Thanksgiving and Immunity

This Thanksgiving, let’s take a moment to look at the colonization through the lens of public health by examining the impact that intercontinental travel and first time contact with outside populations had on European settlers and the established Native American tribes in the Americas throughout the 15th to the 19th centuries.

Before contact with the Europeans, Native Americans suffered relatively few diseases (in comparison) and were generally very healthy. This is largely due to their culture and lifestyle. Native Americans did not often live in as close quarters as their European counterparts, giving infectious diseases fewer avenues to thrive and spread from person to person. Additionally, their culture supported the sharing of food and resources. This meant that very seldom did someone in a tribe go hungry or become malnourished because it was a source of pride and culturally normal to display wealth by sharing crops and resources with less fortunate tribe members. It is also important to understand that Native Americans did not domesticate animals in the same way that Europeans did. This reduced the opportunity for zoonotic infections to jump from animal hosts to human hosts. As a result, the prevalence and types on infections that permeated the communities in the Americas were inherently different than the landscape of European diseases. In the article “Health Conditions Before Columbus: Paleopathology of Native North Americans” indicates that while the Native American populations already experienced infectious diseases and chronic conditions, there are numerous diseases that caused epidemics upon the “discovery” of the New World by European explorers. Examples of “diseases that were not present in the Americas until contact include bubonic plague, measles, smallpox, mumps, chickenpox, influenza, cholera, diphtheria, typhus, malaria, leprosy, and yellow fever.” (Side note: You can read about the eradication of smallpox on the blog here!)

Many of the infections brought to North America by European settlers were completely foreign to the natives. As a result, these populations lacked immunity or sufficient resources to fight infection. Many of the most devastating infections from across the Atlantic were diseases that stemmed from the cramped living quarters in cities and contact with domesticated animals. The diseases spread among trade routes and other avenues, affecting many native populations long before they ever came into contact with the European explorers. The article “The Cultural Implications of European Disease on New World Populations with Primary Focus on the Abenaki, Powhatan, and Taino Groups” indicates that “the population of the American continents may have fallen by 90 percent between the beginning and end of the 16th century.”

The implication of these disease exposures was one of the largest unintended upheavals of human population in recent history. And while infectious diseases are known to be large factors in shaping the course of human history and evolution, this historical event was largely unprecedented in that is virtually pitted one evolutionary line against another in an “Old World versus New World” sort of fashion. In fact, an article in Science Magazine indicates that due to exposure to new illnesses, specifically during the occurrence of a smallpox outbreak approximately 175 years ago, there was a genetic shift in the genome of the Native American population. What is significant about this shift is that the change occurs in the portion of the genome responsible for the composition and function of our immune system. It appears that there was some sort of genetic selection occurring that had a huge impact on our genome as a population. Due to the increasing globalization since that time, the article states that there are some relatively new (in the history of living species) genes that appear with almost 100% in the human genome that were not as prevalent almost 200 years ago.

While there is infinitely more we could do to delve into this topic, a brief reminder of the unique history of the Americas, particularly as it pertains to our health. Today, have a happy thanksgiving and be thankful for your amazing immune system!


Air Pollution

Air pollution is unfortunately not a new issue among our civilization. There have been health risks and diseases linked to poor air quality documented since at least the beginning of the Industrial era. In fact, this is not even the first time I have discussed the negative effects of air pollution in a blog post. I discussed “The Great Pea Souper” on The Phiver blog for UT Dallas’s Public Health Initiative back in February. This was a smog event in London in 1952 that caused thousands of respiratory problems and deaths due to stagnant, polluted air in the city. The city was essentially shut down until the weather patterns changed and moved the smog out of the city. The UK’s BBC has a video about it here.

Recently, there has been a similar smog covering the city of Delhi, India. Due to the severity of the pollution, CNN states, “all public and private schools [were closed], requesting instead that … children remain indoors… they banned incoming trucks and halted civil construction projects” and are even contemplating a partial ban on private car use as a means to limit the resident’s contribution to the polluted air in the city. To put this into perspective, Berkeley Earth has a study that equates air pollution to damaged caused by smoking cigarettes.

Air quality levels are monitored globally due to their link to health conditions. The WHO outlines the process of measuring condition and why it is so important. Of all the cities that the WHO collects air quality data on, 14 of the 15 worst cities are located in Asia and the Middle East. The lone remainder is Cameroon in Africa. The US cities with the worst air pollution and with the cleanest air levels are determined in an annual State of the Air report. National Geographic does a great job of breaking down the report into brief highlights about the US regions. This makes the states of US air quality a little easier to grasp. While we are not the worst country for air pollution, we certainly do have our problems with achieving clean, healthy air.

If you are interested in determining the quality of the air in your zip code, you can determine this on the American Lung Association’s website.

Famous Names · Uncategorized

Dr. Harvey Cushing

This month, for the third edition of “Famous Names in Public Health!” I will focus on the medical side of healthcare by recognizing a figure who contributed significantly to the fields of neurosurgery and epidemiology, Dr.Harvey Cushing.

Dr. Cushing graduated from Harvard Medical School in 1895 and he continued his medical training in surgery at Johns Hopkins Hospital. During the time of his training, neuroscience was a rapidly growing field of medicine making numerous advances and discoveries. Neurosurgery claimed Dr. Cushing’s professional interest as he drifted from general surgery into peripheral-nerve surgery. After this, he became more and more focused on the brain, ultimately making neurosurgery his focus for his career. In 1913, Dr. Cushing accepted a position as the surgeon in chief at Peter Bent Brigham Hospital that was associated with Harvard. He continued to practice neurosurgery even in this position. According to the article “Harvey Cushing: A Life in Surgery,” Dr. Cushing’s major interest was cerebral tumors, leading him to study and treat more than 2,000 verified tumors. These studies are documented within 5 books published between 1912 and 1938.

Throughout his years of practice, he developed the Cushing Brain Tumor registry in 1902. It is an archive “of over 2,200 case studies which includes human whole brain specimens, tumor specimens, microscopic slides, notes, journal excerpts and over 15,000 photographic negatives dating from the late 1800’s to 1936. ” What makes this collection even more unique is that Cushing was an avid bibliophile, so he meticulously recorded and documented each patient story, including the stories of the patients of the collected specimens. Today, this provides a unique history of neurosurgery’s progression throughout his career.

Most notably, Dr. Cushing made numerous contributions to science and medicine, including the control of bleeding with silver clips, the development of electro-surgery, the development of technical methods for performing surgical operations, an increased understanding of intracranial pressure, the development of the pathological classification of glioma, and the description of pituitary basophilia (also known as Cushing Syndrome). Through this work on the pituitary gland, Cushing is also considered to be one of the founders of endocrinology. Even more of his pioneering research and medical practice can be found here.