Human parasites are those that have humans as their host. They can generally be divided into two major groups, internal parasites and external parasites, mainly including different categories such as protozoa, nematodes, flattened animals, annelids, and arthropods. In parasitology, protozoa are often referred to as protozoa, while nematodes and flattens are collectively referred to as helminthes. The important species of endoparasites mainly include protozoa, nematodes, flukes and tapeworms.
These parasites usually enter the body through ingestion. The larvae of some parasites, such as cysts, may also be found in the lungs, under the skin, and even in the brain and eyes. The harm caused by parasites to the human body is usually negative, they will rob the human body of nutrients, cause inflammation, cause various pathological problems such as blood vessel blockage.
1. Hookworms
The life cycle of this parasitic nematode begins outside the human body and often enters the body through contaminated water, fruits and vegetables. Once inside the human body, hookworm larvae grow in the host's internal organs. They attach themselves to the visceral walls of their hosts, sucking on their blood, sometimes causing the host to develop intestinal parasitic disease, a disease associated with anemia.
Symptoms: weakness, abdominal pain, nausea, diarrhea, anemia
2. Scabbards
This parasite, commonly known as human scabies, spreads mainly through contact with the body. Female scabies chooses human skin as a place to lay eggs, which causes skin reactions and inflammation. When female scabies lays eggs under human skin, it triggers a strong host reaction, including severe itching and other scabies symptoms.
Symptoms: Itching, pain, pus, skin irritation
3. Ascaris
Ascaris is one of the most parasitic nematodes in the human body and can grow up to 15 to 35 cm long. They are mainly transmitted through food intake. Once the roundworm eggs hatch, they quickly pass through the walls of the body's internal organs and enter the blood circulatory system. As the blood flows to the lungs, roundworms are coughed up and swallowed back into the intestines, where they re-enter the visceral area.
Symptoms: Fever, fatigue, allergies, rash, vomiting, diarrhea, nerve problems, wheezing, and cough.
4. Blood flukes
These tiny parasites invade the host's bloodstream, causing the host to become infected with schistosomiasis. They usually inhabit water, and schistosomes can penetrate the body through the skin when people come into contact with contaminated water. These parasites cause inflammation (swelling) and cause damage to organs, especially the liver. Adult schistosomes can live in human hosts for many years, sometimes asymptomatic for several years. They leave the body through the host's excrement and spend the remainder of their life cycle in the snail as a host.
Symptoms: fever, aches, cough, diarrhea, swelling, lethargy
5. Tapeworms
Tapeworms are usually spread by food contamination, using "hooks" of the head to attach to the host's internal organs. Mature tapeworms may form in as little as 3 to 4 months, while they can live in the human body for up to 25 years. The eggs of tapeworms can be excreted through excreta, survive in plants, and then be ingested by cows, pigs, or spread to humans.
Symptoms: nausea, vomiting, inflammation of internal organs, diarrhea, weight loss, dizziness, cramps, malnutrition
6. Spiders
Pinworms are a common human parasite that can cause pinworm disease. Adult females can range in length from 8 mm to 13 mm. Pinworms have long needle-like tails, hence their name. They mate through traumatic insemination, and the male uses his penis to pierce the female before he dies. Pinworms often choose the internal organs of their hosts to settle in, and unlike other parasites, they do not enter the bloodstream and cannot survive in other parts of the body. Pinworms lay eggs in the external environment, usually around the anus, causing people to feel itching, and the larvae can be transmitted by scratched human hands.
Symptoms: Inflammation and itching
7. Anthropitis elegans
Mosquitoes carry this parasite and release it into the human bloodstream by biting humans. The larvae of the nematode banserii invade the lymph glands, especially the lymph glands of the legs and reproductive organs, and take up to a year to become adults. They can cause tropical diseases and sometimes lead to elephantiasis.
Symptoms: fever, chills, skin infection, lymphatic pain, thickening of the skin, swelling
8. Toxoplasma gondii
This common crescent-shaped parasite has the potential to invade the central nervous system in humans. Humans can become infected by eating uncooked meat or by touching infected pets. While most people have been infected with the parasite and have shown antibodies, few people show symptoms. Individuals with weakened immune systems are more susceptible to Toxoplasma gondii infection, while pregnant women can experience severe or even fatal effects on their fetuses once they are infected with Toxoplasma gondii.
Symptoms: flu symptoms, fever, chills, weakness, headache
9. Giardia lamblia
Giardia lamblia is a protoparasite with flagella. It parasitizes and multiplies in human internal organs and can cause giardiasis. Once this parasite is infested in human internal organs, it can trigger inflammation and other damage, weakening the ability of internal organs to absorb nutrients, which can cause symptoms such as diarrhea. This parasite is usually found in drinking water and is a potential hazard.
Symptoms: diarrhea, nausea, abdominal pain, weight loss, burping with the smell of rotten eggs.
10. Dysentery amoeba
Amoebic dysentery is a disease caused by a single-celled organism that can be transmitted by amoebic protozoa. This parasite mainly infects humans and other primates. Dysentery amoeba can be found in water bodies, humid environments, and soil, and may contaminate fruits and vegetables. The mode of transmission is mainly through feces. Unlike other protozoa such as Plasmodium, amoebic parasites have a higher lethality rate and are more likely to lead to severe consequences.
Symptoms: abdominal pain, weight loss, weakness, diarrhea, liver abscess