Changes

=Equine roundworm, Ascarid=

=Equine roundworm, Parascaris=

==Introduction==

==Introduction==

[[Image:Parascaris equorum donkey.jpg|right|thumb|250px|<small><center>Adult ''P. equorum'' in a four-year-old donkey that died of colic. Most worms were found blocking the ileocaecal junction and in the caecum, with a few in the small intestine. (Image courtesy of [http://drupal.thedonkeysanctuary.org.uk The Donkey Sanctuary])</center></small>]]

[[Image:Parascaris equorum donkey.jpg|right|thumb|250px|<small><center>Adult ''P. equorum'' in a four-year-old donkey that died of colic. Most worms were found blocking the ileocaecal junction and in the caecum, with a few in the small intestine. (Image courtesy of [http://drupal.thedonkeysanctuary.org.uk The Donkey Sanctuary])</center></small>]]

'''''[[Parascaris equorum]]''''' is among the largest nematodes that affect equids. Generally it is believed that it is the same species of ascarid that is found in horses affects donkeys. They are large roundworms up to 40 cm in length. Ascarids are considered to mainly affect foals, as adult horses develop a strong protective immunity.  

'''''[[Parascaris equorum]]''''' and ''P. univalens'' are the two species of the genus Parascaris that affect equids. ''P. equorum'' was considered to be the most prevalent and common equine ascarid, however available evidence now suggests that ''P. univalens'' is the main ascarid (Nielsen, et al., 2014; Nielsen, 2016).  Generally it is believed that it is the same species of ascarid that is found in horses affects donkeys. They are among the largest nematodes/roundworms up to 40 cm in length. Parascaris spp are considered to mainly affect foals, as adult horses develop a strong protective immunity.

However, the situation in donkeys appears to be different.. High infection prevalence, patent infections with high egg counts and a high number of adult worms are a common finding in adult donkeys in Ethiopia and South Africa (Getachew, et al., 2008; Wells, et al., 1998). This indicates age-dependent immunity may not develop in donkeys like in horses, or they may have been immunocompromised. Anecdotal evidence from the UK over recent years suggests there has been a rise in the number of ascarid infections seen in mature donkeys.

Characterisation of ascarid infections:

Characterisation of ascarid infections:

* The infective stage eggs containing L2, once ingested from grazing and hatched, migrate through the liver and lungs before returning to the small intestine

* The infective stage eggs containing L2, once ingested from grazing and hatched, migrate through the liver and lungs before returning to the small intestine

* Infestations are usually derived from allowing foals to graze on the same pastures year after year, but adult donkeys can also be a source of infection.

* Infestations are usually derived from allowing foals to graze on the same pastures year after year, but adult donkeys can also be a source of infection.

*There is no evidence of prenatal infection

* There is no evidence of prenatal infection

* Heavy infection can cause '''stunted growth''', '''ill thrift''' and '''diarrhoea'''

* Heavy infection can cause '''stunted growth''', '''ill thrift''' and '''diarrhoea'''

* Adult worms can block the gut, causing '''colic''' and even '''ruptures of the gut''', which may be associated with anthelmintic  administration

* Adult worms can block the gut, causing '''colic''' and even '''ruptures of the gut''', which may be associated with anthelmintic  administration

 

==References==

==References==

* Trawford, A. and Getachew, M. (2008) Parasites In Svendsen, E.D., Duncan, J. and Hadrill, D. (2008) ''The Professional Handbook of the Donkey'', 4th edition, Whittet Books, Chapter 6

 

 

 

* Trawford, A. and Getachew, M. (2008) Parasites.  In:  Svendsen, E.D., Duncan, J. and Hadrill, D. (eds), The Professional Handbook of the Donkey (4th ed), , pp.82-110. Whittet Books, UK.

 

 

{{toplink

{{toplink