EryC PCR assay as DIVA tool for Bovine Brucellosis

The present study focuses on differential identification of vaccinated and infected animals of brucellosis (DIVA) by EryC PCR assay. Clinical specimen (400) comprising of 200 (162 blood, 27 milk, 10 vaginal swab and one tissue) samples from vaccinated and 200 (51 blood and 149 milk) samples from unvaccinated cattle. These samples were collected from four different regions of Maharashtra. The RBPT recorded overall prevalence of 39.9% (85/213) with 50.98% (26/51) in unvaccinated animals and 36.41% (59/162) in vaccinated animals. According to MRT results, the overall percent positivity observed was 58.5% (103/176) with vaccinated animals showing a 74.07% positivity (20/27) and unvaccinated animals showing 55.70% positivity (83/149).

A sum of 199 clinical samples (85 blood, 103 milk, 10 vaginal swab and one tissue sample) subjected to differentiate vaccine strain and wild strains of B. abortus,by targeting deletion of 702bp. The EryC PCR assay generated amplicon in 57 clinical samples i.e. 28.64% (19 from vaccinated and 38 from unvaccinated animals) of them found positive by EryC PCR. 16 samples from vaccinated animals amplified amplicon of 1257bp and only three samples showed amplicon of 555bp. Eight samples from unvaccinated animals amplified amplicon of 1257bp, 30 milk samples from unvaccinated animals generated amplicon of 555bp suggesting infection is due to vaccine strain.