Avian nephritis virus (ANV)

Test code: S0261 - Ultrasensitive qualitative detection of avian nephritis virus by reverse transcription coupled real time polymerase chain reaction

Avian nephritis virus (ANV) is a small, non-enveloped, single-stranded RNA virus with a genome of about 6.9 kb. It has three open reading frames: ORF1a encodes a serine protease; ORF1b encodes an RNA-dependent RNA polymerase; and ORF2 encodes structural proteins. This virus is a member of the family astroviridae within the genus avastrovirus.

ANV is a contagious virus that primarily affects chickens, but it can also infect other avian species including turkeys, ducks, and geese. Infected birds, especially young chickens under 7 days old, can develop kidney-related issues, such as renal damage, growth retardation, and visceral urate deposits. Transient diarrhea can be seen in these infected chicks. Birds up to 4 weeks of age can also be affected.

ANV spreads mainly through the fecal-oral route, or direct or indirect contact with contaminated feces. Vertical transmission (from hen to egg) is possible but less common.

ANV has been detected in both commercial and specific pathogen-free (SPF) flocks. It has a worldwide distribution. Economic losses due to stunted growth and occasional mortality are a significant concern to chicken breeders. ANV infection can be one of the causes in chickens affected with runting-stunting syndrome (RSS). RSS, a malabsorption syndrome, is an enteric disease in chickens characterized by stunted growth, poor feather development, and other clinical signs. ANV is one of the several different causes of this syndrome (Nuñez et al., 2018).

Diagnosis of this viral infection using methods such as ELISA, direct/indirect immunofluorescence, or seroneutralization to detect ANV antibodies is of limited utility. Antibody to the virus usually appears 4 days post-infection so that serological methods will miss the acute infection phase. In addition, due to ANV’s high antigenic diversity, serology testing may miss some strains. PCR is highly sensitive and specific, and has become the gold standard for detecting infection by this virus (Todd et al., 2010).

Utilities:

• Help confirm the disease causing agent
• Environmental monitoring
• Help ensure that bird populations are free of ANV
• Early prevention of spread of the virus among bird populations
• Minimize human exposure to the virus
• Safety monitoring of biological products and vaccines that derive from birds

References:
Nuñez, L.F.N., Parra, S.H.S., De la Torre, D., Catroxo, M.H., Buim, M.R., Chacon, R.V., Ferreira, C.S.A. and Piantino Ferreira ,A.J. (2018) Isolation of avian nephritis virus from chickens showing enteric disorders. Poult Sci. 97:3478-3488.

Todd, D., Trudgett, J., McNeilly, F., McBride, N., Donnelly, B., Smyth, V.J., Jewhurst, H.L. and Adair, B.M. (2010) Development and application of an RT-PCR test for detecting avian nephritis virus. Avian Pathol. 39:207-213.

Specimen requirements: 0.2 ml feces, or cloacal swab, or 0.2 ml whole blood in EDTA (purple top) tube, or 0.2 ml fresh or frozen tissue, or 0.2 ml cell culture.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative reverse transcription coupled real time PCR

Normal range: Nondetected