If I were to tell you that the single most deadly event in recorded human history took place in the 1900’s, what would you think it was? Probably one of the Great Wars – which would be close, but not quite right. The event took place from 1918 to 1919, but the killer was no human; the weapon neither bullets or gas. It was an enemy so small it cannot be seen by the naked eye: the 1918 Spanish Influenza virus, also known as “La Grippe.” During its year-long reign, this tiny virus killed between 50 and 100 million people across the globe. It killed more people in a single year than the Black Death did in the entire 14th century, more than either World War, and well over 6 times the population of New York City. Some even say that more Americans were buried in France having died of influenza than had been killed fighting on the battlefield. We get outbreaks of the flu every year without batting an eyelash, so what went so terribly wrong in 1918?
There’s nothing quite like a mail-order disease to propel a pathogen into notoriety. In 2001, several envelopes containing spores of the bacteria Bacillus anthracis were shipped across the United States, infecting those exposed with anthrax. This was hardly the first time B. anthracis cropped up as a prominent pathogen or agent of biological warfare; the bacterium has a sordid history as a major player in biological warfare in the past century, along with a biblical history of outbreaks.
No other disease has captured the modern imagination with such sensational horror as Ebola. The possibility of infection being transported into dense cities and the western world along with the possibility of bioterrorism captures our attention. However, much of the disease’s infamous reputation is due to sensationalized stories of the outbreaks along with the popular perception of the disease causing a disconcerting amount of bleeding from every orifice. In actuality, the disease’s outbreaks are relatively rare (although increasing) and the presentation itself only includes external bleeding in less than half of the cases. Still, with a mortality rate ranging between 40-90% and no current treatments, Ebola is not a disease to be taken lightly.
Leprosy is known as the Death before Death; a disease of unparalleled historical stigma and fear that has earned the appellation kushtha, ‘eating away.’ Today, whilst its effects are none the less awful, it is known under the more innocuous title of Hansen’s Disease. In 1948, Dr. Earnest Muir wrote that leprosy was the most dreaded disease—ironically, not because it kills, but rather, because it leaves its victims alive. Leprosy and humans have a long, bitter relationship. Though it has plagued us since at least 2000 BC, we barely understand it four thousand years later and we are still wrestling with its legacy of stigmatization.
When someone mentions the plague, the Black Death often leaps to mind: an infamous, decimating disease that we tend to associate with the medieval period. However, since the beginning of recorded history the plague has sinisterly spread across the globe and wiped out up to 30-40% of the world’s population three times, as well as hundreds of smaller outbreaks. The most recent pandemic (a worldwide outbreak of disease) was less than two hundred years ago, and is arguably still going on. Several thousand cases of plague occur worldwide each year, and the plague has now been classified as a reemerging disease. While we may view the plague as an ancient disease, when we consider the facts that we lack a vaccination, there are antibiotic resistant strains, and the pathogen has been utilized for biological warfare, it is very much a modern issue.
Source: nocturnalmoth (click for gallery)
Remember my past post on botulinum toxin, the deadliest substance known to mankind? Well, it’s time to visit the second runner up. Tetanospasmin is a neurotoxin created by another member of the Clostridium genus: Clostridium tetani. That is one genus you don’t want to mess with! This particular member of Clostridium is the cause behind all those lovely tetanus shots and boosters you have been subjected to through the years. When you consider the fact that you’re being vaccinated against the second deadliest toxin in the world, maybe you won’t mind the needle jab quite as much. In a rather bizarre twist, the neurotoxin has no apparent use or benefit to C. tetani in its natural environment. The intoxication of other organisms, such as us, appears to be mainly incidental.
Photographs adapted from cedarcrest.edu
If you had to name the most epic, mindboggling bacteria in the world, Deinococcus radiodurans would be a top contestant. D. radiodurans has managed to make it into the Guinness Book of World Records, quite the feat for microbiology, and is pretty darned close to invulnerable. It is the most DNA damage-tolerant organism we have ever discovered. One of its natural habitats is the frigid dry valleys of Antarctica and it can also survive in a vacuum (think outer space!). There is no phage or virus capable of infecting it, and it can survive over six years with no water [2,3]. D. radiodurans shrugs off having its genome shattered into thousands of pieces, while other organisms die with only a handful of breaks. Last but not least, it can survive 2,000 to 6,666 times the gamma radiation that would kill a human and 250 to 5,000 times the UV radiation used to kill microbes in our water supply [2,4]. Luckily for us, it is so focused on being the coolest microbe around that it has no pathogenic qualities. In fact, there’s no sign of it ecologically interacting with any other organism out there.