Identification of Brucella spp. in Aborted Fetuses by Guineapig inoculation

Abstract

Background: Brucellosis is a zoonotic disease which is endemic in Bangladesh. The prevalence of bovine brucellosis in subsistence management system in Bangladesh is low. However, the prevalence of bovine brucellosis at Central Cattle Breeding and Dairy Farm (CCBDF) is reported to be very high and Brucella abortus DNA has also been detected from cows’ milk of this farm. The principal manifestation of bovine brucellosis is abortion in pregnant cows, which is common at CCBDF. The role of brucellosis in abortion at CCBDF has not been ascertained. Hence, this study was undertaken to confirm Brucella spp. as the etiology of abortion in cows at CCBDF.

Materials and Methods: Aborted fetal membranes and vaginal swabs from 3 cows, in which late abortion occurred, were collected aseptically from the CCBDF.  The samples were initially stained with modified Zeihl-Neelsen staining method. The stain-positive samples were ground individually using a pestle and mortar, and a homogenized mixture was prepared by adding normal saline. Two milliliters of the homogenate from each sample were inoculated subcutaneously into a guinea pig. The sera of guinea pigs were collected after 3rd week of inoculation to perform rose Bengal test (RBT) and rapid antibody test (RAT).

Result: Samples from two cows showed positive staining result in which numerous pink-colored coccobacilli were seen. All the sera collected were tested positive for both RBT and RAT. It is evident from this study that three of two abortions at CCBDF were due to brucellosis.

Conclusion: Guineapig inoculation technique could be used as a good alternative of culture for confirming the diagnosis of brucellosis from contaminated clinical samples like placenta.

DOI