Worst Parasites for Humans | Worms in People

Worst Parasites for Humans

What can be the worst parasites for humans? Parasites are organisms that are the ultimate opportunists. They survive on the nutrition of the host, and they do not contribute anything to it. In humans, they live off the food and nutrition of the human feeds on and they thrive on it. Worst parasites in the world are those parasites can’t even survive without a host, rather a human host. Meaning if the host for some reason dies; the parasite will also die, since they will not be able to derive nutrition anymore from the host, so eventually it will die.

There are many parasites that can be considered worst parasites in the world or worst human parasites, let’s see if the following list can be considered the same


Ticks are the one of the most well- known external worst parasites for humans. Since they live outside the body that is on the surface of the body and do not enter the body; they are known as ‘ectoparasite’. The problem with the tick is the bite of the tick, through which a number of harmful diseases can be caused, e.g. rickettsia and Lyme disease.

Although the tick bites can be considered harmless, they can cause trouble if they transmit some sort of infection. Mostly they won’t even be noticeable, if no symptoms are visible. But there is almost always a chance of some sort of allergic reactions to occur. Some people might be allergic to the ticks’ bite, which may become quite dangerous for the human host. In some instances they can also become deadly if not treated immediately.


There are a lot of people who contract malaria the world over, millions of cases every year. However the world over everyone believes mistakenly that malaria is an infection caused by a bacteria or a virus. Although caused by a single celled organism; plasmodium, this is not a bacteria or a virus. Plasmodium is a protozoa species which is also a parasite. It is transferred to humans through an infected mosquitoes bite. Plasmodium may not appear to be worst parasites but the harm generated from the disease that they cause can certainly be considered to be one of the worst. The disease malaria although treatable is not preventable from vaccination, but you can take measures to prevent it through various means like spraying, using mosquito repellants, nettings etc.

Worm infestations

Various types of worms can be a reason for problems in the human hosts of worm parasites. There are many types for example tapeworms, roundworms, hookworms. There are some types of pinworms also known as threadworms, which are more common in some countries like Australia. Nevertheless these worms in humans or infestations as the infections of worms in humans are called, are a huge problem and do pose a health risk. There are some significant symptoms of the infestation of worms in humans. These diseases of worms in people start with a feeling of pain in the abdomen, which can be along with nausea and vomiting, diarrhea is also a feature, along with bloating and gases. An unexplained weight loss, also with a prolonged sense of fatigue. The abdominal pain can be with tenderness in the same region.


Having uncooked food or drinking contaminated water may make you susceptible to tapeworm infection. Tapeworms are one of the different types of flatworms. They are usually transferred to our bodies in their eggs or immature states. Inside the body, especially in the gastrointestinal tract these forms of larvae or eggs get the environment that is considered ideal for the development and growth of this parasite. Since being a parasite, the nature of the parasite is to derive their nutrition from their hosts, so they may not seem to be harmful but they do cause of risk to health. As their nutrition comes from the host, the host is usually deprived of nutrition and can cause low immunity. This may well become a health risk in itself as it makes the host susceptible to numerous infections. That includes tapeworms on the list of one of the worst parasites for humans.

Worms in Human Poop

The diagnosis of worm infestations is done along with the symptoms of the disease. Health Care providers (HCP) usually order a stool test to look for parasites in human stool, which generally is the right place to look for signs of the infestations. These worms since are present in the GI Tract i.e. the Gastro Intestinal Tract, are then tracked through the eggs or larvae that can be found in the stool or even some segments of the worm. So, literally there are worms in human poop to look for in such a case. Additionally, the HCP can also request blood culture to see if there are some specific antigens present in the blood that are there whenever there is a worm infestation.

Roundworms in humans

While traveling in different parts of the worlds, there is always a risk of contracting different kinds of infections. At times in different countries people are also exposed to different types of parasites like roundworms as well. This is due to the lack of hygiene and lack of proper sanitation in those countries. Most of the time the tourists try to have the best of the world by not just visiting exotic places, but also eating the most exotic and popular food, which might not always have proper sanitation or hygiene.  Symptoms of roundworms in humans may mimic symptoms of indigestion e.g. high fever and diarrhea.

Hookworms in Humans

Approximately 600 million people are suffering worldwide from the helminthes, as they are known the hookworms in humans and is considered one of the worst parasites for humans. Usually due to poor living conditions these infestations occur.

These are soil transmitted and are parasitic as they live in the small intestine which they achieve adult form. These hookworms in humans can be a cause of concern. At times, there are some different issues in the infected individual which may cause issues of lung, heart or eyes or some neurological issues as well. But these are very easily dealt with by medicine. If there are symptoms (as mostly) there are no symptoms at all, may lead to loss of protein in the body or loss of blood (anemia).

But this infestation is very easily dealt with by medication when diagnosed by the HCP (the health care provider). In this case mostly it the family doctor, who prescribes the medicine to the whole family, as they are also at risk of exposure.