Akabane HE calves usually appear 'stupid', may walk poorly, are depressed and appear blind.
Varying degrees of cavitation of cerebral hemispheres including extreme hydranencephaly may be found at necropsy.
Rarely, calves may have both hydranencephaly and arthrogryposis.
Age of Animal: 3 days
Sex of Animal: female
Akabane virus is an arbovirus transmitted by Culicoides brevitaris insects.
If it infects non-immune cattle during mid-gestation, calf deformities may ocurr, such as hydranencephaly.
If infection occus betwen about 80 and 105 days in gestation.
Calves infected in mid-gestation, between 120 and 160 days, have loss of lower motor neurones resulting in non-inervation of lower limb musculature known as arthrogryposis (sometimes also torticollis, kyphosis, and scoliosis from neurogenic muscle atrophy). Rarely cases affected in late gestation may be unable to stand or incoordinated and on necropsy show a disseminated encephalomyelitis.
Contributor: Peter Windsor, Carly Smith, Kathleen Grahame