bovis - Articles
Fasciola hepatica: parasite
Synonym(s): Liver fluke
Introduction
Classification
Taxonomy
- Trematoda; Fasciolidae; Fasciola hepatica.
Etymology
- There are two species of Fasciola that infect cattle:
- Fasciola hepatica in temperate climates.
- Fasciola gigantica mainly found in tropical climates such as sub-Saharan Africa.
- Species distribution can overlap as it is governed by the presence of snail intermediate host species that are integral to Fasciola species life cycles.
- Losses in production are related to the Fasciola species complex lifecycle and subsequent disease termed fasciolosis.
- Ruminant infections account for £2.5 billion of production losses per annum globally.
- Adult and juvenile migratory stages of the parasite contribute to disease in cattle.
- Fasciolosis, was first described in sheep, in the 13th century:
- Similar findings in cattle were first described in the 17th century although disease in cattle is more associated with chronic infections.
- The intermediate host stages were not discovered until the 19th century.
- Herbivorous species can be infected with Fasciola hepatica:
- These include ruminants such as cattle, buffalo, sheep and goats.
- Fasciolosis also occurs in some other domestic species such as swine and horses and in wildlife, notably rabbits, hares and deer
- Man may also be affected in certain regions.
Distribution
- Worldwide distribution with particular significance in the UK, Europe, North America, South America and the Caribbean:
- Also significant in parts of North Africa, Eastern Sub-Saharan Africa, the Middle East, Southern Asia and Australasia.
- In the UK the distribution of Fasciola hepatica infection in cattle has been historically recorded in the North West of England and Wales, Northern Ireland and Scotland; particularly the wetter Western regions.
- Recent serological studies demonstrate nearly 80% of dairy herds have been exposed to Fasciola hepatica infection, with similar reports in other European countries.
Significance
- A subclinical production-limiting disease of cattle; fasciolosis Fasciolosis: the disease results in poor growth rates, reduced milk yield and poor fertility.
- Fasciola hepatica has also been shown to be associated with certain co-infections leading to misdiagnosis or increased risk of disease.
- The parasite is zoonotic - the metacercariae stages may be ingested when affected raw herbage in ingested:
- Occasional cases have been noted in Europe with consumption of un-washed watercress.
- This is of particular significance in parts of South America, particularly Peru and Bolivia, along with parts of the Middle East and Asia, whereby the encusyeted stages may be ingested in soups and fresh teas.
Active Forms
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Resting Forms
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Clinical Effects
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Diagnosis
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.