Astroviral Flashcards
General characteristics of Astroviral
*+ssRNA virus with an icosahedral shape and which has no envelope
Good resistance: pH3, 60℃ for 5 minutes
Astroviridae —>Mamoastrovirus: • Human Astrovirus • Swine Astrovirus • Cow Astrovirus • Cat Astrovirus
Occurrence
Mainly in winter
Astroviridae —>Mamoastrovirus: • Human Astrovirus • Swine Astrovirus • Cow Astrovirus • Cat Astrovirus
Clinical signs
Gastroenteritis
Avian Nephritis 1 and 2
Species affected
Chicken
Avian Nephritis 1 and 2
Most susceptible
- In all the age groups
* Clinical signs in the first 4 weeks of life
Avian Nephritis 1 and 2
Occurrence
*Widespread: • Japan • USA • Europe • New Zealand
Avian Nephritis 1 and 2
Spread
Spreading by contaminated faeces
Avian Nephritis 1 and 2
Pathogenesis
PO Infection —> Gut —> Viraemia —> Kidney
Avian Nephritis 1 and 2
Primary replication
Gastrointestinal Tract
Usually incubation period of 3 days
Avian Nephritis 1 and 2
Target organs
Epithelial cells of the proximal tubule of the kidney
Avian Nephritis 1 and 2
Clinical signs
*In young animals it is more severe
*Symptoms may vary from none (subclinical) to mortality resulting from kidney damage or severe growth retardation
*Day old chicken:
• Acute: non-specific general clinical signs
• Diarrhoea, kidney lesions
• Decreased weight gain, growth retardation
*2-4 week old chicken:
• Nephritis and Nephrosis
*Chronic cases:
• Visceral urate deposits
• Death
*In the presence of immunosuppressive agents, the signs are more severe:
• Immunosuppressive agents: Mycoplasma, Herpes, Infectious Bursal Disease, Chicken Infectious Anaemia
*Mortality is 1-10% in the chicken in the first week
Avian Nephritis 1 and 2
Pathology and histopathology
- Enteritis
- Nephrosis, interstitial nephritis—> swelling, paleness, urate deposition
- Enlarged kidneys showing prominent tubular pattern
- Chronic cases —> urate deposition
- Degenerated tubules, mononuclear infiltration and desquamation
Avian Nephritis 1 and 2
Diagnosis
Clinical signs, PM lesions and Kidney Histology Detection of virus: RT-PCR, IF, IHC Isolation of virus is difficult! (primary chicken embryo kidney) Detection of antibodies: ELISA, VN, IF
Avian Nephritis 1 and 2
Treatment
No effective treatment
Avian Nephritis 1 and 2
Prevention and immunity
General epidemiological rules
No vaccines available!
