Avian Reticuloendotheliosis virus (Reoviridae, Orthoretrovirinae, Gammaretrovirus): Molecular diagnosis (RT-PCR).
The avian reticuloendoteliosis virus (REV) is an oncogenic and immunosuppressive virus of the genus Gammaretrovirus, of the Retroviridae family. This agent infects multiple species of domestic and wild birds, causing a group of syndromes that include significant growth retardation, immunosuppression and neoplasms. Geographically, the highest incidence rate has been recorded in chicken and turkey farms in Australia, Japan, Israel and the southeastern United States.
This virus is a retrovirus morphologically similar to the leucosis/avian sarcoma virus, although it is genetically different. Gammaretroviruses are enveloped viruses, symmetric to pleomorphic, with an approximate size of 80 to 100 nm in diameter. They have a single chain RNA (+ssRNA) and a genome of approximately 8.3 kb.
Transmission of the virus can occur vertically, horizontally through direct contact or through the ingestion of food and water contaminated with feces or body fluids of infected birds, through the use of contaminated syringes during administration of vaccines to birds or through mosquitoes or other biological reservoirs carrying the virus, which would transmit the infection during feeding. In addition, cases of birds accidentally infected by commercial vaccines such as vaccines against the fowlpox virus and Marek's disease, as well as the Herpesvirus vaccine in turkeys have been described.
Specifically, the syndromes associated with REV include a syndrome of dwarfism, chronic lymphoid neoplasia and other tissues, and acute neoplasia of reticular cells. Likewise, some strains can cause a non-neoplastic syndrome with high mortality and severe disuniformity without the development of apparent physical injuries. In addition, in experimentally infected chickens, REV can cause a disease that is pathologically indistinguishable from lymphoid leukosis.
The Office International des Epizooties (OIE) considers the avian neoplastic disease produced by the REV of special importance and commercial interest in poultry, due to the economic losses generated by mortality and the low productive performance caused in the birds.
Recommended tests for diagnosis:
The diagnosis by molecular methods by means of RT-PCR (Reverse Transcriptase Polymerase Chain Reaction), is the most recommended method at present.
Tests carried out in IVAMI:
- Molecular diagnosis (RT-PCR: Reverse Transcripase Polymerase Chain Reaction), to detect RNA of avian reticuloendotheliosis virus (REV).
- Total blood extracted with EDTA (2 to 5 mL).
- Neoplasm biopsy.
Conservation and shipment of the sample:
- Refrigerated (preferred) for less than 2 days (essential for microscopic examination).
- Frozen: more than 2 days (only for molecular diagnostic tests).
Delivery of results:
- Molecular diagnosis (RT-PCR): 24 to 48 hours.
Cost of the test:
- Molecular diagnosis (RT-PCR): Consult email@example.com.
- Diagnosis and molecular identification (RT-PCR and sequencing): Consult firstname.lastname@example.org.