The swine flu seems to be taking a big toll these days and it caught most (if not all) of us completely unprepared. However, there seems to be a lot of progress made and if everything goes alright, it will be contained really soon, without getting anywhere close to the epidemics we are about to present.


Cholera is basically an infectious gastroenteritis caused by a bacteria called Vibrio cholerae, and it’s transmitted by eating food or drinking water that has been previously contaminated with the bacteria from other infected persons; so as you can guess, it spreads like wildfire, and it’s also one of the diseases that can kill you faster (just three hours after the infection). However, most infections are mild, and just 5 percent of those infected present diarrhea, leg cramps and heavy vomiting. A strong organism can defeat it easily if well hydrated for a long period of time; the disease presents itself with dehydration and diarrhea in all cases.

Current cholera affected areas around the world

There were several cholera outbrakes. It is endemic from the Lower Ganges River, but in the seven years that the first pandemic lasted (from 1817 to 1824) it reached almost every country in Asia. Also, it killed some 10.000 British soldiers, drawing some European attention too; it was actually the Royal Navy movement that helped the disease spread and cover such a vast territory before receding, ironically, because a very cold winter.

The second cholera pandemic was way more devastating, and it reached the European capitals of the time, Paris and London. During the industrial revolution in the mid 1800s, conditions were pretty bad and everybody’s health was shaky. At the time, doctors pressed for better conditions, believing the disease was air-related, but when they found out it was related to the water people were drinking, the number of cases greatly decreased. However, it killed several hundreds of thousands of people before that, some estimating a number over a million.

Chilred of cholera victims were quarantined without questions

Chilred of cholera victims were quarantined without questions

Believe it or not, there were seven cholera pandemics all in all, causing several millions of deaths. Most of them affected Russia, but due to improvements in the living conditions and health systems, most countries have been able to deal with it and defeat it quickly, whenever the case. Even in the 21th century, there are local epidemics that affect thousands of people and there is still a chance of an outbreak, especially in poorer areas or wherever there’s a lack of water.

Doctors without frontiers still fight with the many areas plagued by cholera

Doctors without frontiers still fight with the many areas plagued by cholera


Malaria is a disease carried by protozoan parasytes and it affects tropical and subtropical regions. Every year there are at least 350 million cases of malaria throughout the world, killing 1 million people or more. The irony is that it is a disease that’s attracted by poverty, and it also attracts poverty; the disease is a major public health problem throughout Africa, but epidemics occur in areas that aren’t normaly exposed to it, taking health services by surprise and resulting in numerous cases. Mosquitoes play a crucial role in carrying the disease and spreading it.

However, nowadays large scale epidemics are fairly predictable, affecting people with a weakened immune system. It occurs almost without exception in cataclysms, that can be either natural (earthquakes or other natural disasters) or man made (wars, logging, irrigation or other agricultural projects, etc).

Malaria epidemics often come at the worst times, as a consequence

Malaria epidemics often come at the worst times, as a consequence

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There have been some claims of erradication, but this has been proven untrue a number of times. The thing is, the disease constantly adapts and it has the greatest selective pressure on the human genome in recent history.

The black death

Illustration of a city plagued by the black death

Illustration of a city plagued by the black death

The black death was perhaps the deadliest pandemic mankind has ever faced. It came in three forms: the bubonic, pneumonic, and septicemic; each was deadlier than the other. It is now believed that all the forms were caused by a bacteria called Yersinia pestis that was carried by fleas, with the help of rats. The disease was also called the bubonic plague, because it presented itself with buboes (swellings in lymph nodes) and the symptoms included very high fever, headaches, nausea, vomiting, and even delirium in some cases.

Despite the fact that there was more than one epidemic, one rose above all others, and it will be rememberd as the great plague (1347-1351), killing 75 million people throughout the world (when the worlds population was ~350 million) and halving Europe’s population, with a mortality rate that sometimes went as high as 75%. It returned every generation (!) until sometime in the 1700s. It’s estimated that there were all in all somewhat 100 outbreakes.

