Question: How long does it take for a tapeworm to kill a human ?

Franco Falcone answered on 18 Jun 2016:

@755parf34 A good question!

There are different species of tapeworms, and different ways of getting infected with them. Let’s start with the tapeworm living in one’s gut. This can be either Taenia solium (pork tapeworm – transmitted by pork) or Taenia saginata (beef tapeworm – transmitted by beef). You can get infected with these by eating raw or undercooked meat. This pathway leads to adult worms growing in your gut, usually without any major symptoms, perhaps some weight loss, diarrhea, abdominal pain, and in the long term some Vit B deficiency. In other words, they don’t kill you. But it can be embarrassing to see creepy-crawly segments of tapeworms come out of your bottom. This kind of infection with tapeworms is called Taeniasis, and is relatively harmless.

There is a problem with the pig tapeworm however, and that is if you accidentally ingest eggs released by pigs themselves infected with tapeworms. This can lead to extremely dangerous diseases called cysticercosis or neurocysticercosis. This is where the parasite ‘thinks’ it is in the definitive host (where it would end up in the muscles) and will penetrate the gut wall and spread into tissues and organs, for example liver, lungs, and very frequently, the brain. There it will grow very slowly but like a cancer and will eventually, after many years, cause symptoms that will lead to its detection, for example when the doctorperfroms a CT or NMR scan. However this infection if often recognised very late, often after decades, where the cysts have become so big and there are so many of them, that the disease becomes very difficult to treat. Cysts can become infected with bacteria and can burst, releasing allergens which can cause fatal anaphylaxis (that’s the worst possible allergic reaction).

The beef tapeworm is less risky as it cannot cause cysticercosis or neurocysticercosis in humans. This is possibly one of the reasons which have led two of the three major monotheistic world religions (Judaism and Islam) to consider pigs as ‘dirty’ animals; I don’t know to which extent the Christian Old Testament advises against eating pork, I am no expert in Religion, but perhaps others can comment on this.

There are other tapeworms which are even more dangerous, belonging to the gender Echinococcus (dog tapeworm and fox tapeworm). These can be trasmitted by foxes, wolves and other canids and can be very deadly as they are usually detected very late. There are hundreds of people in Europe dying from th elong term consequences of Echinococcus infection (hydatid disease) every year. One of the two main species, Echinococcus granulosus, also occurs in the UK and is acquired by dogs allowed to feed on carcasses of infected sheep. So if you are a pet holder, it is good practice to de-worm your dog every three months or at least twice a year. This will also benefit your dog’s health (and the Vet’s wallet..). Luckily, the other, more dangerous tapeworm called Echinococcus multilocularis, which foxes can get from eating rodents, does not occur in the UK, so the foxes in your gardens are not a problem.