Medical Care
Triclabendazole, a benzimidazole derivative, has become the drug of choice for the treatment of fascioliasis. [18] It is recommended by the World Health Organization (WHO). Although available from the CDC for many years, triclabendazole was approved in the United States for fascioliasis in patients aged 6 years or older in February 2019. It is given as a 2-dose regimen of 10 mg/kg/dose separated by 12 hours. A study of 24 subjects in Chile revealed cure rates of 79.2% with one dose and 100% with 2 doses. [29] Another study comparing a group of 68 patients treated with one dose to a second group of 66 patients treated with two doses showed better cure rates of 93.9% in second group as compared with 79.4% in the first group. [30] A study of 90 pediatric subjects treated with triclabendazole in Bolivia reported no serious adverse effects and reduction of high intensity infections (>400 eggs per gm of stool) from 7.8% to 0% with two doses. [30] Resistance to triclabendazole in livestock is well known and now has been reported in human subjects as well. [31]
Nitazoxanide is a good alternative to triclabendazole, especially in the chronic stage of infection. It is given as 500 mg twice a day for 7 days in adults. [32, 33, 34] A pediatric study done in Mexico showed cure efficacy of 94% after one course and 100% after repeating the course. [35]
Bithionol, a halogenated phenol previously used as first line agent for the treatment of fascioliasis in USA is no longer available. [34] Praziquantel, previously used as an alternative drug is no longer recommended due to poor efficacy against Fasciola species. Other drugs that were used previously and are no longer recommended due to toxicity include emetine, dehydroemetine, metronidazole, albendazole, niclofolan, chloroquine, hexachloro-para-xylol, artesunate and artemether. [18]
Fascioliasis complicated by ascending cholangitis requires treatment with appropriate antibacterial antibiotics.
The condition of the patient with fascioliasis determines inpatient care versus outpatient care. Transfer is necessary only when specialized services or care (see Consultations) are unavailable.
Surgical Care
Patients with ascending cholangitis may require surgery.
Consultations
An infectious diseases specialist and gastroenterologist should be consulted in patients with suspected fascioliasis.
A surgeon may be consulted.
Patients with an ectopic infection or a visceral larva migrans–like illness may require additional consultations for specific manifestations of the condition.
Consult the CDC Drug Service (404-639-3670) to obtain bithionol. See Drugs Available Through the CDC Drug Service. See CDC Drug Service: Bithionol.
Diet
Regular diet as tolerated.
Activity
Activity as tolerated.
Prevention
Fascioliasis can be prevented through public education about avoiding consumption of contaminated water plants, water, and raw liver.
A vaccine candidate comprising activated dendritic cells shows promise in mouse infection. [36]
-
Life cycle of Fasciola hepatica. Immature Fasciola eggs are discharged in the biliary ducts and in the stool (1). Eggs become embryonated in water (2), eggs release miracidia (3), which invade a suitable snail intermediate host (4), including the genera Galba, Fossaria and Pseudosuccinea. In the snail, the parasites undergo several developmental stages (sporocysts (4a), rediae (4b), and cercariae (4c)). The cercariae are released from the snail (5) and encyst as metacercariae on aquatic vegetation or other surfaces. Mammals acquire the infection by eating vegetation containing metacercariae. Humans can become infected by ingesting metacercariae-containing freshwater plants, especially watercress (6). After ingestion, the metacercariae excyst in the duodenum (7) and migrate through the intestinal wall, the peritoneal cavity, and the liver parenchyma into the biliary ducts, where they develop into adult flukes (8). Courtesy of the CDC's DPDx, Division of Parasitic Diseases and Malaria.
-
Adult Fasciola hepatica fluke stained with carmine (30 mm by 13 mm). Courtesy of the CDC's DPDx, Division of Parasitic Diseases and Malaria.
-
Fossaria bulamoides, a snail host for F hepatica in the western United States. Courtesy of the CDC's DPDx, Division of Parasitic Diseases and Malaria (Conchology, Inc, Mactan Island, Philippines).
-
Fasciola hepatica egg in an unstained wet mount (400x magnification). F hepatica eggs are broadly ellipsoidal, operculated, and measure 130-150 μm by 60-90 μm. Courtesy of the CDC's DPDx, Division of Parasitic Diseases and Malaria.
-
Adult of F hepatica observed with ERCP imaging in the common bile duct of a human patient. Courtesy of the CDC's DPDx, Division of Parasitic Diseases and Malaria (Dr. Subhash Agal, Kokilaben Dhirubhai Ambani Hospital, Mumbai, India).
