Akabane disease (sheep and cattle)

Description

Akabane virus is a member of the Simbu serogroup of the family Bunyaviridae, genus Orthobunyavirus. It is spread by biting midges (Culicoides spp). Akabane virus infection is associated with abortion, stillbirth and congenital abnormalities such as arthrogryposis and hydranencephaly however, the severity of clinical signs and pathology are variable depending on the species of animal and time of infection. Disease due to Akabane virus is mostly observed in cattle due to the long period of gestation and breeding throughout the year.

Diagnosis and tests available

Diagnosis

Diagnosis is supported by the history, clinical signs, pathology and supportive tests.

Tests available

Test

Sample(s) required

Days of the week test is conducted

Turnaround time1

Akabane virus antibody ELISA

Clotted blood (red top tube) or foetal fluid

Batched tested weekly

Up to 1 week

Akabane virus PCR

Fresh tissue

According to demand

2-3 working days

Akabane VNT2Clotted blood (red top tube)Batch tested on Thursday1-2 weeks

Histopathology examination

Fixed tissues

Monday – Friday

Up to 2 weeks for brain samples. Up to 5 days for other sample types.

1 Turnaround times are provided as a guide only. For specific information about your submission please contact Customer Service.

2 This test is predominantly used for regulatory testing.

Specimen requirements

Blood (without anti-coagulant)

  • 10 ml of blood (including at least 2 ml of serum) from the dam or neonate that has not suckled collected in a plain red top tube.
    • Submit chilled
    • Do not use a serum separator tube.

Fixed tissues

  • Brain, spinal cord, muscle and other tissues as indicated by gross examination
    • Submit fixed in neutral buffered formalin at a ratio of 10:1 formalin: tissue

Foetal fluid

  • 2 ml; preferably pericardial or pleural rather than heart blood or peritoneal fluid which are more likely to be contaminated
    • Submit chilled

Fresh tissue

  • Fresh brain submitted from the aborted foetus
    • Submit chilled

Note

  • Appropriate tissues and fluids for serology should also be submitted to exclude Pestivirus infection which can cause arthrogryposis and CNS lesions.
  • Serum samples are only useful in eliminating a diagnosis of Akabane virus infection in the dam however, the presence of antibody in an unsuckled calf or lamb is diagnostic
  • Akabane virus may be detected in the brain of clinically affected new-bon calves or lambs by PCR. A negative result on this test does not preclude a diagnosis of Akabane disease as the infection has usually occurred months earlier. However, Akabane virus is more readily detected in the brains of aborted fetuses as abortion may occur relatively soon after infection.