Student guest post: Cholesterol, a bacterium, and gallbladder cancer

It’s time for this year’s second installment of student guest posts for my class on infectious causes of chronic disease. Fourth one this round is by Kristen Coleman. 

If you are anything like me, you have been told countless reasons over the years why we must watch what we eat, keep our cholesterol intake down, and try to work out. It shouldn’t really come as a surprise then that I, since I am a public health student after all, aim to convince you of yet another reason why a healthy diet and exercise are valuable. What is this huge reason to avoid Big Macs and think about taking the stairs instead of the elevator you ask? Well, it may help you to prevent gall bladder cancer, is all.

All of this begins with gallstone formation. Gallstones are hard deposits, usually of cholesterol, that become lodged in your gallbladder over time. Your gallbladder is an organ that helps to aid in digestion through the storage and release of bile which helps to break down fats in your small intestine. The gallbladder is located on the right side of the body attached to the liver. The process of gallstone formation is called cholelithiasis. In this process, cholesterol, which is not very soluble, becomes clustered together in droplets in the bile called micelles. This cholesterol droplet then hardens into the crystals that make up a gallstone. Obesity causes bile to transit the gallbladder less rapidly and increased cholesterol in the diet means there is more cholesterol available to form stones. It does not require and active imagination then, to understand how obesity and high cholesterol intake contribute to stone formation, but how does this all tie into cancer you ask?

It all comes down to infection with a bacterium known as Salmonella typhi. Yes, this is the same bacterium that causes Typhoid fever and was the malady that afflicted the famous Typhoid Mary. While many people may become infected with S. typhi over the course of their lives, those individuals with gallstones are 6-15 times more likely to become carriers of S. typhi in the gallbladder. This is important because those people with a chronic infection of S. typhi have been shown to have 3-200 times higher risk of developing gallbladder cancer then non-carriers. Furthermore, chronic carriers have a 1-6% lifetime risk of developing gallbladder cancer. In fact, gallbladder cancer is so linked to S. typhi infection that gallbladder removal, called cholecystectomy, is recommended for those people with gallstone disease who live in high risk areas. Where is a high risk area? Most developing countries of the world are high risk areas for S. typhi, especially countries in Asia, Africa, and Latin America. This means that travelers from the USA and other developed countries to these regions are at risk for developing the infection. However, even at home in the USA, low risk doesn’t mean no risk, and we should be vigilant against emergence of this bacterium.  

In conclusion for all my gallbladder-containing friends out there (I make this distinction because I, myself, am no longer at risk for gallbladder cancer since I had mine removed in 2006 after a bout with gallstone disease) stay aware of your cholesterol levels and pay attention to making sure you have a healthy diet because, like every health care professional will tell you, it might just save your life….perhaps in a way you don’t expect!


  1. University of Maryland Medical Center. Gallstones and gallbladder disease. Online
  2. Ferreccio, Catterina. Salmonella typhi and Gallbladder Cancer.

Center for Disease Control online source.

The Epidemic: Typhoid at Cornell

In the United States, we tend to take our clean drinking water for granted. Even though there are periodic concerns which bubble up about pharmaceuticals or other chemicals in our water supply, we typically believe–with good reason–that we have little to fear when it comes to contamination from microbes. Our drinking water, while far from perfect, is heads and shoulders above what it once was–something many of us forget or have never realized. There have been notable breakdowns, such as the 1993 outbreak of Cryptosporidium in Milwaukee that sickened over 400,000 individuals, but these days such events are few and far between.

This hasn’t always been the case. In the early 1900s, the safety of the water supply even in many large U.S cities wasn’t monitored, and there were no standards in place to guarantee that individuals receiving pumped water wouldn’t be made ill by it. This is the setting for David DeKok’s new book, “The Epidemic,” detailing a 1903 outbreak of typhoid fever (caused by Salmonella enterica serovar Typhi) in Ithaca, New York, that hit at least 512 homes in the town and left 82 dead, including 29 Cornell students. It’s estimated that 10 percent of the populace was sickened, one of the last of the major typhoid outbreaks in the U.S.

The book begins with a description of those behind Ithaca’s water supply back in the day. It was an ugly mess of local businessmen and members of Cornell’s Board of Trustees, who unwittingly set the outbreak in motion with the 1901 sale of Ithaca Water Works to local businessman William Morris. Morris was a Cornell alum, a lawyer and entrepreneur who had previously invested in power companies. He had agreed to buy the Water Works only as a side deal that provided him with his main interest, Ithaca Gas Light Company. The deal was financed in part by Cornell University, with some of Morris’s buddies on the Board of Trustees greasing the deal.

Morris had never run a water company before and while others in town had suggested adding in a filtration plant upon Morris’s purchase of the company, Morris ultimately refused, and began construction on a huge new dam. For this, he hired Italian workers–from an area of Italy where typhoid was still endemic. This was prior to the discovery of the carrier state for typhoid, so while the workers appeared to be quite healthy, at least one of them was unwittingly spreading the deadly organism. Coupled with the atrocious state of the dam construction site–including limited access to outhouses, so workers urinated and defecated near the creek where they were working–this assured that Six Mile Creek would be contaminated, and a good portion of Ithaca’s water supply along with it.

Soon, the cases started to roll in. From January 1903 until May of that year, they piled up even as students began to flee the campus, sometimes unknowingly taking their infection home with them to family members. What followed was a mess of blame-gaming and politicking, with no one taking responsibility and officials contending that the very victims of the outbreak were responsible by being careless about what they ate and drank. Even well into the epidemic, the need for boiling contaminated water was debated and put aside as students and townfolk were dying. Indeed, a letter from late February 1903–well into the epidemic–shows that university officials were still denying they carried any blame, or even that their students were drinking contaminated water.

DeKok uncovers a story that will make anyone interested in public health seethe in anger, and yet it’s one that can–and does–still happen today, as the good ol’ boys’ network and corporate interests trump the health of the populace. Our drinking water is much improved, but corporations are still allowed to pollute with little more than a slap on the wrist. Sadly, DeKok recounts how Morris’ wealthy friends ended up protecting him from any kind of fallout, while Andrew Carnegie came through and donated enough funds to cover medical and funeral bills for the affected students. Finally, in an ironic turn of events, DeKok also notes how Morris’ companies evolved over the years into the General Public Utilities Corporation, which ran the Three Mile Island nuclear power plant.

“The Epidemic” is a story of an outbreak that, with just a bit of foresight and concern for the public good over private profits, could have been prevented entirely. It sadly mirrors many public health controversies that still thrive today. For instance, one passage notes that any government funding for the water works was fear-mongered as “socialism,” a platform that could have come from our current Republican leadership. It’s a tragic reminder that we don’t always learn from our mistakes, and while our water may be safer today than in 1903, public health still gets trampled on by private industry. Will we ever learn?