Longest parasite in world: It can grow up to 40 meters
Which is the largest parasite in the world (collage: RBC-Ukraine)
Parasites that live inside mammals are not only dangerous but also impressive in size. For example, the largest of them can reach up to 40 meters in length.
IFL Science shares information about the longest parasite in the world.
Where was the longest parasite found
The tapeworm Tetragonoporus calyptocephalus, which inhabits the intestines of whales, is a true giant, reaching lengths of around 40 meters. This remarkable record was set by T. calyptocephalus, formerly known as Polygonoporus giganticus.
While many species of tapeworms grow to impressive sizes, the size of T. calyptocephalus makes it one of the longest parasites on the planet.
The most common tapeworms that affect humans are those that infest the tissues of pigs, cows, and salmon. This is why chefs emphasize the importance of properly cooking food - if you don’t want a giant worm living in your intestines.
However, the longest human tapeworms don't reach the staggering length of T. calyptocephalus, but there are still some unsettling statistics that might make you instinctively clutch your stomach.
One prominent example can be found at the Meguro Parasitological Museum in Tokyo: an 8.8-meter specimen of Dibothriocephalus nihonkaiensis, a rare giant tapeworm that was removed intact from a human’s intestine.
Sometimes, they can grow even larger. A 2009 article noted that their typical size range is between 2 and 15 meters. However, the largest recorded specimen of this species reached about 25 meters in length.
What is known about tapeworms
Tapeworms have been infesting stomachs for at least 99 million years, as revealed by a unique amber fossil described in March 2024.
This marks the first time that a part of one of these parasites has been found in fossil form - previously, only a few shark eggs had been discovered.
According to researchers, fossilized remains of tapeworms are extremely rare due to their soft tissues and parasitic habitats, which makes it challenging to understand the early evolution of these creatures.
No matter what prehistoric animal this particular fossil came from, cestodes (tapeworms) have proven to be incredibly successful parasites, infecting everything from birds to bears. However, when it comes to length, the whale tapeworm is hard to beat.
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