Montezuma’s Revenge

Diarrhoea is considered by many to be a somewhat humorous disease. However, it is by no means a mere awkward, laughing matter in poor countries, especially if it affects children.

Many visitors who find themselves in the poorer countries of the world will notice within a few days that their stools have thinned and become much more frequent, with a number of very unpleasant accompanying symptoms — bloating, stomach cramps, and sometimes nausea and vomiting. Fortunately, in most cases, this kind of “traveller’s diarrhoea” will pass spontaneously within four days. Only about every tenth infected passenger will suffer for more than a week, with the fever still requiring more serious treatment. These inconveniences are caused by a very diverse range of bacteria and viruses, which can enter the digestive system through ingested water or food. Their names are unusual, such as “enterotoxic Escherichia coli”, “Campylobacter”, “Salmonella”, “Shigella”, “Norovirus”, “Rotavirus”, “Vibria”, “Giardia” and “Cryptosporidium”.

Therefore, in the poorest countries, “classic” mistakes should never be made — such as brushing teeth with tap water in a hotel, agreeing to add a few kindly offered ice cubes to an otherwise originally tightly closed canned drink, or consuming food that was not cooked immediately before being served, or a salad washed with hotel’s tap water. Diarrhoea in developing countries will affect every second to every fifth traveller from more developed countries, and most often younger people. It is especially common in the countries of Southeast Asia, the Middle East, Africa, and Central and South America, while Mexico is especially significant on the American continent. Interestingly, modern-day Mexico is the place where traveller’s diarrhoea got the name by which it is now known in popular culture — “Montezuma’s revenge”.

The man called Montezuma, or more precisely — Moctezuma II. — lived from 1466 to 1520 and ruled the Aztec civilization. He, therefore, lived even into his fifties, which was quite a decent age for that time. Still, he could have probably lived quite happily for a few more years, had he not been killed by the Spanish conquistador Hernando Cortez. Through this act, Cortez added large parts of present-day Mexico and Central America to the Spanish crown. The Spaniards, lighter-skinned people, were remarkably cruel to the darker-skinned domicile population in the area, and as they also transmitted European infectious diseases to which the Aztecs did not have any immune resistance, the struggle between the two civilisations was unequal. A rare inconvenience that the European newcomers would feel in their conquest was frequent diarrhoea. This is why it was named “Montezuma’s revenge” — it was a rare counter-measure that Aztec’s culture and territory were able to inflict on its superior conquistadors. Thus, in the eyes of the locals of Latin America, every fair-skinned tourist who visits Mexico and gets diarrhoea becomes a victim of “Montezuma’s revenge”.

However, one has to wonder how Cortez could, having come from Europe with only a few hundred men, conquer the whole proud kingdom of the Aztecs, of whom there must have been hundreds of thousands? It is estimated that Tenochtitlan must have had about 200,000 inhabitants in the early 16th century, making it one of the largest cities in the world at the time, comparable in size to the two largest European cities of that period — Paris and Naples.

This is an interesting question, on which historians fail to completely agree, but it points to several important circumstances that helped Cortez out. Firstly, any microbial cause of influenza, measles, smallpox, typhus or other diseases from Europe that survived in the bodies of sailors on Cortez’s ships would have killed most Aztec populations who, throughout history, have not had the opportunity to acquire immunity to these diseases. The huge death toll of the Aztecs due to epidemics of new infectious diseases was inevitable.

In addition, Montezuma opened the entrance to Tenochtitlan to Cortez and greeted him in a friendly manner, as his guest. Part of the reasons was that Aztecs were impressed by the Spanish soldiers, the horses they rode, and the pistols and rifles they had with them. However, what probably cost them the most was the old legend, which they obeyed. The legend said that one day the “God of the white skin” would descend among their people, and the Aztecs must at all times be ready to host him. Montezuma probably concluded that Cortez was that God from the legend and made quite a mistake.

