Flukes in stool


  • Watch out for liver flukes this summer
  • Liver, Intestinal and Lung Flukes
  • Watch this beautifully disgusting liver fluke parasite explore man’s innards
  • Helminthic Infections of the Gastrointestinal Tract Learning Objectives Identify the most common helminths that cause infections of the GI tract Compare the major characteristics of specific helminthic diseases affecting GI tract Helminths are widespread intestinal parasites. These parasites can be divided into three common groups: round-bodied worms also described as nematodes, flat-bodied worms that are segmented also described as cestodes , and flat-bodied worms that are non-segmented also described as trematodes.

    The nematodes include roundworms, pinworms, hookworms, and whipworms. Cestodes include beef, pork, and fish tapeworms. Trematodes are collectively called flukes and more uniquely identified with the body site where the adult flukes are located.

    Although infection can have serious consequences, many of these parasites are so well adapted to the human host that there is little obvious disease.

    Ascariasis Infections caused by the large nematode roundworm Ascaris lumbricoides, a soil-transmitted helminth, are called ascariasis. Over million to 1 billion people are estimated to be infected worldwide.

    At present, infections are uncommon in the United States. The eggs of the worms are transmitted through contaminated food and water. This may happen if food is grown in contaminated soil, including when manure is used as fertilizer.

    When an individual consumes embryonated eggs those with a developing embryo , the eggs travel to the intestine and the larvae are able to hatch. Ascaris is able to produce proteases that allow for penetration and degradation of host tissue.

    The juvenile worms can then enter the circulatory system and migrate to the lungs where they enter the alveoli air sacs. From here they crawl to the pharynx and then follow the gut lumen to return to the small intestine, where they mature into adult roundworms. Females in the host will produce and release eggs that leave the host via feces. In some cases, the worms can block ducts such as those of the pancreas or gallbladder.

    The infection is commonly asymptomatic. When signs and symptoms are present, they include shortness of breath, cough, nausea, diarrhea, blood in the stool, abdominal pain, weight loss, and fatigue. The roundworms may be visible in the stool. In severe cases, children with substantial infections may experience intestinal blockage.

    The eggs can be identified by microscopic examination of the stool Figure 1. In some cases, the worms themselves may be identified if coughed up or excreted in stool. They can also sometimes be identified by X-rays, ultrasounds, or MRIs. The first line of treatment is mebendazole or albendazole.

    In some severe cases, surgery may be required. Figure 1. Fertilized eggs can be distinguished from unfertilized eggs because they are round rather than elongated and have a thicker cell wall.

    Hookworm Two species of nematode worms are associated with hookworm infection. Both species are found in the Americas, Africa, and Asia. Necator americanus is found predominantly in the United States and Australia. The eggs of these species develop into larvae in soil contaminated by dog or cat feces. These larvae can penetrate the skin. After traveling through the venous circulation, they reach the lungs. When they are coughed up, they are then swallowed and can enter the intestine and develop into mature adults.

    At this stage, they attach to the wall of the intestine, where they feed on blood and can potentially cause anemia. Signs and symptoms include cough, an itchy rash, loss of appetite, abdominal pain, and diarrhea. In children, hookworms can affect physical and cognitive growth.

    Some hookworm species, such as Ancylostoma braziliense that is commonly found in animals such as cats and dogs, can penetrate human skin and migrate, causing cutaneous larva migrans, a skin disease caused by the larvae of hookworms.

    As they move across the skin, in the subcutaneous tissue, pruritic tracks appear Figure 2. The infection is diagnosed using microscopic examination of the stool, allowing for observation of eggs in the feces. Medications such as albendazole, mebendazole, and pyrantel pamoate are used as needed to treat systemic infection.

    In addition to systemic medication for symptoms associated with cutaneous larva migrans, topical thiabendazole is applied to the affected areas. Figure 2. In the parasitic form, the larvae of these nematodes generally penetrate the body through the skin, especially through bare feet, although transmission through organ transplantation or at facilities like day-care centers can also occur.

