Astroviruses (Astroviridae) are a type of virus that was first discovered in 1975 using electron microscopes following an outbreak of diarrhea in humans.

Astroviruses are 28–35 nm diameter, icosahedral viruses that have a characteristic five- or six-pointed star-like surface structure when viewed by electron microscopy.

Along with the Picornaviridae and the Caliciviridae, the Astroviridae comprise a third family of nonenveloped viruses whose genome is composed of plus-sense, single-stranded RNA.

[2] Astrovirus has a non-segmented, single stranded, positive sense RNA genome within a non-enveloped icosahedral capsid.

[3] Human astroviruses have been shown in numerous studies to be an important cause of gastroenteritis in young children worldwide.

[5] The International Committee on Taxonomy of Viruses (ICTV) established Astroviridae as a viral family in 1995.

They are non-enveloped RNA viruses with cubic capsids, approximately 28–35 nm in diameter with T=3 symmetry.

[4] The virion capsid is expressed from a subgenomic mRNA and its precursor undergoes multiple cleavages to make the VP70 protein.

This protein is probably involved in the first steps of viral infection, being a key factor in the biological cycle of astroviruses.

In turkey poults 1–3 weeks of age, some symptoms of enteritis include diarrhea, listlessness, liver eating and nervousness.

[4] Avastrovirus species often infect extraintestinal sites such as the kidney or liver resulting in hepatitis and nephritis.

Necropsies show swollen and discolored kidneys and there is evidence of death of the epithelial cells and lymphocytic interstitial nephritis.

Histological examinations showed neuronal necrosis and gliosis of the cerebral cortex, cerebellum, spinal cord and brainstem.

Presence of viral particles in fecal matter and in epithelial intestinal cells indicate that the virus replicates in the gastrointestinal tract of humans.

Astrovirus infection is not usually a severe situation and only in some rare cases leads to dehydration.

This could be due to climatic factors influencing the life cycle or transmission method for that particular strain of Astrovirus.

[40] Electron microscopy, enzyme-immunoassay (ELISA), immunofluorescence, and polymerase chain reaction have all been used for detecting virus particle, antigens or viral nucleic acid in the stools of infected people.

[42] Some RT-qPCR techniques are able to simultaneously detect human astroviruses and other enteric viruses associated with gastroenteritis.

[45] Humans of all ages are susceptible to astrovirus infection, but children, the elderly, and those that are immunocompromised are most prone.

A study of intestinal disease in the UK, published in 1999, determined incidence as 3.8/1000 patient years in the community (95% CI, range 2.3–6.4), the fourth most common known cause of viral gastroenteritis.

Early studies carried out in Glasgow demonstrated that a significant proportion of babies excreting virus particles did not exhibit gastrointestinal symptoms.

[47] Seroprevalence studies carried out in the US have shown that 90% of children have antibody to HastV-1 by age 9, suggesting that (largely asymptomatic) infection is common.

In temperate climates, infection is highest during winter months possibly due to lower temperatures which enhance the stability of the virus.

The seasonal distribution in tropical climates can be explained by the effect of rain particularly on the breakdown of sanitation in developing countries.

Young children in childcare backgrounds or adults in military barracks are most likely to develop the disease.

[52] Furthermore, some human, duck, chicken and turkey astroviruses are phylogenetically related and share genetic features.

[53] In a study by Tellez et al., extracts from a plant Achyrocline bogotensis was used to develop an antiviral therapy for both rotavirus and astrovirus.