose fleas carry the bacterium Yersinia pestis. When fleas jump from an infected animal to a person, usually lymph nodes enlarge – called bubos – hence the name, Bubonic Plague. If the infection spreads to the lungs the resulting Pneumonic Plague is easily passed to other humans through sneezing. The last great bubonic plague outbreak in Europe hit London in 1665. It started around seaports, suggesting that sailors brought it from elsewhere. It spread rapidly, and everyone who could fled to the countryside, where it was less common. During August, 1665, as many as 6,000 people died each week from the plague. The entire government moved out of London, and the city barely operated with so many deaths that proper burials were impossible. A year later the Great Fire of London destroyed much of the city, killing many of the rats that harbored the fleas, and the plague abated.
Epidemics and Pandemics – Their Impacts on Human History – J.N. Hayes, 2005 (Ch. 13).
White Coat Tales – R.B. Taylor, 2016 (Ch. 2). Image of London deaths from Wikipedia.
| 1793: Yellow Fever in Philadelphia
Yellow Fever is named from the fact that people with the disease develop yellow eyes and skin. It is caused by bites from the Aedes aegypti mosquitos that carry the virus from the normal host – monkeys – to people. In 1793, Philadelphia was the capital of the newly formed United States, whose increasing trade with Caribbean islands probably brought the disease northward. About 40% of the population fled the town, but nearly 30% of the remaining died from August to October, before the cold weather killed the mosquitos. Fortunately, George Washington, John Adams, Thomas Jefferson and other leaders did not die, for their loss might have led to failure of the new nation.
Epidemics and Pandemics – Their Impacts on Human History – J.N. Hayes, 2005 (Ch. 21).
Mosquito image from Wikipedia.
|1802: Yellow Fever and the French Invasion of North America
By 1802 Haitian general Toussaint and his revolutionaries had defeated the British who then abandoned their island possession to the French. Napoleon sent tens of thousands of French soldiers to capture the island of Santo Domingo (now known as Haiti), and then to sail to New Orleans to consolidate French control of the Mississippi valley. But an epidemic of yellow fever, which had killed up to 70% of the British troops in Haiti, struck the French resulting in 55,000 dying from the disease. Napoleon abandoned the idea of a French colony in the center of North America and in 1804 sold the land to the US as the Louisiana Purchase. Without yellow fever the United States may have stretched from the Atlantic only to the Ohio River, not from sea to shining sea.
“The 1802 Saint-Domingue yellow fever epidemic and the Louisiana Purchase”. JS Marr and JT Cathey. J Public Health Manag Pract. 2013 Jan-Feb;19(1):77-82.
Image of Toussaint from Wikipedia
| 1812: Napoleon & Typhus
Napoleon’s calamitous defeat in his invasion of Russian was due to a variety of factors including the brutal winter (temperatures to -37°C), constant attacks by Russians, and a broken supply line. But an epidemic also had a significant role. While marching through Poland enroute to Moscow some men in Napoleon’s army were infected by typhus and even before the army reached Moscow 80,000 soldiers had died of the disease. There is only uncertain numbers of how many succumbed to typhus on the retreat towards Paris, but of the original army of 500,000 only a few thousand made it back to France. Wounds, starvation and freezing accounted for many of these deaths but one estimate is that disease killed 220,000 of Napoleon’s doomed army. Typhus so often has followed marching armies that it has been called war fever. Overall during Napoleon’s battles, four soldiers died of disease for each one lost in battle.
White Coat Tales – R.B. Taylor, 2016 (Ch. 2).
“Insects, Disease and Military History” by R.K.D. Peterson in American Epidemiologist, Fall 1995, p 147-160.
Image of Napoleon’s retreating – and freezing – army from Wikipedia.
|1918-9: Influenza Pandemic
In March 1918 an Army cook at Ft. Riley, Kansas developed the flu, or influenza. It spread to soldiers who then went to fight World War I battles in France, and from there the flu spread around the world in four months. This was a much more virulent strain of flu than normal and an estimated 50 to 100 million people died and billions more became sick. Severe lung complications and pneumonia contributed to the extraordinary number of deaths, largely because the antibiotics and other medicines we now use did not exist in 1918. By examining the dates when outbreaks were first reported it is evident that people on ships carried the flu from port to port around the world. Within an effected community the disease spread rapidly, coming, killing, and going in only a few weeks. In some small communities half or more of the population died, and in poor regions such as India and in Africa, bad nutrition and lack of basic medical care resulted in much higher death rates. One major consequence of the outbreak was that a German attack on Paris stalled because half a million German soldiers were sick with the flu. By the time they had recovered American troops had arrived to reinforce the French, and the German offensive failed.
Epidemics and Pandemics – Their Impacts on Human History – J.N. Hayes, 2005 (Ch. 42).