    When excreted in the stool, larvae can become free-living adults rather than developing into the parasitic form. These free-living worms reproduce, laying eggs that hatch into larvae that can develop into the parasitic form. In the parasitic life cycle, infective larvae enter the skin, generally through the feet. The larvae reach the circulatory system, which allows them to travel to the alveolar spaces of the lungs. They are transported to the pharynx where, like many other helminths, the infected patient coughs them up and swallows them again so that they return to the intestine.

    Once they reach the intestine, females live in the epithelium and produce eggs that develop asexually, unlike the free-living forms, which use sexual reproduction. The larvae may be excreted in the stool or can reinfect the host by entering the tissue of the intestines and skin around the anus, which can lead to chronic infections. The condition is generally asymptomatic, although severe symptoms can develop after treatment with corticosteroids for asthma or chronic obstructive pulmonary disease, or following other forms of immunosuppression.

    When the immune system is suppressed, the rate of autoinfection increases, and huge amounts of larvae migrate to organs throughout the body. Signs and symptoms are generally nonspecific. The condition can cause a rash at the site of skin entry, cough dry or with blood , fever, nausea, difficulty breathing, bloating, pain, heartburn, and, rarely, arthritis, or cardiac or kidney complications.

    Disseminated strongyloidiasis or hyperinfection is a life-threatening form of the disease that can occur, usually following immunosuppression such as that caused by glucocorticoid treatment most commonly , with other immunosuppressive medications, with HIV infection, or with malnutrition.

    As with other helminths, direct examination of the stool is important in diagnosis. Ideally, this should be continued over seven days. Serological testing, including antigen testing, is also available. These can be limited by cross-reactions with other similar parasites and by the inability to distinguish current from resolved infection. Ivermectin is the preferred treatment, with albendazole as a secondary option.

    Think about It How does an acute infection of S. Pinworms Enterobiasis Enterobius vermicularis, commonly called pinworms, are tiny 2—13 mm nematodes that cause enterobiasis. Of all helminthic infections, enterobiasis is the most common in the United States, affecting as many as one-third of American children.

    The itching contributes to transmission, as the disease is transmitted through the fecal-oral route. After being ingested, the larvae hatch within the small intestine and then take up residence in the colon and develop into adults.

    From the colon, the female adult exits the body at night to lay eggs Figure 3. Infection is diagnosed in any of three ways. First, because the worms emerge at night to lay eggs, it is possible to inspect the perianal region for worms while an individual is asleep.

    An alternative is to use transparent tape to remove eggs from the area around the anus first thing in the morning for three days to yield eggs for microscopic examination. Finally, it may be possible to detect eggs through examination of samples from under the fingernails, where eggs may lodge due to scratching.

    Once diagnosis has been made, mebendazole, albendazole, and pyrantel pamoate are effective for treatment. Figure 3. Trichuriasis The nematode whipworm Trichuris trichiura is a parasite that is transmitted by ingestion from soil-contaminated hands or food and causes trichuriasis.

    Infection is most common in warm environments, especially when there is poor sanitation and greater risk of fecal contamination of soil, or when food is grown in soil using manure as a fertilizer.

    The signs and symptoms may be minimal or nonexistent. When a substantial infection develops, signs and symptoms include painful, frequent diarrhea that may contain mucus and blood. It is possible for the infection to cause rectal prolapse, a condition in which a portion of the rectum becomes detached from the inside of the body and protrudes from the anus Figure 4. Severely infected children may experience reduced growth and their cognitive development may be affected.

    When fertilized eggs are ingested, they travel to the intestine and the larvae emerge, taking up residence in the walls of the colon and cecum. They attach themselves with part of their bodies embedded in the mucosa. The larvae mature and live in the cecum and ascending colon.

    After 60 to 70 days, females begin to lay to 20, eggs per day. Diagnosis involves examination of the feces for the presence of eggs. It may be necessary to use concentration techniques and to collect specimens on multiple days. Following diagnosis, the infection may be treated with mebendazole, albendazole, or ivermectin. Figure 4. It occurs when the rectum loses its attachment to the internal body structure and protrudes from the anus. These microscopic nematode worms are most commonly transmitted in meat, especially pork, that has not been cooked thoroughly.

