A parasite is an organism that lives in or on another organism, known as the host, from which it derives benefits such as nutrients or shelter, and it may cause harm to the host.
Parasites can be found in various environments and take different forms, from microorganisms to multicellular organisms, and are classified into three main groups.
- Protozoa: single-celled organisms.
- Helminths: parasitic worms.
- Ectoparasites: include organisms such as lice, fleas, and mites that live on the surface of the skin.
Parasites have evolved to adapt to their hosts, developing mechanisms that allow them to evade the immune system and ensure their survival.
Among the main parasites that can infect humans are:
- Plasmodium spp: causes malaria and is transmitted by mosquitoes of the Anopheles genus.
- Entamoeba histolytica: responsible for amoebiasis, which affects the intestinal tract and liver.
- Giardia lamblia: causes giardiasis, an intestinal infection associated with diarrhea and malabsorption.
- Toxoplasma gondii: parasite associated with toxoplasmosis, related to the consumption of raw meat.
- Ascaris lumbricoides: known as intestinal roundworm, mainly affects children in regions with poor sanitation.
- Taenia solium and Taenia saginata: cause intestinal infections; Taenia solium can also cause cysticercosis when larvae invade tissues.
- Schistosoma spp: responsible for schistosomiasis, which affects the liver, bladder, and intestinal tract.
- Ancylostoma duodenale and Necator americanus: worms that cause hookworm disease, associated with iron-deficiency anemia.
- Pediculus humanus capitis: head lice.
- Sarcoptes scabiei: the mite responsible for scabies.
- Fleas: can act directly as vectors of other diseases.
Although these are the parasitic infections that most commonly affect humans, there are many other types that occur less frequently.
Symptoms of parasites
There are various ways a person can be affected by a parasite and its consequences. This will vary depending on the type, location, and parasitic load.
Parasites such as tapeworms or nematodes can damage the intestinal lining or invade vital organs such as the brain and heart.
Those like intestinal worms absorb essential nutrients, causing malnutrition and vitamin deficiencies.
Another consequence is related to the immune system’s response to the parasite, which may cause chronic inflammation, tissue damage, or autoimmune diseases.
Some protozoa may produce toxins that affect the normal functioning of the host’s cells.
Ectoparasites such as fleas or mosquitoes can act as vectors, transmitting diseases like bubonic plague or malaria.
Based on all these characteristics, symptoms may include abdominal pain, diarrhea, nausea or vomiting, unexplained weight loss, fatigue, anemia, fever, itching or skin rashes, visible lesions, or difficulty breathing.
How to know if I have parasites
The diagnosis of parasitic infections combines clinical evaluation, medical history, and specific laboratory tests. Among the most common methods are:
- Stool test: detects eggs, larvae, or trophozoites of intestinal parasites.
- Blood tests: identify systemic infections or detect specific antibodies against parasites.
- Diagnostic imaging: ultrasound, CT scan, or MRI to visualize lesions caused by parasites in tissues.
- Biopsy: used to identify parasites present in tissues such as muscles or internal organs.
- Molecular tests: PCR (polymerase chain reaction) detects specific genetic material of parasites, particularly useful in hard-to-diagnose infections.
- Immunological tests: includes techniques like ELISA to identify specific antigens or antibodies against parasites.
An early and accurate diagnosis is essential to start appropriate treatment and prevent serious complications.
How to deworm
Proper medical deworming requires the use of specific medications to eliminate parasites from the body. The approach depends on the type of parasite and the severity of the infection.
As a first step, a prior medical evaluation is necessary to diagnose and identify the type of parasite and determine the appropriate treatment.
The basic approach is the use of antiparasitic medications specific to each type of parasite, but in advanced cases hospitalization and monitoring may be required, as well as combination therapies when multiple parasitic infections coexist, or even surgical procedures, as in some cases of intestinal worms.
If you suspect contact with a type of parasite or are experiencing symptoms, it’s important to seek specialized medical attention.
At the ABC Medical Center’s Internal Medicine Department, we can provide you with specialized care. Contact us!
Fuentes
CDC, MedlinePlus, MSD Manuals
