In-Vitro testing of the safety of Marek's disease virus vaccines [electronic resource].

Includes references.

The traditional methods for safety testing of Marek's disease (MD) virus vaccines is based on the clinical signs and pathological alteration that recorded within 120 days post vaccination of one day old susceptible specific pathogen free chicks. To provide a rapid, sensitive and simple means of evaluating MD vaccine for freedom of oncogenicity, we have used the polymerase chain reaction (PCR). The primers chosen to detect MDV sequences flank the 132 bp tandem repeat of the Bam HI-H fragment, whose PCR product is specific for serotype I MDV. The CVI 988 vaccine yielded amplified products of various size corresponding to the number of 132-bp repeat units, while virulent GA strain yielded a strong 434 bp PCR product. Multiplex PCR contained primers specific for serotype I and 3, yielded 388 bp fragment specific for herpes virus of turkey (HVT) in addition to the above result. The sensitivity of the multiplex PCR was studied by experimental contamination of both CVI 988 and HVT by 100 and 10 plaque forming unit (PFU) of GA strain. The detected GA strain at the two concentrations indicates the high sensitivity of the multiplex PCR. Using multiplex PCR was found to be simple, rapid and sensitive for testing ofMD vaccines for safety.

Summary in Arabic.

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