A tapeworm is like something out of a horror movie. It's a wiggly, creepy looking, ribbon-shaped creature that lives inside its host, absorbing nutrients and laying millions of eggs. They can reach 80 feet (25 meters) or more in length and live in a host for up to 30 years [source: Mayo Clinic]. And if the idea of having a worm living inside of you doesn't have you shuddering in revulsion, just wait until you hear how they reproduce.
Fortunately, the average person living in the developed world isn't likely to wind up with a tapeworm infection, as it's strongly linked to poor sanitation practices both on a personal and societal level. People with subpar hand washing and bathing practices are more likely to transfer contaminated fecal matter to the mouth, as are those people who are exposed to livestock and live in locations that lack proper animal and human feces disposal methods. Ingesting undercooked or raw meats also put people at risk because any tapeworm eggs present in the food doesn't get killed off during the food preparation process, so you might want to take a beat to consider whether you really want that steak rare, or not [source: Mayo Clinic].
Despite the extreme "gross" factor of tapeworms, it has been suggested that acquiring one intentionally would be a relatively simple way to lose weight. In fact, tapeworm pills may have been sold as weight-loss aids in the past. In some ways, it seems to make a certain amount of sense – that is, if you can get past the gross-out factor. If a tapeworm is absorbing your body's nutrients and calories, you can eat all you want and enjoy the taste. Then the worm diverts it all before it hits your waistline, right?
We'll see about that! Actually, there are lots of rumors and myths surrounding tapeworms, so we're going to untangle this bizarre mystery. How do you get a tapeworm, anyway? Once you have one, how does it come out? Did a legendary opera singer lose her girth (and some say, her voice) by intentionally ingesting a tapeworm? Also, how much weight can a tapeworm really help you lose?
Try to repackage it as a diet aid all you want, but a tapeworm is a parasite through and through. It obtains all its nutrients from the digestive system of its host animal. But here's a strange fact – a tapeworm doesn't even have a digestive system of its own. It absorbs nutrients (mostly carbohydrates and sugars) that have already been partially broken down by the host's digestive system [source: Zimmer].
An adult tapeworm lives inside the intestines of the host animal, which could be a pig, cow, dog, sheep, fish or even a human. Different species of worm prefer different hosts, although most can infect several different types of animals. At the top of the worm is the head, called the scolex. The scolex has suckers or hooks that it uses to attach to the intestinal wall. Without this feature, the peristaltic action in the host's intestines – the rhythmic muscular contractions that move material through the digestive tract – would push the worm out. Below the scolex is the neck. The rest of the worm's body buds off of the neck [source: Encyclopedia.com].
Here where it starts to get really creepy. The tapeworm's body, called the strobila, is made up of many segments, sometimes thousands. Each individual segment is known as a proglottid (pronounced proh-GLAH-tuhd). A proglottid is either male or female. The segments closest to the neck are mostly male and produce sperm. Segments farther along the body are female and are basically egg sacks. A tapeworm can produce millions of fertilized eggs. In fact, each individual body segment is home to about 100,000 eggs [source: Bradford].
Proglottids frequently break off from the worm and are passed out of the host along with feces. However, each proglottid has functional muscles, allowing it to crawl. Sometimes, a detached proglottid will crawl out of the host through the anus. More often, a proglottid crawls away from the pile of fecal matter left by the host, increasing the chances that it will be eaten by a different animal. Eventually, the proglottid disintegrates, leaving behind the eggs.
When the eggs are eaten by an herbivore, they are "hatched" by the conditions within this intermediate host's digestive system. The larval stage, known as a hexacanth, uses hooks to burrow through the host's intestinal walls to reach the bloodstream. There, it turns into a scolex and forms a cyst. The resulting condition is known as cysticercosis. Pigs, cows and sheep are most commonly infected. Humans can act as an intermediate host for the pig-born species of tapeworm, and therefore can contract cysticercosis [source: Pearson]. We'll get back to the horrors of cysticercosis in a minute.
Once the cysts form, the parasite simply waits within the host. When the host animal dies, the meat may be eaten by other animals (or by humans) raw or undercooked. The ingested cysts pass into the primary host's digestive system, where the scolex attaches to the intestine wall and the whole cycle begins again.
Once a person has a tapeworm, they're officially saddled with a parasitic infection known as "human taeniasis." On its own, human taeniasis isn't such a big deal, as it is often asymptomatic. However, it can develop into cysticercosis, the condition resulting from tapeworm hexacanths burrowing their way into your bloodstream, which is decidedly not pleasant. The cysts can end up pretty much anywhere in your body, including in your eyes or your brain. The cysts sometimes grow, and they inflame the surrounding tissue. The resulting pressure can cause temporary symptoms or permanent damage, including blindness, brain damage or even death in some extreme cases. In developing countries it's considered to be the main cause of adult-onset seizures, and is far more likely to happen to people who are living with someone who has a tapeworm already [sources: CDC, CDC].
Tapeworms can also wreak digestive havoc if they get really big and block the appendix, bile ducts or pancreatic ducts. Tapeworm cysts can also grow within organs like the lungs and liver, and if they get large enough they'll disrupt the functioning of said organs. Occasionally, one of these cysts will even rupture, which can cause itching, hives, trouble breathing and swelling not unlike a severe allergic reaction [source: Mayo Clinic].
