Many organisms are living in human body, like worms, bacteria, even some kind of mites. But most of them offer good things to you, so, it is kind of symbiosis mutualism. Like the bacteria that live in your digestive system, they help you to digest the food you eat.

But not only the good ones, some parasites may also live inside your body. They are organisms that rely on you to live but instead of helping you they will harm you. Even though not all of you have it, but you have to be aware of them.

Here we give you some examples of the worst organisms that may live in human body derived from ThoughtCo. Better pray you don’t have any of it.

1. Australian Paralysis Tick

Ticks are usually not venomous, yes, they may cause nasty diseases such as Lyme and Rickettsia, but it’s not because of the venom of the ticks itself. However, there is one kind of tick that is highly venomous and may even cause death from its bite.

It is the Australian paralysis tick or Ixodes holocyclus, this tick secretes a kind of neurotoxin that may paralyze you. The tick may also carry usual tick-related diseases, making the condition worse. Most of the cause of the death that Australian paralysis tick bites cause is the paralysis in respiratory system.

More bad news, there is no antivenom for the tick’s bites, so maybe the only overcome it is by praying. And another addition, some people are deathly allergic to this tick’s bites. Luckily, if you live outside Australia, you might never encounter this human parasite tick.

2. Plasmodium

Plasmodium is a parasitic protozoan carried by a species of mosquito called anopheles. When the female anopheles mosquito bites you, some plasmodium may enter your body through the mosquito’s saliva and the single-celled organism gets in into your red blood cells, making you the host.

Inside your red blood cells, they multiply and cause it to bursts. In this process, you might get an infection, thus even it doesn’t look as severe as other kinds of infections this may result to death too. This is the process of what we call malaria. The cycle is completed when a mosquito bites the infected host.

There are actually more than 200 million cases of this illness all around the globe each year. Until now, there are no vaccine that can cure the illness. Treatments are available just to make the infected human feel better from the fever and chills.

3. Scabies Mite

This skin disease will make your skin intensely itchy and red bumps, even sometimes horribly wounded like suffering from burns. The cause of this skin disease is a little mite named scabies mite. Unlike ticks that only do their things outside the skin, this kind of mite burrows itself into your skin.

Every part and activity of this mite, including the feces is the cause of the itch. And this mite is usually active in the night. The itch will force the infected person to choose between two torturing options, scratching it or just let the itch be.

Scratching is a bad idea, since it may cause serious skin infection, and it won’t solve the problem. Medicinal and traditional treatments are available, but usually it need days, even weeks to totally cure this disease.

If the infected person has weak immunity, or high sensitivity to the mite, the person may develop a Norwegian crusted scabies. This condition will make the skin of the person crusty and it will remain so even if the disease has been cured.

Not only that, this skin disease is highly contagious. The parasite can easily be transmitted by skin contact. So, if you see an itchy person in public that shows the signs of scabies mite infection, you might better avoid that human.

4. Filarial Worm

Filarial worm is a kind of roundworm that is parasitic to human. This roundworm may enter your body in many ways, like from the water you drink, mosquito bites, even just by slipping through the gaps between your skin cells.

The disease it carries is called elephantiasis, because of the massive swelling and tissue deformity. It happens when the roundworm enters your body and clogs your lymphatic vessels. Thus, your lymphatic fluid can’t drain properly.

For most people infected with filarial worm, the signs are not visible, or there are only little to know signs of infection. However, for some people, the disease can reach horrible stage. An example is John Merrick The Elephant Man, the deformity level is so severe that he doesn’t appear as normal human.

5. Screwworm

Screwworm can be found in Central and South America. Its scientific name, Cochliomia hominivorax, means man-eating fly. Indeed, the larvae of this parasite will eat human flesh when infecting a host because your flesh is its source of food.

Female screwworm fly may lay up to a hundred eggs in an open wound, thus you’d better get a bandage when you visit the area while getting an open wound. The eggs will hatch in a few days and will result in the flesh-eating maggots.

The maggots use its cutting jaws to dig deeper into your flesh through your muscle, blood vessels, and nerves. Thus, the infected person usually feels agonizing pain when suffering from the screwworm infection. If anyone try to remove the maggots, they will dig deeper and deeper.

While eating the host alive, the maggots will grow bigger and give more immense pain to the host. Not only that, the wounds caused by the maggots may also cause secondary infection that leads to death. However, data shows that the mortality rate of such kind of infection is only about 8%.

6. Tapeworm

This one type of flatworm is quite famous to us, because the infection is quite common among modern people and happen all around the world. Tapeworms may enter your body from the food you ingest in the form of their eggs.

Inside your body, the eggs will stick to your gastrointestinal tract and grows from the food you eat. That’s why, people with tapeworms are usually lack of nutrients, because they share it with the parasite in their body.

At this rate, it might be non-lethal, but if the worms meet the perfect condition in the host’s body, they may grow into cysts. The cysts can travel through your body, and if it reaches some parts of your body, like heart, liver, and brain, it may cause death.

If the cysts travel to other parts of the body, it may cause a disease called cysticercosis. This disease will reduce the function of the part because the tapeworm will rob the nutrients transmitted to the body part.