    They develop into mature adults within the large intestine. The larvae produced in the large intestine are able to migrate into the muscles mechanically via the stylet of the parasite, forming cysts. Muscle proteins are reduced in abundance or undetectable in cells that contain Trichinella nurse cells. Animals that ingest the cysts from other animals can later develop infection Figure 5.

    Although infection may be asymptomatic, symptomatic infections begin within a day or two of consuming the nematodes.

    Abdominal symptoms arise first and can include diarrhea, constipation, and abdominal pain. Other possible symptoms include headache, light sensitivity, muscle pain, fever, cough, chills, and conjunctivitis. More severe symptoms affecting motor coordination, breathing, and the heart sometimes occur. It may take months for the symptoms to resolve, and the condition is occasionally fatal.

    OVERVIEW: What every clinician needs to know Parasite name and classification There are three major types of liver flukes pathogenic for humans: Clonorchis sinensis, various Opisthorchis species viverrini, felineus and Fasciola species hepatica and gigantica. All flukes are trematodes, a subset of platyhelminthes flatworms. There are many species of intestinal flukes that infect humans, primarily in Asia. Of these, the major human pathogens discussed here will be Fasciolopis buski, Heterophyes heterophyesand Metagonimus yokogawai.

    Eight lung flukes of the genus Paragonimusare known to be pathogenic in humans. Of these the most prevalent is P. Continue Reading What is the best treatment? Praziquantel is the drug of choice for Clonorchis and Opisthorchis species. It is also the first-line therapy for all the intestinal flukes and Paragonimus infection. Praziquantel causes a spastic paralysis of the worms and alteration and disintegration of the worm tegument by incompletely understood mechanisms. The dose is the same for children.

    Observed side effects include dizziness, sleepiness, headache, and diarrhea, but are generally transient. Praziquantel is FDA-approved but considered investigational for the treatment of intestinal flukes. For cerebral disease, a short course of corticosteroids may be given with praziquantel to minimize the inflammatory response to dying flukes.

    Triclabendazole is the first-line therapy for F. Two doses hours apart may also be given for severe infections. Fasciolaserologic testing can be used to assess the response to therapy. Seroreversion loss of detectable antibodies usually is noted 6 to 12 months after cure.

    Are there issues of anti-infective resistance? Clinically important resistance of liver flukes to praziquantel has not been observed but low cure rates for schistosomiasis have been reported, indicating the possibility of development of resistance in the future. What alternative therapies are available? A single mg dose of tribendimine has also been highly effective in initial clinical trials against both C.

    For Fasciola infection, nitazoxanide may also be effective but is unproven. The adult dosage of nitazoxanide is mg po bid twice a day for 7 days, with food. What are the clinical manifestations of infection with this organism? Clonorchis and Opisthorchis Acute infection with C. Shortly after infection with C. High-grade fever, arthralgia and lymphadenopathy as well as abdominal pain may occur after O.

    Chronic symptoms include abdominal pain and discomfort, weight loss and anorexia. Hepatomegaly and right upper quadrant tenderness may be observed both in the acute and chronic setting. Fasciola Distinct syndromes are associated with the acute and chronic phases of infection: The acute phase may last for a few months and occurs within a few weeks of infection.

    Symptoms are associated with migration of the larval parasite through liver parenchyma see life cycle below , and include abdominal pain, cough, urticaria and fever. Symptoms of chronic infection are subtle and similar to those seen with Clonorchis and Opisthorchis described above. Intestinal Flukes Heavy infections may be associated with fever, weight loss, abdominal pain, diarrhea, anasarca and obstruction.

    Lung flukes Predominant symptoms include chronic cough, hemoptysis and production of brown sputum. Chest pain and shortness of breath are common. Acute infection may be accompanied by abdominal pain, diarrhea and urticaria or remain asymptomatic.

    Extrapulmonary migration may result in symptoms dependent on the site of involvement. CNS involvement may result in headache, seizures, other neurological deficits or meningitis.

