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Diagnosis is the same as with liver flukes: examination of feces or other samples and immunoassay. Praziquantel is used to treat infections caused by intestinal flukes.

  • How are flukes transmitted?

Helminthic gastrointestinal infections

Numerous helminths are capable of colonizing the GI tract. Many such infections are asymptomatic, but others may cause signs and symptoms ranging from mild GI stress to severe systemic infection. Helminths have complex and unique life cycles that dictate their specific modes of transmission. Most helminthic infections can be treated with medications.

Table titled: Helminthic Infections of the GI Tract. Columns: Disease, Pathogen, Signs and Symptoms, Transmission, Diagnostic Tests, Antimicrobial Drugs. Ascariasis; Ascaris lumbricoides; Shortness of breath, cough, nausea, diarrhea, bloody stool, abdominal pain, weight loss, fatigue, worms in stool or sputum; Ingestion of eggs in fecally contaminated food and water; Microscopic observation of eggs in stool sample, X-rays, ultrasounds or MRIs; Albendazole, mebendazole. Hookworm; Necator americanus, Ancyclostoma doudenale; Cough, itchy rash, wheezing, loss of appetite, abdominal pain, diarrhea, cutaneous larva migrans; Larvae in soil contaminated by dog or cat feces penetrate the skin; Microscopic observation of eggs in stool sample; Albendazole, mebendazole, pyrantel pamoate, thiabendazole. Hydatid disease (cystic echinococcosis); Echinococcus granulosus ; Cysts in lungs, liver, and other organs causing nausea, GI distress, and weight loss; severe anaphylaxis or death if cysts burst; Exposure to eggs in feces of infected dogs or livestock; CT, MRI, or ultrasonography to detect cysts; ELISA, indirect hemagglutinin test; Albendazole or mebenazole. Intestinal flukes (fasciolopsiasis); Fasciolopsis buski; Diarrhea, abdominal pain; in severe cases, vomiting, nausea, intestinal obstruction, anemia, allergic reactions; Ingestion of raw or undercooked aquatic plants containing cysts; Microscopic examination of eggs in stool or other samples; immunoassays; Praziquantel. Liver flukes; Fasciola hepatica, F. gigantica, Clonorchis sinensis, Opisthorchis viverrini, O. felineus; Fever, malaise, anemia, abdominal signs and symptoms, transaminitis; cholangitis, cirrhosis, pancreatitis, cholecystitis, gall stones in chronic phase; Ingestion of raw or undercooked aquatic plants (Fasciola spp.) or freshwater fish (Clonorchis spp.) contaminated with eggs or cysts; Microscopic observation of eggs in stool or other samples; immunoassays; Triclabendazole for Fasciola; praziquantel, albendazole for Clonorchis and Opisthorchis. Pinworms (Enterobiasis); Enterobius vermicularis; Itching around the anus, abdominal pain, insomnia, irritation of female genital tract Fecal-oral route; Visual observation of worms in anal region; microscopic observation of eggs from anal area or under fingernails; Mebendazole, albendazole, pyrantel pamoate. Strongyloidiasis; Strongyloides stercoralis; Often asymptomatic; cough (sometimes bloody), skin rash, abdominal pain, diarrhea; in immunosuppressed patients, may become disseminated, causing serious and potentially fatal complications Soil-dwelling larvae penetrate the skin, usually bare feet; Microscopic observation of larvae in stool; serological testing for antigens; Ivermectin, albendazole. Tapeworms (taeniasis) ; Taenia solium, T. saginata, T. asiatica, Diphyllobothrium latum; Asymptomatic or mild GI distress; cysts in muscle, eye, or brain (cysticercosis); brain cysts can cause headaches, seizures, or death; Ingestion of raw or undercooked pork or beef from infected animal; Observation of worm segments or microscopic eggs in stool; CT or MRI to detect cysts; Praziquantel, niclosamide. Trichinosis; Trichinella spiralis, other Trichinella spp. Diarrhea, constipation, abdominal pain, headache, cough, chills, light sensitivity, muscle pain, fever, conjunctivitis; in severe cases may affect motor coordination, breathing, heart function; Ingestion of raw or undercooked pork or other meat of infected animal; Observation of cysts in muscle biopsy, enzyme immunoassay; Albendazole, mebendazole. Whipworm (trichuriasis); Trichuris trichiura; Abdominal pain, anemia, diarrhea (possibly bloody), rectal prolapse; Ingestion of eggs in fecally contaminated food Microscopic observation of eggs in stool; Albendazole, mebendazole, ivermectin.
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Resolution

