“A man without worms is a dead man.” ML Cavaracoc

The modern world, despite great technological and scientific advances, still harbors a large number of parasitic diseases. The poor sanitary conditions of some people, their habits, their culture and their level of education can be classified as the main causes of this situation.

In large cities, where accelerated growth and internal migrations are responsible for the emergence of an unemployed population, devoid of any notion of hygiene and education, without adequate living conditions, we can observe a great spread of diseases caused by parasites.

Continuing education among health professionals is necessary, associated with the improvement of sanitary conditions, so that in the near future we can achieve greater control of these parasitic diseases.

HELMINTHIASIS

OXYURIASIS OR ENTEROBIASIS

Etiological agent: Enterobius vermicularis .

Location: large intestine (rectum and cecum).

Transmission: direct (anal/oral ingestion of eggs), but may also occur indirectly or secondary (eggs present in food or dust are ingested or aspirated).

Clinical presentation: the main symptom is anal itching, predominantly at night; vulvovaginitis may occur in girls.

Diagnosis: clinical; laboratory (parasitological [positivity does not reach 5%]; anal swab or gummed tape method [in the morning, before washing the body]).

Treatment: pyrvinium pamoate; mebendazole; albendazole.

General measures: the patient should wear tight pants; always have their nails cut short; wash all underwear, bed linen and bath linen with boiling water; treat the entire family.

TRICHOCEPHALIASIS

Etiological agent: Trichocephalus trichiura .

Location: large intestine (colic and cecum) and last portion of the ileum.

Transmission: ingestion of eggs.

Clinical picture: may be asymptomatic or present with digestive manifestations (colic, diarrhea, enterorrhagia leading to anemia and rectal prolapse).

Diagnosis: clinical; laboratory (parasitological [quantitative method of Kato-Kats and qualitative method such as Hoffman, Pans and Janer]; blood count [microcytic and hypochromic anemia]; rectosigmoidoscopy).

Treatment: mebendazole; albendazole.

ASCARIDIASIS

Etiological agent: Ascaris lumbricoides .

Location: lumen of the small intestine (duodenum, jejunum and ileum). It may occasionally be located in the common bile duct, gallbladder, Wirsung’s duct, appendix, etc.

Transmission: ingestion of eggs.

Clinical presentation: the most common clinical manifestations are colic, nausea, vomiting, diarrhea, anorexia and abdominal discomfort. During the migratory larval phase, transient acute pneumonitis (Loeffler’s syndrome) associated with fever and marked eosinophilia may occur.

Complications: intestinal occlusion, peritonitis, appendicitis, obstruction of the bile ducts and hemorrhagic pancreatitis due to obstruction of the Wirsung’s duct. Adult worms may be eliminated through the mouth and nose.

Diagnosis: clinical; laboratory: parasitological examination of feces (qualitative technique, such as Hoffman, Pons and Janer, or quantitative technique such as Kato-Kats); complete blood count (eosinophilia); Plain abdominal radiography: images suggestive of an ascaris bolus.

Treatment: mebendazole; albendazole; pyrantel pamoate; levamisole.

Treatment of intestinal occlusion: zero diet; continuous gastric aspiration; piperazine introduced through a gastric tube; mineral oil; intravenous hydration.

HOOKWORM

Etiological agents: Ancylostoma duodenale and Necator americanus .

Location: small intestine.

Transmission: through the larvae, through the skin.

Clinical picture: pruritus in the acute phase; transient acute pneumonitis during the migratory larval phase associated with fever and eosinophilia (Loeffler’s syndrome); nausea, vomiting, diarrhea, anorexia or bulimia and, very characteristically, appetite perversion (geophagia); microcytic and hypochromic anemia, which may be severe, leading to fatigue, drowsiness, edema of the lower limbs and cardiovascular manifestations (heart failure).

Diagnosis: clinical; laboratory: parasitological (quantitative method such as Kato-Kats and qualitative method such as Hoffman, Pons and Janer); blood count (microcytic and hypochromic anemia, eosinophilia).

Treatment: mebendazole; albendazole; pyrantel pamoate.

STRONGYLOIDIASIS

Etiological agent: Strongyloides stercolaris .

Location: small intestine.

Transmission: through larvae through the skin; in immunocompromised patients, by auto-endoinfection (migration of larvae through the intestinal mucosa), carrying out the pulmonary cycle, and auto-exoinfection (migration of larvae from the perianal region to the lungs).

Clinical picture: skin pruritus; bronchopulmonary symptoms depending on the passage of larvae through the respiratory tract; abdominal discomfort, diarrhea, dysentery crises, vomiting, etc.; irritability, asthenia, insomnia, loss of appetite and weight loss.

Diagnosis: clinical; laboratory: parasitological (Baerman Moraes technique); complete blood count (marked eosinophilia); radiography of the duodenum, jejunum and possibly colon: morphological and functional alterations that suggest the possibility of strongyloidiasis; search for larvae in duodenal fluid, sputum, urine, etc.; jejunal biopsy.

Treatment: thiabendazole; albendazole and irvermectin.

TAENIASIS

Etiological agents: Taenia solium (pork tapeworm) and Taenia saginata (cattle tapeworm).

Location: small intestine.

Transmission: ingestion of undercooked or raw pork or beef.

Clinical picture: may be asymptomatic or may present with anorexia or bulimia, nausea, vomiting, stomach ulcer-like pain, weight loss, irritability, headache, asthenia or fatigue.

Diagnosis: clinical: elimination of gravid rings expelled with feces; laboratory: parasitological (sieving is the method of choice; gummed tape or Graham method).

Treatment: praziquantel; mebendazole; niclosamide.

HYMENOLEPIASIS

Etiological agent: Hymenolepis nana .

Location: terminal portion of the ileum.

Transmission: ingestion of embryonated eggs through food.

Clinical picture: most patients are asymptomatic. The main symptoms are abdominal cramps, nausea, vomiting, anorexia, weight loss, diarrhea, epileptiform seizures and allergic phenomena (urticaria, anal pruritus and eosinophilia).

Diagnosis: laboratory: parasitological analysis of feces, using the qualitative technique of Hoffman, Pons and Janer and quantitative technique of Kato-Kats.

Treatment: praziquantel; niclosamide.

PROTOZOOSES

GIARDIASIS

Etiological agent: Giardia lamblia .

Location: duodenum and upper portions of the jejunum.

Transmission: ingestion of cysts contained in contaminated food and water.

Clinical picture: most patients are asymptomatic. The main symptoms are acute or chronic diarrhea with steatorrheic stools, flatulence, cramps, nausea, and vomiting.

Laboratory diagnosis: parasitological-a) formed stools (cyst search): direct fresh method or stained with Lugol, method of Faust et al.; b) diarrheal stools (trophozoite search): direct fresh method or stained with Lugol or iron hematoxylin; duodenal aspirate; duodenojejunal biopsy.

Treatment: furazolidone; metronidazole; tinidazole; secnidazole; albendazole.

AMOEBIASIS

Etiological agent: Entamoeba histolytica .

Location: colon.

Transmission: through contaminated food and water and by fecal/oral route.

Clinical picture: asymptomatic forms; symptomatic forms: a) intestinal (dysenteric amoebic colitis and non-dysenteric colitis); b) extra-intestinal (hepatic, pulmonary, cerebral, splenic and genital abscesses).

Diagnosis: parasitological; rectosigmoidoscopy; search for parasites in tissues and exudates; ultrasonography and tomography in hepatic forms.

Treatment: metronidazole; tinidazole.