Notwithstanding this big error of King Montezuma, whom Cortez immediately captured and later killed, Tenochtitlan did not only “fall with a whisper”. Furious at the capture of Montezuma, the Aztecs soon changed their welcoming attitude of their unexpected visitors, who arrived from afar with their large ships. They raised an uprising in June 1520 which prompted the Spaniards to withdraw from the city. Cortez then began gathering allies among the rivals of the Aztecs. The following year, he gathered all his new allies and managed to completely surround the capital for three months. This eventually lead to the surrender of Tenochtitlan. Hunger and infectious diseases decided the final fate of the capital and of the entire Aztec kingdom. The first strong blow was the smallpox epidemic of 1520, which was followed by two major epidemics of typhoid fever during the rest of the 16th century. Today, historians believe that smallpox was most likely the cause of death for at least half of the entire Aztec population.

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The twenty million inhabitants of Dhaka in Bangladesh consider the neighbourhood Banani to be quite elite, so many good hotels were built there. A great film about a post-apocalyptic civilisation could be made in Banani because it is a rare place with bare concrete buildings about twenty floors high, which somehow look at least a few centuries old. Some of them also have elevators. But in every elevator, the warning “Don’t panic” can be found because they do not always have reliable electricity. On my travels to Bangladesh, however, I tend to try my luck with these elevators, because if the power goes out, I will at least be able to tell stories about spending part of my life in pitch darkness, stuck in an elevator on the 17th floor of a concrete hotel in Bangladesh. At the same time, on the ground floor, there are guards who protect entrances to these tall buildings and their better-off residents. Meanwhile, out on the streets, which are often ruined by ravines, there are little less fortunate people, in indescribable numbers, trying to survive the best they can. Many of them inevitably suffer from diarrhoea.

In a country that has a reasonably small territory, and with a population of 163 million, perhaps hundreds of millions of cases of defecation can be reached on a daily basis, prompting a massive need for a good sanitation infrastructure. Many of these episodes take place outdoors, as toilets and sewers in Bangladesh are still a luxury for many. This represents a risk for the safety of food and water, creating a vicious circle. A very specific problem with diarrhoea in Bangladesh is its combination with the worst traffic jams in this part of the galaxy. When getting into any vehicle in Dhaka, it is remarkably important to be absolutely diarrhoea-free. Otherwise, it is not possible to get anywhere in less than a few hours and during that time staying in the vehicle is very much advised. If diarrhoea strikes while in a car, van or bus, every second of being stuck in the vehicle tends to feel like hours, unfortunately. In local traffic, drivers typically pull out their seat belts so that as many people as possible can fit inside the vehicles. Elsewhere, such a move would be life-threatening for all passengers. But in Dhaka, even the fastest vehicles do not move any faster than a four-year-old can walk.

In all countries where there is a high risk of being ‘’overtaken’’ by Montezuma’s revenge, I always carry a dozen chocolates and even more cans of Coca-Cola for at least seven days, a few decagrams of Imodium tablets and five rolls of toilet paper. By no means, and I really do mean by no means, do I ever drink the water unless it comes from some reliable foreign company. When I arrived at the hotel in Banani, I was greeted in my room by two bottles of water and a sterilised glass. The only problem was that this bottled water was produced by the company ACME, as it was pointed out in capital letters on the label. Anyone who grew up watching cartoons about Road Runner and Wile E. Coyote will know that the ACME company was behind the production and instant delivery of some of the most unimaginable possible products (e.g., “1000 Tornado Capsules”), none of which ever worked. That’s why it entered popular culture as a synonym for catastrophic products, the use of which would always harm the poor Wile E. Coyote. That’s why I always drink my Coca-Cola supplies first, and only when I run out do I consider ACME water.

I suppose I deliberately wrote these last few paragraphs with a tongue-in-cheek to remind the reader that diarrhoea is considered by many to be a somewhat humorous disease. However, it is by no means a mere awkward, laughing matter in poor countries, especially if it affects children. Fifteen years ago, two million children in the world would die each year from diarrhoea, that’s more than 5,000 every day. If you’ve ever wondered where the world’s most famous centre for diarrhoea research in poor countries is, which I doubt you have, it’s the ICDDR,B in Dhaka (an acronym for “International Centre for Diarrhoeal Disease Research, Bangladesh”). This centre operates within their large Institute of Public Health and Nutrition.

