A History of Discovery: Fever
Chances are, you were laid up in bed, trying to rid yourself of a fever and the chills this flu season.
Why do we get fevers with the flu, and what is the origin of this phenomenon? Who discovered it?
As it turns out, the early groundbreaking studies on the function of fever in disease were done on reptiles. That's right, cold-blooded animals can get a fever.
In 1967, a man by the name of Cal DeWitt went into the desert with a fishing pole and a mobile lab, where he caught desert iguanas and observed their ability to regulate body temperature.
By his account, the study was the most cited of the year by scientists studying temperature regulation in ectotherms.
In fact, he told me the whole story. His fascination with ectotherms began with the painted turtle, when, as a young boy, Cal turned his Michigan backyard into a zoo. He started with painted turtles, and grew it into a reptile house.
“I think I had every species of turtle in the state of Michigan, along with no less than a few other reptiles and amphibians,” Cal told me.
During his graduate studies, Cal tried to study heat transfer and temperature regulation in turtles…
“…but it was [pause] challenging, to say the least. The turtles would dive and get tangled in the equipment, and then come up and bask in the sun, causing rapid evaporation and a sudden change in temperature.”
So, after months of frustration, Cal’s professor suggested that he study the desert iguana, Dipsosaurus dorsalis.
Wow! Cal thought. Now here is a creature – out in the open – that doesn’t have to drink water, and yet is composed of mostly water!
So Cal set out in a mobile lab with his young wife, a fishing pole and bucket, and thermometer to catch desert iguanas and observe their ability to regulate body temperature.
“Every day, my wife would sit in the shade of the mobile lab and read a book while I measured the surface temperature of the desert sand, and every day, the temperature would read above the upper limit of my thermometer – 150 degrees, Fahrenheit.”
“We each drank one liter of water an hour, sitting and watching an animal that didn’t have to drink water at all!”
Wait a second, all living creatures need water, right? Let me ask, where do you think the desert iguana gets its water, if it doesn’t need to drink?
Cal discovered a few things out in the desert:
1. Desert iguanas do regulate their body temperature.
“If I put them in a bucket where they couldn’t find a way out of the heat, they’d begin to pant, and form spiral salt crystals in each nostril. Of course, they’d die if I didn’t let them out…”
2. The desert iguana doesn’t need to drink water because it regulates osmosis in the blood; it gets its water from the metabolism of glucose!
Ok, fast forward.
A graduate student by the name of Matthew Kluger, knowing that Cal DeWitt had established the groundwork for temperature regulation studies in the desert iguana, fed the reptile bacteria, and found that it selected a higher body temperature, which he called a behavioral fever.
Kluger is now at George Mason University and was featured on NPR's People's Pharmacy in January. His landmark work on the physiology of fever was published in 1974, in Nature.
Fast forward again, to the invention of synthetic aspirin in the 19th Century.
According to Kluger, this is when people really started to believe that fevers were bad; that is, doctors and pharmaceutical companies began to advocate the use of aspirin, and aspirin-like drugs, to reduce fever, and the pain associated with it.
So is fever bad? Well, no.
“Fever is not due to a loss of the ability to regulate body temperature, but is an extremely sensitive resetting of the thermostat that regulates body temperature, and it’s probably protective,” said Kluger.
You can listen to the podcast and an interview with Kluger, in which he talks about his work with the desert iguana, here.
Based on Kluger's work, researchers have discovered a positive role for fever in fighting infections.
Next time you have a fever, consider sweating it out.