Development of irradiated brucella abortus vaccine candidate from field strain

Abstract

Brucellosis is a strategic contagious animal disease in Indonesia, which is caused by Bru/:ella abortus (B. abortus). Brucellosis causes abortion, still birth, orchitis; arthritis, infertility and sterility lowering milk production. Eradication of cattle in many countries have been conducted by test and slaughter and vaccination programme. At the moment there are two vaccinations available to control bovine brucellosis; those are B. abortus S 19 and B. abortus RB51. One of the problems in the eradication is not enough a vaccine. The objective of this research was to develop irradiated brucellosis vaccine from B. abortlls local isolate through isolation, identification and biotyping B. abortus from field cases. Determination of B. abortus radiation dose and in vivo study was done in guinea pigs. The samples were collected from milk (Bandung, west Jawa), amnion fluids (diagnostic sample) and higroma fluids (Be1u, NIT). In this study we use three isolates that were SBDG-13C (milk), CAM-08/306 (amnion fluids), and CH09- BL (higroma fluids). Biotyping of the three isolates categorized as B. abortus biotype I. Standard curves of B. abortus was made by calculating bacteria cells number indirectly. Linear equation of the standard curve of SBDG- J3C; CAM- 08/306 and CH09-BL isolates were y = 7.2119x + 6.7723; y = 3.889lx + 7.5278 and y = 2.9829x + 7.9612 respectively (x is absorbance value and y is log number of cells/ml). Observation on the growth of the isolates after Gamma irradiation showed variation responses to the value LDso of isolate CAM-08/306, CH09-BL and SBDG-I3C were 13.5; 11.9, and 17.9 Gy, respectively. The in vivo study showed that the spleen of irradiation vaccinated guinea pigs was a swelling (splenomegaly) and contained 102 to 106 CFU bacteria. Based on the results, It seems likely that those three isolates have not been defined as candidate isolate for brucellosis vaccine.