Changes

==Signalment==

==Signalment==

The disease affects '''chickens''' but can also affect quail. Disease is more '''severe in chicks'''. <u>Immunity occurs once the bird has become infected.</u>

The disease affects '''chickens''' but can also affect quail. Poultry that have previously been exposed to CAV and have CAV antibodies develop immunity.  Disease is more '''severe in chicks'''

==Clinical Signs==

==Clinical Signs==

==Epidemiology==

==Epidemiology==

Fomites may assist the transmission of the virus and the disease  can be '''spread both horizontally and vertically''', resulting in '''clinical and subclinical infections, respectively''' and the latter being of particular '''importance''' to '''intensive breeding populations'''. '''Chicks hatching''' from infected layers of naive flocks '''show clinical signs after 10-14 days of age''' over a '''period of 3 to 6 weeks. After which the breeder layers develop sufficient CAV antibodies to stop the transmission of the virus to the egg. '''Mortality peaks''' during the '''third week of life''' around 5 to 10% but can be as high as 60%.   

Fomites may assist the transmission of the virus and the disease  can be '''spread both horizontally and vertically''', resulting in '''clinical and subclinical infections, respectively''' and the latter being of particular '''importance''' to '''intensive breeding populations'''. The age of the bird has a marked effect on the development of clinical signs.'''Chicks hatching''' from infected layers of naive flocks (vertical transmission)'''show clinical signs after 10-14 days of age''' over a '''period of 3 to 6 weeks. After which the breeder layers develop sufficient CAV antibodies to stop the transmission of the virus to the egg. '''Mortality peaks''' during the '''third week of life''' around 5 to 10% but can be as high as 60%.  Whereas older chicks greater than 14 days old that become infected with CAV do not exhibit clinical signs.

 

<u>'''Horizontal transmission''' can occur in '''older chickens that lack maternal derived antibodies''' from '''faecal-oral route, fomites''' and as the '''virus is excreted''' by a small number of '''vertically infected hatch mates'''.</u>

 

CAV isolates can be distinguished by using restriction endonuclease analysis of amplified DNA, but only a single serotype has so far been detected.

    

    

==Distribution==

==Distribution==