Friday, November 11, 2016


Sitting in North America we usually think of pandemics as something in horror movies or news from across the ocean.  They are a natural phenomena made more critical by modern life.  "Pandemic" could have been a very boring recital of scientific data, but Sonia Shah has made it very interesting, like a detective novel uncovering a variety of factors for past pandemics and predicting likely future configurations.

The pathogens that lead to epidemics and pandemics have always been in our midst, but modernization has provided new opportunities.  Mixing of animals with humans and poor waste management.  As transportation improved such as the developmnet of steam boats allowed spread of diseases that might previously have died a natural death.

It is not just humans that are effected, but animals can have their own episodes as well as cross contamination between species.  Amphibians were decimated in 1998.  Wild birds are not normally able to infect humans, however an overlapping with domestic birds and pigs sped up new variations that could and did infect humans.  Bats were another carrier of disease.

In Egypt in 2009 to combat a contagious disease over 300,000 pigs were killed.  They had been raised by the Christian minority and were responsible for dealing with about 60% of citizen trash, thus their demise led to other serious problems.

Political decisions play an important role.  One of the richest banks in the world, J.P. Morgan was connected to a cholera epidemic.  A more logical source of clean water for the city of New York was the Bronx, but using it was blocked to give one banking group an edge.  Cholera occurred with the less healthy water supply.

In south Florida during the 2008 financial problems, large numbers of foreclosures led to abandoned swimming pools which proved to be breeding grounds for mosquitoes.  In 2009 there was an outbreak of dengue.  As sea level rises due to climate change salt water mixes with fresh water complicating the situation.

Science establishment, like other establishments will ridicule new conceptions.  Some individuals had discovered the source of specific diseases and even cures, but they were not always taken seriously.

Quarantines were used effectively as early as 1374 in Venice, but efforts conflicted with trade interests.  Political authorities have too often tried to suppress information about infectious diseases for fear of hurting business.  Examples were given for Italy (1911), China (2002), Cuba (2010 and 2012), Saudi Arabia in 2010.  Poor communications compounded the spread of disease.

The Canadian discoverer of penicillin, Dr Alexander Fleming cautioned the medical establishment of the dangers of over dosing.  Microbes develop resistance to drugs.  Humans often imbibe antibiotics eating farm animals that have been injected to promote growth.

In Haiti after their earthquake disasters, the UN called in troops from Nepal (that were cheaper than alternatives) that had been in cholera infected areas.  The conditions in Haiti were ripe for a cholera outbreak.  Driving into work today heard that Haiti is trying to organize a vaccination campaign for 800,000 people and recognize that will not eradicate cholera, but will help control it.

Vaccinations to prevent spread of some diseases has proved to be very effective, but when resisted has less impact.  There had been a history of forced vaccinations in Asia and more recently a campaign to uncover Osama bin Laden with its success hurt other efforts for vaccination.  In North America and other parts of the world some people have falsely linked vaccination to autism.  With high levels of vaccination a  herd immunity develops that gives some protection even to those not vaccinated.

Contagious diseases have played a key role in history.  Malaria kept Europeans out of the African interior for many years.  Europeans brought smallpox to North America and significantly weakened native resistance.

Climate change is having an impact as warmer temperatures allow a variety of pathogens to spread further.  A scary possibility is presented by fungi that can carry some threatening diseases is limited by temperature.  They infect cold blooded animals much more than warm blooded animals.  But as temperatures rise and the environment gets more compromised, fungi could represent a future danger for humans and other warm blooded animals.

It is very common for the general population and often politicians to look for scapegoats.  Among them may be immigrants, poor people, pigs and Asians.  Sonia gives an example of the  SARS scare of 2003 in Toronto that found many Asians shunned as it was thought to have originated in China.   One of my favourite movies, the Bollywood production of "Kal Ho Na Ho" started filming in Toronto, but overlapped with SARS arriving in the same city.  Before too long the film crew was transferred to New York and the script revised.  You can still see bits of Toronto in the finished product as they had already invested a good part of their resources.

The author uncovered in her research a link between sexual reproduction and pathogen immunity.  Originally all reproduction was asexual such as simply splitting cells  Asexual reproduction had most of the advantages against our favorite recreational activity, but sexual reproduction would not have survived if it did not offer some protection against pathogens as bio diversity is critical.  This history was due to studies by William Hamilton in the 1970's.  It was suggested that even in human mating activities that an underlying factor is pathogen fighting complementaries.

Read more about the author:

No comments:

Post a Comment