Isolation and Characterization of Foot and Mouth Disease Viruses from Vaccinated Cattle in Egypt Years 2015-2016-2017
Dina A. Abdulzaher;
Abstract
In this study, antigenic and genetic characterization of FMDV strains isolated from vaccinated animals in Egypt was conducted as following:
A total of 94 clinical samples were collected from vaccinated animals showing signs suspecting of FMD from different Egyptian governorates during 2015, 2016 and 2017. The presence of serotypes O, A, SAT1 and SAT2 FMD virus antigen was detected in the collected samples using sandwich ELISA kit. The test revealed that 30 samples were positive for serotypes A, O and SAT2. Serotype O was the most predominant (19 out of 30 samples) followed by serotype A (9 samples) then serotype SAT2 (2 samples).
The samples that tested positive by ELISA were inoculated in BHK-21 cell line. This resulted in the isolation of FMDVs from 6 serotype O, 7 serotype A and 2 serotype SAT2-positive samples. Testing the isolates by serotyping ELISA confirmed the successful isolation of the FMDVs. The virus titer in the third passage of each isolate was determined according to Reed and Muench equation.
Polyclonal sera against each of serotypes O, A and SAT2 vaccine strains were used in the β procedure neutralization test to confirm the serotype identity of the isolated viruses. The end-point titers were calculated as the logarithm (base 10) of the reciprocal of the last serum dilution that could neutralize 100 TCID50 of FMDV in 50% of the wells.
The molecular study of the isolates was done by extracting total RNA from the tissue culture harvests of the isolates and Amplification of the VP1 gene. The RT-PCR products were purified and sequenced and the sequences were subjected to phylogenetic analysis.
Although all the serotype O isolates belonged to EA-3 genotype, the isolates of 2015 were more closely related to each other than the other isolates of 2016 and 2017. Six of the seven serotype A isolates belonged to A-Iran-05 lineage with one isolate grouped alone with G-IV of the African A strains. Meanwhile, the phylogenetic analysis placed the two SAT2 isolates in one cluster with the strains of SAT2/VII/Alx-12 lineage. A drop in the
English Summary
107
neutralizing antibody titer of some serotype O and A isolates was accompanied
A total of 94 clinical samples were collected from vaccinated animals showing signs suspecting of FMD from different Egyptian governorates during 2015, 2016 and 2017. The presence of serotypes O, A, SAT1 and SAT2 FMD virus antigen was detected in the collected samples using sandwich ELISA kit. The test revealed that 30 samples were positive for serotypes A, O and SAT2. Serotype O was the most predominant (19 out of 30 samples) followed by serotype A (9 samples) then serotype SAT2 (2 samples).
The samples that tested positive by ELISA were inoculated in BHK-21 cell line. This resulted in the isolation of FMDVs from 6 serotype O, 7 serotype A and 2 serotype SAT2-positive samples. Testing the isolates by serotyping ELISA confirmed the successful isolation of the FMDVs. The virus titer in the third passage of each isolate was determined according to Reed and Muench equation.
Polyclonal sera against each of serotypes O, A and SAT2 vaccine strains were used in the β procedure neutralization test to confirm the serotype identity of the isolated viruses. The end-point titers were calculated as the logarithm (base 10) of the reciprocal of the last serum dilution that could neutralize 100 TCID50 of FMDV in 50% of the wells.
The molecular study of the isolates was done by extracting total RNA from the tissue culture harvests of the isolates and Amplification of the VP1 gene. The RT-PCR products were purified and sequenced and the sequences were subjected to phylogenetic analysis.
Although all the serotype O isolates belonged to EA-3 genotype, the isolates of 2015 were more closely related to each other than the other isolates of 2016 and 2017. Six of the seven serotype A isolates belonged to A-Iran-05 lineage with one isolate grouped alone with G-IV of the African A strains. Meanwhile, the phylogenetic analysis placed the two SAT2 isolates in one cluster with the strains of SAT2/VII/Alx-12 lineage. A drop in the
English Summary
107
neutralizing antibody titer of some serotype O and A isolates was accompanied
Other data
| Title | Isolation and Characterization of Foot and Mouth Disease Viruses from Vaccinated Cattle in Egypt Years 2015-2016-2017 | Other Titles | عزل و توصيف لفيروسات مرض الحمى القلاعية من الأبقار المحصنة في مصر عام ۲۰۱٥ | Authors | Dina A. Abdulzaher | Issue Date | 2018 |
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