Avian rotavirus

Test code: S0263 - Ultrasensitive qualitative detection of avian rotavirus A by reverse transcription coupled real time polymerase chain reaction
Test code: S0267 - Ultrasensitive qualitative detection of avian rotavirus D by reverse transcription coupled real time polymerase chain reaction

Avian rotavirus is a double-stranded RNA virus from the genus rotavirus within the reoviridae family.  It infects birds, primarily poultry including chickens and turkeys; as well as pigeons, quail, and some wild species. Avian rotaviruses are non-enveloped viruses; their genome consists of 11 segments of dsRNA, encoding six structural (VP1–VP7) and six non-structural (NSP1–NSP6) proteins. Because of reassortment, avian rotavirus is very diverse genetically.

Avian rotaviruses are classified into groups (A–I) based on the VP6 inner capsid protein. Avian rotaviruses mainly belong to groups A, D, F, and G, with groups A and D being the most widespread, whereas groups F and G are uncommon. Infections with group A or group D rotavirus are associated with diarrhea and runting-stunting syndrome in poultry.

Rotaviruses are very stable in the environment. They resist many disinfectants and can survive in feces or litter for weeks. Transmission is primarily through the fecal-oral route, such as through ingestion of contaminated feed, water, or litter. Horizontal transmission of the viruses can be very rapid in flocks due to high viral shedding in feces. Vertical transmission is not common.

Infection with avian rotavirus results in enteritis, with symptoms varying by age, strain, and other cofactors. Young birds have watery diarrhea (white, yellow, or green), dehydration, lethargy, reduced feed intake, and stunted growth. Mortality is low (1–5%) for this age group unless secondary infections also occur. Infected adults are often asymptomatic but may show mild diarrhea or reduced egg quality/production.

Serological methods, such as ELISA, are used to detect the viral antigens in the feces of flocks, but these methods have low sensitivity. Adult birds that are clinical carriers may have low titers; thus serology in these birds may yield false negative results. PCR is highly specific and sensitive and is now a preferred method to screen for these viruses and diagnose the cause of disease symptoms (Izzo et al., 2012; Otto et al., 2012).

Utilities:

• Help confirm the disease causing agent
• Environmental monitoring
• Help ensure that bird populations are free of avian rotavirus
• 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:
Izzo, M.M., Kirkland, P.D., Gu, X., Lele, Y., Gunn, A.A. and House, J.K. (2012) Comparison of three diagnostic techniques for detection of rotavirus and coronavirus in calf faeces in Australia. Aust Vet. J. 90:122-129.

Otto, P.H., Ahmed, M.U., Hotzel, H., Machnowska, P., Reetz, J., Roth, B., Trojnar, E. and Johne, R. (2012) Detection of avian rotaviruses of groups A, D, F and G in diseased chickens and turkeys from Europe and Bangladesh. Vet. Microbiol. 156:8-15.

Specimen requirements: 0.2 ml feces, or cloacal swab, or 0.2 ml cell culture, or environmental swab or swipe.

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