Archive for October, 2012

Panique au village: the revolution that caused an epidemic…

It boasts, struts, and flaunts with that kind of assurance that only comes from the mentality of knowing that you are right, and that even if you may be wrong, others will admire you for it. This is Paris.

Where other cities flowed and spilled out to occupy a space larger than its originality, Paris said enough is enough and contained itself. To this day only the “arrondissements” count. Anywhere outside “le périphérique” and you are demoted to “les banlieues”, with all the meaning that entails.

And so, with this in mind, we begin our story in 19th century Paris. Paris was suffering under the weight of its own self-importance. With an ever-increasing population, an almighty scourge was about to inflict itself on a population.

In the past, much like in the future, people will give it all up to live in cities. Immigrants from the countryside in search of employment came to Paris in their numbers — only to be met with the other side of urbanity’s progress.

The image of Paris was one only metaphor can convey. Paris was sick. So sick even the bourgeoisie avoided its inner ‘beauty’. By 1832 cholera would firmly appropriate this metaphor.

The story is one we could talk about in statistics. But the story of cholera in Paris in 1832 is one best talked about in revolutions (both scientific and social) and repercussions. The story of cholera in Paris is one that goes hand in hand with the mindset of Paris. The mentality and mindset of an entire city, right from its lofty bourgeoisie to its most lowly inhabitants.

Writers, academics, philosophers and the French societal elites became obsessed with poverty and the poor. We must remember that at this point in time not much was known about disease. Koch and germ theory were a few decades away. Thus poverty and its stench were written about and debated through this lense.

The perfect fictional disease goes something like this: the germ spreads in all directions, no safe place, no cure and no protection. It spreads when the diseased are still symptomless. Quarantine is the only escape — don’t let them in, not even your friend. Some are still in doubt of its existence — the naive will be the next to fall. Some call it forgiveness and some refer to it as God’s vengeance. The poor say the rich have the cure, the rich say the poor are the cause. Retired revolutionaries say it’s nothing more than a psychological war, invented by the press just to sell column inches. The nuns blame the whores and the whores blame the nuns. The scientists are lost without consensus. Some say it only infects the mind… the others say it steals the soul. The hobo on the street corner with the sign that reads “the end is nigh” knew it all along.

Translate that to 19th century Paris, and it ticks a lot of the boxes. Urban decay and a populus in panic. Immigrants were seen as symbols of such an urban decay. Poor and sick, not as a result of disease or poverty, but as a result of the victim’s own wrong doing. It is this mentality we must keep in mind when exploring 19th century Paris.

Then… cholera came to Paris!

Cholera attacked Paris with a discrimination that is hard to believe wasn’t personal — the disease claimed no other life outside of Paris in its early days. Passing through the countryside and with a single jump arriving in the nation’s capital. It first came to France in 1832 from England via Calais. March 15th was the first recorded case. Even with no railways at this time the disease moved remarkably quickly, taking only 11 days to traverse the 260 km to Paris. In March, 90 people died. In April it was 12,733. In 1832 the population of Paris was a meek 785,862 so this was no small portion of the damned and meek.

Like love, a new epidemic disease is most fatal in the first instance. Further epidemics of cholera would not leave as much of an imprint on the city. Due, in part, to the fact that Paris had learned its lesson.

The diseases came to a halt just as quickly and with as much verve as it had started. By July the worst of it was over and deaths were on their way down. Those that had fled the city looking for a safe place began to return. By September it was over. In total 18,402 people perished.

17 years would elapse before cholera yet again returned to Paris, by that time Haussmann had already recreated Paris in a Napoleonic image. The difference being that many districts had been demolished… to make way for light and air and space in the heart of the city. “Les grandes boulevards” being a symbol of this rebirth.

Haussman’s Paris was the much needed tonic for an ailing city. Slums, crammed, without air or light — people and animals living in the putrid flows of waste were now consigned to the history books. The proof was in the numbers — deaths per 100 000 inhabitants decreased at each successive wave of cholera epidemic in the 1800s across Paris.

The revolution that caused a disease

For three glorious days in 1830 there was revolution. The cholera epidemic of 1832 brought Paris right back to those three days. Social unrest as a result of the disease was not uncommon during 1832. Where some commentators saw the cholera epidemic as a direct result of revolution, others saw the two as evidence of an empire in decline.

Cholera and revolution were one and the same. Both hidden in plain sight until it was too late. Both unable to control. Both linked to indulgence and over-excess. Government’s preventive literature of the time distributed to the public about cholera cautioned Parisians to avoid “excesses of any kind.”

As a result, the disease was given a familiar face.

