Large liver fluke

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. 

Fig. 25.11 Fasciola hepatica (large liver fluke), 2.9 X 1.1 cm (X 3). Ovum of Fasciola hepatica, approx. 0.13 X 0.07 mm, in bile fluid (obtained by means of a nasogastroduodenal probe) (X 400)...

Zurita, M., Bieber, D., Ringold, C. and Mansour, T.E. (1 988) cDNA cloning and gene characterization of the mitochondrial large subunit (LSU) rRNA from the liver fluke Fasciola hepatica. Evidence of heterogeneity in the fluke mitochondrial genome. Nucleic Acids Research 16, 7001-7012. 

A variety of protozoa, helminths (worms) and arthropods are parasites. They are large, multicellular organisms. They are different from other organisms that are parasitic in nature because they live in or on other plants or animals. Some well-known parasites are tapeworms, liver flukes, and hookworms. 

The operator MNOS is used to specify the range of numbers to be searched and, if required, to limit the number of hits. The operator OUT is used to specify what sample and result data is to be printed for each hit. The operators EVER and NEVER (similar to OR and NOT) are used to search the data on the property file and the summary result file, using the screen file, if relevant, as a preliminary screen. Thus, for example, one may search for all the active anthelmintics Dr Robinson made and reserved in 1977 or all the solids in large size bottles which are active in an anthelmintic test but have not been tested in any of the liver fluke tests. 

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