Doctors wore protective clothes and beaks to prevent infections

Doctors wore protective clothes and beaks to prevent getting sick, but it didn't work all the time

It’s still uncertain where the great plague originated, some believe it was in central Asia, while some believe it was somewhere near the Black Sea. What’s sure is that from there, it went to Italy where it began a rampage of death through Europe like no other. At the time, people had virtually no defense and no knowledge of the disease, and so, men, women and children without discrimination were caught in the onslaught, allowing panic to settle in. The result was a major loss of trust in the Church, as well as a blaming of minorities for the plague (including jews, gypsies and lepers).

The Italian writer Giovanni Boccaccio was living in Florence at that time, and he survived the plague. This event inspired him to write the Decameron, one of the best literary works ever, describing seven men and three women that flee from the black death. He describes in the book that “No doctor’s advice, no medicine could overcome or alleviate this disease“, which was pretty what everybody was thinking at the time. Whether you lived or you died, was just a matter of luck. It was a perfect example of a Malthusian limit. Its impact was so big that it defined the art currents for years and years to come, and it decided political situations in many cases.


Acquired immune deficiency syndrome or acquired immunodeficiency syndrome or AIDS, is something you should know if you’re over 18 14… man times change. It’s a disease caused by the human immunodeficiency virus (HIV). The disease basically destroys your immune system from the inside, leaving the infected person vulnerable to infections and tumors.

It’s transmitted by “anal, vaginal or oral sex, blood transfusion, contaminated hypodermic needles, exchange between mother and baby during pregnancy, childbirth, or breastfeeding, or other exposure to bodily fluids”, according to wikipedia. Today, AIDS is a pandemic and it will probably remain at this status for quite a while; it’s also responsable (not totally, but significantly) for the retardation and lack of human capital in sub-Saharan Africa, basically making economic growth impossible. Despite some vaccines or treatments that slow down the disease and some reports of people that have been cured, there is, at the moment, no definitive vaccine or cure.

AIDS kills, almost every cemetery in the southern part of Africa has this kind of tombs

The truth is, the situation is pretty dire. Because it’s a disease that’s transmitted sexually, if you want to tackle it, you have to inform people about contraceptive methods that also prevent disease transmitting and also, basically, give them condoms. Sadly, things aren’t moving very fast and there is still very much to do regarding both this issues. Mother to child transmission is also a big issue, and many clinics encourage people to get tested, especially if they had unsafe sex or if they came in contact to an infected person. So get informed, here or here or google it or even better, ask your local doctor.

The Spanish flu

In 1918, the world was watching the end of World War I, living conditions had improved greatly and significant breakthroughs had been made in medicine, when a strain of influenza that seemed no different from the others turned so deadly and undefeatable that many believed the end of the world was coming, or perhaps divine punishment for the world war. The virus hit very hard and very fast, and it had a very uncommon way of attacking young and healthy people, unlike the usual influenza, that attacks infants, elder people or those with a weakened immunity system, and to this day, most researchers label it as the deadliest disease.

The fact that the age distribution was completely reversed caused panic and almost inflicted a total collapse of European societies. Instead of going for the weak, it went for those who were doing all the work and maintaining it, but at the end of 1918 it went to an abrupt end. It’s still unclear why that happened.

The pandemic affected a billion people (more than half of the population) and killed three times more people than WWI (~100 million). The thing is that even in areas where mortality rates were low, it caused a social disaster, because it incapacitated the working population. Stores everywhere were closed, doctors were too sick to cure people, grave diggers were too sick to bury and everything was frozen.

So what stands in the way of another such influenza?? We would be tempted to say the better living conditions, the better health system, our superior knowledge of medicine, but the truth is… nothing. It will probably hit less harder in urbanized areas, but in third world countries, things are pretty much as they were a hundred of years before, and the fact that people travel from anywhere to anywhere in the world can help spread it and also, a more dangerous strain could appear. Still, hopefully, researchers throughout the world could figure it out before anything too bad happens