The official government report for the epidemic saw it necessary to look into the relationship between disease and revolt. Could civil unrest really cause or leave a populus more suceptible to disease? Is the fear and panic from political insurrection the same as the fear and panic from disease?

In the end, revolution, they put it, could not cause cholera. But as we have seen elsewhere — cholera can cause revolution.

Originally appearing in Australian Science

Kudlick CJ (1999). Learning from cholera: medical and social responses to the first great Paris epidemic in 1832. Microbes and infection / Institut Pasteur, 1 (12), 1051-7 PMID: 10617936

World Polio Day: The curious case of Nigerian polio…

Nigeria: Polio’s Last African Stronghold

It is easy to forget the rows of iron lungs that filled hospital wards at the height of the polio outbreaks in the 1940s and 1950s, and it is easy to forget that it starts with a simple fever and ends in irreversible paralysis. We have forgotten what it is like to suffer from this undiscriminating disease.

Fortunately, polio has largely been eradicated, but for those living in the countries in which it remains endemic, the disease continues to be a threat. Launched in 1988, the Global Polio Eradication Initiative has seen over the years seen a 99% drop in the number of polio cases. In 1994, the World Health Organisation (WHO) Region of the Americas, consisting of 36 countries, was certified polio-free. In 2000, 37 more countries across the Western Pacific Region all gained that stamp of approval and the 51 countries of the European region followed in June 2002.

Today, polio’s playground is largely restricted to three countries, which remain polio endemic. Whenever a global effort reaches its last mile, it serves to highlight the weakest among us – those with systemic problems unlike elsewhere. Regarding polio, these are Afghanistan, Pakistan and Nigeria.

Read the rest at Think Africa Press

Blogging global health…

Karen Grepin has a great blog on global health. In a latest post she rundowns some of the other great resources and blogs that are out there. What’s interesting is that it’s a list that takes a look at global health from all the angles. She remarks on the steady increase of global health blogs over the short time she herself has been blogging.

Some highlights on the list are the Center for Global Development Global Health Policy Blog, your one stop shop for all things policy.

Sarah Boseley’s Global Health Blog at the Guardian. I can’t throw enough superlatives at this woman, her writing, and the topics she covers. The right balance of old-fashined ‘newspaperly’ and new topics most papers wouldn’t even touch. I had the opportunity to meet her at AIDS2012 when she spoke at one of the media panel sessions. We talked about how, in the digital space, the line is blurring between blog and traditional article. She gave some good advice for freelancers wanting to write more on global health. Genuine class.

End the Neglect also makes Karen’s list. A blog I’ve written for on more than one occassion, and one that works tirelessly to raise the profile of neglected tropical diseases. With a never-ending list of guest bloggers that are all passionate about tropical diseases. The right blend of advocacy and information.

On Karen’s list is also I used to love this blog. It always served to highlight the latest research on tropical disease as well as some of the over-arching policy decisions behind it all. But for some reason it seems the blog hasn’t been updated in a while. Anyone know why?

There are plenty more on Karen’s list. And her blog itself is definitely one to add to the RSS feed.

Making the Moon…

It began… where it always begins — out there — in the vastness of space. What would it look like, that void of empty nothingness? So early on in the sound of creation, indescribable things all around. Not yet planets, not yet moons. Not yet defined. A titanic mass of rock. Different. Ugly and melancholic. Mischievous and cumbersome. As immediately as it’s gone, another smaller rock — about a tenth the size of its predecessor — in the other direction. We will come to realise that they are almost on the same path. A perilous planetary orbit around our sun.

One is a destroyer. The other is to be destroyed. The larger mass continues to grow as it gobbles up remnants from a cloud of dust. A hot, violent place with molten rock mantles wrapped around a dense hot core. On the other side of our sun swings the smaller mass. Both will have the same fate. On the far side, they collide. A cataclysm of apocalyptic proportions. In the vacuum/vacuous of space not a sound is heard. The smaller rock ploughs into its destroyer, like the little man in a fight with a lot to prove. It sinks deep into its molten core. Spiralling vast amounts of debris in long arcs into orbit. Debris, drawn together by nothing more simple than gravity, clump together, forging something close to a primitive moon. And with primitive moons come primitive planets. Finally, one defines the other.

This has always been the theory… at least, more eloquently put in the form of maths, calculations, numbers and analysis. The origin of our Moon by giant impact has always been the leading theory. Leading because it is able to explain so many features of the Earth-Moon system. From it’s current spin and angular momentum to its composition. Both Earth and Moon are very similar in their oxygen, tungsten, chromium, and titanium isotopes — leading to the logical conclusion that one was formed from the other, since these isotopes vary differently in different planetary bodies and meteorites.