    Do other diseases mimic its manifestations? Symptoms caused by other causes of hepatic inflammation or mass lesions may mimic those of liver fluke infection, and include amebic and bacterial liver abscess, schistosomiasis, cholecystitis, cholangitis and acute hepatitis.

    Pulmonary tuberculosis, other fungal and chronic bacterial pneumonias or malignancy may resemble Paragonimiasis radiologically. Extrapulmonary involvement, especially by Paragonimus, may resemble central nervous system CNS tumor or other infections including brain abscess or neurocysticercosis.

    What laboratory studies should you order and what should you expect to find? Liver and intestinal flukes The most useful test for diagnosis of Clonorchis and Opisthorchis liver flukes is the detection of eggs in the stool by microscopic examination.

    Wet mount preparations are examined for the presence of characteristic eggs. A small knob or hook is often seen projecting from the other end. Opisthorchis eggs are visually virtually identical. Adult worms may occasionally be identified from surgically or endoscopically obtained samples. Clonorchis and Opisthorchis species are approximately mm X mm whereas adult Fasciola worms are larger and approximately 30mm X 15mm.

    Ultrasound examination of the biliary tract and gallbladder may occasionally visualize motile worms. Abdominal computed tomography CT scan frequently reveals small hypodense nodules and linear tracks within the liver parenchyma caused by migration of Fasciola hepatica.

    Characteristic magnetic resonance MR imaging findings in F. Peripheral eosinophilia is common, especially with acute fascioliasis and paragonimiasis.

    The pleural fluid in Paragonimiasis usually contains numerous eosinophils. Serological tests are useful for diagnosis of F. Diagnosis of intestinal flukes is made by clinical picture and microscopic detection of eggs in the stool although Fasciolopsis eggs are morphologically indistinguishable from those of F.

    Specific diagnosis is possible by identification of adult worms passed in the stool after treatment. Lung flukes Detection of eggs in sputum and stool may be difficult and insensitive. Levels of seropositivity decline with treatment and may be used to monitor therapy. Other Paragonimus species may be missed by the P.

    Chest XCXR and CT may show a wide variety of pulmonary abnormalities, including cystic lesions, nodules, infiltrates or pleural effusions. The radiological picture may suggest tuberculosis or malignancy. What imaging studies will be helpful in making or excluding the diagnosis of infection with flukes? In liver fluke infection, ultrasound and abdominal CT scan may be useful to assess the presence of complications requiring surgical intervention or antibiotic therapy.

    MR imaging of the liver may also add sensitivity to the diagnosis of F. Pulmonary imaging is often highly suggestive although not specific for Paragonimus infection. What complications can be associated with this parasitic infection, and are there additional treatments that can help to alleviate these complications? Liver flukes Long-term complications associated with chronic infection with all liver flukes include right upper quadrant pain, loss of appetite and weight loss.

    In addition, complications associated with heavy worm burden, inflammation and obstruction include cholecystitis, cholangitis, hepatic abscess and pancreatitis. Cholangiocarcinoma is associated with chronic Opisthorchis and Clonorchis infection.

    Ectopic migration of F. Intestinal flukes Ileus and obstruction may occur with heavy worm burdens. Rarely, embolization of eggs via the circulation has been reported to cause severe CNS complications. Lung flukes Cerebral invasion by migrating larvae are the most common and serious extra-pulmonary manifestation of P. Clonorchis and Opisthorchis species have a similar life cycle that requires three distinct hosts: a mammalian host, a snail and a fish or crustacean see Figure 1.

    Adult worms resident in the biliary tree produce up to embryonated eggs per day that are shed in the stool. When these eggs reach fresh water, they are ingested by specific species of snails in which the eggs hatch and each egg releases a miracidium.

    The miracidia undergo several stages of maturation, initially becoming sporocysts that each release rediae, that each release up to 50 cercariae. Thus each egg results in the release of approximately a thousand free-swimming cercariae. When the cercariae encounter an appropriate fish intermediate host, they invade the skin and encyst as metacercariae. These metacercariae remain viable for up to a year in the muscle of the fish.

