Intestinal Flukes Treatment & Management

Updated: Feb 21, 2019
  • Author: Joseph Adrian L Buensalido, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Treatment

Medical Care

Praziquantel 10-20 mg/kg as a single dose or 25 mg/kg 3 times a day is the recommended treatment for intestinal flukes (including F buski infection). It should be taken with liquids during a meal. [4] Praziquantel is the drug of choice for most intestinal fluke infections, although niclosamide has been reported to have some in vitro efficacy. [55]

Praziquantel is a pyrazinoisoquinoline anthelmintic that was discovered in 1972 by Bayer Germany. Although widely used, praziquantel exhibits low and erratic bioavailability because of its poor water solubility. Nanostructured lipid carriers (NLC), second-generation solid lipid nanoparticles, were developed in the 1990s to improve the bioavailability of poorly water-soluble drugs. [56]

After 4 weeks, if the repeat stool examination result is again positive, retreatment with praziquantel is indicated. [41]

Artesunate has been used in vitro and in vivo for Echinostoma and Heterophyes infections, with promising results as alternative therapy. Although the exact mechanism of action for artesunate is still unknown, studies have demonstrated that parasites exposed to artesunate had slowed movement, tegument damage, and death at higher drug concentration and longer exposure time (72 hours). [57, 58]

The CDC recommends a 2-dose regimen of triclabendazole as the drug of choice for fascioliasis (liver fluke infection with F hepatica or F gigantica). Triclabendazole was approved by the FDA in 2019 after being available from the CDC for many years. [59]

Based on limited data from the CDC, nitazoxanide might be effective in some patients. Bithionol, a halogenated phenol previously used as a first-line agent for the treatment of fascioliasis in the United States, is no longer available. Praziquantel, which is active against most trematodes (flukes), is typically not active against Fasciola parasites. Therefore, the CDC does not recommend praziquantel therapy for fascioliasis. [60]

For Opisthorchis infections, praziquantel 25 mg/kg 3 times a day for 2 days taken with liquids during a meal is the recommended treatment. [4] An open-label phase II trial found that tribendimidine had similar tolerability and efficacy to praziquantel against O viverrini. [61] In contrast, mefloquine, artesunate, and mefloquine-artesunate were not effective in the same trial and were associated with vertigo, nausea, vomiting, and anxiety. Further large-scale clinical trials are needed to identify the best role of tribendimidine; future data may support this drug as yet another potential treatment option.

For Clonorchis infections, praziquantel 25 mg/kg 3 times a day for 2 days taken with liquids during a meal is also the recommended treatment, although albendazole 10 mg/kg as a single dose for 7 days may also be used. [4]

The WHO states that all confirmed cases of fascioliasis, opisthorchiasis and clonorchiasis should be treated, as well as all suspected cases in endemic areas. [62]

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Diet

Proper cleaning and processing of raw vegetables by immersing in boiling water for a few seconds, followed by peeling and washing in clean water is important in preventing infection with intestinal flukes, especially in endemic areas.

The importance of thoroughly cooking contaminated vegetables cannot be overemphasized.

Do not eat raw or undercooked fish.

The diet in infected individuals should contain adequate protein.

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Activity

The patient should be on bed rest.

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Prevention

Eliminating the intermediate host snail is the key to controlling infection with intestinal flukes.

Proper cleaning and processing of raw vegetables by immersing in boiling water for a few seconds, followed by peeling and washing in clean water, is important in preventing infection with intestinal flukes, especially in endemic areas.

Night soil (human excreta) and pig excreta should not be used as fertilizers.

Metacercariae are not necessarily inhibited or destroyed by interventions such as smoking or freezing; and the practice of fish pickling is ineffective. Irradiation practices may be of benefit in managing the burden of metacercariae in the process of food preparation.

Many strategies to control opisthorchiasis have been used in Thailand. The strategies include mass drug administration and education to decrease the consumption of raw fish. Over the last decade, these methods have changed the epidemiology of O viverrini infection in Thailand. In the past, O viverrini infections were characterized as heavy infections that were concentrated in particular villages. Now, because of these strategies, O viverrini infections have become "lighter" but more widespread in terms of geographic distribution. [63]

Parasitic helminths reside in immunologically exposed extracellular locations within their hosts, yet they are capable of surviving for extended periods. To enable this survival, these parasites have developed complex and multifaceted mechanisms to subvert or suppress host immunity. There are studies on the immunomodulation by helminth parasites of ruminants and the parasite-derived molecules involved in driving this modulation. Such immunomodulatory molecules have considerable promise as vaccine targets. [64]

Triclabendazole 10 mg/kg as a single dose is the preventive chemotherapy for fascioliasis and is recommended in subdistricts, villages, or communities with clustering of cases. The WHO recommends that all school-aged children (aged 5-14 years) or all residents should be given the preventive chemotherapy every 12 months. [62]

Praziquantel 40 mg/kg as a single dose is the preventive chemotherapy for clonorchiasis and opisthorchiasis and is recommended in all people residing in areas where the prevalence of infection is 20% and above. Among people who live in areas with less than 20% prevalence, the recommendation is to administer preventive chemotherapy (1) to everyone every 24 months or (2) every 12 months to those who eat raw fish. [62]

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Further Inpatient Care

Antispasmodics may relieve abdominal pain.

Iron supplements may be used to treat anemia, which may require transfusions in severe cases.

Vitamin C (ascorbic acid) may be administered to facilitate iron absorption.

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