Tapeworm Symptoms and Prevention
Let's assume that, after reading all of this, you've decided against intentionally acquiring a tapeworm. How can you prevent them? First, practice excellent hygiene by thoroughly washing hands with soap and warm water after every bathroom visit and before handling or eating food. Doing so will greatly minimize your chances of becoming an unwitting host.
The good news is that, in the United States at least, inspection of meat keeps tapeworms out of the food supply. You apparently can see the cysts in the meat if you know what to look for. In addition, thoroughly freezing meat at minus 31 degrees Fahrenheit (-35 degrees Celsius) for 10 days will kill any parasites [source: Mayo Clinic].
Also, if you're cooking meat resist the urge to make it rare and instead cook to a safe temperature to effectively kill larvae and eggs. Always use a food thermometer, and for whole cuts of meat (not poultry, though) cook to a minimum of 145 degrees Fahrenheit (63 degrees Celsius), making sure to let it "rest" for at least three minutes before cutting. This resting period (where the meat is off the fire but not yet carved) will kill off pathogens. Ground meats should also be cooked carefully, to a temp of 160 degrees Fahrenheit (71 degrees Celsius) but don't require a resting period [source: CDC].
If you're traveling to or living in a developing area of the world, take extra precautions by using safe water to thoroughly wash and cook veggies and fruits. If you're not sure about the water quality boil it for a minute and allow to cool. Also, avoid contact with animal and human feces by making sure they're properly disposed of, particularly in a livestock-relevant situation.
Tapeworm infections often give off no symptoms, but if you notice weakness, nausea, abdominal pain, diarrhea, dizziness, loss of appetite, weight loss and salt craving it's worth a visit to the doctor to be assessed for possible intestinal infection. Usually a stool sample will be checked for tapeworm segments or eggs. Signs of a more serious, invasive infection include headaches, allergic reaction, seizures, other neurological symptoms and cystic lumps [source: Mayo Clinic].
Ideally, such an event will be caught long before it gets too serious, when it can be quickly handled by a single dose of niclosamide or praziquantel, anti-worm medications, which will kill the parasite by forcing all its muscles to permanently contract. The tapeworm will then leave your body along with your feces [source: CDC]. Severe cases may require surgery.
Weight Loss and Other Tapeworm Myths
There are a few tapeworm legends floating around in addition to the weight-loss one, so let's clear some of those up first. One is that you can get rid of a tapeworm by coaxing it out with a bowl of milk and cookies placed near your mouth. Not true. A tapeworm is not Santa Claus, and not only does it live in your intestine – with a stomach and esophagus between it and anything near your mouth – but it doesn't even have any sensory organs that would allow it to detect the presence of food. Remember, this is a very simple creature. It can't smell or see. This is the same reason that putting some enticing food near the other end of your digestive tract won't draw out a tapeworm either. If you have a tapeworm, simply take your pill and let nature take its course.
Opera singer Maria Callas was rumored to have used a tapeworm to achieve a remarkable loss of weight in the mid-1950s. She did, in fact, lose more than 60 pounds (27 kilograms) over several months. She was also known to have contracted a tapeworm at some point in her life. However, the two incidents are probably unconnected. Callas enjoyed rare steak, so she probably got her tapeworm accidentally. These two aspects of her life were jumbled into a persistent rumor.
There is evidence of advertising, from the late 19th and early 20th century, hawking "sanitized tapeworms" to help women maintain a slim figure. Whether the pills sold actually contained tapeworms or whether women actually ingested them hoping to acquire a tapeworm is difficult to verify. Such a pill would likely contain the cyst part of the tapeworm's life cycle, but one would imagine that cultivating a large supply of these would make for a rather unpleasant day's work. It seems unlikely, but there's also a good chance that somewhere in the long, strange history of humanity, someone somewhere did try using a tapeworm to lose weight. So, the answer to the question, "Did it happen?" is most likely yes, but it was probably never widespread [source: Mikkelson].
That leaves us with just a few more interesting questions. What happens to your body when you have a tapeworm? Do the pounds just melt away? Can you stuff your face with all manner of delicious, unhealthy foods and get off consequence-free? Well, not exactly. For one thing, tapeworms are not large enough to absorb all the calories a human takes in. If your diet is already limited, the tapeworm could steal enough from you to cause malnutrition, or it will cause you to eat more. If you're chowing down on carbs, both you and the tapeworm will probably pack on the pounds. In most cases, a tapeworm infection is completely symptom-free. In fact, you might never know you have one until a proglottid makes its presence known in your toilet.
Some tapeworm hosts do suffer from intestinal discomfort or diarrhea. And some also experience reduced appetite, which could lead to weight loss. However, we can assure you that simply reading about tapeworms can cause a similar loss of appetite, so more drastic measures might not be necessary. But even if a tapeworm did trim some pounds, it still wouldn't be a good way to lose weight.
For most people, the goal of losing weight is to look better. However, as a tapeworm steals certain vitamins from your body, notably vitamin B12, you'll suffer ill health due to a shortage of those nutrients. Sure, you might slim down, but no one is going to be impressed with your sickly appearance. If that weren't enough, there's always ascites. Ascites is a condition in which the body's immune response to a parasitic infection leads to a build-up of fluid in the abdominal cavity. This manifests itself physically as a swollen, distended belly. Not exactly the intended result of a tapeworm diet plan [source: Wells].
And don't forget about good old cysticercosis, with the brain damage, blindness and possible death. Given this information, we think it's safe to say that if you really want to lose some weight, eat less and ride your bike.
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