    When consumed by humans, the metacercariae excyst and release larvae in the duodenum, where they rapidly travel via the ampulla of Vater to take up residence in the biliary tree and begin producing eggs. Mature worms may survive for decades. Figure 1. Life cycle of Clonorchis and Opisthorchis species. Fasciola hepatica has a life cycle similar to that of Clonorchis and Opisthorchis but does not have an intermediate fish host see Figure 2.

    Adult worms that reside in the biliary tree of sheep and cattle produce unembryonated eggs that embryonate in water and release free-swimming miracidia that invade snails. Further development through the stages of sporocysts, rediae and cercariae occurs in the snail. Free-swimming cercariae encyst as metacercariae on aquatic plants such as watercress, which are consumed by cattle, sheep or humans.

    The metacercariae excyst in the duodenum and then invade the intestinal wall, migrate through the peritoneum and eat through the liver parenchyma until the reach the large biliary ducts where maturation into adult worms and oviposition occurs. Figure 2. Fasciola hepatica life cycle. Intestinal flukes reside in the small intestine of the mammalian host see Figure 3 and Figure 4.

    Eggs are passed in the stool and embryonate in fresh water. The eggs are either ingested by snails in the case of Fasciolopsis or miracidia are released and invade an intermediate snail host in the case of Heterophyes and Metagonimus.

    Cercariae released from the snail either invade fish and encyst Heterophyes andMetagonimus or encyst on water plants Fasciolopsis and are subsequently consumed by humans. The larva excyst and take up residence in the wall of the small intestine where they develop into adult egg-laying worms. Fasciolopsis adults are 20 to 75 mm by 8 to 20 mm, whereas Heterophyes and Metagonimus are much smaller 1.

    The signs and symptoms may be minimal or nonexistent. When a substantial infection develops, signs and symptoms include painful, frequent diarrhea that may contain mucus and blood. It is possible for the infection to cause rectal prolapse, a condition in which a portion of the rectum becomes detached from the inside of the body and protrudes from the anus Figure 4.

    Severely infected children may experience reduced growth and their cognitive development may be affected. When fertilized eggs are ingested, they travel to the intestine and the larvae emerge, taking up residence in the walls of the colon and cecum. They attach themselves with part of their bodies embedded in the mucosa.

    Watch out for liver flukes this summer

    The larvae mature and live in the cecum and ascending colon. After 60 to 70 days, females begin to lay to 20, eggs per day. Diagnosis involves examination of the feces for the presence of eggs. It may be necessary to use concentration techniques and to collect specimens on multiple days. Following diagnosis, the infection may be treated with mebendazole, albendazole, or ivermectin. Figure 4. It occurs when the rectum loses its attachment to the internal body structure and protrudes from the anus.

    These microscopic nematode worms are most commonly transmitted in meat, especially pork, that has not been cooked thoroughly. They develop into mature adults within the large intestine. The larvae produced in the large intestine are able to migrate into the muscles mechanically via the stylet of the parasite, forming cysts. Muscle proteins are reduced in abundance or undetectable in cells that contain Trichinella nurse cells. Animals that ingest the cysts from other animals can later develop infection Figure 5.

    Although infection may be asymptomatic, symptomatic infections begin within a day or two of consuming the nematodes. Abdominal symptoms arise first and can include diarrhea, constipation, and abdominal pain.

    Other possible symptoms include headache, light sensitivity, muscle pain, fever, cough, chills, and conjunctivitis. More severe symptoms affecting motor coordination, breathing, and the heart sometimes occur. It may take months for the symptoms to resolve, and the condition is occasionally fatal.

    Mild cases may be mistaken for influenza or similar conditions. Infection is diagnosed using clinical history, muscle biopsy to look for larvae, and serological testing, including immunoassays.

    Enzyme immunoassay is the most common test. It is difficult to effectively treat larvae that have formed cysts in the muscle, although medications may help. It is best to begin treatment as soon as possible because medications such as mebendazole and albendazole are effective in killing only the adult worms in the intestine. Steroids may be used to reduce inflammation if larvae are in the muscles. Figure 5. Tapeworms Taeniasis Taeniasis is a tapeworm infection, generally caused by pork Taenia soliumbeef Taenia saginataand Asian Taenia asiatica tapeworms found in undercooked meat.

