Liver-fluke

Livera Liver cancer Liver disease Liver flukes Liverworts Liverwurst Livetins... 

Chinese Liver Fluke. The adult worm of the Chinese Hver fluke Clonorchis sinensis) can grow to be 2 cm long. Worms infect the bihary tree where they cause local inflammation, diarrhea, and hepatomegaly in the acute infection. Progressive biUary obstmction and cirrhosis can occur in the more advanced disease state. The presence of 20—200 worms is common, but they may number over 20,000. Infection is the consequence of eating raw fish that contain viable parasites. Untreated worms can Hve for up to 30 years. Treatment is with pra2iquantil (1). 

A phenylacetonitrile derivative, closantel (41), is an anthelmintic agent useful against sheep liver flukes. Its patented synthesis involves a Schotten-Baumann amidation... 

CA C1 C01.033 Cathepsin L-like peptidase (Fasciola sp.) Potential drug target for liver fluke infection... 

Organic and low input farmers who are dependent on anthelmintics should optimise the benefit of these treatments by monitoring levels of infestation on their farms. By minimising treatment frequency, optimal timing of the treatments should result in a parasitological status that is both tolerable for herd health and also economically justified. With the exception of the large liver fluke, F. hepatica, the parasites treated in this chapter should therefore not be controlled on the basis of a standardised schedule, which most likely leads to excessive use of anthelmintics. 

International Agency for Research on Cancer Infection with Helicobacter pylori, in Schistosomes, Liver Flukes and Helicobacter pylori. Lyon, IARC, 1994, pp 177-202. 

At the least, we should more systematically classify those drugs that produce a psychedelic sequence in man and show cross tolerance with LSD with respect to the different receptor systems that apparently rank order these drugs in terms of their potency. Such rank order effects have been noted on molluscan ganglia (35) in the clam heart on excitation of cardiac muscle in liver fluke on glycolysis... 

Mansour, T. E., Sutherland, E. W., Rail, T. W., and Bueding, E. (1960) The effect of serotonin (5-hydroxytryptamine) on the formation of adenosine 3, 5 -phosphate by tissue particles from the liver fluke, Fasciola hepatica. J. Biol. Chem., 235 466-470. 

Acute exposure of sheep to 500 mg/kg hexachloroethane resulted in tremors of the facial muscles immediately after the exposure (Fowler 1969b). In sheep that were suffering from liver fluke infections, the neurotoxicity of hexachloroethane was even more pronounced. A dose of 170 mg/kg given for treatment of the fluke infection rendered 2 of 15 sheep immobile and unable to stand on the day after treatment, and a dose of 338 mg/kg affected 6 of 15 animals. Tremors of the facial muscles, neck, and forelimbs were apparent. The animals that were able to stand had a staggering gait, and when they fell, they were unable to... 

Ataxia, tremors, and prostration in sheep given hexachloroethane (170 or 338 mg/kg) for a liver fluke infection were successfully ameliorated with calcium as calcium borogluconate. This suggests that the neurological action of hexachloroethane may be the result of interference with the availability of calcium within excitable cells. This mechanism would explain the transient nature of the hexachloroethane neurotoxicity and is compatible with the low affinity that hexachloroethane shows for brain tissue (Fowler 1969b). 

Acute oral doses (500 mg/kg) given to healthy sheep caused tremors of the facial muscles (Fowler 1969b) several liver-fluke-infected sheep experienced prostration with even lower doses (170 or 338 mg/kg) (Southcott 1951). Treatment of sheep with calcium relieved the clinical signs of neurotoxicity, suggesting that cellular availability of calcium ion may be related to the neuromuscular symptoms noted (Southcott 1951). Therefore, mechanistic studies of neuromuscular impulse transmission and cognitive function in animals would be useful. These neurological studies should examine the effects of different concentrations of hexachloroethane in several species. 

The molluscicidal activity of imidazo[2,l-/][l,3,4]thiadiazoles and imidazo[2,l-/][l,3,4]oxadiazoles, such as compounds 112 and 109 (Figure 25), have been evaluated against the snail Lymnaea acumiata, which is a vector of the giant liver flukes, Fasciola gigantica and Fasciola hepatica <2004IJC(B)901>. 

Clonorchiasis (Chinese liver fluke) Clonorchis sinensis Praziquantel... 

Fascioliasis (Sheep liver fluke) Fasciola hepatica Praziquantel or Bithionol-... 

Opisthorchiasis (Liver fluke) Opisthorchis viverrini Praziquantel... 

Clonorchis spp. Chinese liver fluke, occurs in raw fish 0.15 In vitro minimum effective dose... 

Liver fluke. Fasciola hepatica Egg through miracidium... 

Liver flukes (see Clonorchis sinensis, Opisthorchisfelineus and Opisthorchis viverrini)... 

Clonorchis sinensis (liver fluke) Opisthorchis species Praziquantel Albendazole... 

Fasciola hepatica (sheep liver fluke) Bithionol or triclabendazole ... 

Bithionol is an alternative to triclabendazole for the treatment of fascioliasis (sheep liver fluke). Bithionol is also an alternative drug in the treatment of pulmonary paragonimiasis. 

Triclabendazole is a very potent anthelminthic used against all stages of liver flukes in sheep, goats, and cattle at dosages of 10-12 mg/kg bw. This drug does not exhibit nematocidal activity and is not teratogenic. 

Closantel, niclosamide, oxyclozanide, rafoxanide, dibromsalan, and tribromsalan are the better-known members of the salicylanilides group of anthelminthics (Fig. 4.5). They are all used to control primarily liver flukes in animals. On absorption, most salicylanilides are bound strongly to plasma proteins, with the exception of the tapeworm remedy niclosamide. These drugs are not soluble in water nevertheless, solutions have been formulated that enable closantel and rafoxanide to be administered parenterally. 

Closantel is used primarily in cattle and sheep for treatment of mature and immature liver flukes, hematophagous nematodes, and larval stages of some arthropods. It is administered orally or parenterally at dosages of 5-15 or 2.5-7.5 mg/kg bw, respectively. Closantel does not exhibit carcinogenic, teratogenic, or embryotoxic activities. 

Oxyclozanide possesses activity against only adult flukes, but at elevated dosage levels some activity against the later parenchyma stages (flukes of more than 4 weeks of age), may be obtained. In sheep and cattle, recommended oral dosages are 10-15 mg/kg bw. It is frequently combined with levamisole or oxibc-ndazole for combined treatment of gastrointestinal nematodes and liver fluke infections. 

A wide range of substituted phenols has been used for treatment of liver flukes and tapeworms in animals. Most drugs within this group have a low safety index... 

Clorsulon (Fig. 4.9) is a benzenesulphonamide derivative recommended for treatment and control of adult and immature liver flukes in cattle and sheep (68). It is administered orally or subcutaneously at a dosage of 7 or 2 mg/kg bw, respectively, in association, frequently, with ivermectin. 

The types of compounds that are of concern as contaminants are chlorinated insecticides, organophosphates, herbicides, fungicides, fas-ciolicides (phenolic compounds administered to cattle to control liver flukes), antibiotics and sulfonamides, detergents and disinfectants, and polychlorinated biphenyls (PCBs). Contaminants in milk have been reviewed by Kroger (1974) and Snelson (1979). In several cases, allowable levels for specific contaminants in milk have been set by the World Health Organization. Surveys have seldom revealed levels in excess of such standards. 

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