However, simulations have shown this not to be the case. It is the Moon that should have a similar isotopic composition to the smaller impactor in this scenario, but instead it is made up mostly of material from Earth. Researchers had been tinkering around with the permutations and combinations to find such a scenario of impact that could satisfy all conditions. But to date, none had come close.

In papers published in Science by researchers from Harvard and the Southwest Research Institute, a new model is proposed. One that adequately accounts for a similarity in composition while also coming out with an appropriate mass for Earth and Moon. One paper describes two bodies of similar mass colliding slowly, while the other describes a giant erosive impact (with a small impactor) happening really fast. Both have the same solution to the problem. That is to have the Earth-Moon system losing angular momentum over time, reaching its present state through the Sun’s gravitational influence. Thereby, in the end, both coming to a compromise in explaining the physics and the overall geo-chemistry of the Earth-Moon system.

Originally appearing in Australian Science

Cuk, M., & Stewart, S. (2012). Making the Moon from a Fast-Spinning Earth: A Giant Impact Followed by Resonant Despinning Science DOI: 10.1126/science.1225542

Canup, R. (2012). Forming a Moon with an Earth-Like Composition via a Giant Impact Science DOI: 10.1126/science.1226073

The evolution of human mortality…

How long until we live forever?

The general consensus is that we are getting older and living longer. Despite consequences and kryptonite, it is getting easier to stay alive. Heaven can wait, it seems. Every year each baby born is expected to live 3 months longer than its predecessor of the previous year. This has been the case for the last 160 years. A stunning display of the ability we humans have to prolong the length of life. And it is this simple fact of life that economists and politicians are struggling to deal with — an ageing population and not enough resources to go around.

But outside of this there are some interesting and important questions to pose when thinking about human mortality. Does our mortality have a basis in our genetics? Researchers, publishing in PNAS, wanted to know if this reduction of mortality was as a result of a possible genetic shift or something much simpler. They wanted to understand the evolutionary context for variation in human mortality patterns — particularly comparing those of today to hunter-gatherer populations. Modern-day hunter-gatherer populations which are used as a proxy in evolutionary terms.

What they found was a significant decrease in human mortality. The vast majority of this mortality reduction has only occurred since 1900 and has been experienced by only about 4 of the 8,000 human generations that have ever lived. An astounding fact.

The average age-specific levels of mortality experienced through most of human existence hasn’t changed much. Before the late 1800s, humans in the lowest-mortality nations were not experiencing mortality much lower than was typical during most of human evolution. This “mortality revolution” is only a recent phenomenon. Given the rapidity of the recent mortality revolution and the simple fact that it is similar in different nations, researchers come to the conclusion that it seems highly unlikely that genetic change has played more than a minor role.

The profile is the same but the shifts are dramatic. After being born your chance of dying decreases, and continues to do so — until you’re ready to bring forth a new generation (sexual maturity). Then your chances get progressively worse. The shift between past and present is in the orders of magnitude. Up until age 15 or so, hunter-gatherers experience death rates greater than 100-fold higher than today’s Japanese and Swedish populations, and hunter-gatherer mortality remains greater than 10-fold higher for the entire lifespan.

Japan in 1947 is no different from Sweden in 1800; which is marginally better than the hunter-gatherers sampled. However, if you were a slave in Trinidad during the 19th century then you would have experienced the worst-case scenario for mortality. You had more chance of dying at any age than hunter-gatherers.

The longevity of humanity has had its bearing on another uniquely human facet — war. The evolution is simple — individuals grouped themselves into communities; communities became villages, villages became towns, and cities; states and empires arose from those foundations. Eventually, populations would go to war with one another in the hunt for resources and land to feed their ever increasing numbers of people.

In the past, human longevity has increased by removing the environmental factors that lead to death. Injuries and illnesses are less fatal. Nutrition counts for so much in the early stages of life. A greater proportion of us now have the right to such adequate nutrition. Education, medicine, sanitation and housing have all played their major part. We have democratised living longer. No longer does it belong to the fittest. No longer does it belong to a specific set of genetic characteristics.

In the end it is a study that throws up more questions than answers. Why does the human genome give humans a license to drastically reduce mortality by non-genetic change? The most interesting of which, however, is — for how long will life expectancy continue to rise and by what means?

Originally appearing in Australian Science

Image — source

Oskar Burgera, Annette Baudischa, and James W. Vaupela (2012). Human mortality improvement in evolutionary context PNAS : 10.1073/pnas.1215627109

What had I twaught…

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