Human Intestinal Parasites

Whip Worm Intestinal Parasite
Whip Worm Intestinal Parasite

What is a Parasite?

A parasite is an organism that lives off, feeds, grows and is sheltered on other organisms without any contribution to benefit the host and often even causing harm. Even the parasites in humans are mostly harmful in nature and lead to various diseases like trichinosis.

What Are Intestinal Parasites?

Human parasites are usually single cell organisms or worms. A lot of these are found in the intestines and therefore are referred as intestinal parasites. These are microscopic and the single celled organisms called protozoa.

The protozoa like Giardia lamblia, Cyclospora, Cryptosporidium (Crypto) are all single-celled organisms and feed on the nutrients from human stool. These organisms lead to inflammation of intestine, particularly the small intestine, and thus affecting the process of absorption of nutrients. Some protozoa like the entamoeba hystolytica are primarily found in the colon.

Human intestinal parasites can lead to infection of the intestines. Even though these do not often show any clear signs, the treatment for any kind of a parasitic infection is quite simple and clear.

The intestinal parasites are found in both the large and small intestines. These parasites feed on the blood or stool from the intestinal wall. Also referred as helminthes, the intestinal worms in human are round worms, flukes and tapeworms. These organisms eat the bowel content or feed themselves on the blood from the walls of intestines.

They often transmit through contaminated water and food. Even intimate sexual or nonsexual contacts lead to the transmission of parasites with poor sanitation and hygiene the main factors responsible for the growth and development of human intestinal parasites.

A condition of intestinal parasites can be life-threatening to individuals with weak immune system, like HIV-infected persons.

Intestinal parasites spread due to unhygienic conditions. These are usually shed in the human stool and any stool-contaminated water or food is the main source of parasitic infections. Some other sources that lead to the spread of these infections are unwashed or uncooked food, unclean hands, skin contact with infectious area, public places like swimming pools, oral sex, anal sex, homosexual men and also non sexual contact like diaper changing.

Intestinal Parasites Symptoms

The symptoms of parasites in intestines can often be misleading and unclear and sometimes there are no parasite symptoms. On being present, the symptoms include some common ones like abdominal pain, bloating, nausea and vomiting.

Diarrhea is also a very commonly observed symptom of intestinal parasites and it usual is in chronic state. A diarrhea caused due to intestinal parasites can be distinguished from bacterial diarrhea by its duration and severity. A diarrhea caused by bacteria start suddenly following a contaminated meal and heals by itself in few days whereas an intestinal parasitic infection leads to gradual development of mild diarrhea which lasts for several days to months.

Entamoeba histolytica invades the lung, liver, brain and various other organs forming cysts and giving rise to a disease called amebic dysentery. The symptoms for amebic dysentery include abdominal cramps and severe colitis along with developments of ulcers. In addition, blood and pus are also observed occasionally in the stool.

The human intestinal parasites do not let the intestines absorb minerals and vitamins resulting in a pale skin and fatigue. This tiredness is sometimes accompanied with a tingling sensation mainly in the abdomen.

Parasites in stool lead to development of mucus in bowel movement, flatulence and bloating. Worms in stool or the laying of their eggs in intestines lead to weight loss.

Some other common signs of parasites in the intestine are fever, coughing, skin-itching and decrease in sex drive.

Some of the intestinal parasites are not stationery and keep moving form the lungs to intestines and back. They also keep moving to various other parts of the body. Intestinal parasites also lead to a decrease in the number of red blood cells (R.B.C.) leading to anemia. Intestinal parasitic infection can also lead to deficiency of B-12, dysuria, impairment of central nervous system, chills, blindness, colitis, chronic fatigue and hemoptysis.

Apart from these, there are numerous other symptoms of parasites in intestines which are common and may indicate other disorders in the body. These include symptoms like myositis, constipation, anorexia, colitis, hematochezia, rectal hemorrhage, jaundice, headaches and vaginitis.

Human intestinal parasites also result in swelling of face, insomnia and excessive sweating, especially at night. Ulcers are seen developing on the surface as a result of the internal disturbance and certain various organs increase in size. Digestive disturbance, weakness, weight loss and dizziness are also commonly seen when the harmful parasites enter the gastro-intestinal tract.

Few other symptoms of human intestinal parasites that are characteristic of various other disorders too are lack of immunity, lung congestion, rectal prolaspe, muscle spasms and loss of memory leading to mental problems.

Intestinal Parasites Diagnosis

Since most of the signs of intestinal parasites are in common with various other illnesses and diseases, the correct diagnosis becomes a little complicated by just studying the symptoms. The presence of intestinal parasites is suspected by the most common symptoms like chronic bloating or diarrhea. To confirm or dismiss any of such suspicions, there are various laboratory tests for intestinal parasites which include the following:

  • O&P tests of stool. To get accurate results, this test is carried out for 3 times, once every alternate day.
  • An increase in the levels of eosinophils and IgE antibodies in the blood tests indicate intestinal parasites. Also there is a decrease in ferritin, R.B.C. and hemoglobin count.
  • A hemoccult test shows blood in stool for an infected person.
  • A proctoscopy test involves rectal insertion of thin tube with a light on the tip.
  • For diagnosing any cysts in lungs, liver or brain, a biopsy and CT scan are considered the best options.

Intestinal Parasites Treatment

Intestinal parasites can be treated by simple methods but these keep reoccurring as long as the source causing the infection exists. For treating intestinal parasites, there are various anti-parasitic medications which have proved to be effective. These include tinidazole, quinacrine, metronidazole and furazolidone. These anti-parasitic drugs should however be used according to the doctor’s prescription as the treatment regime differs for each person based on different factors. Trimethoprim-sulfametoxazol is recommended for patients with cases of diagnosed cyclospora.

Intestinal parasites treatment for pregnant women differs slightly as some of the above mentioned medicines are to be avoided completely and some do not work effectively as the intestines absorb these into the blood. However, paramomycin is left unabsorbed and is also safe for pregnant women and hence is usually prescribed in parasitic infection. Treatments for parasitic infection may not work even for HIV patients and others with a weak immune system.

Observing clean hygiene habits and keeping the surroundings clean help prevent intestinal parasites. Food should be cooked thoroughly as the heat kills the parasites. Using antibiotic soaps, especially after bowel movement and before eating, is quite necessary as this washes away the parasites on hands. Travelers should be extra cautious about hygiene and should avoid unclean and unhygienic food and contaminated water.



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