50 Shocking Facts about Parasites

One of the most common causes of seizures worldwide in humans is neurocysticercosis. It is an infectious parasitic disease acquired by ingesting the pig tapeworm, which causes cysts to form after the infection takes hold within the brain.

27. There is a parasite that "zombifies" snails and forces them to march to their death to the tops of trees to be eaten by birds so that the parasite can spread via bird droppings.

28. Plasmodium Falciparum is the parasite which causes malaria in humans. It first infests your liver. It can stay there for months on end developing without symptoms. Afterward, they infect red blood cells and cover themselves with the cell membranes to protect themselves from the body's immune system.

29. There is a species of parasitic nematode (Myrmeconema Neotropicum) that induces "fruit-mimicry" in tropical ants. Infected ants develop bright red abdomens, tend to be more sluggish, and walk with their abdomens in a conspicuous elevated position. This causes birds seeking fruits to confuse them for berries.

30. Helminthic therapy is an experimental form of immunotherapy in which a patient is deliberately infested with specific parasitic intestinal nematodes (worms). This form of therapy aims to treat immune-mediated diseases such as inflammatory bowel disease, Crohn's disease, and multiple sclerosis by mitigating or alleviating immune responses via the infection.

California condor louse exclusively parasitized the California condor. During efforts to save the condor from extinction, it became extinct itself due to all condors being deloused. This led to major debates about the ethics of saving one species from extinction by killing another.

32. There is one particular species of tick named ‘Lone Star Tick’ that can cause permanent red meat allergies when it bites a human.

33. There is an extremely itchy kind of rash called ‘Swimmer's Itch,’ which humans can experience after swimming or fishing in lakes. It is caused by a very minuscule flatworm parasite (Trichobilharzia Regent) that tries to burrow into human skin. It finally dies in the skin after being entrapped by immune response, which causes the rash.

34. In 1993, an outbreak of Cryptosporidiosis in a water treatment facility in southern Milwaukee caused what would be the largest waterborne epidemic in US history, making 403,000 people ill and killing 104 people, many of which had compromised immune systems (such as AIDS patients). Cryptosporidiosis is a parasite whose infection causes diarrhea.

35. Male menstruation was considered a normal part of growing up in 20th century Egyptian culture but was actually due to an endemic parasitic bladder infection from schistosomes causing bloody urine.

Freshwater snails are one of the world's most deadly animals because they transmit a worm that causes schistosomiasis (aka bilharzia), which is, in and of itself is one of the most deadly parasites on the planet. Nearly 230 million people were infected by it in 2014 and there are approximately 200,000 deaths annually caused by it.

37. Screwworms were last seen in USA in the 1970s and had been considered eradicated. If it returned, its effect could be catastrophic to wildlife and livestock. In 2016, however, this parasite made reappearance, with first signs that seemed baffling. Infected deer were stumbling around in confusion, howling in pain, found with their heads hideously disfigured as if eaten alive.

38. There are parasitic wasps that produce viruses and inject the viruses into caterpillars along with their eggs. The Polydnavirus suppresses the caterpillar’s immune system, protecting the wasp eggs.

39. The Sputnik Virophage is a parasite of Mamavirus, which infects Acanthamoeba, which can infect humans. So it is a parasite of a parasite.

40. Neglected diseases in the U.S. are largely ignored, undetected, and untreated since they primarily affect people in poverty. Toxocariasis, for example, afflicts an estimated 2.8 million African Americans and can cause childhood cognitive delays and even epilepsy.

In the 1880s, 20% percent of autopsies performed in Iceland revealed echinococcosis, a type of tapeworm that can be passed from dogs to humans, causing blindness and severe complications. As a result, the city of Reykjavik had a ban on keeping dogs as pets for decades.

42. Parasitic botflies grow under the skin of animals and humans while feeding on their flesh. Once mature, they burst out from the skin of their host.

43. The closest relative of the common head louse is the gorilla louse (Pthirus Gorillae), which only infects gorillas. It is speculated that modern human lice are descended from gorilla lice that parasitized early humans that slept in gorilla nests or butchered gorilla corpses.

44. The Diplozoon Paradoxum is a parasite belonging to the class Monogenea in the order Platyhelminthes. For it to mature, two larvae need to fuse in an X shape, spending their lives in lifelong copulation. They never let go of their partner and if they are forcibly separated they will die.

45. The reason children get lice but adults rarely do is because your scalp gets more acidic after puberty.

Baylisascaris or "Raccoon Roundworm" can infect humans and other mammals through ingestion of Raccoon feces. In smaller animals, the larva migrates to the brains and eyes and damages it, making the organism an easier prey for the raccoon. Infection in humans is extremely rare; however, if it is successful in infecting humans, it can be fatal or cause permanent neurological damage.

47. Rat lungworm disease is an illness where parasitic worms (Angiostrongylus Cantonensis) invade the human brain. Transmission to humans can occur after eating raw food containing slugs or snails and the pain caused by these worms has been likened to setting a hot iron inside the brain and pushing the steam button.

48. Several diseases and parasites can be transmitted by the various species of deer fly. These include anthrax, tularemia, equine infectious anemia, anaplasmosis, hog cholera, filariasis (including the Loa Loa worm), and Lyme disease.

49. Oxpeckers not only eat ticks off of African wildlife (like elephants), it also drinks their blood and makes their wounds even larger. Scientists now think the birds are parasites and are not an example of mutualism, where both parties benefit.

50. The red velvet ant is a native to the eastern US and is nicknamed the "cow killer" because of its extremely painful sting. Despite its name, the red velvet ant is a parasitic wasp. Female wasps lay their eggs on the larvae of eastern cicada killers, and the wasp grubs then consume their hosts.