INTESTINAL PARASITOSIS In the Republic of El Salvador, as in other tropical and sub-tropical countries, intestinal parasitosis is a major public health problem and a frequent cause of medical consultation. According to statistics, up to 80 % of the population is afflicted by parasitosis. Although most of the affected population remains asymptomatic, symptoms such as unspecific abdominal pain, diarrhea, anemia, and even serious complications such as perforation and intestinal obstruction may arise.
The most frequent intestinal parasites found in El Salvador are Giardia Lamblia, Entamoeba Hystolitica, Trichiuris Trichiura, Enterobius Vermicularis, Ascaris Lumbricoides, Uncinarias, Taenia Solium and Saginata , the smaller taenias, Strongyloides Stercoralis, Banatidium Coli and Blastocystis Hominis. A high degree of enviromental contamination, lack of hygiene amongst a large part of the population, a high population density with large groups of people living in close quarters, fecal contamination of water supplies, as well as the presence of large amounts of vectors are factors that contribute to a high prevalence of parasitoses in this region of the world. Amoebiasis is a common form of parasitosis in this country. Fortunately only aproximately 10% of the Entomoebas Hystolitica known to inhabit the bowel are considered pathogenic. This is corroborated by colonoscopic findings in which most patients diagnosed with amoebas in their stool examination, demonstrated no mucosal lesions on endoscopy. Lesions comonly produced by Entamoeba Hystolitica range from discrete erythematous areas, to flask-shaped ulcerations of varying magnitude. Life threatening complications such as intestinal perforation or extrahepatic invasion into liver (liver abscess) and the lung may occur. Another feared complication is the development of a mass-like lesion known as an amoeboma, which may be initially mistaken for a neoplasm. (tumor) Flies play an important role in the transmission of amoebiasis, since they act as vectors, transporting infected fecal material from one human reservoir to be ingested by another. Amongst the symptoms experienced by patients afflicted with amoebas one finds tenesmus, a persistant sensation of defecation even though the rectum has already been evacuated as well as pujo, described as feeling a need for defecation , even though feces are not present. These symptoms are caused by inflammatory changes at the rectal mucosa and may also appear with other conditions such as a benign or malinant tumor of the rectum (see Chapter on carcinoma of Colon and Rectum).

Giardia Lamblia is the most frequent pathogen of the intestine here in El Salvador,
Worldwide is one of the most common of the intestinal parasites, due to the fact that it is easily transmitted by the ingestion of contaminated uncooked food such as vegetables or salads, as well as by the ingestion of water. Although it is often claimed by officials that water out of the faucet is of drinking quality this is very doubtful and many pathogens probably find their way into the public water supply. A comparative study between water quality in third world countries and industrialized nations would be interesting. The symptoms caused by Giardia Lamblia are diverse and range from non-specific peri-umbilical discomfort to abdominal cramping with explosive diarrheas. The target organ of Giardia Lamblia is the small intestine and duodenitis, flatulence, lactose intolerance and malabsorption syndrome may be present. To prevent this disease hygienic measures such as boiling the drinking water and disinfecting uncooked foods such as salads, with special iodine solutions, must be taken. Soak the salads in these iodine solutions for at least two hours since amoebas are very resistant. In one experiment amoebas survived within a lemonade inside a refrigerator for over eleven days.

Enterobius Vermicularis (Oxiurios) is a parasite that lives within the colon, especially the cecum. The female parasites deposit their eggs around the anus usually during night hours while the patient sleeps, giving rise to anal itching (pruritus). This leads to scratching and contamination of fomites (bed sheets), which facilitates further infection. This parasite is not usually found on general stool examination.

Trichuris Trichuris (whipworm).  A female Trichuris has been found in the cecum that is the normal habitat of this worms.  Trichuriasis is an intestinal infection found in human beings which is caused by Trichuris trichiura, more commonly known as  whipworm because of its whip-like appearance. It is characterized by the invasion of the colonic mucosa by the adult  Trichuris and produces minor inflammatory changes at the sites of localization. It is prevalent throughout the world, especially in  tropical areas. Its diagnosis is usually made by identification of the typical eggs in the stool; adult whipworm is rarely seen during  colonoscopy. Colonoscopy can directly diagnose trichuriasis, confirming the threadlike form of worms with an attenuated end.  The worms can be overlooked, particularly if colon preparation is imperfect. Attenuated whip-like ends of whipworms, which are  embedded in the colonic mucosa, were removed with biopsy forceps.

