Molecular detection of integrated reticuloendothelial virus genes in fowlpox virus field isolates and live vaccines of poultry

RANJANI RAJASEKARAN; J JOHN KIRUBAHARAN; S RAJALAKSHMI; M VIDHYA

doi:10.56093/ijans.v89i4.89092

Authors

RANJANI RAJASEKARAN PhD Scholar, Tamil Nadu Veterinary and Animal Sciences University, Chennai, Tamil Nadu 600 007 India
J JOHN KIRUBAHARAN Dean, Tamil Nadu Veterinary and Animal Sciences University, Chennai, Tamil Nadu 600 007 India
S RAJALAKSHMI Assistant Professor, Tamil Nadu Veterinary and Animal Sciences University, Chennai, Tamil Nadu 600 007 India
M VIDHYA Assistant Professor, Tamil Nadu Veterinary and Animal Sciences University, Chennai, Tamil Nadu 600 007 India

https://doi.org/10.56093/ijans.v89i4.89092

Keywords:

Envelope gene, Field isolate, Fowlpox virus, Live vaccine, LTR region, Reticuloendothelial virus

Abstract

Two field isolates (FWPV-W1 and FWPV-W2) obtained from unvaccinated backyard poultry chickens and four commercial live vaccines (FWPV-G, FWPV-V, FWPV-B and FWPV-H) of fowlpox virus origin were isolated on chorio-allantoic membrane (CAM) of embryonated chicken eggs. The CAM tissues infected with FWPV-W1, FWPVW2, FWPV-G, FWPV-V, FWPV-B and FWPV-H individually were subjected to DNA isolation. The isolated DNA was tested for the presence of P4b gene by PCR to confirm FWPV. Then, each of the field isolates and commercial vaccines were screened for presence of reticuloendothelial virus envelope (REV-env) gene and long terminal repeat (LTR) region by PCR. FWPV-W1 isolate was positive for REV-env gene (807 bp) and REV-LTR region (370 bp), which confirmed presence of near full-length REV integration in its genome. Whereas, FWPV-W2 isolate was positive for LTR region and negative for REV-env gene. This suggested that full-length REV is not present in all FWPV field isolates. All the four commercial live vaccines, were negative for REV-env gene. This showed that full-length REV is absent in these commercial vaccines, ensuring safety of the usage of these vaccines in India. However, the commercial vaccines were positive for REV-LTR region, which does not affect the vaccine safety.

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