Every cloud has a silver lining, and diarrhoea in children is relatively easy to combat through major public health programmes. The reason is that the mother of a small child, no matter how young and poorly educated she may be, and no matter how far away she lives from the nearest doctor, can still easily recognise that her child has diarrhoea, and then prepare the medicine herself — the so-called “oral rehydration bag,” with a solution that will keep the baby alive. It is, therefore, necessary to educate young mothers about the problem and the solution. Two or three decades ago, only half of the world’s young women would have completed their education at elementary school, but now more than 90 per cent of them are completing elementary school. Therefore, they now accept health education with interest. All they need to save the life of their sick child is access to water, fire, salt and sugar.

As soon as a small child develops diarrhoea, which is something that is practically impossible not to notice, then it is necessary to boil about a litre of water on the fire, put six teaspoons of sugar and half a teaspoon of salt in it, and give the solution to the child to drink. This action will make the difference between a child’s life and death. Thanks to the understanding that diarrhoea is dangerous for young children, child mortality due to diarrhoea has been significantly reduced today. The number of children dying from diarrhoea has dropped from two million a year, which was the figure back in the year 2000, to less than half a million a year by the year 2015. The total number of children in the world has grown, so the relative reduction in this mortality has actually been more than 80 per cent over the past fifteen years. It would be nice if other causes of child death could be so easily diagnosed and treated, but this is not the case for many of them, which I will explain in further detail below.

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When our small group of experts, working for the World Health Organisation in the early years of the 21st century, first unequivocally found, to everyone’s surprise, that pneumonia and diarrhoea are not just occasional, uncomfortable hassles, but are actually the cause of half of the child deaths worldwide, it led to extensive action in dozens of poor countries to curb the two diseases. Child mortality in the world has halved since those days. At the time, I was conducting research on pneumonia, but also developing methods that prioritised investment in research and public health interventions that could combat the dire consequences of these two diseases.

Curbing diarrhoea was much easier, as I explained in my previous text. Pneumonia in children, however, has proven to be a much more persistent problem in recent years. A baby, usually in its first or second year, seems warmer to its mother than usual. Then the baby becomes uninterested in breastfeeding and in food. Maybe there is a little sniffling, too, but that still means very little because such episodes are common in young children. A few hours later, the baby begins to breathe with more difficulty and more hoarsely. With each breath, the fight to hold onto life begins. The intercostal muscles begin to visibly retract due to the effort exerted by each breath.

This is a sign that the child needs to be taken to the hospital immediately, given antibiotics and an oxygen mask, and perhaps be assisted in its breathing. But even though mothers can already see clearly that something is wrong with their child, they don’t recognise the seriousness of this danger, nor do they know what to do in such cases. They usually do not seek help, and unfortunately, the child could die by the time morning rolls around.

If the mother does choose to seek health care, it can be located dozens of kilometres away. This path then needs to be walked, with the sick child in tow, because the affected families are usually poor and live out in the remote countryside. The nearest health care post may have antibiotics in stock on the shelf, but they also may not have any, because replenishing drug stocks in poor countries is often delayed. If antibiotics are available, they may work against the pathogen that attacked the child, but they also may not. That depends on whether it is a virus that has caused the problem or a specific bacterium. The mother will have to leave a few more of her children at home during this time — perhaps five, six or nine of them — and their father often works out in the fields or as fishermen, to provide food for his family.

Therefore, without a mother in the house, there is often no one to feed the other children. When the mother returns from the doctor, she may find two or three more of her children with the same disease. She has no money to go to the hospital in the city, which is also often far away. She doesn’t even have anywhere to stay in a big city if she needs to leave her child in the intensive care unit there. During that time, her children are all left alone in the countryside, and at high risk of getting sick in a similar way. This is a very common scenario within which, in the end, the number of deaths of young children from pneumonia is still large.

That is why it is important to ensure universal health care which is accessible to absolutely everyone. There are general practitioners in Bangladesh who care for more than one hundred thousand people — so it would be like the whole town in Europe only having one general practitioner. In addition, pneumonia is best prevented, if possible, because it is very difficult to treat in such conditions.

