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{{Taxobox
{{Taxobox
|name = DHV-1 and DHV-III
|name = DHV-II
|kingdom =
|kingdom =
|sub-kingdom =
|sub-kingdom =
|sub-class =
|sub-class =
|super-order =
|super-order =
|order = RNA Viruses
|order = RNA viruses
|sub-order =
|sub-order =
|super-family =
|super-family =
|family = Picornaviridae
|family = Astroviridae
|sub-family =
|sub-family =
|genus = Enterovirus
|genus = Astrovirus
|species = Duck Hepatitis Virus I and III
|species = DHV-II
}}
}}
{{Taxobox
{{Taxobox
|name = DHV-II
|name = DHV-1 and DHV-III
|kingdom =
|kingdom =
|sub-kingdom =
|sub-kingdom =
|sub-class =
|sub-class =
|super-order =
|super-order =
|order = RNA viruses
|order = RNA Viruses
|sub-order =
|sub-order =
|super-family =
|super-family =
|family = Astroviridae
|family = Picornaviridae
|sub-family =
|sub-family =
|genus = Astrovirus
|genus = Enterovirus
|species = DHV-II
|species = Duck Hepatitis Virus I and III
}}
}}
Also Known As – '''''Duck Viral Hepatitis''''' – '''''DVH''''' – '''''DH'''''
Caused By – ''Duck Hepatitis Virus 1 and 3'' – ''DHV-I'' – ''DHV-III''
==Introduction==
Duck hepatitis is caused by the '''enteroviruses''' DHV-I and DHV-III.
It is a '''highly fatal''' disease of ducklings causing very high '''mortality''', '''opisthotonus''' and '''hepatitis'''.
The disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]
==Signalment==
Ducks are the only species naturally affected.
DHV-I occurs only in '''young ducklings''', usually '''<6weeks''' of age and spreads rapidly within a flock. It is the '''most virulent''' of the three.
DHV-II is only reported in outdoor ducks on open fields.
Duck Hepatitis is not considered zoonotic.
==Distribution==
DHV-I is present worldwide.
DHV-II has only been reported in Norfolk, England <ref> Asplin, F. D. (1965). Duck hepatitis: vaccination against two serological types. Vet. Rec., 77:1529-1530</ref> and no outbreaks have been recorded since the 1980’s.
DHV-III has only occurred in the USA.
The '''rat''' acts as a vector for Duck Hepatitis.
==Clinical Signs==
'''Sudden deaths, Opisthotonus, Paresis''', Paralysis, Enopthalmos.
DHV-I infection is most virulent. Death usually occurs within 1-2 hours of clinical signs.
Mortality rates are lower in DHV-II infections, reaching only 20%.
==Diagnosis==
On post-mortem examination, the '''[[Liver - Anatomy & Physiology| liver]]''' is '''enlarged''', appears '''greenish''' and displays distinct '''ecchymotic haemorrhages'''.
[[Spleen - Anatomy & Physiology | Splenic]] and [[Renal Anatomy - Anatomy & Physiology | kidney]] swelling may also be evident. Cutaneous haemorrhage is often noted.
On histopathology, '''necrosis''' and inflammatory infiltrate are visible within hepatic cells.
'''Innoculation''' from liver suspensions an be used for confirmation of all DHVs.
'''Direct immunofluorescence''' can also confirm presence of DHV-I.
'''Virus Neutralisation (VN)''' serological tests can be used to monitor vaccination response and epidemiology.
==Treatment==
No treatment is effective once infected.
==Control==
'''Vaccination''' is only commercially available against '''DHV-I'''. Immunisation involves two or three innoculations. Live, live attenuated and inactivated forms are available.
DHV-I can be prevented by '''strict isolation''' in the first 4-5 weeks of life.
The viruses are resistant to inactivation by heat, acid and some disinfectants. Only 5% phenol and formaldehyde are successful in inactivating the viruses.
Duck Hepatitis is a '''Class B''' disease listed by the ''Office des International Epizooties'' and thus any ducks '''exported''' require an international veterinary '''certificate''' that they are from a DVH free establishment and are not exhibiting clinical signs of DH. Vaccination status must also be disclosed.
==References==
<references/>
Animal Health & Production Compendium, Duck Hepatitis Virus datasheet, accessed 05/06/2011 @ http://www.cabi.org/ahpc/
[[Category:To Do - Steph]]
[[Category:To Do - Steph]]