Carli’s doctor explained that she had bacterial gastroenteritis caused by Salmonella bacteria. The source of these bacteria was likely the undercooked egg. Had the egg been fully cooked, the high temperature would have been sufficient to kill any Salmonella in or on the egg. In this case, enough bacteria survived to cause an infection once the egg was eaten.

Carli’s signs and symptoms continued to worsen. Her fever became higher, her vomiting and diarrhea continued, and she began to become dehydrated. She felt thirsty all the time and had continual abdominal cramps. Carli’s doctor treated her with intravenous fluids to help with her dehydration, but did not prescribe antibiotics. Carli’s parents were confused because they thought a bacterial infection should always be treated with antibiotics.

The doctor explained that the worst medical problem for Carli was dehydration. Except in the most vulnerable and sick patients, such as those with HIV/AIDS, antibiotics do not reduce recovery time or improve outcomes in Salmonella infections. In fact, antibiotics can actually delay the natural excretion of bacteria from the body. Rehydration therapy replenishes lost fluids, diminishing the effects of dehydration and improving the patient’s condition while the infection resolves.

After two days of rehydration therapy, Carli’s signs and symptoms began to fade. She was still somewhat thirsty, but the amount of urine she passed became larger and the color lighter. She stopped vomiting. Her fever was gone, and so was the diarrhea. At that point, stool analysis found very few Salmonella bacteria. In one week, Carli was discharged as fully recovered.

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Key concepts and summary

  • Helminths often cause intestinal infections after transmission to humans through exposure to contaminated soil, water, or food. Signs and symptoms are often mild, but severe complications may develop in some cases.
  • Ascaris lumbricoides eggs are transmitted through contaminated food or water and hatch in the intestine. Juvenile larvae travel to the lungs and then to the pharynx, where they are swallowed and returned to the intestines to mature. These nematode roundworms cause ascariasis .
  • Necator americanus and Ancylostoma doudenale cause hookworm infection when larvae penetrate the skin from soil contaminated by dog or cat feces. They travel to the lungs and are then swallowed to mature in the intestines.
  • Strongyloides stercoralis are transmitted from soil through the skin to the lungs and then to the intestine where they cause strongyloidiasis .
  • Enterobius vermicularis are nematode pinworms transmitted by the fecal-oral route. After ingestion, they travel to the colon where they cause enterobiasis .
  • Trichuris trichiura can be transmitted through soil or fecal contamination and cause trichuriasis . After ingestion, the eggs travel to the intestine where the larvae emerge and mature, attaching to the walls of the colon and cecum.
  • Trichinella spp. is transmitted through undercooked meat. Larvae in the meat emerge from cysts and mature in the large intestine. They can migrate to the muscles and form new cysts, causing trichinosis .
  • Taenia spp. and Diphyllobothrium latum are tapeworms transmitted through undercooked food or the fecal-oral route. Taenia infections cause taeniasis . Tapeworms use their scolex to attach to the intestinal wall. Larvae may also move to muscle or brain tissue.
  • Echinococcus granulosus is a cestode transmitted through eggs in the feces of infected animals, especially dogs. After ingestion, eggs hatch in the small intestine, and the larvae invade the intestinal wall and travel through the circulatory system to form dangerous cysts in internal organs, causing hydatid disease .
  • Flukes are transmitted through aquatic plants or fish. Liver flukes cause disease by interfering with the bile duct. Intestinal flukes develop in the intestines, where they attach to the intestinal epithelium.

Fill in the blank

Liver flukes are often found in the _________ duct.

bile

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Short answer

Why does the coughing up of worms play an important part in the life cycle of some helminths, such as the roundworm Ascaris lumbricoides ?

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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