Therefore, over the past decade, enormous efforts have been made to vaccinate hundreds of millions of children against the two most common bacterial causes of pneumonia — Streptococcus pneumoniae and Haemophilus influenzae type B. This was made possible through a global initiative, a mechanism called “advance market commitment” (AMC), where philanthropists like Bill Gates pay part of the money and the governments of developed countries pay the other part, thus significantly expanding the market for vaccines against these two pathogens. In developing countries, namely, there are about ten times more preschool children than there are in developed countries. Thanks to such an increased market and secured funds, investors were able to enter negotiations with the pharmaceutical industry to significantly reduce the prices of these vaccines, by more than two-thirds of the market price before this initiative. That allowed for the continuation of a revenue stream for the pharmaceutical industry from vaccines that were sold, but the AMC programme brought the vaccine prices closer to what developing countries should be able to afford in the foreseeable future. Thanks to such a reduced price, children from poorer countries could also be protected by vaccination. Although reduced-cost vaccines were still too expensive for most developing countries, the implementation plan of the AMC programme also included the prediction of the expected economic growth of these countries.

In addition to receiving the vaccine as a gift immediately, future economic growth of poorer countries should allow for a gradual increase in their contribution to the cost of the vaccines. The AMC programme aims to adjust this participation to the progress in the economic development of each country until they themselves become wealthy enough to fully cover all the purchasing costs of vaccines.

This pragmatic approach, which required the goodwill, coordination and cooperation of all stakeholders, found a solution to preventing pneumonia in children around the world whether they are wealthy or poor and have the access to health care or not. This avoids the need for treatment in many children, which is difficult for their parents to organise and afford, as I described earlier. Importantly, through the AMC vaccine assistance programme, the rules of constructive behaviour have been imposed on poorer countries. Those that do not adhere to the strict conditions, and where corruption and irregularities are found, will be denied this assistance. Unfortunately, there are also examples where local politicians in some poor countries have been denied AMC vaccine donations due to apparent corruption, and the children in their countries have continued to die, but this has not affected politicians’ behaviour.

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Clearly, diarrhoea is not a disease that is terribly attractive for anyone to study, but some pioneers of global health have dedicated their entire careers to fighting this disease. Probably the most well-known among them is Professor Robert E. Black, the longtime head of the Department of International Health at Johns Hopkins University in Baltimore, USA. Professor Black was also the leader of the World Health Organisation’s advisory group, known as CHERG (abbreviated from “Child Health Epidemiology Reference Group”). This group, funded by a donation from the Bill and Melinda Gates Foundation, was the first to determine the causes of child deaths in the world. This only happened in the first years of the 21st century. It has thus triggered a series of developments that have resulted in a significant reduction in child mortality worldwide.

I worked in the CHERG group, under the coordination of Professor Black, for more than fifteen years as a consultant and leader of the working group for pneumonia, meningitis and sepsis. As such, I had the opportunity to learn a lot from him. Therefore, I was very happy to learn that Professor Black received the Gairdner Award for Global Health for his achievements in the treatment of diarrhoea back in 2011. Given that there is no “glamour” in studying this deadly disease, I was really glad that the Canadian commission for this extremely prestigious award still recognised how much progress has been made in reducing global child mortality thanks to the curbing of diarrhoea. Prof. Black was a true pioneer in the research of childhood diarrhoea, and prevented and treated it over the years he spent working in Bangladesh, India, Peru and Zanzibar. Through his research, he also showed how the addition of zinc to children’s diets can strengthen their immune protection against most causes of diarrhoea. His research prompted the introduction of dietary zinc supplementation as a means of both preventing and treating diarrhoea in more than forty developing countries.


Declaration: Professor Igor Rudan, FRSE, is the President of the International Society of Global Health; co-Editor-in-Chief of the “Journal of Global Health”; Joint Director of the Centre for Global Health and the WHO Collaborating Centre at the University of Edinburgh, UK.

TWITTER: @ProfIgorRudan

FACEBOOK: Professor Igor Rudan



Image credit: Sylvie Charron,

Director of the Centre for Global Health and the WHO Collaborating Centre at the University of Edinburgh, UK; Editor-in-Chief, Journal of Global Health