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.
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DHV-I occurs only in '''young ducklings''', usually '''<6 weeks''' 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.
DHV-II is only reported in outdoor ducks on open fields.