Changes

=== Control ===

=== Control ===

'''Anthelmintics''' - few flukicides kill all parasitic developmental stages. Not all products, therefore, are suitable for controlling acute outbreaks. The anthelmintic with the broadest spectrum of activity against immature and adult ''F. hepatica'' is triclabendazole. Triclabendazole-resistant ''F. hepatica'' populations are beginning to emerge. The more potent products tend to be the most expensive. Many flukicides bind to plasma protein and have long plasma half-lives.

*'''Anthelmintics''' - few flukicides kill all parasitic developmental stages. Not all products, therefore, are suitable for controlling acute outbreaks. The anthelmintic with the broadest spectrum of activity against immature and adult ''F. hepatica'' is triclabendazole. Triclabendazole-resistant ''F. hepatica'' populations are beginning to emerge. The more potent products tend to be the most expensive. Many flukicides bind to plasma protein and have long plasma half-lives.

'''Chemoprophylaxis''' - there are several control objectives:

*'''Chemoprophylaxis''' - there are several control objectives:

a) to prevent fluke eggs dropping onto snail habitats - this can be done by treating sheep/cattle with an adulticidal drug in the late winter/early spring.

a) to prevent fluke eggs dropping onto snail habitats - this can be done by treating sheep/cattle with an adulticidal drug in the late winter/early spring.

iii) the persistent effect of the drug (i.e. the period after dosing, during which the animal is protected from reinfection).

iii) the persistent effect of the drug (i.e. the period after dosing, during which the animal is protected from reinfection).

'''Vaccination''' - a recombinant vaccine which provides approximately 70% protection for cattle is being developed. It exerts its effect by stimulating a range of immune responses not normally seen in chronically infected animals (including TH1-type responses).

*'''Vaccination''' - a recombinant vaccine which provides approximately 70% protection for cattle is being developed. It exerts its effect by stimulating a range of immune responses not normally seen in chronically infected animals (including TH1-type responses).

'''Molluscicides''' - have been employed with success in the past, but are no longer used. This is because they have to be applied before any fluke forecast can be issued. (Farmers are unwilling to invest in control measures before they are known to be necessary). Also, they have to be applied very carefully as snails can rapidly recolonise sprayed land if any habitat has been missed.

*'''Molluscicides''' - have been employed with success in the past, but are no longer used. This is because they have to be applied before any fluke forecast can be issued. (Farmers are unwilling to invest in control measures before they are known to be necessary). Also, they have to be applied very carefully as snails can rapidly recolonise sprayed land if any habitat has been missed.

'''Alternative strategies''' - an ability to recognise and define the extent of snail habitats allows alternative cost-effective control options such as fencing and drainage.

*'''Alternative strategies''' - an ability to recognise and define the extent of snail habitats allows alternative cost-effective control options such as fencing and drainage.