Ascariasis: History & Prevalence
Parasitic Worms
You play host to many people in your life as you throw one party or another. But you, as a person, can also play host to about 300 of something else. They are unwelcome guests, so to speak. They are parasitic worms. One of these worms is Ascaris lumbricoides, one that leads to a condition known as ascariasis. Ascariasis can lead to everything from difficulty breathing to diarrhea and much more.
Let's find out about this disorder's history and prevalence in this lesson.
History
People who live in developing countries around the world today know of some parasitic worms, especially large ones like Ascaris lumbricoides. Sure, they might not know the scientific name, but they are aware of them. So, it's equally likely our very earliest ancestors were very much aware of them as well. Why? Well, it's because this worm can grow up to 35 cm in length! You can't miss that as it emerges from your hind end on its own or as it leaves your bowel when you defecate.
There is also some evidence for the basic awareness of worms like Ascaris lumbricoides found in the Bible, ancient Chinese works, ancient Egyptian medical texts, and ancient Greek texts as well. The ancient Roman physician Galen appears to have described Ascaris lumbricoides itself.
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We know for a fact that ancient peoples were infected by this worm because evidence of Ascaris lumbricoides has been found in an ancient Egyptian mummy that dates from around 1938 BCE. Its eggs have also been found in fossilized feces from Peru, dated to 2277 BCE.
Swedish naturalist Carl Linnaeus described and named Ascaris lumbricoides in the 1700s, just as the study of parasitic worms was really beginning to take shape. It wasn't until the 1800s that the mode of transmission of this worm was elucidated as scientists, such as Giovanni Battista Grassi, infected themselves with this worm's eggs in order to figure this out! And, in 1922, Japanese physician Shimesu Koino infected himself and a volunteer to figure out the life cycle of this worm as well.
Prevalence
Ascariasis has a worldwide prevalence of roughly 25%. This means that over 1.5 billion people are affected right now! It's especially prevalent in warm and wet regions. This means tropical and subtropical places around the world. This is especially true if the region is known for inadequate sanitation and hygienic practices. Most of the people with ascariasis, 73%, are found in Asia; with 12% in Africa, and 8% in South America.
In the U.S., modern sanitary and hygienic practices have greatly decreased the prevalence of ascariasis. About a few million people are thought to be affected by this disorder, and most of those are likely to be immigrants from places where the infection is more common.
With respect to age, ascariasis is most prevalent in children between the ages of 2-10 years of age.
Lesson Summary
Ascariasis is a medical condition caused by ascarids, which are parasitic worms. The most important of these ascarids is Ascaris lumbricoides. This worm has been described by ancient people around the world, and its eggs have been discovered in fossilized human feces dating as far back as 2277 BCE. It wasn't until the 1800s that its mode of transmission was discovered by scientists, such as Giovanni Battista Grassi. In 1922, Japanese physician Shimesu Koino discovered this worm's life cycle.
About 25% of people around the world have ascariasis, most of those are children aged 2-10, and most of those live in tropical and subtropical regions around the world.
Medical Disclaimer: The information on this site is for your information only and is not a substitute for professional medical advice.
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