Introduction

Classification

Taxonomy

• The Astroviridae family contains non-enveloped, positive-sense, single-stranded RNA viruses within two genera:
  • Mamastrovirus: infect mammals.
  • Avastrovirus: infect birds.
• The International Committee on Taxonomy of Viruses currently recognizes 19 species (Mamastrovirus-1 through -19), within the Mamastrovirus genus. There are numerous strains awaiting classification, some of which may be new species.

Etymology

• Astro: from the Greek word for “star”.

Active Forms

Clinical Effects

Epidemiology

Transmission

Pathological effects

• Clinical signs may include:
  • Progressive neurological signs, including:
    • Unusual behavior.
    • Aimless walking.
    • Circling. 
    • Ataxia.
    • Repetitive and uncoordinated tongue movements.
    • Seizures.
    • Recumbency.
• Duration of clinical signs may range from 1 day to 3 weeks.

Other Host Effects

• Histological examination of infected brain may reveal:
  • Moderate to severe, lymphocytic, histiocytic and plasmacytic meningoencephalomyelitis.
  • Perivascular cuffing and lymphoplasmacytic and histiocytic inflammation and neuronal necrosis/neuronophagia with gliosis in the adjacent neuropil.
  • Satellitosis of affected, necrotic neurons.

Control

Control via environment

• Good biosecurity and hygiene are important given the likelihood of feco-oral transmission.
• Astroviruses are resistant to many disinfectants and so products should be chosen carefully.

Vaccination

• None available.

Diagnosis

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• Giannitti F et al (2019) The first case of bovine astrovirus-associated encephalitis in the Southern hemisphere (Uruguay), uncovers evidence of viral introduction to the Americas from Europe. Front Microbiol 10, 1240 PubMed.
• Spinato M T et al (2017) Identification of bovine astrovirus in cases of bovine non-suppurative encephalitis in eastern Canada. Can Vet J 58 (6), 607-609 PubMed.

Other sources of information

• CABI International (2019) Astrovirus Infections. In: Invasive Species Compendium. Website: www.cabi.org.