Real time RT-PCR assay for detection of different serotypes of FMDV in Egypt

Abstract

Aim: The present study indicated that rRT-PCR could be provided for the detection of FMDV in infected, contact and carrier cattle and also provide a rapid sensitive tool aiming to aid in rapid disease detection and control. Foot and Mouth disease virus serotypes O1 and A still existing in Egypt. In January 2012, sever outbreaks struck the animal population in most Egyptian 1 governorates. The causative virus was identified as FMDVSAT2. Material and Methods: Five samples of tongue epithelium (ET) and five oesophageal-pharyngeal (OP) fluid samples were collected from FMD suspected cattle in infected farm at El-Fayoum and 20 OPsamples from in-contact cattle at the same farm in addition to 30 OP samples from apparently healthy cattle at three different localities in El-Fayoum governorate (12 from Fayoum; 9 from Sinoras and 9 from Edsa) in order to detect carrier cattle. All of these samples were collected during November and December 2011 and January 2012. Results:All the ETand OPsamples were inoculated on BHK cell culture and baby mice. The obtained results were identified using complement fixation test in addition to real-time reverse transcriptase polymerase chain reaction (rRT-PCR). In the infected farm at El-Fayoum FMDVtype SAT2 was detected in cattle which are considered as the first introduction of this type while FMDVtype O and SAT2 were detected in the in-contact cattle in the same farm. The sensitivity of rRT-PCR was cleared in the in-contact cattle as 13 out of 20 OP samples were positive to FMDV by rRT-PCR while 11 out of 20 OP samples were positive to FMDV by CFT. The OP samples collected from apparently healthy cattle from Fayoum, Sinoras and Edsa localities in Fayoum governorate demonstrate the circulation of the FMDV type A, O and the recent SAT2 in carrier cattle which threaten cattle population in Fayoum governorate. Also the sensitivity of real time RT-PCR over the CFTin detection of FMDV carrier cattle was clearly noticed in these localities as 19 out of 30 OP samples were positive by rRT-PCR while in contrast there were only 16 out of 30 samples positive by CFT. Conclusion: In conclusion, this study demonstrates that real-time RT-PCR currently used at the WRLfor FMD provides an extremely sensitive and rapid additional procedure for improved laboratory diagnosis of FMD especially in-contact and carrier cases. The rRT-PCR generated results in less than one day from test commencement, in contrast to up to four days to define some positive and all negative samples by combined use of CFT and virus isolation. This is an important feature when definitive diagnostic results are required in a short timescale during emergencies. Also this study demonstrates the current situation of FMDVcirculating in EL-Fayoum governorate and the introduction of new SAT2 serotype beside type Aand O.