Detection of reticuloendotheliosis virus as contaminant of fowl pox vaccines

Abstract EN

This study was performed to detect reticuloendotheliosis virus (REV) as a contaminant in fowl pox vaccines.

A total of 30 fowl pox vaccine samples for the presences of REV using the in vitro a total and in vivo methods.

In the in vitro test, the fowl pox vaccine samples were inoculated into chicken embryo fibroblast (CEF) cultures prepared from SPF embryonated chichen egg and examined by PCR test for detection of REV.

In the in vivo test, each fowl pox vaccine sample was inoculated in five days old SPF chicks and kept under observation up to 12 weeks post inoculation (PI); serum samples were collected on 15th , 30th and 45th day PI for the detection of antibodies against REV by commercial ELIZA kit, and tissue specimens were collected at 8th and 12th weeks PI for histopathological examination.

The results revealed that: only one imported vaccine sample gave positive results by PCR test a product of 291- bp was obtained by the vaccine sample.

Serum samples collected from positive vaccine batch were tested for REV antibodies by ELIZA test and the sera were positive.

Histopathological examination of liver, spleen and bursa of fabricius revealed the presence of tumor cells in the organs examined and these changes confirmed the results obtained by PCR and ELIZA test and indicated that the sample is contaminated with REV.

The data clearly indicated that screening of all commercial poultry vaccine to be virus free is an important factor in assuring the biosafety of animal vaccines.