The people have spoken! You love the parasites. This week I'm bowing to a perennial request from our own Stan Muller, to do an episode on tapeworms. Make sure you eat before watching. Tapeworms are the topic on this week's Healthcare Triage.

Tapeworms, officially known as taenia are parasites found in a variety of meat. There's taenia saginta in beef, taenia solium in pork, and taenia asiatica or Asian, which is also in pork. You infected when you eat meat that hasn't been properly cooked. Tapeworm infections are more common in places where sanitation is bad and people eat a lot of raw or undercooked meat. Higher rates are seen in Latin American, Eastern Europe, Sub-Saharan Africa, India, and Asia. But infections with taenia solium do happen in The United States, especially in immigrants from Latin America. Taenia asiatica, not surprisingly, occurs pretty much only in Asia.

The good news is that the symptoms are usually mild, if you experience any at all. The bad news is this means that most people infected with tapeworms have no idea. So you know, you could be infected right now and not know it. Getting uncomfortable? It's going to get worse! The pork variety of tapeworms are the smaller ones. They grow to be, I don't know, only 3 meters in length. Beef tapeworms are much longer, and can grow to be 10 meters in length or much more. Try sleeping now that you know that. When they get big they can, not surprisingly, cause you belly pain, and an upset stomach. You can lose your appetite, and you can lose weight. Those things are pretty non-specific though. A lot of things can cause those symptoms. What's more specific of the sign of infection is when you start passing proglottids, or tapeworm segments, in your poop.

Taenia solium varieties can also cause another infection, called cysticercosis. That's what you're infected with the larval cysts of the bigger tapeworm. People get that not by eating under-cooked meat, but by somehow eating the eggs found in the feces of another person infected by taenia solium. When you eat those, the eggs hatch into larvae, which go through your body to form cysts in brain, muscle, or other tissue. This is REALLY BAD, and it's one of the main causes of adult onset seizures in poorer countries. 

So let me recap the circle of life of these guys. When people in tainted meat, they consume cysts, which develop into adult tapeworms over two months in their gut. Then the adult tapeworms can survive inside you for years. An adult can release about six pregnant proglottids a day. Depending on the type of tapeworm, they can release somewhere between 1,000 and 2,000 proglottids in their lifetime. Each of the proglottids can have between 50 and 100,000 eggs. If pigs or cows eat the eggs or proglottids found in that poop, they hatch, become larvae, and travel to muscle where they form cysts, which can live for years. Then we can eat the tainted meat, and the whole thing starts all over again. But if people eat the eggs in the poop, then we get cysticercosis, because the larvae hatch in people and move where they shouldn't. The tapeworms don't want us eating the eggs in the poop. They want the cows to eat those eggs, but we're not so good with the hand washing sometimes. 

It's estimated that there are probably less than 1,000 cases of infection in The United States each year, but it's hard to know for sure. And that's still too many! We don't know how many we're missing. The best thing to about tapeworms is NOT GET THEM! Cooking meat properly is a good start. Meat cooked to 145F (or 63C) and then rested for 3 minutes should be fine. Ground meat should be cooked to 160F (71C) and that doesn't need to be rested. But that temperature for a steak is considered medium or medium well. That's sacrilegious, as everyone knows medium rare is the proper temperature for a steak at 135F. Many people aren't willing to cook their steaks to tapeworm killing temperatures, me included. Pork is a little easier, because the recommended temperatures will achieve medium rare. So just do that. 

If a doctor's concerned you have a tapeworm, they might look in your stool. You might have a segment or eggs there. They might also do a blood test to check for antibodies, and then maybe a CT or MRI scan to see if there's any damage a tapeworm may have caused. There's medicine you can take if you're infected, most commonly praziquantel. That'll kill the tapeworm, which will then dissolve and/or pass through you. Again, try to sleep knowing that. It's not always pleasant, as you can imagine. 

Like most of the parasites discussed in the last few weeks, these things are much scarier than they are dangerous. Parasites live and thrive by not making themselves known and not harming their hosts, but that doesn't make them pleasant. Wash your hands! And cook your meat well.