    Consumption of raw or undercooked fish, including contaminated sushi, can also result in infection from the fish tapeworm Diphyllobothrium latum. Tapeworms are flatworms cestodes with multiple body segments and a head called a scolex that attaches to the intestinal wall.

    Liver, Intestinal and Lung Flukes

    Tapeworms can become quite large, reaching 4 to 8 meters long Figure 6. Figure 5 in Parasitic Helminths illustrates the life cycle of a tapeworm. Figure 6. After ingestion by animals, the eggs hatch and the larvae emerge. They may take up residence in the intestine, but can sometimes move to other tissues, especially muscle or brain tissue.

    When T. This occurs through ingestion of eggs via the fecal-oral route, not through consumption of undercooked meat. It can develop in the muscles, eye ophthalmic cysticercosisor brain neurocysticercosis. Infections may be asymptomatic or they may cause mild gastrointestinal symptoms such as epigastric discomfort, nausea, diarrhea, flatulence, or hunger pains.

    It is also common to find visible tapeworm segments passed in the stool. In cases of cysticercosis, symptoms differ depending upon where the cysts become established.

    Neurocysticercosis can have severe, life-threatening consequences and is associated with headaches and seizures because of the presence of the tapeworm larvae encysted in the brain. Cysts in muscles may be asymptomatic, or they may be painful. To diagnose these conditions, microscopic analysis of stool samples from three separate days is generally recommended. Eggs or body segments, called proglottids, may be visible in these samples.

    Molecular methods have been developed but are not yet widely available. Praziquantel or niclosamide are used for treatment. As foods that contain raw fish, such as sushi and sashimi, continue to increase in popularity throughout the world, so does the risk of parasitic infections carried by raw or undercooked fish. Diphyllobothrium species, known as fish tapeworms, is one of the main culprits.

    Watch this beautifully disgusting liver fluke parasite explore man’s innards

    Evidence suggests that undercooked salmon caused an increase in Diphyllobothrium infections in British Columbia in the s and early s. In the years since, the number of reported cases in the United States and Canada has been low, but it is likely that cases are underreported because the causative agent is not easily recognized.

    Cases have increased around the world as raw fish consumption has increased. The extremely low and high temperatures associated with freezing and cooking kill worms and larvae contained in the meat, thereby preventing infection. Ingesting fresh, raw sushi may make for a delightful meal, but it also entails some risk. Hydatid Disease Another cestode, Echinococcus granulosus, causes a serious infection known as hydatid disease cystic echinococcosis.

    The cestodes are transmitted through eggs in the feces from infected animals, which can be an occupational hazard for individuals who work in agriculture. Symptoms associated with liver flukes include reduced weight gain, reduced milk yields, reduced fertility, anemia, and diarrhea. However, a liver fluke infestation is typically subclinical, so you may not even know you have liver flukes unless you have a post-mortem completed or you receive feedback from the packing plant about condemned livers.

    Therefore, producers should look at post-mortem examination or carcass information from the packing plant as an essential diagnostic tool. Condemnation of the liver at the packing plant can be caused by just one liver fluke. One would expect that most economic losses would be due to liver condemnation at slaughter.

    However, there are greater hidden financial losses experienced by beef producers once their cattle become infected with liver flukes. Reduced average daily gain, lower feed conversion, reduced milk production, and lower weaning weights are the most common productivity losses. In addition, several feedlot studies in feeder cattle infected with even low levels of liver flukes indicate that rate of gain can be significantly reduced.

    Hepatomegaly and right upper quadrant tenderness may be observed both in the acute and chronic setting. Fasciola Distinct syndromes are associated with the acute and chronic phases of infection: The acute phase may last for a few months and occurs within a few weeks of infection.

