Daily Science Dose

We have been looking at the danger posed by once-tropical diseases spreading into more temperate zones as the world warms. Hey, that may be a good idea for a new soap opera, As the World Warms. Just remember, you heard it her first.

First we looked at Malaria and Dengue Fever, and today’s topic is our not-so-friendly stomach flora, Cholera.

The yellow areas are local cholera outbreaks, and the black dots represent imported reported cases. I believe Alaska is only colored yellow due to it being part of the US.

Cholera is a water-borne and food-borne (as water is a major component in food production) disease that is spread by the Vibrio cholerae bacterium. According to the Centers for Disease Control (CDC), cholera has not been present in the industrialized nations in 100 years, other than the rare case of a traveler returning to a non-cholera country from a nation where cholera is common, for instance India and Sub-Saharan Africa. In fact, cholera is currently at “pandemic” status in the poorer parts of the world

The major problem with getting cholera is that the bacterium causes an intestinal infection which leads to diarrhea. The problem with diarrhea is of course dehydration. If your body er, uh, ejects too much fluid before that fluid can be replenished, you can die. Remember in high school US history classes, when you were studying any of the major wars, and it would come up that not every casualty was due to violence, but that some soldiers died from things like dysentery. Dysentery is a severe intestinal infection that also causes rather horrible diarrhea…a terrible way to die.

Cholera is easily treated, but that treatment is important to get in the first few hours if the infection is bad enough. But what is bad enough, and how do I know if I get it, you may be asking. Hopefully, you will never have to worry about cholera — at least not in the industrialized world. Effective sewer systems and water treatment processes have for the most part eliminated the presence of cholera in the US and Europe, although the bacterium can exist in these areas. Some people get cholera from eating raw seafood from the Gulf of Mexico, but the chances for that are fairly low, so I don’t want you to panic. I write about cholera because of the relationship between cholera (and other tropical diseases) and a warmer world.

Cholera is commonly associated with higher sea temperatures.

From the Environmental Protection Agency’s page on climate change:

…algal blooms could occur more frequently as temperatures warm — particularly in areas with polluted waters — in which case diseases (such as cholera) that tend to accompany algal blooms could become more frequent.

Also, warmer waters accompany rising sea levels, which could flood areas and contaminate water meant for agricultural uses and drinking water. Higher need for potable water due to increased population may also strain sewer systems and treatment plants efficacy. I promise I am not trying to scare you, but a warmer climate can change the playing field when it comes to combating pandemics like cholera.

Here is a cute little rule of thumb when choosing water and food when traveling, or when the US turns tropical.

Boil it, cook it, peel it, or forget it.

tropical disease, diseases, cholera, malaria, dengue fever, Centers for Disease Control, CDC, pandemic, dehydration, India, Africa, US, Gulf of Mexico, World Health Organization, sewer system, water treatment, water, travel, algal blooms, sea level rise, climate change, global warming