White Coat Tales – R.B. Taylor, 2016 (Ch. 2). Ft. Riley sick bay image from Wikipedia.
| 1993: Contaminated Water in Milwaukee
Cleansing water of parasites that carry diseases is one of the triumphs of the public health movement that swept across the United States more than 100 years ago. But carelessness or inattention can still cause water treatment plants to contaminate water and distribute it through a city. This happened in 1993 in Milwaukee, Wisconsin, when cryptosporidium, a microscopic parasite infected more than a quarter (400,000) of the city’s population. People had watery diarrhea, fever, stomach cramps and dehydration. 104 people died, nearly all of whom had weakened immune systems because they were elderly or had AIDS.
Drawing of cryptosporidium from CDC.
| 2015-7: Contaminated Water in Flint
The collapse of much of the American automobile industry reduced funds to run many towns in Michigan, at one time the car capital of the world. As a cost-saving measure, in 2014 the manager of Flint, Michigan decided to bring drinking water from the Flint River, a cheaper source than previously used Lake Huron. Immediately problems arose with coliform bacteria in the water, and then high levels of chlorine, disinfectants, cancer-causing chemicals, and finally lead that the chemical pollution corroded from pipes. Lead levels as high as 13,200 parts per billion (ppb) were found in one home; the federal limit is 15 ppb. Public officials covered up the danger of the water and some were charged with felonies. The brains of many of Flint’s children probably have been permanently damaged.
Image widespread on web without any credit.
|2014-6: Ebola in West Africa
The largest outbreak of the virulently infectious disease Ebola started with the death of a one-year-old child in Guinea in December 2013. People who contacted that child were infected, and as they traveled across the region Ebola spread quickly. All of an Ebola patient’s fluids – blood, sweat, saliva, vomit, semen, and urine – carry the virus so that merely touching a patient, their bodies or clothes can transmit the disease. This was devastating because local burial rituals required mourners to wash the bodies of the dead. Because so many infected people died, some local people became frightened and said the doctors brought the disease; the military had to protect some clinics. Because there was no effective medical treatment the disease was finally contained by March 2016, only by isolating patients and tracing and isolating their contacts. Most cases were in the three West African countries of Sierra Leon, Guinea and Liberia, with a total of 28,639 cases and 11,316 deaths (including 513 doctors, nurses and other health care workers). An estimated additional 10,600 patients with other diseases died during the epidemic because general medical care was diverted to Ebola. The economies of the three countries lost $2.2 billion in 2015 because of the pandemic, and the USA and other aid-giving countries spent $3.6 billion to fight the disease. Travel restrictions were emplaced because a single plane passenger with Ebola could spread the disease anywhere in the world in just a few days. And the lack of a vaccine means that millions of people could have been infected. A global tragedy was averted.
Information and map from CDC website: 2014-2016 Ebola Outbreak in West Africa. https://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/index.html
|2016: Zika in Brazil
In July 2015 Brazilian doctors started reporting an outbreak of an unidentified disease that caused mild fever, skin rash, muscle and joint pain, malaise and headache. After delays this was identified as being genetically identical to a 2007 outbreak in Micronesia due to the Zika virus, a rare virus transmitted largely by mosquito bites that previously had caused little aftereffects. By the fall of 2015 pregnant Brazilian women with Zika were giving birth to babies with microcephaly, small heads and damaged brains. Since then the disease has spread rapidly, and by summer 2017 there were Zika cases in 52 equatorial nations and 38 American states, with most US cases in Florida. During the summer of 2015, one infected area in Florida saw a decline of business by 20-30%, with tourists going elsewhere.
There is no vaccine, nor cure for Zika but fortunately most people have no or only minor symptoms. The real scare is possible brain damage to babies.
Control of mosquitos is by spraying and also by release of genetically modified male mosquitoes that are sterile. In some places where this has been tried the mosquito population has declined as much as 90%.
Information from CDC: https://www.cdc.gov/zika/index.html
and the Miami Herald:
Mosquito image from CDC.
|20xx – Alien Invasion
In the classic War of the Worlds science fiction story, invading Martians with unstoppable military hardware are defeated by Earth’s microscopic pathogens against which the aliens have no immunity. [But wouldn’t we have no immunity against their pathogens?] The possibility of transferring Earth microbes to planets explored by spacecraft caused NASA to sterilize early spacecraft to the Moon and Mars. In fact, the failure of the first six of the Ranger spacecraft to the Moon has been blamed at least partially on the high temperature heating to avoid contamination by microscopic Earth hitchhikers. Sterilization was minimized and the remaining three Rangers worked perfectly. The concern then was to avoid back-contamination of the Earth by quarantining Apollo astronauts who had landed on the Moon. Returning astronauts spent 3.6 days in a specially built Mobile Quarantine Facility before being allowed to step onto the Earth’s surface. No lunar bacteria or other flora were ever found and after three Apollo crews were quarantined, the final three were not. The Moon is biologically dead.
If alien spacecraft ever visit Earth, or if astronauts ever return from Mars, protection from non-Earthly biological agents will be paramount.
Images and info from Wikipedia.