    Symptoms are associated with migration of the larval parasite through liver parenchyma see life cycle belowand include abdominal pain, cough, urticaria and fever. Symptoms of chronic infection are subtle and similar to those seen with Clonorchis and Opisthorchis described above. Intestinal Flukes Heavy infections may be associated with fever, weight loss, abdominal pain, diarrhea, anasarca and obstruction.

    Lung flukes Predominant symptoms include chronic cough, hemoptysis and production of brown sputum. Chest pain and shortness of breath are common. Acute infection may be accompanied by abdominal pain, diarrhea and urticaria or remain asymptomatic.

    Extrapulmonary migration may result in symptoms dependent on the site of involvement. CNS involvement may result in headache, seizures, other neurological deficits or meningitis. Do other diseases mimic its manifestations? Symptoms caused by other causes of hepatic inflammation or mass lesions may mimic those of liver fluke infection, and include amebic and bacterial liver abscess, schistosomiasis, cholecystitis, cholangitis and acute hepatitis.

    Pulmonary tuberculosis, other fungal and chronic bacterial pneumonias or malignancy may resemble Paragonimiasis radiologically. Extrapulmonary involvement, especially by Paragonimus, may resemble central nervous system CNS tumor or other infections including brain abscess or neurocysticercosis. What laboratory studies should you order and what should you expect to find? Liver and intestinal flukes The most useful test for diagnosis of Clonorchis and Opisthorchis liver flukes is the detection of eggs in the stool by microscopic examination.

    Wet mount preparations are examined for the presence of characteristic eggs. A small knob or hook is often seen projecting from the other end. Opisthorchis eggs are visually virtually identical.

    Adult worms may occasionally be identified from surgically or endoscopically obtained samples. Clonorchis and Opisthorchis species are approximately mm X mm whereas adult Fasciola worms are larger and approximately 30mm X 15mm. Ultrasound examination of the biliary tract and gallbladder may occasionally visualize motile worms.

    Abdominal computed tomography CT scan frequently reveals small hypodense nodules and linear tracks within the liver parenchyma caused by migration of Fasciola hepatica.

    Characteristic magnetic resonance MR imaging findings in F. Peripheral eosinophilia is common, especially with acute fascioliasis and paragonimiasis. The pleural fluid in Paragonimiasis usually contains numerous eosinophils. Serological tests are useful for diagnosis of F. Diagnosis of intestinal flukes is made by clinical picture and microscopic detection of eggs in the stool although Fasciolopsis eggs are morphologically indistinguishable from those of F.

    Specific diagnosis is possible by identification of adult worms passed in the stool after treatment. Lung flukes Detection of eggs in sputum and stool may be difficult and insensitive. Levels of seropositivity decline with treatment and may be used to monitor therapy. Other Paragonimus species may be missed by the P. Chest XCXR and CT may show a wide variety of pulmonary abnormalities, including cystic lesions, nodules, infiltrates or pleural effusions.

    The radiological picture may suggest tuberculosis or malignancy. What imaging studies will be helpful in making or excluding the diagnosis of infection with flukes? In liver fluke infection, ultrasound and abdominal CT scan may be useful to assess the presence of complications requiring surgical intervention or antibiotic therapy.

    MR imaging of the liver may also add sensitivity to the diagnosis of F. Pulmonary imaging is often highly suggestive although not specific for Paragonimus infection. What complications can be associated with this parasitic infection, and are there additional treatments that can help to alleviate these complications? Liver flukes Long-term complications associated with chronic infection with all liver flukes include right upper quadrant pain, loss of appetite and weight loss.

    In addition, complications associated with heavy worm burden, inflammation and obstruction include cholecystitis, cholangitis, hepatic abscess and pancreatitis. Cholangiocarcinoma is associated with chronic Opisthorchis and Clonorchis infection. Ectopic migration of F. Intestinal flukes Ileus and obstruction may occur with heavy worm burdens. Rarely, embolization of eggs via the circulation has been reported to cause severe CNS complications. Lung flukes Cerebral invasion by migrating larvae are the most common and serious extra-pulmonary manifestation of P.


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    • 22.08.2021 at 16:25
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