This worm seem to be a female, Note : A filariform anterior part. See the histopathologic below. The worm derives its name (whipworm) from its  characteristic whiplike shape; the adult (male - 30-45 mm,  female - 35-50 mm) with males being somewhat smaller than females. Buries its thin, threadlike anterior half into the intestinal mucosa, After 10-14 days in soil, eggs become infective. Soil-containing eggs must be swallowed.  no tissue migratory phase occurs. Larvae hatch in the small intestine, where they grow and molt, finally taking up  residence in the large intestine. The time from ingestion of eggs to development of mature worms is approximately 3  months. Adult females lay eggs for up to 5 years.

Another trichuris is observed in the appendicular hole.  This worm seem to be a male, Note : A filariform anterior  part and coiled posterior end.  More than 700 million people are infected worldwide.  The adult worms (approximately 4 cm in length) live in the  cecum and ascending colon. The adult worms are fixed in  that location with the anterior portions threaded into the  mucosa. Most cases are asymptomatic. Heavy parasite  loads cause diarrhea, anemia and pain.

One of the worm was taken with the biopsy forceps, see  below the sequences of video clips and pictures of this  whipworm.  Eosinophilia is uncommon; however, when present, it ranges from 5-20%.

Macroscopic and histopatologic images are displayed in  this sequence, see below.

Caudal aspect of female Trichuris trichura.  ( Stereoscopic view).  The history of T. Trichuria dates back to the times of prehistoric man; however, the first written record of T.  trchiura appeared in 1740 when an Italian scientist by the  name of Morgani discovered the residence of adult T.  trichiura worms in the colon. In 1761 Roedere, a German physician, gave a report of the exact morphologic  description and provided accurate drawings of the parasite. The organism received its taxonomy classification in the  18th C.

Cephalic part of the Trichuris trichura separated from the body.  To the left there is a portion of caudal part of the parasite. The mouth is a simple opening, lacking lips. The buccal  cavity is tiny and is provided with a minute spear.

Stereoscopic view of the body of the parasite.  The esophagus is very long, occupying about two thirds of the body length and consists of a thin-walled tube  surrounded by large, unicellular glands, the stitchocytes.

Sections of the worm, demonstrated a gravid female adult  nematode with numerous immature ova.  This is a longitudinal section of Trichuris trichura, showing eggs in the uterus.  Female worms in the cecum shed between 3,000-20,000 eggs  per day.

A complete section of the uterus with numerous eggs.  Life cycle of T.trichiura:  Eggs, after are discharges with the feces, require between 12 days and several weeks (based on the environment condition) for development of larvae. When infective eggs are ingested, the larvae hatch in the small  intestine, and migrate to the lower intestine and colon, and enters the epithelium of the intestine.  They become sexually mature in about 3 months. The larvae bore into the mucosa with the slender anterior part of the body.

Characteristic eggs of Trichuris trichura with typical extremes.  Each worm causes an estimated 5 mL of blood loss every day. Heavy infections are required to cause anemia

A 10x view of eggs into the uterus.

A 4x view of eggs.  Whipworm infections transpire as a result of accidental  ingestion of Trichuris trichiura eggs or embryos. After  they are swallowed, the eggs move to the host's small  intestine, where they develop into juveniles. The young  worms then move to the large intestine and attach their  anterior ends to the intestinal wall. After approximately  three months, the parasite becomes a sexually mature  adult, females producing up to 10,000 eggs per day, which  are passed out of the host's system with digestive wastes.  The eggs need a warm moist environment to survive  outside the body and become infective in about three  weeks. Since whipworms do not actually multiply inside a  host, each individual worm represents a separate incident  of infection.

Colonic mucosa with erosion and chronic inflammatory changes, and hemorrhages, 10x.

The colonia mucosae shows chronic inflamation and superficial hemorrage (Low power 4x).

Flask-shaped ulcer caused by amoebas. Note fibrin deposition . Patient had dark enteric bleeding.

Amoeboma of the sigmoid colon. Same case as above. Amoebomas were once thought to be exclusive of cecum and ascending colon.

Small ulcerations of the colon displaying erithematous borders, caused by amoebas

Colonoscopic image of the case described above.

45 year old male patient with rectal ulcers due to amoebiasis.

Same patient as above. Colonoscopy reveals ulcerations at the pectine line ??

Trichiurus trichiura in the cecum. Casual finding on colonoscopy. Note the inflammatory response and the hemorrhage caused by this organism, which can cause anemia in patients and is associated with rectal prolapse in children.

Hypertrophic Brunner´s glands, characteristic endoscopic finding in Giardia Lamblia infection.

Ascaris Lumbricoides in descending colon. Casual endoscopic finding. Note the diverticulae.

Same patient as above. . Same patient as above.

Amoebiasis of the cecum. Note multiple lesions caused by intestinal presence of entamoeba hystolitica. Towards the center of the image one can observe the aperture to the appendix, which displays similar lesions.

Same case as above.